Saltpeter, Horse Sweat, and Biltong: The origins of our national food. By Eben van Tonder 11 August 2017
Summary
On the history and curious background of South Africa’s national food.
Myself on Poon on Oupa Eben’s farm.
EARLIEST MENTION OF BILTONG
The earliest mention of biltong that I could trace is a quote dating back to 1815 when Dr Henry Lichtenstein mentions biltong in his book, “Travels in Southern Africa.” Near the Winterhoek Mountains in the Cape, his party met an old German who once worked for the East Indian Company and a veteran of the Esterhazy’s regiment who “for the greater part of the year saw no other human being but his black subjects and lived almost entirely on dried mutton and biltong.” The Guardian (London, England), 21 July 1952, page, from the article, “Biltong for the Arctic.” This 1815 reference Lichtenstein is now the oldest biltong reference that I could find.
The historical facts seem to point to the following origins of Biltong.
DRIED BEEF – A DUTCH FAVOURITE
The Dutch brought with them to the new world at the Cape of Good Hope, a recipe for dried beef. A recipe book from 1664 described the process as follows. “Take of the Buttock-beef (This was called the “bil” and is the first part of the word “biltong”) of the oxe, salt it well with bay-salt four of five daies, then hang it a draining one day, then sew it up in thin cloth, and hang it up in a chimney to dry; when you would eat any of it, boil it very tender, and slice it so thin that you may almost see through it and eat it with a sallet”. (Hannah Woolley, The Cook’s Guide) As was the case with bacon at this time, one of the ways it was consumed was to boil it before consumption into a stew-form. Another recipe from the same time (1683) is entitled To dry Beef after the Dutch Fashion (M. H. The Young Cooks Minor). I am still trying to locate the recipe, but it seemed as if drying beef, in a variation on the recipe of Hannah Woolley, was well known by the Dutch Settlers.
VINEGAR
The second fact from this time (1600’s), is that the use of vinegar as a preservative became very popular and the science of producing it from fermenting grapes was widespread in France, Belgium, and the Netherlands. Grapes were cultivated right from the start by the 1652 Dutch settlers to the Cape and vinegar would have been produced right here in the Cape, right from the founding of the refreshment station.
The production of biltong, “bil” (cut from the buttocks of the oxen) and cut into a “tong” (strips, resembling a tongue), and cured with salt, vinegar, spices, and saltpetre was probably done from as early as farms were allocated to Dutch Settlers in the Cape. I am reluctant to say that this was an invention by personnel of the VOC due to the many records that exist of bacon being sent to the outposts of the VOC at the Cape as a primary meat source for the officers and men stationed at outposts such as Saldana.
The literature from the time favours the hunting of game for the production of biltong. It is instructive to consider the relationship between game meat and vinegar at this time. Ursula Heinzelmann wrote a brilliant article on Carl Friedrich von Rumohr’s Falscher Rehschlegel going back to his Geist der Kochkunst, Spirit of Cookery of 1822. She beautifully describes the hunting of game and the prestigious position it came to occupy in German society. The role of vinegar and game meat in fascinating and instructive to our evaluation of biltong. She writes, “Venison was wrapped in vinegar-soaked cloth or marinated in buttermilk to or vinegar only to prevent off flavours from developing, that is, to conserve the meat or to make the meat from older animals more palatable.” She quotes Mary Hahn who said that “freshly shot game should hang for eight to fourteen days, but it must not develop a bad smell. She said that skinned venison can be kept for several days if wrapped in vinegar-soaked cloth”. (Heinzelmann, 2006) The use of vinegar thus described from the early 1800’s undoubtedly extended back into the 1700s and possibly much earlier. We will return to this notion of preventing off-odors from developing while venison is hanged. It was technology well familiar to the immigrants to the new world of the Cape of Good Hope.
THE PROBLEM OF DISTANCE AND MOVEMENT
Dried meat (biltong) seems to have been a progression of old Dutch recipes by the Dutch farmers at the Cape. What did they do, however, when they moved into the interior? When many of them decided to move to the north, their saltpetre and salt must have run out when they reached Smithfield. From here on they lived from the meat of abundant game they hunted and injured oxen which they killed and while on the move probably cured their meat with the sweat of their horses and hung under the wagons to dry out properly. As I found out, this was almost a universal practice at some point and solid science supports it and links horse saltpetre or sweat saltpetre with rock or cave or produced saltpetre.
Growing up, on my Grandparents farm Stillegoogte in the Fredefort district of the Orange Free State, we called white horse sweat, saltpetre. Marius (my cousin) and I spend our days riding horses and I know horse saltpetre. How it burns your inner thighs when riding without a saddle; its smell and taste. I entered the meat curing industry years later and initially wondered if people cured their meat by using horse sweat. I knew no other substance called saltpetre. I felt a bit silly when I discovered that saltpetre was the salt, sodium nitrate and kept my initial thoughts to myself. Quietly, I continued to wonder why we call horse sweat, saltpetre.
Reading through countless newspaper articles in my research on the origins of biltong, I came across a curious mention by Christina Dodwell, from her book An Explorers Handbook, in the London Times of 12 October 1984. Writing about biltong, she says that “early pioneers in Africa made biltong by putting strips of raw meat under their horses’ saddles, to be cured by the salty sweat of the horses.”
I Googled the general idea and discovered that when the Huns (3rd or 4th century AD) entered from Asia into the Roman Empire, they placed freshly killed venison, cut into thin strips, under their saddles to be cured by the horses’ sweat and tenderised it by the action of the saddle. (Altschul, A. M.; 1976: 123)
The exact same is attributed as being later Mongol Technology (AD 1206 – 94). They too, reportedly, placed meat, cut into thin strips, under the saddle of horses and the weight of the rider, the action of the saddle on the meat and the sweat of the horse tenderised and cured it. There are reports that this was common practice amongst the American Indians. They would cut buffalo meat into strips and place them under their saddle blankets to be cured by the sweat of the horse and dry the meat before eating it. (Cahners; 1969: 196)
There are references to Tartars practicing the same. A quote from Appleton’s Journal: a magazine of general literature, published in the 19th century as a weekly in New York, with its first issue dated April 3, 1869, makes mention of this. In the third of a series of articles entitled Life in Russia, published on 3 April, 1875, it is reported that “the Tartars of the plains cut the horse-meat into long strips and put them under their saddle in order to render it more tender.” (Wottrich, R.. 2012) (1)
Tenderizing the meat was obviously the first object of the well-documented practice. In the 1825 work of Brillat Savarin, The Physiology of Taste, he speaks about the Philosophical History of Cooking. He is discussing the fact that raw meat tasts very nice and that our ancestors probably salted the raw meat before they grilled it (before fire-making was discovered). He remembers an instance when his guest gave him great insight into a way that meat was made tender. He writes, “‘Mein God,’ said the Croat captain, who dined with me in 1815, ‘good cheer can be had without all these trimmings. When we are in the field, and feel hungry, we shoot down the first beast that comes our way, cut off a good meat slice, salt it a little (for we always carry a supply of salt in our sabre-tasche) and put it under the saddle, next to the horse’s back; then we gallop a few minutes, after which [moving his jaw like a man chewing lustly] gnian, gnian, gnian, we feed like princes.’ (Brillat-Savarin, 1825 )
The curious practice undoubtedly had unintended consequences which would have been noticed if we consider the chemistry and functionality of sweat. Sweat, it turns out, contains nitrite along with rapid nitric oxide production. The nitrite exists as part of the well-known reduction sequence we know so well from bacon curing where saltpetre (NO3-) was used and through bacterial action, reduced to nitrite (NO2-). Sweat “contains nitrate in appreciable amounts (secreted by glands) and skin commensal bacteria” which reduce nitrate to nitrite. It has been established that under the right temperature, this reduction step can be achieved in under 4 hours. The mean concentration of nitrate in sweat has been reported to be 2.5 NO3- in day -1 or more. Skin pH is normally between 5 and 6.5. (Weller et al, 1996) This means that skin conditions are “favourable for acidified nitrite” and functionally, the nitrite and NO play and “anti-infectious role.” (L’hirondel, J., 2002: 87)
It is interesting to think about what was happening to the meat under the weight of the rider and the saddle and the sweat of the horse. Nitrate-rich sweat, constantly being replenished from the sweat glands of the horse, being exposed to the meat, being reduced to nitrite and the action of the saddle and the weight of the rider, massaging the meat and aiding in the absorption of the salts into the meat.
WHEN THE DUST SETTLED
It is easy to see how the practice was discontinued as supply lines to Cape Town and Durban was established by the Boer settlements. Salt, spices, vinegar, rock saltpetre again became the regular ingredients for biltong as we know it today, but I am sure the practice of using sweat-saltpeter resurfaced during the two Anglo-Boer wars and in general, during times of distress or want. In seeking the origins of Biltong, this fact of history is both curious and fascinating.
PULLING IT ALL TOGETHER
Upham reports on the following course of events from 1709 which may be at least some of the progressions that led to the creation of biltong. This is an extract from 28 March 1709 from a Broad Council Meeting at the Cape of Good Hope.
“Not one hardly offered himself for the supply of dried or smoked meat. Only 2,500 or 3,000 Ibs. were offered – a quantity very little among so many vessels. The necessity of supplying the ships properly is re-iterated.
Governor and flag officers inspect some meat salted 8 days ago by the contractor Husing. The lean parts were found good, but the thick parts already spoiling.
Decided that the treat should first lie some days in the brine to draw out the blood, and after that placed in new salt. That was not the idea of Husing but of his fellow-contract or Michiel Ley.
The former believed that the meat should be left in its first salt and not pickled beforehand; And was prepared to guarantee supply remaining good.
Decided, however, to adopt the plan of double salting, recommended by Ley; Husing ordered to supply in that manner; “Meervliet” having brought sufficient casks for the purpose. Ley to supply his share according to his plan. Company to supply the pepper.
Decided to take over for the Company, the meat already salted by Husing. The good portions to be distributed among the crews, & the tainted ones among the slaves …”
What is happening is that in the sweltering heat of March in Cape Town, the meat that was salted for sale to ships passing from Europe to the East-Indies were off. Michiel Ley then suggested that the meat is salted in a two-step process. In other words, salt it and let it lay for a couple of days, giving time for blood and meat juices to be drawn out. Then, give it a second salting. This would have worked if the bones were removed before the salting and if the meat was kept under chilled conditions (around 5 deg C) for least the full 8 days – better even, for 10 days, especially the thick cuts so that the salt penetrated through the meat. In the heat that can reach between 35 deg C and 40 deg C in March in Cape Town, it is would certainly not have worked and the meat would spoil.
Upham, however, offers the following additional information about Ley. Contained in this description may be the some of the answers we are looking for. Again, I give it as he published it.
“Michiel LEY [Löw] (1670-1716) (from Basel in Switzerland) – likely same person as Hans Michiel LEY born Benken BL 18 December 1670 [Loew pronounced `Ley`]), son of Ulrich Löw & Katharina Schwarz …
Arrives (1696) as soldier thereafter master butcher;
Likely biologically fathers illegitimate daughter by Company Slave Lodge matres Armozijn Claes: van de Caep, Machteld / Magdalena Ley halfslag baptized (26 August 1697) …
Marries (8 December 1697 Engeltje Breda (from Delft, Holland) daughter of Nikolaas Breda & Aagje Keisers – her mother is recorded (1690) having a kindergarten in Cape Town …
Buys (1699) house in Eerste Dwars Street from Hans Hendrik Smit … Contracts as Company’s Butcher with Company to loan a soldier to work for him; after expiry of 5-year contract, continues as free-master butcher always employing at least 1 soldier loaned from the Castle & supplying meat to public & Company by buying animals from the farmers …
Contracts (1708) with 3 others to press grapes harvested by Company’s servants on the farm “Vergelegen” (present-day Somerset West) for a half share of the produce …
Deacon of Groote Kerk (1703) & Orphan Master (1707); nurses (1701) Hans Jacob Loets (from Schaffhausen) when very sick & lends money to compatriot Jan Oberholster (from Zurich) …
With Cape-born mestiço Willem Basson, compatriot Jan Oberholster & Anthony Abrahamsz: (dies 1718), contracts to supply all the meat required by the Company – price Company prescribed for purchasing animals is however so unfavourable to farmers who refuse to sell that Adam Tas collects signatures petitioning against the governor, citing also other grievances & this is sent to Holland while Van der Stel draws up a Defence which his faithfuls sign.“
Note that in 1708 he was contracted to press grapes harvested by the Company on the farm Vergelegen in Somerset West for half share of the produce. (Linder) At this time he is a free master butcher, meaning that he was free from his employment with the Dutch East Indian Company. It was also in 1708 on 30 January that he again took up a contract to supply the Company for three years. (Stamouers)
Let’s review what we know.
Ley was a master butcher who was working on the problem of preserving meat in the hot South African summer in March 1709.
The beef that he was salting went off, 8 days after the process was started due to the high temperatures. Beginning with the thick parts of the cut.
He had experience with grapes since 1708. Grapes that were not properly pressed easily lead to the formation of vinegar, a known preservative.
His contract to salt the meat was with the largest employer at the Cape, the cornerstone to its existence namely to provide freshwater and provisions to ships passing southern African, en route to the East Indies and back to Europe.
He would, therefore, have been under pressure to find a solution and the pressure would have mounted in light of the fact that his first suggestion of double salting the meat would not have been effective. Double salting in the winter is a good strategy, but not in the summer since spoilage overtakes salt penetration of the meat which reduces available water sufficiently to limit bacterial spoilage, especially if the meat juices drawn out by the first salting are discarded to prevent them from being reabsorbed into the meat. Let’s look at the dates again to reconstruct some of what was happening.
The meat that went bad happened in 1709. This was when he started coming up with alternatives. At least one of such alternatives we knew about. At this time, he was contracted to supply all the meat required by the Company together with Willem Basson, Jan Oberholster, and Anthony Abrahamsz. The prices offered by the Company for meat was however too low and the farmers refused to sell. One of these farmers, Adam Tas collected signatures for a petition against Van der Stel which eventually was sent to Holland. Van der Stel’s reply to this was a document drafted by him in his defense and signed by among other Ley and Oberholster. The four partners requested that the contract is canceled and it was taken over by Claas Henderiksz Diepenaar. Adam Tas was locked up in the Castle’s notorious dungeon and finally, Van der Stel was recalled in 1708. The meat contract was the issue at the heart of Van der Stel’s recall. (Linder) To show the great relationship that existed between Ley and Van der Stel, upon the latter’s recall, Ley acted as one of his representatives to finalize the sale of his assets. (Stamouers)
There was reportedly great friction between Ley and the new governor, Von Assenburgh. The events of 1709 must-have put tremendous stress on Ley. He was 39 years old. He had his own farm and produced wine. A census of that year reveals he was married with three sons and a daughter. He had two servants and fourteen slaves. Four horses and 30 heads of cattle. Three hundred sheep and two pigs. Six thousand vines and two leaguers of wine. That year he also bought the farm Welgemeent, south-east of Table Mountain. (Linder)
He could very well have been the person responsible for adding vinegar, a key ingredient to the production of biltong in order to sort the inconsistent preservation out. Lets now go back to the German (and possibly north European) practice of using vinegar on game meat to prevent the development of off flavours, especially in the summer. This would undoubtedly have been known to the butcher at the Cape who were trained by German, Dutch and Swiss butchers on the continent. The fact that the large pieces spoiled first could have been his motivation to slice the legs into thin pieces, resembling the tongue. This part of the solution would have been an obvious first step.
Hanging the meat to dry out was a well known Dutch way of drying meat for preservation. This may have influenced Dutch farmers to incorporate Ley’s progression of possibly adding vinegar and cutting the meat in thin slices, together with his known progression of double salting to the Dutch method of drying meat and instead of hanging it in the fireplace combining it with local tradition of hanging the meat in the sun and wind.
There have been recent claims that biltong is an old Khoe tradition of salting meat and hanging it to dry. This probably paints a part of the picture. The traditions seem to originate from Schapera (1930) who writes that “when not eaten immediately, or when plenty of game has been caught and not all of it can be taken home, the meat is cut into thin strips, which are salted and dried in the air (by the Khoe). In this condition, it will last for a considerable time, and can also be eaten raw.” He speculates that “the Boer method of making “biltong” is probably derived from this old Hottentot practice.”
There are many references to this Khoe practice and many of them relate to game meat being sun/air dried if large game were killed by them. No question here. By itself, hanging fresh meat out to dry in the sun and wind would also not prevent it from going off according to our moderns standards and taste but this was likely what the Khoe did. The Dutch farmers would have seen this and being familiar with drying as a preservation technique already would have undoubtedly concluded that what they achieved in their chimneys and kitchens in Holland by hanging salted and cured meat to dry was effectively achieved here by hanging it outside in the wind and heat. Combining the influences and traditions yielded a very acceptable product.
The salting and use of vinegar were undoubtedly European inspired. At this point, I believe Schapera to be wrong. I don’t for a second believe that salt preservation of meat was something completely unfamiliar to the San and Khoe people and I am convinced that salt was generally available throughout the region replete with salt wells and marshes. Whether one can rely on one reference from one author in the 1930’s to say that the Khoe made biltong and that this is its origin is a hard sell. I think it is far more plausible that biltong is the slight re-working of an old Dutch dish with Khoe inspiration to hang it outside to dry in the wind and sun.
M. G. Upham sent me a note and referred me to the work of Anders Sparrman. He published his 1786 account entitled, “A Voyage to the Cape of Good Hope, towards the Antarctic Polar Circle, and Round the World: but chiefly into the Country of the Hottentots and Caffres, from the year 1772 to 1776. He writes about the Khoe, “that they absolutely detest salt.” It is a sweeping statement. I have never come across people who “absolutely detest” salt. The context of the statement refers to the use of salt in meat. If his statement means that they detest the European heavy salted meat – they would be in good company as most people, even in Europe detested this taste which is one of the reasons why sugar was added at this time in curing recipes (to break the extremely salty taste) and why even bacon was first left in freshwater to draw some of the salt out before consumed.
He says that they either eat the meat fresh or else dry it in the sun. The fresh meat is “dressed” by “broiling” it over coals. According to Sparrman, meat preservation of the Koe was sun-drying without salt being added.
Lets pause for a minute here. For years I believed that no salt was used by the native peoples of South Africa in curing meat, or at least in salting it for preservation. I was wrong! I discovered that some of the tribes to the northeast of the country covered their meat in ash before they dried it in the sun and wind by hanging it in trees and on shrubs.
In 2019 Minette and I drove up to visit Lauren at Timbavati Game Reserve where she was doing an internship. On the way there we visited a cave on the way to Echo caves that have been intermittently inhabited since 85 000 before present. The interesting thing was the guide at the cave whos memory through his father goes back at least 170 years. He gave a very definitive link between dried meat, salting, and preservation. Not in the form of salt, but in the form of ash. He clearly remembers his dad telling him that before meat that was hung out to dry is consumed, the meat is either boiled again or roasted in ash.
This speaks to the entire issue of the history of biltong, but it shows that meat was indeed, as one can expect, roasted “in the ash” and was probably done so for many years before cooking pots were invented. That the ash gave a flavour to the meat is evident from the enduring nature of the practice and by the testimony of the elder at the cave. Not only is it improbable for the ancients of Southern Africa not to have known about the preserving power of salt, but in all likelihood, the regularly supplemented their diet with salt through ash. The percentage of salt is dependant on the type of tree or shrub used for the source of the ash, but that they received a variety of minerals through this practice is clear.
FAR more important than any of this, he remembers that they rolled the meat in the ash BEFORE it was hung out to dry. He makes a very interesting point that if you don’t do that, how else will you keep the flies and other insects from the meat. This is a remarkable statement. It means that salt and minerals like potassium were definitely applied to the meat BEFORE it was hung out to dry.
I give the video we recorded where I draw these conclusions and also the original interview at the cave.
Elanor Muller sent me the following additional information regarding the practice of drying meat and then rehydrating it in a stew. The Zimbabwean Ndebele people have a traditional dish which they call Ewomileyo. Modern-day people add peanut butter to the dish. This is no doubt done in accordance with an old practice of adding nuts to the meat dish. It is also called Umhwabha or the Zulu name for it is Umqayiba. In Venda, it is done in two ways. Dried meat is placed on a braai or they grill it and stump it. It is then cooked, or dried meat is recooked and mixed with peanuts. All vegetables and meat, mixed with peanuts are called Dovhi.
The fact of dried meat as something that was customarily done when large game was killed is by now a well-documented fact and one that reaches back into antiquity. The thing that everybody probably omits when they describe the practice of drying may be the rubbing of the meat with ash because even in rural Africa today, there are today other ways to keep flies and insects off the meat. In describing the way it is currently done, eyewitnesses may either omit the testimony by the elder at the cave or they may, in reality, use different modern methods. Their purpose in antiquity for rubbing or rolling the meat in ash may have been to manage the flies, but in actual fact, they achieved the rapid kind of dehydration required to lower the water activity in the meat to a level where microorganisms could no longer proliferate. This dehydration (lowering of the water activity) is even today the main reason why salt is used. In many ways, preservation IS the removal of free, unbound water from meat. The dehydration would be achieved through the salts as well as the air movement in the form of wind as the meat hangs in the trees. If this was done in the cool of the day and sufficient dehydration occurred before the meat temperature was raised to levels that would favour microbial growth (through the sun), the ancients of Southern Africa would have indeed cured their meat! If the curing was not effective, the meat would be roasted in ash again, as explained by the elder at the cave, which would have mitigated the off-flavours in exactly the same way as we use garlic or pepper or any other strong spice to “mask” off flavours today.
The clear evidence, however, stands that at least in this area, local people salted and dried their meat. The salting was achieved through ash. I have no doubt that this, in all likelihood, did not affect biltong making that much, but the fact of “salting” meat with ash remains intriguing.
Let us return to the Sparrman account and allow me to give the full quote from Sparrman and read it with the insight from the northern tribes about “ashing” of meat before drying them. “The [Khoe] all roast their uyntjies in the ashes, in the same simple way; and almost every one of them dresses his meat by boiling it over the coals, as it is a very uncommon thing for a Hottentontot to have earthen vessels of his own manufacturing, for the purpose of boiling or stewing his victuals; and as the Hottentots absolutely detest salt, they must eat all their meat (which is either fresh, or else dried in the sun) dressed in this manner, it occurs to me, that their diet may be varied also by the addition of a little more less fat.” (Sparrman)
“Dressed in this manner” undoubtedly refers to “almost every one of them dresses his meat by boiling it over the coals” which refers back to “roasting in the ashes.” The group of meat referred to meat both fresh and those dried in the sun. This seems to indicate that what is being described is the exact same practice as found to be done by some from the northern tribes in South Africa. That even the southern regions of the country, salting was done before the meat was dried through the use of ash. The colonists simply did not realise it. So, despite the fact that the techniques of salting and using vinegar were probably solely influenced by European tradition, the hanging of the meat in the wind and son could have been strongly influenced by local custom.
Sparrman gives us an account where the Dutch farmers imitated the Khoe practice of hanging (presumably) fresh meat (ash salted) out to dry in the same manner as the Khoe, clearly indicating cross-pollination of the culture related to meat preservation and by implication, offering support to the notion that biltong was in part inspired by the Khoe. His account dates to December 1775. His party was traveling from what he calls the “Sea-cow river” to the Sunday River. They were themselves out of provisions, left only with some biscuits and very salted meat that was spoiling on account of the hot temperatures and being kept in a skin bag.
They arrived at the Zwart-Kops river planning to spend the night. Here they found to farmers who came there to find salt and to hunt. The farmers had already shot several heads of game which they cut up into slips of meat and threaded onto bush branches, fences and even onto their wagons “to dry in the sun, in the same manner as Hottentots (Khoe) did the elephant’s flesh near Diep River.”
He mentions that there was a “crude and rank smell” in the air around where the meat was hung. There was a putrid smell from meat that started rotting. The farmers’ wives, children and some of the Khoe that accompanied them were feasting on this meat. Some were sleeping and some were engaged in scaring away the birds of prey that gathered to steal their meat. They were so disgusted by the sight that despite their severe hunger, decided not to partake of the dried meat. Again, the German method of treating such game with vinegar exactly to prevent the development of these flavours would have come to mind.
If biltong was invented by 1775, it was not technology widespread in application. There seems to be no use of salt in the description by Sparrman. The technique also did not prevent meat spoilage and clearly shows that the air/sun drying of the meat by the Khoe should not be romanticized from a modern-day perspective. If anything, it points to the fact that “putrid” and “off-meats” were viewed very differently by Europeans and indigenous people. What seems to be going on here is that the farmers and their families adopted the local customs and attitude towards putrid meat rather than a reflection of anything that would resemble biltong as we know it today. So far, then, I can only find the statement of Schapera about salt used by the Khoe to produce a kind of biltong.
CONCLUSION
Biltong is a South African dish, created probably between the early 1700s and the early 1800’s. It pulls together influences mainly from old Dutch recipes of drying meat for the purpose of preservation and known technology of salting and inspired by the Khoe to hang it outside in the wind and sun to dry. Vinegar was undoubtedly added for preservation in the hot Cape summer climate and a possible candidate for its development is the master butcher Ley.
Voortrekkers later cured biltong by hanging raw meat over the neck of their horses and placing it under the saddles. Interestingly enough, biltong is mainly sold sliced, to this day, as it was done in Hanna Wooley’s old Dutch recipe. She instructs, “slice it so thin that you may almost see throrow it and eat it with a sallet“. (Hannah Woolley)
The much-publicized notion that the recipe originates from local Khoe people is doubtful even though there may most certainly be influences in the way it is hanged to dry. The Khoe achieved technically what makes salting effective as a preservative namely reducing the moisture in the meat and thus retarding bacterial meat spoilage. By combining salting and pickling in vinegar with rapid drying, a powerful and effective meat preservation technique is enacted.
The Boers later used salting by using the sweat of horses and in the process added saltpeter to the dried meat. Saltpeter did not survive as an ingredient in biltong and is seldom used today.
(c) Eben van Tonder
Note 1:
Burry (1911) disputes the conclusion that this was done to cure and tenderize the meat. He speculates that the Huns and the Tartars put meat under the saddles, probably to cover sores on the horse before they are saddled. He suggests that the meat itself would be unedible. (Wottrich, R.. 2012) My immediate response is that the preponderance of current evidence would point away from Burry’s objection. Wottrich believes that Burry simply could not bring himself to believe that such a vulgar practice could exist. Researching the issue will elucidate the question. The source documents must be studied and Burry’s original argument, his own background and the grounds for his objection must be scrutinized before a definite conclusion can be reached. (So many interesting avenues to investigate – so little time) 🙂 The reality is, however, that there are accounts from all over the world of the practice and that this meat was further dried and later consumed. Recent scientific facts would support the practice and establish a clear link between the sweat of horses and men alike and saltpetre.
Note 2: On the value of horse manure
In response to this post, my Uncle Jan Kok, my mom’s brother, tells the following story. I translate from Afrikaans, “I remember a time when Sannie (my mom) and I had whooping-cough. Every morning my dad (my Grandfather, Eben) took us to the horse stables and we had to smell the horses and this prevented us from bad fits of coughing.
I think the actual issue was the smelling the fresh horse manure and urine. We had to be in the stables very early in the morning before they were cleaned and the horses were taken out to the fields. I remember how my dad picked us up so that we could smell on the back of the horse where he sweated under the saddle when he was last ridden.
Grandpa had two apple-blue “skimmel” horses with the names of Moskou and Breker. They were not only riding horses, but Grandpa also had a horse buggy that was pulled by them. I was still very small when, one day, we had to go and collect a soap pot from the neighbours with the horses and buggy. Grandpa got off to open the gate and I had to hold the reigns to take the horses through. It was at that moment when they decided they want to get home fast and there they went, running with me alone on the horse buggy. Fortunately, myself, the horses and the buggy got home scot free but Grandpa had to walk home.”
I heard a similar story from a woman in Cape Town. I suffer from asthma and have been buying my medication for years from a pharmacy in the Riverside Mall in Rondebosch. One of the pharmacy assistants who, as a young girl, grew up in Cape Town, was sent to the horse stables where she had to sit between the manure with a blanket over her head to ensure that the inhalation of the gasses is maximised. According to her, she was developing asthma and after one winter of following this routine every morning between 5 and 6, she stopped showing any symptoms of asthma. Again, I suspect that low dosages of hydrogen sulphide and possibly nitric oxide may have played a role.
Several gasses are released by manure. Hydrogen sulphide, carbon dioxide, methane, and ammonia. In high dosages these gasses are dangerous, but in low dosages, “over the past 2 years, a number of independent groups have reported the beneficial effects of hydrogen sulphide.” One of the mechanisms identified related to it is an anti-inflammatory response.
Our study on sweat has shown the production of nitric oxide on the surface of the skin due to sweating. This explains the curious curing of meat when strips are placed under the saddle of the horse. It seems that a close link exists between its action and nitric oxide (Szabó, C. 2007), a known gas, released from the sweat of the horse through the reduction of saltpetre. Nitric Oxide and hydrogen sulphide have been shown to be the key and independent regulators of many physiological functions in mammals including in the cardiovascular, nervous, respiratory, and immune systems. (Nagpure BV and Bian JS.; 2010) The fact that they had to inhale hydrogen sulphide and possibly NO (if this was still being released, 12 hours after the horse was ridden) is interesting. If these gasses were both inhaled in low quantities, it could have been responsible for some therapeutic effects.
Note 3: Interesting biltong-dates
1973. A CSIR report warns consumers that biltong not sold in sealed plastic bags is often contaminated by bacteria that are known contributors to food poisoning. (Lubbock Avalanche-Journal, 1973)
1963. Dr. Bokkenheuser from the Institute of Medical Research in Johannesburg raised the alarm about possible health hazards associated with the form that biltong was sold in (not packed in vacuum, sealed plastic pouches). (Star-Gazette, 1963)
1946. The commission on wildlife conservation in Johannesburg proposed a ban on the sale of biltong in order to prevent game from being hunted to extinction. (Daily Tribute, 3 August 1946) Gettysburg Times, 1939.
1939. A law is passed in South Africa to regulate the sale of springbok biltong to save the species from extinction.
1900. Biltong is hailed as a sure cure for seasickness given to a couple en route to England in 1898 by a man from Rosebank in Cape Town. It was plain sailing to Engeland, but It turned out to be an excellent remedy for seasickness on a subsequent cross-Atlantic voyage. Game meat was used. (Democrat and Chronicle, 1900)
1842. The account of Captain T. C. Smith making biltong to survive an attack by Boers in Natal.
The background to the incident is that “early in 1842, Captain T. C. Smith, who was commanding a detachment of the 27th Regiment stationed on the Umgazi River in Pondoland, was ordered to march with two companies to take occupation of the Bay of Natal as a retaliatory measure against the immigrant farmers who had declared themselves an independent Republic. This force arrived in May 1842, their march being disrupted in the latter stages by the farmers under Commandant Pretorius who later demanded its evacuation.”
“After being repulsed in an unsuccessful attack on the Boer camp at Congella on 23rd May 1842, Captain Smith was besieged in the fort which he had erected until the end of June when a relief force, consisting of five companies of the 25th Regiment under the command of Lt-Col A. J. Cloete arrived to raise the siege.” (The South African Military History Society)
Smith writes about the time of the siege. “We were no longer inhabitants of the earth but of the underworld, living in subterraneous caves and caverns or sepulchral tombs.” “Our provisions now were getting very scarce, and the enemy shot most of the few cattle we had in the kraal, to keep us from living, if possible. All the oxen we now had left alive were killed immediately to make ‘biltong’ of, lest the enemy should destroy any more of us. The enemy still kept up a formidable fire every day on the camp – upwards of 100 rounds every day. We were living now on six ounces of biscuit-dust and half a pound of biltong. Our coffee and sugar were all out in like manner. This only kept the human frame from failing; and this was not all; after the biltong was all out we were obliged to feast on horse flesh.” (The Times, 1842)
In another interview, he described the events and his biltong making as followed, “”finding that the few cattle remaining at the kraal were dying either from wounds or want of sustenance, I directed that they should be killed and made into biltong reducing the issue to half a pound daily.” Later, either on the 8th or 9th of May 1842, he writes, “Upon inquiring into the state of the provisions this day, I found that only three days provisions remained. I, therefore, directed that such horses as were living might be killed and made into biltong.” They started eating the horse meat on the 22nd. (Sydney Morning Herald, 28 Dec 1842, page 4)
My Complete Work on Nitrites
References:
Altschul, A. M.. 1976. New Protein Foods: Technology, volume 2, part B. Academic Press.
Brillat-Savarin, J. A., Cahners. 1969. Volume Feeding Institutions, Volume 64
Brillat-Savarin, J. A., Translated by Jean Anthelme. First published in 1825. The Physiology of Taste. Published by Peter Davis Ltd and Doubleday and Company, 2002
Cripps, E.. 2012. Provisioning Johannesburg, 1886 – 1906. Submitted in accordance with the requirements for the degree of MASTER OF ARTS IN HISTORY at the UNIVERSITY OF SOUTH AFRICA. February 2012 (PROVISIONING JOHANNESBURG, 1886 – 1906)
De Salcedo, A. M.. 2015. Combat-Ready Kitchen: How the U.S. Military Shapes the Way You Eat. Penguin Random House.
L’hirondel, J. 2002. Nitrate and Man: Toxic, Harmless Or Beneficial? CABI Publishing.
Linder, A. 1997. The Swiss at the Cape of Good Hope, 1652-1971. Basler Afrika Bibliographien.
Nagpure BV, Bian JS. 2010. Interaction of Hydrogen Sulfide with Nitric Oxide in the Cardiovascular System. Oxid Med Cell Longev. 2016;2016:6904327. doi: 10.1155/2016/6904327. Epub 2015 Nov 10.
The South African Military History Society; Military History Journal Vol 2 No 5 – June 1973; The Imperial Garrison of Natal by R G CROSSLEY. ttp://samilitaryhistory.org/vol025rc.html
Schapera, I.. 1930. The Khoisan Peoples of South Africa, Bushman and Hottentots, Routledge & Kegan Paul Ltd., London.
Sparrman, A. 1786. A Voyage to the Cape of Good Hope, towards the Antarctic Polar Circle, and Round the World: but chiefly into the Country of the Hottentots and Caffres, from the year 1772 to 1776. G G J and J Robinson, London
Szabó, C. Hydrogen sulphide and its therapeutic potential. Ikaria Inc., 1616 Eastlake Ave East, Suite 340, Seattle, Washington 98102, USA. e-mail: csaba.szabo@ikaria.com doi:10.1038/nrd2425 Published online 19 October 2007.
The Times (London, Greater London, England) 25 October 1842, page 4.
Weller, R., Pattullo, S., Smith, L., Golden, M. Ormerod, A., Benjamin, N.. 1996. Nitric Oxide Is Generated on the Skin Surface by Reduction of Sweat Nitrate. Journal of Investigative Dermatology; Volume 107, Issue 3, September 1996, Pages 327-331
The story of salt is older than humanity itself. Our interest is in its use as a meat preservative. When did this start and how and what are its functional benefits? We begin very general by asking if there is any evidence that Homo Habilis or Neanderthal used salt to preserve meat. Then we consider Africa which leads to a surprising productive line of inquiry. From the life of David Livingston we learn that salt was not used in Africa to preserve, but as a condiment, added during or after cooking. Salt preservation of meat was known. We learn that from events surrounding Livingston’s death. I am not sure how wide-spread this knowledge was, but in this particular instance, it was applied to the preservation of Livingston’s corps.
This leads to the realisation that studying mummies and mummification technology through the ages may be a very productive way of searching for the oldest known meat preservation technology and the use of salts at a time before writing was invented. I applied this thinking and did an internet search of the oldest mummies on earth which yielded the most startling two results.
The oldest mummies on earth, dating from around 7000 BCE are the Chinchorro mummies from the one place on earth that is at the same time the dryest and is replete with the highest concentration of natural sodium nitrate, the Atacama Desert from Chili and Peru! I have always thought that the use of sodium nitrate in meat curing became popular due to the cured colour it imparts to meat and that its preserving ability was a secondary application. I also thought that its widespread use was a very recent development which reached a height in Europe at the end of the 1800’s when it was replaced by the use of sodium nitrite, starting from the early 1900’s. Following my logic about mummification technology, I was certainly not expecting a date of 7000 BCE for a known use of sodium nitrate in meat curing.
I turned my attention to Asia from where, in an iconic review article from Binkerd and Kolari (1975), they claim that the use of nitrates in the curing of meat was first used as meat preservative “in the saline deserts of Hither Asia and in coastal areas. Desert salts contained nitrates and borax as impurities.” I wanted to examine the veracity of their claims. I followed the same logic of mummification and again, I was startled by the results. The oldest mummies in China are found in the Taklimakan Desert in the Tarim Basin. Right here, in the region where the mummies are found, in the Turpan-Hami Basin, massive nitrate ore fields, close in proximity to the Tarim Basin exists. Nitrate deposits, so massive that it is estimated to be at least 2.5 billion tonnes and comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile.
At the graves near Loulan, one of the bodies were subjected to radiocarbon dating which indicated that she died she died about 1200 BCE. This takes the known date for meat preservation, by our logic of linking this with mummification, to 3200 years ago in China.
The two areas in the Atacama Desert and the Taklimakan Desert in China share a striking similarity in weather. They are both some of the aridest regions on earth. A second factor that plaid a role in the natural mummification is rapid-freezing due to extreme cold conditions in the winter and then, of course, the very high sodium chloride content of the soil. The sodium nitrate content in the soil surrounding the mummies is something that must still be studied in great detail (if you are looking for me during my next vacation, I will be at the mummy sites, taking soil samples for analysis, and if you are joining me on the two expeditions, mail me at ebenvt@gmail.com)).
I honed in on this region in China for its geographical importance as being on the important Silk Road connecting Asia with the Middle East and Europe. I asked if there is any evidence of the development of sophisticated thinking pertaining to the use of sodium nitrate salt from this particular region. My reasoning is that if meat curing as an art developed here, that would have been a springboard for the development of related applications.
The results of my enquiry have been nothing less than startling and leave me with little doubt that I have identified the exact location on earth from where the art of curing of meat developed and was spread into Europe and back into Asia. Not that they were the only ones who would have discovered this. I am convinced the ancients in the Atacama Desert would have easily made the same link with meat preservation but it was here, in China’s Western front, on the Silk Road, where a level of sophistication in thought related to the application of sodium nitrate developed that is unrivaled, as far as I am aware off, by any other location on earth.
The first factor is then the enormous natural deposits of sodium nitrate deposits. Secondly, you have the mummies which are something that observant ancients would have noticed almost immediately. It won’t take you 3200 years to realise that something extraordinary is happening with the corpses. The third fact relates to the level of sophistication in the application of sodium nitrate.
The clue of such sophistication of thought comes to us in the discovery of an ancient medical prescription dating from some time between CE 456 and 536, during the life of the famous Daoist alchemist and physician Toa Hongjing in a cave close to the city of Dunhuang, right in our area of interest.
The text describes the treatment of a condition identified as a case of severe angina, i.e. restricted blood flow due to the narrowing of the cardiac arteries. The treatment was to place saltpetre (potassium nitrate) under the tongue.
The basic curing pathway that alleviates the condition by the ancient prescription is a reduction of the nitrate through bacteria under the tongue to nitrite and in the tissue, transported there by the blood, the nitrite is converted to nitric oxide. The role of nitric oxide as vasodilator was, amazingly, only discovered in 1987 simultaneously by a group of researchers at the Wellcome Research Laboratories in Beckenham led by Professor Salvador Moncada and by a group in the USA led by Professor Louis Ignarro. So momentous was this discovery that the 1998 Nobel Prize in Physiology and Medicine was awarded for the work. Once nitric oxide was identified as playing a role in physiological processes, it was found to be involved in many processes from inflammation to crying. So, here we have a text, detailing a medical prescription in 5th and 6th decade of the Christan Era, from China, that has only been fully understood by modern science in 1987! This by itself is an astounding fact!
It gets even more startling. It turns out that this exact reaction sequence of nitrate ion that is reduced to nitrite through bacterial reduction and changed to nitric oxide, along with the influence of acidity and various reductants on the speed of the process is something that is well known in meat science. Humphrey Davy, in 1812 (cited by Hermann, 1865) was the first one to note the action of nitric oxide upon haemoglobin. On 7 May 1868, Dr. Arthur Gamgee from the University of Edinburgh, brother of the famous veterinarian, Professor John Gamgee (who contributed to the attempt to find ways to preserve whole carcasses during a voyage between Australia and Britain), published a groundbreaking article entitled, “On the action of nitrites on the blood.” He observed the colour change brought about by nitrite. He wrote, “The addition of … nitrites to blood … causes the red colour to return…” Over the next 30 years, it would be discovered that it is indeed nitrites responsible for curing and not the nitrates added as saltpeter. It was Polenski who first speculated that saltpeter is reduced to nitrite in the curing of meat in 1891 and 1901 Haldane showed that nitrite is further reduced to nitric oxide (NO). (Fathers of Modern Meat Curing)
Meat curing has been known to follow this exact pathway since 1901. The tantalising possibility, now presents itself that the preserving nature of the salt was recognised in aspects of everyday life such as natural mummification in this exact region in China. The salt was applied to meat in which it had an amazing preserving impact as well as, what must have been, a mysterious reddening effect. To the ancients, it probably looked as if the meat was coming to life again. The Chinese alchemists in all likelihood naturally gravitated to this as a possible key component of the elusive elixir of immortality. Finding such an elixir was the goal of Chinese alchemy. They probably applied its preserving power to all kinds of ailments and in a process of trial and error, a treatment for angina must have been especially effective.
Such experimentation takes years and if this was a known cure and part of a medical prescription by CE 400 or CE 500, it means that curing of meat must have been very advanced in terms of it being practised in this region by this time. From here, in terms of its key position on the Silk Road, the curing technology would have spread across Asia and into Europe.
This is then the introductory article on one of the greatest journeys of discovery into the nature of salt in curing. Later, in subsequent articles, we will follow the search for understanding the different salts and what accounts for their power and different characteristics. We will follow developments in China and in Europe until the brilliant Antoine-Laurent de Lavoisier arrives on the scene, pulls all available data together and formalise a scientific discipline, we today know as chemistry. We go beyond this and see how modern science is only now unlocking the secrets in Chinese applications of nitrate, showing a level of sophistication millennia ago in China that is staggering.
In the process, our understanding of our world will be enriched, our view of history challenged and as meat curing professionals, we will become more proficient in our trade. We may even develop a bacon brine, based on the results of our discovery. What an adventure!!
There is another reason why this story is important. High throughput factories are constantly being accused that they are not “authentic”. By this, it is meant that the old, original and by implication, the “healthier” and better tasting way of meat curing has been abandoned and is now in the exclusive domain of “artisan curers”. What I will show is that a proper historical view thoroughly debunks this myth. That humans, throughout the ages, have used current prevailing meat technology to its fullest in order to create meat such as hams, of excellence. When Ladislav Machtmulner invented the ham press in the early 1900’s, I am sure he was accused of the same. Or when meat curers started incorporating saltpetre into their brine mix as opposed to salt only. Far more important is to identify the broader trends such as the application of technology with an “artisan flair,” which can and should be done even if one is producing 20 000 metric tonnes of bacon each day. I will argue, in other articles, that such artistic principles include matters such as a thorough understanding of the technology, a meticulous and rigorous methodology in application and wide collaboration. (see related article published on Linkedin)
Edward Smith writes in his 1867 publication, Foods, “the oldest and best-known preserving agent (for meat) is salt, with or without saltpetre.” (Smith, E, 1867: 34) (1)
It is reported in the American Encyclopedia of 1858, that “Very excellent bacon may be made with common salt alone, provided it is well rubbed in, and changed sufficiently often. Six weeks in moderate weather, will be sufficient for the curing of a hog of 12 score.” (Governor Emerson . 1858: 1031)
This introduces us to the use and function of salt in bacon. What is the earliest use of salt as a food preservative and flavour enhancer? What is a salt exactly and when was the composition of different salts identified? How does salt preserve food and what is the mechanics behind its enhancement of flavour and taste?
Here we introduce these fascinating subjects which can easily occupy someone’s attention for a lifetime.
Salt has been in wide use from the earliest time, but fixing the earliest date by when we can, with confidence claim that salt was used to preserve meat is not easy. The use of salt in food probably predates the existence of modern humans. Sodium chloride may have been collected and stored by one of the oldest species of the genus Homo, Homo Habilis who existed between 1.4 and 2.4 million years ago. (Munas, F.; 2014 :213) From this, we can however not conclude that salt was used to preserve meat.
It is speculated that a much closer ancestor, the Neanderthal who lived between 40 000 and 400 000 years ago, dried meat as a way to preserve it. Bent Sørensen suggests that in order for Neanderthal to have carried large carcases to their settlements (after hunting), they could have employed a technique used by later hunter-gatherer societies in Africa and American Indiens of drying the meat at the site and carrying it home by threading a stick through it. He speculates that solar energy could have been used in the summer for drying and wind energy with low air moisture during the winter. Such techniques could have reduced the meat mass that had to be carried by a third.” He also suggests that “storing times could have been prolonged by smoking or salting the meat. Smoking seems fully accessible to Neanderthal societies.” He adds that “we do not know if they used salt.” (Soresen, B.. 2012) The likely use of smoke to preserve meat along with drying is important when we ultimately will apply all this to bacon curing, which remains our primary subject of interest, but so far, we do not have a definite date for the preservation of meat through salting.
There is clear evidence that salt was mined since before the last ice age, some 12 000 years ago in the hills of Austria and Poland, the shores of the Mediterranean and the Dead Sea, the salt springs and sea marches across Europe and Asia. (Bitterman, M, 2010: 16) Similar evidence exists for salt mining across Africa and South America. It seems as if there is not a time known to humans when salt was not mined, in all likelihood to amend our diet, as an ingredient in the manufacturing of a range of products including pottery making and quite possibly to preserve meat. Again, we know that salt was used, but no automatic connection to meat preservation is established for any of these.
In Africa pre-salting of meat, for preservation was not known until Europeans introduced the practice during colonialization. The need to preserve meat was not there. When an animal was killed, the animal was slaughtered and the meat consumed by the tribe, that same day. If salt was added, it was done after cooking the meat as a condiment.
Salt, in precolonial Africa, as was the case around the world at some point, was a scarce and expensive commodity. Ordinary people, generally speaking, had little or no access to salt. For many years it was reserved for royalty and the elite of society. David Livingston, for example, refers to the poor in Africa in the 1840’s with the adjective, “who had no salt” and to salt, as that which “the rich alone could afford to buy.” (Hyde, A., et al.; 1867: 150)
Livingston makes an interesting observation about salt. He was working among a tribe, the Bakwains, while living at Kolobeng, approximately 20kms west of Gaborone in the present day Botswana. He described how the poor often suffered from indigestion on account of their lack of salt. The region has no natural sources of salt. Native doctors who, according to Livingston, was aware of the fact that the lack of salt, was the reason for the malady, prescribed salt along with other ingredients. The doctors themselves did not have any salt and so, the missionaries were approached for help. They “cured” the disease by giving them a teaspoon of salt (minus the other ingredients). He mentions that either milk or meat had a similar effect, but not as rapid as salt. (Hyde, A., et al.; 1867: 150) This has subsequently been well described and explained by modern science. Another important observation from this account is that Livingston confirms the use of salt in food as a condiment only and not to preserve.
The lack of information on meat preservation by ancient societies is challenging. It was probably initiated at a time before these things were written down. Linking salt works of the ancient world and salt preservation of meat, as most authors on the subject do, is not valid as is clear from the African example. There are locations in Southern Africa where archaeologists have traced the mining of salt back to 4000 years ago and yet, preserving of meat with salt is a very recent, post-colonial development in Africa. They mined salt, but they did not preserve the meat using the salt. Salt was simply used in other ways.
This does not mean that the technology of using salt for preserving meat was unknown in Africa. Livingston’s life becomes an example of this knowledge. When he passed away in Zambia in 1875, the tribe used salt to preserve his body after which his body was exposed to the sun for 14 days to dry in an embalming ceremony. Livingston’s embalming was done in order to facilitate repatriation of the body. (Hyde, A., et al.; 1867: 150) How far South down the African continent this was known is an interesting question and the Livingston example indicates that the technology and practice were known further South than one would have expected.
The use of salt in embalming is an obvious application of the preserving power of salt to meat. It also seems reasonable to speculate that salt for preserving meat for domestic consumption came first and the application of the technology to mummification was probably a later development. One obvious reason for this is that meat preservation for consumption would have been a daily requirement. An immediate need, for a large group of people. So, many people, over a long time would have been engaged in experiments with various salts and ingredients to determine by a simple process of observation which salts ingredients and combination of factors preserved meat best. Burying the dead and mummification, on the other hand, was a far more infrequent event, with very few people working on solving the problem resulting in a much slower development trajectory. It is far more probable that techniques for meat preservation in general use would have been applied to the preservation of human bodies after death and in the art of mummification.
If one assumes this logic, it becomes an important tool to establish a date by which food preservation with salt was done by a society. The use of salt in embalming leaves us with clear records with precise dates and exactly what was used in meat preservation. If one assumes that meat preservation for general consumption would have predated the use for embalming, we can fix precise dates by what time a society used which salts to preserve meat.
I found support for this reasoning from Valerie Wohl. She writes, “While we do not know exactly how embalming began, it is likely that methods common at the time for preserving meat, fowl or fish probably suggested a clue for early techniques. One might bleed a fish, for example, then preserve it by salting, smoking, sun drying or otherwise heating it to prevent decomposition and store it for a later time. By the time of the very earliest documentation of the process of embalming (in about 500 BCE), it had become a sophisticated technique that had been evolved over hundreds of years.” (Wohl, V.)
As soon as this logic occurred to me after my reading about the embalming of David Livingston, and thinking through the implications of the African example, I realised that I have to follow the trail of mummification.
This line of reasoning yielded the most surprising results imaginable. Not in my wildest imagination did I think that the oldest mummies and their preservation would be linked, not with sodium chloride, but with what has been the curing salt of choice up until at leat 1905, namely sodium nitrate. I have always thought, based on research on the subject, that sodium nitrate was used for preserving meat from the 1600’s and reached its height in Europe in the 1700’s and 1800 before it was replaced with sodium nitrite from around 1905 and in particular after World War 1. I thought it was used in isolated places around the world where various cultures re-discovered the reddening effect it had on meat, independently and over a long time and that this slowly filtered through to Europe where it gained popularity over time until it became a general practice. Never did I expect sodium nitrite to have been used for meat preservation since between 5000 and 7000 years BCE and not due to its reddening effect, but for its preserving properties. Let’s look at this case.
It turns out that the oldest mummies on earth are the Chinchorro mummies from the Atacama Desert in Chile and Peru, dating from as early as 7000 BCE. (Guillén, S. E.; 2005) Gypsum, a sulphate mineral, was later used with clay (3000 – 1300 BCE), but mud and clay played an important role from as early as 5000 BCE.
The fascinating link is between this region and sodium nitrate. Nowhere on earth are such large natural deposits of this salt found. The soil here is rich in sodium nitrate salt which is known as Chilean Saltpeter to distinguish it from potassium nitrate or regular saltpeter. A war was fought over these deposits and securing it was a major consideration of Germany going into World War 1. The second important factor is that the Atacama desert is the dryest place on earth. The soil is so rich in saltpeter and it is so dry that mummification occurred naturally, leaving mummies that exist since 7020 BCE.
Two of the most important ingredients in meat preservation namely heat/ drying and saltpeter were present in the mummifications rituals of the Chicharro people of then Atacama Desert since as early as at least 5000 BCE. I do not think that it is a too far a stretch to assume that these people knew about the meat preserving ability by drying in combination with their special salts (sodium nitrate). Even though it is completely conjecture, I am comfortable to say that preserving of meat through sodium nitrate salt and drying was probably known since at least 5000 BCE in Chile and parts of Peru. It is then not a stretch to say that this was likely to be known in the other two main regions in the world where saltpeter is found naturally namely in China and India. This is, of course, a fascinating possibility since this particular salt became the curing agent of choice in the 1700’s which gave rise to the food category of cured meats and directly resulted in our use of sodium nitrite in meat curing today. This date of between 5000 and 7000 BCE is completely in line with a date proposed by Binkerd and Kolari.
Despite this tantalising possibility, the actual sodium nitrate concentrations at the burial sites in the Atacama Desert has never been studied. The degree of mummification varies tremendously (Aufderheide, A. C.; 2003: 141) which will indicate that various factors have been present in varying degrees.
This date of between 5000 and 7000 BCE is completely in line with a date proposed by Binkerd and Kolari. According to their iconic 1975 review article about the history and use of nitrates and nitrites in the curing of meat, “it appears that meat preservation was first practised in the saline deserts of Hither Asia and in coastal areas. Desert salts contained nitrates and borax as impurities. However, the reddening effect of nitrates was not mentioned until late Roman times.” (Binkerd, E. F. and Kolari O. E.; 1975: 655) A probable time for this discovery is however not given.
I first thought that what they were talking about was salt preservation generally, but the more I look at events in the Atacama desert, the more I wondered if the particular preserving power of sodium and potassium nitrate was not known from the earliest times and the discovery, focussed on its preserving power and not on its reddening effect on cured meat.
A further elaboration of what Binkerd and Kolari may have been talking about comes to us from a 1977 newspaper article. According to it, the suspicion is that prehistoric nomadic hunters in Western Asia began carrying salt containing nitrate with them to preserve the hunting catch. (The Indianapolis Star; 1977) The focus was indeed on nitrate and its preserving ability and not just on salt generally. I learned that nitrate deposits occur and precipitate as an efflorescent crust in amongst other the Egyptian and Namibian deserts, the Abu Dhabi sabkhas, and deserts of the Mojave, Death Valley and of course, the Atacama Desert and the Gobi Desert. (Warren, J. K.; 2016: 1278)
It is, however, the largest desert in China, the Taklimakan Desert of Western China that offers the biggest surprise when I find the oldest examples of natural mummification in China, right in this desert region, replete with natural nitrate deposits. The conditions are almost identical to those of the Atacama desert.
Like the Atacama desert, the Taklimakan Desert is at the same time one of the aridest regions on earth and massive nitrate ore fields exist in the Turpan-Hami Basin, close in proximity to the Tarim Basin, in the Xinjiang province, where the oldest mummies in China was found. The nitrate deposits are so substantial, that an estimated 2.5 billion tons exist, comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile. (Qin, Y., et al; 2012) The mummification happened, as was the case with the mummies of the Atacama Desert between 5000 BCE and 7020 BCE, spontaneously.
The initial discovery was made in 1939 by the Swedish archaeologist Bergman Folke. A set of tombs were discovered the Chinese province of Xinjiang, known as the Xiaohe Tombs. For 60 years the tombs were forgotten until in 2000 a researcher, head of the Xinjiang Cultural Relics and Archaeology Institute, found the tombs again. It wasn’t until 2005 that the excavations were complete. (www.ancient-origins.net)
The size of the area is unprecedented. So far there have been 330 tombs found in multiple different layers. The tombs include adults and children as well as 15 intact mummies. About half of the tombs were looted by grave robbers. It is the first time anywhere on Earth that so many mummies have been found. (www.ancient-origins.net)
“Several bodies have been excavated from graves near Loulan, a site that once bordered a still shrinking lake fed by the Kongi River. Among these is the body of a young female with remarkably well-preserved facial features, whose radiocarbon date indicates that she died she died about 1200 BCE.” Subsequently, more than 500 tombs have been studied. Dr Wang Bing Hua, director of the Ürümxi’s Archeological Research Institute, attributes the spontaneous mummification to three factors: arid climate, salty soil and shallow, winter burial. Average salt content of the desert soil near Turpan is about 10g/ L but in the very surface layer, it can be five times greater. At Hami the soil contains layers of gypsum and at Cherchen actual salt blocks are obvious within the soil, especially near the surface. Most burials are only about a meter below the surface. (Aufderheide, A. C.; 2003: 268, 269) The nitrate in Xinjiang Lop Nur exists in two forms: natural sodium nitrate mine and natural potassium nitrate. (en.cnki.com.cn)
The Turpan Basin is a “fault-bounded trough located around and south of the city-oasis of Turpan, in the Xinjiang Autonomous Region in far western China, about 150 kilometres (93 mi) south-east of the regional capital Ürümqi.” “The surrounding mountain ranges are the central Tian Shan in the west, the Bogda Shan in the north-west, the Haerlike Shan in the north-west, and the Jueluotage Shan in the south. Beyond the surrounding mountain ranges lie the Junggar Basin in the north and the Tarim Basin in the south.” (www.revolvy.com)
“Some geographers also use the term Turpan-Hami Basin, which is understood as including the Turpan Depression along with the Hami Depression (located to the east of the Turpan Depression, and to the south-west of the city of Hami) and the Liaodong Uplift separating the two depressions.” (www.revolvy.com)
One of these mummies may hold a further clue to their preservation. She became famous for her “excellent preservation and beauty and it is known as the Beauty of Xiaohe. It is a white person with round eyes, perfect eyelashes, and long hair and has features that are more similar to a European person than a Chinese person.” (www.ancient-origins.net)
According to Elizabeth Wayland Barber, her “beautiful eyelashes finally proves an earlier hypothesis, deduced from little detail at Zaghunluq, that those bodies that mummified had to have died in early winter, flash freezing and gradually freeze drying over the next few months whereas other bodies decomposed.” She was dismayed at people’s acceptance or refutation of his arguments without dealing with the arguments posed. In the Beauty of Xiaohe she, at last, had hard evidence. “Eyeballs, being wet, cause rapid decomposition of both themselves and the eyelash-holding eyelids when warm; but by the same token, being wet, cause rapid decomposition of both themselves and the eyelash holding eyelids when warm, but by the same token, being wet, both they and the thin overlaying eyelids will freeze rapidly when being very cold, thus securing the eyelashes in place. Unlike putrefaction, the gentle process of freeze-drying will not dislodge eyelids.” (Mair, V. H., Hickman, J.; 2014: 35)
It has been known from earliest times that meat curing could be done only in the winter in the absence of refrigeration. If not, the putrefying and decomposing forces would overtake the preserving action of saltpetre and decomposition would be unstoppable. It is the combination of cold and dry conditions along with the use of sodium nitrate to preserve and ordinary salt (sodium chloride) to aid in drying out the meat, that forms a link between the earliest forms of mummification and modern meat-curing techniques. It seems unreasonable to think that the result of these forces, in combination, would have gone unnoticed. I further suspect that the power of these forces would have been practised in relation to fish, fowl, game and domesticated animals for centuries before they found inclusion in the earliest mummification practices.
The location of the Turpan-Hami and Tarim Basins is very important. Crossing the Taklimakan Desert is possible at the foot of the mountains surrounding the Turpan-Hami Basin or along its streams such as the Tarim, “that spring from the mountains to enter the desert from its periphery but soon vanish into the sand. As ancient caravans from Eastern China approached Dunhuang at the edge of this segment of what eventually came to be part of the Silk Road to the Mediterranean, the near absence of water in the desert’s centre forced them to make a choice. The southern option skirts the desert along its southern edge at the foot of the steep Kunlun slopes descending from Tibet’s high plateau. Alternatively, the northern route passes through Hami and those communities living along the Kongi and Tarim rivers that lead to Loulan and Lop Nor. It is along these routes that mummies from the Tarim Basin have been found.” (Aufderheide, A. C.; 2003: 268, 269)
The caravans on the Silk Road approached Dunhuang, crossing vast sodium and potassium nitrate deposits. If the knowledge of its power was developed in this region and exported to Europe, I am sure that there should be remnants of this ancient knowledge in this city.
“One of the people who has extensively studied the Caucasian mummies of China, Professor Victor Mair of Pennsylvania University, said that he believes that early Europeans long ago spread out in different directions. He believes that some of these peoples travelled west to become the Celts in Britain and Ireland, others went north to become the Germanic tribes, and still, others journeyed east to find their way to Xinjiang. These ancient European settlers are believed to represent some of the earliest human inhabitants of the Tarim Basin, and Mair has stated that from around 1800BCE the earliest mummies to be found here are exclusively Caucasoid or Europoid rather than Chinese in origin.”
The origins of the mummies have been studied extensively using DNA technology. Writing in the journals BMC Geneticsand BMC Biology, Chunxiang Li, an ancient DNA specialist at Jilin University, and colleagues report on their analysis of human remains from the Xiaohe tomb complex also on the eastern edge of the basin.
They conclude that reconstructing a possible route by which the Tarim Basin was populated, Li and colleagues conclude that “people bearing the south/west Asian components could have first married into pastoralist populations and reached North Xinjiang through the Kazakh steppe following the movement of pastoralist populations, then spread from North Xinjiang southward into the Tarim Basin across the Tianshan Mountains, and intermarried with the earlier inhabitants of the region, giving rise to the later, admixed Xiaohe community.” (Killgrove, K, 2015)
“The populations from the Russian steppe seem to have contributed more genetically to this population than did the populations from the oases of Bactria. “The groups reaching the Tarim Basin through the oasis route,” the researchers note, “may have interacted culturally with earlier populations from the steppe, with limited gene flow, resulting in a small genetic signal of the oasis agriculturalists in the Xiaohe community.”” (Killgrove, K, 2015)
It is however not the origin of these people who interest me as much as their destination and the destination of the traders who passed through this region. The Silk Road that ran through this region reached into the heart of the Middle East and Europe to the West and into the rest of China and India to the East.
The question is if there is any evidence that anything was done with the nitrate deposits and the clear evidence of its preserving power in the mummification. If this was the region where curing of meat was progressed into the art that we know it as today, is there any evidence of this? Any ancient document or reference, not just from China generally, but linked to this region. These were the actual questions I asked myself as I was searching. This is not a device I employ after the fact for the sake of creating drama.
I knew my general geographic area of focus was the one I show below featuring the Tarim Basin.
I started plotting the important points.
Looking at the map above, the saltpetre deposits are the largest at Yuli, marked as NO3-. Loulan is the city where many of the mummies have been found. Dunhuang is a major city before the trip past or across the desert was undertaken on the Silk Road past the Tarim Basin.
I did an internet search for any reference to saltpetre from the city of Dunhuang which would have been a key trading city in the area and important in terms of its location on the Silk Road. Not in my wildest imagination did I expect to uncover what I found!
It is here, in the Mogao Caves, where a remarkable find was made by the Daoist monk, Wang Yuanlu on 25 June 1900. The mix of religious and secular documents date from the 5th to the early 11th centuries. One text is of particular interest to us, the Dunhuang Medical Text. “The text has been carefully studied by China’s leading experts in traditional Chinese medical literature and ancient manuscripts. The text is attributed to the famous Daoist alchemist and physician Toa Hongjing (CE 456 – 536).” (Cullen, C, Lo, V.; 2005) There is evidence that it relies on earlier traditions from the Han and Sui Dynasties. “The original was decorated with images of the Three Daoist Lords and the Twelve Constellations, indicating links with Doist traditions. In Translation, it reads as follows:
(Cullen, C, Lo, V.; 2005)
Until the 1500’s this is the only script of its kind that we know of. “The symptoms described by the patient, as described in the Dunhuang manuscript, suggest an advanced case of cardiovascular distress. The colour of the fingernails (cyanosis) indicates ischaemia (lack of oxygen in the tissue) due to restricted blood flow. Cold hands and feet are additional symptoms of this condition. Also, acute pain suggests that the patient may be suffering from severe angina, i.e. restricted blood flow due to the narrowing of the cardiac arteries.” (Cullen, C, Lo, V.; 2005)
“Modern treatment for angina is glyceryl trinitrate or isosorbide dinitrate. So, at first glance, there seems to be a similarity in treatment. All three remedies contain the all-important nitrate. Salpeter is, however, an inorganic compound that exists as a positively charged potassium cation (K+) and a negatively charged nitrate anion (NO3-). Concerning organic nitrate, such as glyceryl trinitrate, there is a covalent bond or a molecular bond between the nitrate moieties (NO3) where they share electron pairs which form the bond with the rest of the molecule (CH2). Where glyceryl trinitrate relaxes the muscle lining of the artery to relax, enlarging the vessel and so allowing more blood flow, saltpetre by itself will not affect the treatment of angina. (Cullen, C, Lo, V.; 2005)
This is however not the full story. The remarkable feature of the Dunhuang text is that the combination of the use of saltpetre, not on its own, but when applied according to the dictates of the text, becomes a remedy for exactly the condition described.
“The thing about glyceryl trinitrate is that this too, in itself, is not a vasodilator (relaxing of the arterial lining). It is transformed, probably in the arterial wall, into a chemical species which is the vasodilator. Under very special circumstances, exactly as detailed in the Dunhuang text, the nitrate ion from saltpetre also converts to exactly the same species which is the vasodilator. Despite the fact that glyceryl trinitrate has been in use for over a hundred years, the identity of this species has only been discovered in 1987.” (Cullen, C, Lo, V.; 2005)
“Lining almost all blood vessels on the inside is a layer of cells known as the endothelium. A very important function of the endothelium was first reported in 1890 by Furchgott and Zawadzki. The presence of acetylcholine (a small biologically active molecule) in the bloodstream affects vasodilation and it was generally assumed that acetylcholine acted directly upon vascular muscle. However, this was found not to be the case. Furchgott and Zawadzki showed convincingly that acetylcholine acted, not upon the muscle of the artery, but upon the endothelium and the endothelium produces a “second messenger” which then acts upon the muscles to effect relaxation. This second messenger was christened “the endothelium-derived relaxing factor” (EDRF).” (Cullen, C, Lo, V.; 2005)
During the 1980’s, an intense effort was made to identify the EDRF. It was initially assumed that it would turn out to be a complex molecule like a hormone. This speculation enhanced the surprise when the chemical nature of the molecule was finally determined. It turned out to be a small diatomic molecule called Nitric Oxide (NO). “That it had a physiological role, in a process as important as vasodilation, came as a complete surprise.” (Cullen, C, Lo, V.; 2005)
“The discovery was made simultaneously by a group at the Wellcome Research Laboratories in Beckenham led by Professor Salvador Moncada and by a group in the USA led by Professor Louis Ignarro. The 1998 Nobel Prize in Physiology and Medicine was awarded for this discovery. Once nitric oxide had been detected in one physiological process it was found to have roles in many others, from inflammation to crying. That it should have remained undetected during a hundred years of intense scrutiny of human physiology is astonishing. Glyceryl trinitrate is a vasodilator because it is transformed by an enzymatic process (possibly by the enzyme xanthine oxidoreductase) into nitric oxide.” (Cullen, C, Lo, V.; 2005)
Let us now return to the Dunhuang text. Is there any way that the inorganic nitrate could be transformed into nitric oxide? “In a healthy body it is very unlikely, that nitrate which is present in the blood plasma, is converted to nitric oxide. However, there is a species, nitrite (NO2-), very closely related to nitrate (NO3-), for which conversion into nitric oxide is quite possible. Do humans ever convert nitrate into nitrite? Such a conversion can occur in the mouth and it is this aspect of the Dunhuang prescription that is so interesting. The saliva contains many bacteria, some of which contain the enzyme nitrate reductase, which converts nitrate into nitrite.” (Cullen, C, Lo, V.; 2005)
“Experiments on rats have shown that reduction of nitrate to nitrite is confined to a specialised area on the posterior surface of the tongue. If the same applies to humans, the Dunhuang procedure, which specifies that the saltpetre should be placed under the tongue will maximise the conversion of nitrate into nitrite. The retention of saliva as described would also enhance nitrite production. Unlike nitrate, nitrite is physiologically active. It is an antiseptic and a vasodilator, although not a powerful one. It has been suggested that animals, particularly cats, lick wounds because of the antiseptic effect of nitrite in the saliva. Although not a powerful vasodilator, there is now direct evidence that rat hearts, when subjected to global ischaemia, generate nitric oxide and that a significant proportion comes from nitrite present in the tissue. Ischaemic tissue is very acidic and the acid affects the conversion of nitrite to NO via the following equilibria:”
(Cullen, C, Lo, V.; 2005)
“Calculations, assuming only a modest level of nitrite in ischaemic tissue, show that enough nitric oxide from the above equalibria to activate guanylate cyclase, the enzyme responsible for the initiation of the cascade of reactions which lead, eventually, to vasodilation. So, if nitrite enters the plasma, as a result of administration of sublingual saltpetre, it could generate nitric oxide in ischaemic tissue. Because of the abundance of blood vessels under the tongue sublingual administration of a drug is a good way of getting a drug into the bloodstream and bypassing the stomach. Also, the tongue, in traditional Chinese medical theory, is linked to the function of the heart.” (Cullen, C, Lo, V.; 2005)
“The interaction of saliva and nitrate to generate nitrite before conversion to nitric oxide in ischaemic tissue gives considerable credence to the Dunhuang procedure as a treatment for cardiovascular distress.” (Cullen, C, Lo, V.; 2005)
Here, in the Tarim Basin, we have three things present. One of the world’s largest natural salpeter deposits. Natural mummification dates back to just over 3000 years ago. From these, the preserving power of these soils would have been evident to all since the mummies existed then already. The longevity of the corpses would have been evident to the ancients. We have a record of very sophisticated use of saltpetre from very early in the Christian Era from this exact region. In fact, some of the most sophisticated use of the salt on record and the exact mechanics are even today mirrored in the act of curing itself which has been until the early 1900s when the direct addition of sodium nitrite replaced saltpetre as curing agent of choice.
Until that happened, curing was done by the addition of saltpetre which was reduced, through bacterial action to nitrite which diffused into the muscle for preservation. The similarity in the curing action and the mechanism relied on, in the utilisation of saltpetre in the Dunhuang Medical Manuscripts is startling, to say the least. Of course, I am not suggesting that the full or even a partial understanding of the mechanism was known to the ancients, but the application did suggest a much more detailed understanding of saltpetre and its efficacy on meat muscles which could easily have originated from the experience with curing! Seeing the preserving power of the salt and the reddening effect of the meat could have led them to an application of the salt for heart conditions even though the reduction steps may not have been fully understood.
This is without a doubt the best possible location from anywhere in the world where curing of meat could have originated. The picture is not of wondering hunters who stumbled upon the salt and early farmers using it for preserving meat – or at least, it could have started like this. But if it happened in this exact region, it soon found itself in the most advanced society on earth of its time with the most sophisticated thinking about chemistry. The Chinese alchemists in all likelihood gravitated to this as a possible key component of the elusive elixir of immortality. Finding such an elixir was the goal of Chinese alchemy. They probably applied its preserving power to all kinds of ailments and in a process of trial and error, a treatment for angina must have been especially effective.
Here, at a key location on the Silk Road, the knowledge of curing and the power of saltpetre could easily have been spread through India and China to the East and right into the heart of Europe to the West.
Binkerd and Kolari may be correct in speculating that the preserving power of sodium and potassium nitrate was discovered in the deserts of Asia between 5000 and 7000 years ago. Nomadic hunters probably took this salt with them on hunting expeditions if the hunt took them to a region where these salts do not naturally occur. It was in all likelihood discovered in many other regions around the world where these salts naturally occur, including in the Atacama Desert and India. Of all these possible locations, the one region on earth with all the hallmarks of being the birthplace of our modern meat curing is Tarim Basin, in the Xinjiang province. The Silk Road probably was the perfect transport mechanism for the technology and the culture was spread. It is a remarkable glimpse back into human history and turns our gaze decidedly east towards China. Years will be spent building on this one single possibility!
Egypt becomes an interesting case since here the preserving salt of choice was not sodium or potassium nitrate, but natron. We will consider natron in a future article. We will also look at how the ancient knowledge of preservation was transferred from region to region, transforming our modern understanding of migration and travel in the ancient world. We will consider how and when this knowledge arrives in Eastern and Central Europe. What was known in China about potassium and sodium nitrite and how sophisticated was their understanding of these salts? It will be proposed that it was so sophisticated that in certain respects, their technology of 1500 years ago is only being properly understood today and incorporated in the most modern understanding of human physiology. We will trace the Western discovery of the composition of these salts and the formalisation of the scientific discipline of Chemistry. We will look at the role of these different salts in meat curing.
It will be proposed that the modern obsession with hydrocolloids and phosphates in meat processing is misplaced and how a re-evaluation of salts and their efficacy in meat can yield surprisingly beneficial results.
Please mail me with any comments, corrections or contributions or if you are interested in joining me on a trip to China and Chili at ebenvt@gmail.com As always, we will combine such a trip with amazing hikes!
References (applicable to the entire work, still being written)
The Age, Melbourne, Australia, 3 June 1975, Page 1
Aufderheide, A. C.. 2003. The Scientific Study of Mummies. Cambridge University Press.
Bertman, S.. 2010. The Genesis of Science: The Story of Greek Imagination. Prometheus Books.
Brenner, E.. 2014. Human body preservation – old and new techniques Erich Brenner. J. Anat.(2014) 224, pp316–344 doi: 10.1111/joa.12160
Binkerd, E. F. and Kolari O. E.. 1975. The history and use of nitrate and nitrite in the curing of meat. Fd Cosmet. Toxicol Vol. 13. pp. 655–661. Pergamon Press 1975. Printed in Great Britain
Cullen, C, Lo, V.. 2005. Medieval Chinese Medicine: The Dunhuang Medical Manuscripts. Routledge Curzon.
Davy, H. 1840. The Collected Works of Sir Humphry Davy …: Elements of chemical philosophy. Smith, Elder & Co.
Freedman, P. H.. 2007. Food: The History of Taste. Thames & Hudson Ltd. London.
Guillén, S. E. “Mummies, Cults, and Ancestors: The Chinchorro Mummies of the South Central Andes.” Interacting with the Dead: Perspectives on Mortuary Archaeology for the New Millennium. Gainesville: University of Florida, 2005. 142-49.
Gouverneur Emerson . 1858. The American Farmer’s Encyclopedia. A O Moore.
Heilbron, J. L.. 2003. The Oxford Companion to the History of Modern Science. Oxford University Press.
Hui, YH, Wai-Kit Nip, Rogers, R. 2001. Meat Science and Applications. Marcel Dekker, Inc.
Hyde, A., Bliss, F. C., Tyler, J.. 1867. The Life and Life-Work of Dr David Livingston. Columbian Book Company.
The remarkable story of Wright Harris and Jan Kok’s participation in the Second Anglo-Boer War. These stories begin much in the same way. Their faith played an equally important role in surviving the war and it established a legacy where hard work, faith and opportunity determined the actions of their children grandchildren and great grandchildren. Finally, both stories end with the creation of a bacon curing company!
INTRODUCTION
Food science and the meat industry, in particular, have amazing untold stories. I was researching great bacon companies of ages past when I received a scanned copy of Bringing Home the Bacon, A History of the Harris Family’s Castlemaine Bacon Company, by Leigh Edmonds.
I discovered a remarkable link with South Africa in the participation of one of the founders, Wright Harris, in the Second Anglo-Boer War on the side of the British Empire. This peaked my interest since my own great grandfather, Jan (Johannes) Kok fought in the same war, but on the side of the Boers. Despite being adversaries in war, their stories are very much alike. Deep religious beliefs were their compass and following its direction ultimately brought us to bacon curing. In the Harris story, this happened in one generation and in the case of Johannes Kok, it would take 4 generations before his great-grandson would complete the process and become one of the founders of a bacon company. This is the story.
WRIGHT HARRIS
The story of Wright Harris, the Australian protagonist, begins in England where his parents were married in January 1864 and migrated to Victoria, Australia. Wright was the 7th of 11 children. His father was a farm labourer and wood cutter. Wright remarked in later life that he left school at age 12 when hard work was the lot of most boys and added that “it didn’t hurt us.” Wright was a devout Christian. A heritage he got from his mother. By 1900 he was a regular lay preacher at many churches in the area.
JAN KOK
Jan Kok at the house on Kranskop where he was born.
Johannes W Kok was born in Winburg in the independent Boer republic of the Orange Free State on 4 April 1880. The Orange Free State got its independence from Brittain on 23 February 1854. Winburg itself was a self-proclaimed independent Boer territory since 1837 and was incorporated into the Free State in 1854. Jan Kok was christened in Winburg on 02 Mei 1880. He grew up right in the heart of Boer-self determination.
THE SECOND ANGLO-BOER WAR
In October 1899 the second Anglo-Boer war broke out in South Africa. In the first few months, the Boers had the upper hand, but the British government responded by massing its forces from across the empire. Wright enlisted in February 1900 in the Victorian Bushmen Contingent.
P. L. Murray writes about the Third Bushmen Contingent in his work, Official records of the Australian military contingents to the war in South Africa, “This corps was largely subscribed for by the public. It was resolved that, in lieu of drawing the men exclusively from the local forces, a class of Australian yeomen and bushmen should be obtained; hardy riders straight shots, accustomed to find their way about in difficult country, and likely to make an expert figure in the vicissitudes of such a campaign as was being conducted.”
An enormous number of candidates volunteered for enlistment. The men selected were largely untrained in military matters; 230 were farmers or with some connection to farming. The selection criteria were based on their ability to ride and shoot. The men were allowed to bring their own horses. Many brought two.
They left Melbourne for South Africa on 10 March 1900 aboard the Euryalis and arrived in Cape Town on 3 April 1900. Wright suffered from severe seasickness on the voyage to South Africa and wrote only two words in his diary, “sea sick.” Of the 261 men and NCO’s and 15 officers, 17 would loose their lives in the South African campaign.”
In South-Africa, thirty-seven days later, on 5 May 1900, on an autumn evening, the 20-year-old Jan Kok greeted his mum and dad, took his rifle and mounted his horse. At 20:00 he rode off with the kommando from their farm Kransdrif. From there they rode to the farm of A. Nel, Kafferskop. In all, they were 11 people riding together; 6 from Winburg, 1 from Kroonstad, 2 from Thabanchu and two black people. They travel to Ficksburg, where they join this Kommando and on 18 May, they set off from Ficksburg to join larger Boer forces.
From Jan’s diary, there was considerable disagreement where they should go and which Boer forces they should join.
The Australians, on the other hand, had none of the indecisiveness associated with a more informal military organisation of the Boer’s. As soon as they landed at Cape Town, they travelled to Beira and to Marondera (known as Marandellas until 1982), a town in Mashonaland East, Zimbabwe, located about 72 km east of Harare. Here, all the colonial Bushmen were formed into regiments known as the Rhodesian Field Force; “the Victorians and West Australians forming the 3rd, under Major Vialls. They marched in squadrons across the then Rhodesia (Zimbabwe) to Bulawayo. From there to Mafikeng where they were again mobilised and equipped and took part in one of the major battles of the war, the siege of Mafikeng.
Wright noted the following entries in his journal at Mafikeng.
23 July, Monday. “Left Bulawayo for Mafikeng at 3 o’clock. Twenty-five in a truck, packed in like pigs.”
24 July, Tuesday. “Ostrich running alongside the train. A halt for two hours at Palepwe to feed and water horses.” (I am not sure where Palepwe is. The name is probably misspelt)
25 July, Wednesday “Met by an armoured train. Reached Mafikeng at about 6 o’clock, and slept out in the rain.”
26 July, Thursday. “A look around the trenches and around Mafikeng. Saw the Boer prisoners, two sentenced to death.”
27 July, Friday. “Got our saddles. The ponies captured from the Boers allotted to us. Saw the guns that saved Mafikeng.”
28 July, Saturday. “Sent out to hold the river against the enemy with four guns. Got orders to go away and take three months provisions. Order countermanded (rescinded/ cancelled).”
29 July, Sunday. “Church parade. Went to the Wesleyan church in town, had a grand service. Text Timoty 21 and 22. On picket, got a piece of shell which had come through the roof. (This must be a mistake because there is no such reference. My best guess is that it is 2 Tim 2: 21 and 22 which reads: “If a man, therefore, purges himself from these, he shall be a vessel unto honour, sanctified, and meet for the master’s use, and prepared unto every good work. Flee also youthful lusts: but follow righteousness, faith, charity, peace, with them that call on the Lord out of a pure heart.”
On 28 July, Jan notes in his own diary that the kommando, under the leadership of General Marthinus Prinsloo, decide that it is not worth fighting any further since the Boers are heavily demoralised. They ask the British to negotiate a surrender. At this time they are still in Fouriesburg, in the Brandwater Basin.
The formal surrender was on 30 July 1900, but Jan and his fellow Boers lay down arms on 31 July. They are assured by the British that they would be allowed to return to their homes and farms, but in the end, this does not materialise.
Jan writes in his diary on Monday, 31 July 1900, “we have our weapons deposited on the surrender of General Prinsloo to General Hunter. On this day he notes, “a time of new experiences and disappointment, for sure.” On August 11 they sent us by train to Cape Town (Green Point).” He writes that “the Malaaihers (Malays?) and bastards (colourds?) were standing both sides of the street and mocked us all the way.”
They board the ship Dilwara on 15 August. On 18 August they leave Cape Town and stop over in Simonsbaai (probably Simons Town). On 21 August they arrived in Durban. Aboard they are tortured by an infestation of fleas. They leave Durban on 22 August. On 30 August, they anchor at the “Chysellen.” Here they are allowed for the first time to buy some fruit, “12 bananas for 6 “pence.”
On 8 September they arrive in Colombo Bay. From here they travel 160 miles by train and arrive eventually in Diyatalawa.
On 16 September a fellow inmate and an ordained minister, Ds C Ferreira, preach from Matt. 8:12, “But the children of the kingdom shall be cast out into outer darkness: there shall be weeping and gnashing of teeth” That afternoon Ds Postma preach from Luke 18:10 (probably up to : 14). On that day they were very upset that the “koelies” (a derogatory but common term for people of Indian descent) worked on that day, a Sunday as if it was any other day. Ds Postma’s reading dealt with that judgemental attitude towards others who do not observe and worship in the same way as you do.
He writes on 22 September that he and Gert van de Venter from hut 48 started a “Zingkoor” (a choir). He attended bible study at hut 63 where a certain Ds Roux spoke.
This was obviously a time of great reflection and soul searching. On 1 October, he writes that “as I reflect on the past year and what happened to me, I can not say anything else but that the Lord helped me through it all and that he can not but to thank Him for all that He has done for me.” It is interesting that he named his son, years later, Ebenhaezer, God helped me all the way and brought me to this place. He never told my grandfather why he named him Eben. It was not a family name and must have been done deliberately in a time when conservative farmers gave their children the names of their parents or grandparents. From this entry in his diary, I can see how important this thought was to him and, especially in Afrikaans, the wording is similar to the words used in the bible from where we get the meaning of the name, Ebenhaezer. I suspect that in naming his son Eben, Jan was celebrating Gods faithfulness in by allowing him to return and have his own family.
There was also ministers in the camp who used Sunday school for a time to criticise the fact that they laid down arms. Ds Roux accused them of being selfish when they surrendered and say that they were only feeling sorry for their horses and were homesick. He spends lots of time attending bible study and Sunday school. On 3 January when a school was started, he attended. On 7 January he mentions that there was a missions prayer meeting and he starts to attend a missions class.
His grandson, Ds Jan Kok (my uncle), writes a dissertation when he completes his studies as a Dutch Reformed minister, about the development of a missionary zeal in the POW camps and indeed, many of the POW’s returned home to become missionaries. This was later published under the title “Sonderlinge Vrug” (special or unusual fruit).
Jan became one of the founders of the “Zuid-Afrikaansche Pennie Vereniging” on 1 June 1902. The goal of the organisation was to promote the missionary course and through this, to expand the Kingdom of God.
On 31 July, as Jan surrenders and is taken POW, Wright Harris is still very much part of the siege of Mafikeng and writes in his own diary, “Called out to wait for the Boers at daylight. Ordered not to start.” 1 August, Wright notes, “Starting out for Mafikeng. Passed Boer trenches.”
He survives the campaign, but his health deteriorates. He suffers horrible bouts of severe illness. His Christian faith sustains him through everything, like Jan Kok in the Diyatalawa camp. Wright also continues to attend church parades, tent meetings, bible readings and prayer meetings. I wonder if he could have imagined that on the Boer side there were men with much the same commitment and a common experience of faith with him.
In early October, as Jan is getting used to life as a prisoner of war, Wright Harris contracts deadly typhoid fever. He is taken to hospital where he lay for weeks, delirious and close to death. He is so severely sick that later becomes convinced that his eventual recovery is a miracle. As soon as he was sufficiently recovered, he is sent back to Australia and arrived in Melbourne in early Feb 1901.
Wright, deeply committed to his faith, undertakes a year of church work in New Zealand, following the war. Jan is eventually released on 5 December 1902 and returns to South Africa on 27 December 1902.
FOLLOWING THE WAR
There is a deep belief among the young men at these camps that a reason for the war was that they did not do everything in their power to spread Christianity among the native African tribes. It was in a way, Gods judgement upon them for their inaction. It is therefore not surprising that after their homecoming, Jan enrols in the Missionary Seminary of the Dutch Reformed Church in Wellington. The collective Boer nations had matters to resolve that, in their interpretation of events, brought about such devastation on their land and it is completely understandable and commendable that this became the passion of Jan’s life. Jan is confirmed in March 1906 in a missions church in Heilbron.
Wright did not have a nation to save and without the spiritual issues that plagued the young Boer-men, focussed on building his own life. He was ready to do whatever his hands find to do. Events in his life would steer him, not to full-time church ministry as was the case with Jan, but to a life of business and bacon curing.
Probably through the Methodist church at Scoresby, he met John and his daughter, Janet Weetman. William Haine ran a butter factory in Kennedy Street, Castlemaine. He also ran a bacon company part time as the Castlemaine Mild Cured Bacon Company, to earn additional income. Haine and Weetman agreed for John and Janet to take over the running of the bacon side of things and Weetman roped Wright Harris in to assist them. The three arrived in Castlemaine in 1905 and started the Castlemaine Bacon Company in a room in the butter factory. Together with John Kernihan they processed five pigs per week. John Kernihan and John Weetman were the experienced craftsmen. Kernihan had employed Weetman years earlier in his own bacon company in Northcote but lost his business during the depression of the 1850’s.
Wright and Janet eventually marry on 18 April 1906. John Weetman passed away on 28 March 1922 at which time Wright and Janet acquired the company and the land the factory was built on. So started a long and prolific history of the Castlemaine Bacon Company under Wright Harris’s name.
Back in South Africa, Jan remains faithfully at the congregation in Heilbron for 39 years until his retirement in 1945. My uncle, Oom Jan Kok, who was named after his grandfather, follows in his footsteps and become a pastor in the Dutch Reformed Church. He faithfully serves in the Moedergemeente, Warmbad for most of his life. He tells an interesting story that when he was christened, this was done in the “black church” where his grandfather and the man who’s name he received, was the pastor, in Heilbron. In those years this was of course not permitted under the Apartheid Laws. My uncle, Jan, needed a “doopseël” (baptismal seal) for some reason and it was eventually found at the “white church” (Heilbron-South) where his grandfather must have registered it.
I, in turn, am named after my grandfather, Oupa Eben Kok and was destined to follow in the footsteps of my great granddad and uncle to become a pastor. During a year I spent in the USA after my own time in the South African Army (1988 to 1990), I returned to South Africa with a commitment to pursue a career in business. Bacon curing became my life.
I fell in love with Chemistry and in my mid 30’s decided to enter the world of food manufacturing. In 2008, Oscar Klynveld and I created Woody’s Consumer Brands (Pty) Ltd. with the ambitious goal of selling the best bacon on earth. Oscar himself is the son of a Dutch Reformed minister with deep religious convictions. I always loved writing and storytelling and when I discovered that the field of meat science is replete with amazing untold stories, I start a blog where I feature some of these amazing stories.
It was in researching an article for this site on famous bacon curing companies from around the world and a book I am writing on our setting up of Woody’s Consumer Brands that I came across the story of the Castlemaine Bacon Company and the link they have with South Africa. Since the founding of the company, our growth has been meteoric, much like Wright Harris’ Castlemaine Bacon Company. The Harris family now stand and look back at a company which they eventually sold and they have in a sense completed the full circle, a road that we are still excited to be travelling and in a sense, continue to follow in their footsteps.
On Saturday morning I was standing in our own dispatch area, telling Oscar about this article and my attempts to make contact with the Harris family. The commitments, disciplines and great lessons from the words of John Harris and the inspiration we can draw from them.
CONCLUSION
The great story of bacon curing is, from the beginning to the end, a human story. It took the best of humankind, over thousands of years to create a dish that mimics natural processes that are part of human metabolism, every moment. The story of bacon curing is our own story in a very personal way. It is a science and an art – human culture at its best. Telling the story of curing is telling our own personal stories. They are inseparable.
As humans, we identify patterns, we learn, evolve and we connect. Looking at our own experience in Woody’s Consumer Brands fill Oscar and me with a deep gratitude and we take courage from the men and woman of the Harris family with their remarkable heritage which is so close to our own. Bacon curing brings together some of the greatest stories on earth!
References:
I liberally quote and use information from Bringing home the bacon: a history of the Harris family’s Castlemaine Bacon Company 1905-2005 / Leigh Edmonds. Monash University. The photo of Wright Harris, this source.
Murray, P. L.. 1911. Official records of the Australian military contingents to the war in South Africa. Albert J. Mullett, Government Printers.
All information and photos of JW Kok supplied by Jan Kok in private correspondence.
Many years ago people used saltpeter to cure meat. It was discovered that saltpeter or potassium nitrate do not directly contribute to meat curing. Denitrifying bacteria remove one oxygen atom from the nitrogen compound, nitrate, and nitrite is created. Nitrite turns into nitric oxide and it is this molecule that is responsible for curing. I wondered how the composition of saltpeter was discovered and who was the first to identify the change of nitrate to nitrite in old curing brines which paved the way for the development of the modern curing industry which uses nitrite directly, thus shortening the curing cycle considerably. This is the story.
Background
Bacon curing was described in 1876 by Edward Smith as the process whereby pork is “preserved by salt and saltpeter.” (Smith, 1876: 64). Curing gives bacon its characteristic pinkish/ reddish colour, a nice flavour, and it lasts a long time before it tastes “off”. The curing agent was saltpeter.
A typical curing mix used during the late 1800’s to the middle of the 1900’s for dry cured bacon was a mix of 10 pounds salt, 3 pounds of brown sugar, 6 ounces of black pepper and 3 ounces of saltpeter. They used 10 pounds of this mixture per 100 pounds of meat. (1, 2)
Dr. Eduard Reinhold Polenske (3)
Below are the cover of the original journal, the title page and the first page of the actual article.
Dr. Ed Polenske (1849-1911), as friends called him, was a chemist at the Imperial Health Office in Berlin, Germany. He was born in Ratzebuhr, Neustettin, Pommern, Germany on 27 Aug 1849 to Samuel G Polenski and Rosina Schultz. He married Möller and passed away in 1911 in Berlin, Germany. (Ancestry. Polenske)
The Imperial Health Office where he worked was established on 16 July 1876 in Berlin, focusing on the medical and veterinary industry. At first, it was a division of the Reich Chancellery and from 1879, fell under the Ministry of the Interior. In 1879, the “Law concerning the marketing of food, luxury foods, and commodities” was adopted, and the Imperial Health Office was tasked with the responsible for monitoring compliance with it. Established in 1900, the Reichsgesundheitsrat supported the Imperial Health Office in its tasks. (Wikipedia. Kaiserliches Gesundheitsamt)
Dr. Polenske was a prolific food scientist who made valuable contributions to the examination of food preservatives in the 1880 and 1890’s. The subject of preservatives in meat and whether they are safe to use has been one of the subjects he studied. The Wichita Daily Eagle (Whichita, Kansas) reports in an 1890 article on a convention of chemists at Speyer, Bavaria, which took place on 10 September 1888, where preservatives in meat were discussed. A conclusion of the conference was that boric acid, as a food preservative, was to be “regarded with caution.” (The Wichita Daily Eagle, 1890)
It notes that Dr. E. Polenske made an examination of 10 different “commercial preservatives intended for meat.” “Three of the 10 contained sulphurous acid or sulphites; two contained borax, and five boric acid; one each contained alum, arsenious oxide, salycylicacid and free phosphoric acid; two contained glycerine, and two boroglycerine; three contained niter, and six common salt.” (The Wichita Daily Eagle, 1890) The niter is saltpeter.
Three years following the conference (1891), Dr. Polenske published findings on a remarkable discovery that the niter commonly used in meat curing in the form of saltpeter changes into nitrite (4). This was probably the first scientific paper by any scholar on the subject of meat curing where nitrite and meat curing was linked. In a real sense, one can say that he is the father of what became the modern meat curing with sodium nitrite and therefore the modern meat curing industry.
The years following 1891 saw this knowledge being harnessed by industry and advanced upon by science as they worked out that it is indeed the nitrite doing the curing work (through NO) and developed methods of accessing nitrite directly in curing brines. This sped up curing from 21 days to curing in 24 hours. On farms, long curing is less of a problem, but for a commercial curing operation, it means that you keep large stocks of bacon that are in the process of curing.
Dr. Polenske’s goal with the 1891 article was not to unlock the chemistry of curing but “to determine to what extent the nutritional value of beef was affected by brine over different periods of time.” He set up the experiment using three jars of beef with brine. (Polenske, E. 1891)
The containers were sealed for 3 weeks, 3 months and 6 months respectively, before they were opened and the content analysed. The nutritional value was determined by measuring the nitrogen (stickstoffsubstanz) and the phosphoric acid (Phosphorssaeure) components. The brine was a mixture of salt, saltpeter and sugar. (Polenske, E. 1891)
When testing the brine, he found that nitric acid (Salpetersaeure; HNO3) was reduced through “the microorganisms induced reduction” to nitrous acid (Salpetriger Saeure; HNO2) and ammonial (ammonia). (Polenske, E. 1891) (5) Note the presence of nitrite in nitrous acid (NO2).
I approached the South African meat scientist, Dr. Francois Melette, for comment on the nature of the experiment. He observes that “the way the experiment was set up meant it was not possible for Dr. Polenske to determine if the nitrites were released from the proteins. He did the chemical analysis on the cover brine and the meat at the end of the period.” In the end, Dr. Polenske’s experimental design made it difficult to draw conclusions. (private correspondence with Dr. Melette, 2017).
Dr. Polenske postulated that nitric acid, which forms when saltpeter dissolves, dissociates into potassium and nitrate ions and the nitrate ions react with hydrogen ions from the water to form nitric acid; that bacterial reduction change the nitric acid into nitrous acid and ammonia. There is, however, another possible source for the nitrites namely from the meat proteins itself. Dr. Melette explains that “the protein that are broken down yields NH3/NH4 and free PO4 from ATP/ADP and IMP. Traditional Spanish and certain Italian products made with salt only, also cures. This is due to the break down of amino groups from the protein to NH3/NH4, that are aerobically changed into NO2 and then NO3. The microbiological NO reduced product from meat origin reacts with the myoglobin meat pigment to yield the cured colour.” (6) (private correspondence with Dr. Melette, 2017) The time that it takes for this to happen means that in Dr. Polenske’s experiment it would not have plaid a role, but the possibility did not form part of the experimental design.
The interesting question that now comes up is if bacterial reduction of nitrates to nitrites was something that Dr. Polenske speculated about, or was this process generally known by 1891.
It was indeed well known by 1891. Gayon and Dupetit introduced the term denitrification 1883 and in 1886, managed the isolation in pure culture of two strains of denitrifying bacteria. The discovery followed on the discovery of Jean- Jacques-Theophile Schloesing (1824-1919) and Charles-Achille Müntz (1846-1917), when they correctly identified nitrifying bacteria in 1877 in the soil and the importance of identifying denitrifying bacteria, as in the case of nitrifying bacteria, was firstly in terms of its application in agriculture. (Payne, 1986)
W. J. Payne from the Department of Microbiology, University of Georgia, tracked the fascinating historical record of this discovery in a brilliant review article entitled, 1986-centenary-of-the-isolation-of-denitrifying-bacteria. (Click on the title to access the full article. I recommend reading this most fascinating chronology of discovery by a rich cast of characters.) Dr. Polenske undoubtedly drew on this knowledge when he wrote that the formation of nitrites and ammonia from saltpeter is achieved through a “microorganisms induced reduction.”
He immediately saw the controversial nature of his discovery and wrote that “since the same decomposition products (in particular nitrous acid; HNO2) are also found in the cured meat it is likely that this subject matter will receive sharp comment.” He referred to the fact that the presence of nitrite in drinking water was a matter of great concern in the 1890’s and was even reported on in weekly newspapers. The same is true today, but it is kept so well under control that nitrite levels in drinking water are no longer a point of public consideration. He clearly recognised the controversial nature of his discovery that, what was perceived as a poison, was found in cured meat and curing brines. (Polenske, E. 1891)
He further observed that “values indicate that the ammoniac (Ammmoniak) and nitrous acid (Salpetriger Saeure; HNO2) content of the brine increases with age.” (Polenske, E. 1891) As we noted, he could not have known if this was from the saltpeter of the proteins, but his observed that nitrites was present in the brine and meat, makes this 1891 article the first step to a full understanding of the curing reaction which resulted in our modern method of bacon production.
Unlocking the secrets of Saltpeter
We are so far removed from the time when saltpeter was used that it is useful to briefly look at what it was and how its chemical composition was unraveled. I relied heavily on a few authoritative works on the subject, but freely quotes from a brilliant and detailed review article, written by Richard P. Aulie, boussingault-and-the-nitrogen-cycle outlining the chronology of the discovery of the nitrogen cycle by focusing on the work of the prolific French chemist, Boussingault, published in the Proceedings of the American Philosophical Society, Vol. 114, No. 6 in 1970. (The entire article is accessed by the link and readers are encouraged to take the time to study this article thoroughly).
For many years we did not know what saltpeter is composed off. We knew what one could do with it. It is a salt that is used for explosives, meat curing, to fertilize crops, cool beverages and by the late 1800’s, even as a treatment for blood pressure. In many regards, saltpeter was the subject of an arms race between nations in the middle ages as they jostled for superiority in matters pertaining to ammunition and agriculture. Saltpeter was the key ingredient in both these.
By far the largest natural deposits were found in India (potassium nitrate) and the East Indian Companies of England and Holland were in large created to facilitate its acquisition and transport. Later, massive deposits of sodium nitrite were discovered in the Atacama Desert of Chili and Peru and became known as Chilean Saltpeter.
At a few places, some peoples of the ancient world cured their meat with saltpeter and enjoyed its reddening effect, it’s preserving power and the amazing taste that it gave. It was, however, not widely used until the 1700’s when it became more commonly used and by 1750, its use was probably universal in curing mixes.
These ancients could not tell if saltpeter occurred naturally or was it something that had to be nourished or cultivated by humans. Both occurred. It was found naturally and the technology of producing it became common knowledge among farmers in Germany. Generally, when the ancients managed to get hold of it, they wondered how to take the impurities out of the salt which gave inconsistent results in curing meat, fertilising fields and in the quality of gunpowder produced from it.
People were baffled by its power. Almost every great civilization used it in one way or the other. Romans used it to cure meat as early as 160 BCE. The Chinese and Italians used it to make gunpowder. There is a record of gunpowder being used in India as early as 1300 BCE, probably introduced by the Monguls. It was used since ancient times as medicine and as fertilizer. (Cressy, David, 2013: 12) Saltpeter was used in ancient Asia and in Europe from the 1500’s to cool beverages and to ice foods. (Reasbeck, M: 4) The first reported references to the characteristic flavor of cured meat produced by the addition of saltpeter during meat preservation and curing were made as early as 1835. (Drs. Keeton, et al; 2009) Some speculated that it contained the Spiritus Mundi, the ‘nitrous universal spirit’ that could unlock the nature of the universe! (Cressy, David, 2013: 12)
Peter Whitehorney, the Elizabethan theorist who wrote in 1500’s, said about saltpeter, “I cannot tell how to be resolved, to say what thing properly it is except it seemeth it hath the sovereignty and quality of every element”. Paracelsus, the founder of toxicology who lived in the late 1400’s and early 1500’s said that “saltpeter is a mythical as well as chemical substance with occult, as well as material connections.” The people of his day saw “a vital generative principle in saltpetre, ‘a notable mystery the which, albeit it be taken from the earth, yet it may lift up our eyes to heaven’” (Cressy, David, 2013: 12)
From the 1400’s to the late 1800’s scientific writers probed the properties of this magical compound. “Saltpeter encompassed the “miraculummundi”, the “materialuniversalis” through which ‘our very lives and spirits were preserved. Its threefold nature evoked ‘that incomprehensible mystery of … the divine trinity,’ quoting Thomas Timme who wrote in 1605, in his translation of the Paracelsian Joseph Duchesne. “Francis Bacon, Lord Chancellor and Privy Councillor under James I, described saltpeter as the energizing “spirit of the earth.”” (Cressy, David, 2013: 14)
From as early as the mid-1600’s, important observations started to emerge about saltpeter but without any real experimental basis. Some of these conclusions were based purely on speculation but were remarkably accurate. Johan Rudolph Glauber (1604-1670) detected it in plants, animals, and soil in 1658 . He speculated on the chemical relationships that bind them together. Despite the fact that he did not do many experiments on plants, he suggested the efficacy of saltpeter in plant nutrition. He called it “the Universal Menstruum,” since by it, “he wrote. .. every pure Sand destitute of all fatness is quickly so fatted . . . we affirm that the Salt-Petre was of necessity in the Herbs, & Grass, afore the Beasts feeding on them ….” (Aulie, R. P.; 1970: 440)
In 1676 Edme Mariotte (1620-1684) quite brilliantly speculated about the role of the atmosphere in plant nutrition, despite not having any experimental basis for his speculation. He correctly stated that “these volatile salts, etc., are mixed in the air with aqueous vapors, etc., and fall again with the rain formed with these vapors onto the surface of the ground. There they penetrate together as far as then roots of plants, where they enter with some particles of soil…” (Aulie, R. P.; 1970: 440)
From the earliest times, the study of saltpeter was done concurrently with a study in fertilisers and explosives. Beginning with the work of John Woodward (1665 – 1728) of the Royal College of Physicians, the speculation on saltpeter and fertilisers of the 17th century ended and made way in England for a much more practical approach to agriculture. The French chemists, like Boussingault, took up the challenge of rigorous scientific research on the subject.
Another French Chemist, Louis Lemery (1677-1743), “showed for the first time that saltpeter is of organic origin and that it cannot be considered a mineral. In his 1717 paper, “On the Origin of Nitre,” he described its slow production in the superficial layers of the soil. He also recognized the reciprocal relationships that characterize plants, animals, and the soil, while denying the previous “nitro-aerial matter.” (Aulie, R. P.; 1970)
There is an interesting reason behind the changes in focus between the English and the French. England gained access to the saltpeter fields in India reducing the national priority of understanding it in order to manufacture it. The French, on the other hand, never had access to natural saltpeter and it had to find better ways of producing it in order to satisfy the demand of its enormous military and, I am sure, their farmers.
The practical approach of the English to fertilizers became an important backdrop of the future work of the brilliant French chemist Jean-Baptiste Joseph Dieudonné Boussingault (1 February 1801 – 11 May 1887). Boussingault would become one of the most prolific scientists in terms of the research on nitrogen and is rightly credited for laying the foundation for the discovery of the nitrogen cycle. (Aulie, R. P.; 1970)
The next major milestone on the road to the full realization of the role of nitrogen in nutrition was the identification of “nitrogen as a gas in the atmosphere, and as a constituent of both animal and plant tissues”. These occurred in the last quarter of the eighteenth century as a combined achievement of English and French chemistry. (Aulie, R. P.; 1970)
“By 1772 the English pneumatic chemists had isolated “mephitic air,” but they had not yet established its elemental nature. The French quickly saw the importance of the English gas studies and, beginning with Antoine Laurent Lavoisier (1743-1794), rapidly incorporated them into their own work. They invented the names azote and nitrogene for the new gas, established its elemental nature, determined its quantitative percentages in nitric acid, ammonia, and saltpeter, and began to detect les azotates de potasse in many plants, all before the close of the eighteenth century.” (Aulie, R. P.; 1970)
The chemical elements of potassium, nitrogen, and oxygen as constituents of saltpeter were identified even though there remained uncertainty about the exact ratio of atoms. The value of nitrogen in plant and animal nutrition was elucidated by scientists, particularly by Boussingault. His work laid the foundation for the discovery of the role of microorganisms in fixation of nitrogen as well as the reduction of nitrates to nitrite and ammonia.
The next few years saw scientists and in particular, Boussingault, starting to understand the value of nitrogen in plant and animal nutrition. A key question that had to be answered was the source of the nitrogen. One of the possible sources that was still being looked at with great interest was atmospheric nitrogen. Another, more obvious source, at this time, due to the long and well documented use of saltpeter, was nitrates.
Boussingault turned his attention in 1855 to conducted research on nitrates as a source of plant nitrogen. This naturally led him to inquire how they are formed in the soil. He asked the question “if nitrates and ammonium salts are interchangeable in the soil, and which is the more efficacious; is one or the other actually the form in which nitrogen is absorbed by plants? Furthermore, did nitrates act essentially like alkali salts because of their sodium or potassium content, or like ammoniacal salts?” (Aulie, R. P.; 1970)
“Beginning with Boussingault in 1855, various workers attempted to settle these questions with the view of determining how plants get their nitrogen. These essentially chemical attempts continued until the late 1870’s, when the modern biochemical interpretation began to emerge. Kuhlmann thought that nitrates were formed by the oxidation of ammonia in the soil. As a corollary to this view, he also maintained that the utility of nitrates was due to their deoxidation into ammonium compounds in the soil. Noting the constant association of organic materials with nitrification, although, to be sure, missing the importance of microorganisms, he went on to assert that putrid fermentation was a necessary condition for this nitrification.” (Aulie, R. P.; 1970)
“In the spring and summer of 1855, Boussingault examined this hypothesis by investigating the influence of potassium on Helianthus argophyllus, or the sunflower. He wished first to test whether putrescible organic material in the soil was absolutely indispensable for the absorption of the nitrogen of nitrates, and second, to determine whether there was a prior transformation into ammonium compounds.” (Aulie, R. P.; 1970)
“The first part of this hypothesis was easy to test, which he did, by using an artificial soil free of all organic materials. In his first experiment, he reported to the Academie that his sunflowers flourished in a soil composed of calcined sand and ash, when watered with a solution containing 1.11 grams of potassium nitrate (saltpeter).” (Aulie, R. P.; 1970)
“He showed that all the nitrogen could be accounted for by the potassium nitrate (saltpeter). Although Boussingault could not then test for the nitrate “ion,” the contemporary ideas of “equivalents” allowed him to determine the relative proportions of nitrogen and potassium both in the soil and in his experimental plants. At the time he began his nitrate work, there was still confusion about the number of atoms that would combine to make a compound. But chemical equivalents were directly measurable, and this concept Boussingault readily used to good advantage, as did many chemists of his day. Dictionaries and texts gave the composition of potassium nitrate as KO,AzO5.146.” (Aulie, R. P.; 1970)
Boussingault reasoned that by determining the ratio of alkali to nitrogen in his test plants, and comparing this figure with the known value for niter, he would be able to draw a conclusion with respect to its possible prior transformation in the soil. The data show that the action of potassium nitrate was manifest in the absence of decomposing organic material. But did the nitrogen enter as a nitrate or as ammonia? The answer to this question depended on the ratio of potassium to nitrogen in the soil.” (Aulie, R. P.; 1970)
“Boussingault considered his figures close enough to warrant the conclusion that potassium nitrate was absorbed as such by each equivalent of potassium, at least in this experiment, without prior transformation in the soil. Transformation into an ammonium salt prior to absorption would have resulted presumably in different analytical results, owing to the escape of volatile ammonia. His control plant languished in the absence of potassium nitrate; a slight increase in nitrogen he attributed to a visible cryptogamic contamination.” (Aulie, R. P.; 1970)
“From the beginning of his career, Boussingault was aware that nitrogen was far from the only useful element in plant nutrition. As early as 1841 he was “certain that many calcium and mineral salts are indispensable for the development of plants.” His work on nitrates in the late 1850’s was an experimental confirmation of his earlier views. Having demonstrated qualitatively in 1855 with Helianthus the pronounced growth that results with a regimen of potassium nitrate (saltpeter), Boussingault in 1857 then went on to demonstrate the quantitative effects produced in this plant by both mineral and nitrogen components of fertilizer on the elaboration of organic materials.” (Aulie, R. P.; 1970)
Saltpeter, nitrogen and its role in plant and animal, including human nutrition, the nitrogen cycle, nitrifying and denitrifying bacteria are all integrally connected fields of study. It encompasses chemistry, biochemistry, bacteriology, nutrition, medicine and meat science and even today the various complex mechanisms associated with its efficacy as fertiliser and curing agent is not fully understood by science.
Another interesting link between Polenske and Boussingault is the way in which Polenske sought to determine the nutritional value of cured beef. He looked at amongst other, the nitrogen content. This had its origin in work done by Boussingault and Magendie.
“Franqois Magendie (1783-1855) reported in a classic study in 1816 that dogs could not survive on a diet of non-nitrogenous food alone. He wrote that “It would be of fundamental importance in the history ofnutrition,if the source could be determined of the nitrogen which is found in such great abundance in the animal body”. It was this study of Magendie that gave Boussingault the “clue on which he promptly acted in his first research work. This clue was the identification of nitrogen as an important ingredient in animal diet.” It was on the basis of this work that Dr. Polenske wrote his 1891 article, examining the nutritional value of cured beef by focussing on its nitrogen content. The obvious loss of nitrogen in the curing process caused him to view cured meat as inferior to fresh meat. (Aulie, R. P.; 1970) Even today, it is a recognised fact that nitrogen is an important ingredient in a healthy diet.
Conclusion
Saltpeter’s mysterious composition was unlocked by Lavoisier and his contemporaries. This, together with discoveries in the 1880’s about the conversion of nitrite to nitrate and nitrate to nitrite by ground and water bacteria lead to Dr. Polenske’s remarks that nitrite is created through bacterial action from saltpeter (potassium nitrate) in curing brines and cured meat. This simple discovery later precipitated an avalanche of academic discoveries about nitrate, nitrite, nitric oxide and the mechanisms behind curing.
Indian Saltpeter was widely used in brine mixes around the world by the second half of the 1800’s. One such recipe from an American newspaper gives the make-up of a popular brine mix as fifteen pounds of salt, two and one-half ounces of crude East Indian Saltpeter and ten gallons of water with three-quarters of molasses. The meat is emerged in this mix and cures in between forty to forty-five days, ready for smoking. (Shenango Valley News (Greenville, Pensylvania), 26 January 1883, page 3)
Butchers are very observant people and I am convinced that they were aware of the change of nitrate to nitrite and the probability that it was nitrite doing the curing, even before Polenske published and before the curing agent was identified as nitrite in the last decade of the 19th century. There are many examples of butchers through the ages being not only knowledgeable of chemical reactions in their trade but also careful students of the latest scientific work associated with anything remotely associated with meat and blood. Dr. Polenske’s work is indeed the first important scientific work that resulted in our modern way of curing meat by the use of sodium nitrite.
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(c) eben van tonder
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Notes:
(1) A survey was done in the US in the 1950’s to determine the most common brine mix used for curing bacon at the time. Even though it is 60 years after this letter was presumably written, I include it since methods and formulations in those days seemed to have a longevity that easily would have remained all those years later. The survey was also done among farmers, in an environment where innovation are notoriously slow. (Dunker and Hankins, 1951: 6)
(2) How salty was this bacon in reality? The recipe is used by most US farmers by the 1950’s was 10 lb (4.54kg) salt, 3 lb (1.36kg) of brown sugar, 6 ounces (170g) of black pepper and 3 ounces (85g) of saltpeter. 10 pounds (4.54kg) of this mixture per 100 pounds (45.36kg) of meat.
The total weight of dry spices is therefore 6.07kg of which salt is 74% or 3.4kg. This was applied at a ratio of 3.4kg salt per 45kg of meat or 1 kg salt per 13 kg of meat. Not all salt was absorbed into the meat, but the meat was regularly re-salted during then curing time which means that this ratio would be applied many times over before curing was complete. Compare this with the salt ratio targeted by us in 2016 of 25g per 1kg final product, this means that the bacon made with this recipe would be extremely salty, irrespective of the use of sugar to reduce the salty taste. The bacon would have to be soaked in water first to draw out some of the excess salt, before consumed.
(3) Spelling of his surname varies between Polenski and Polenske. His fathers name was spelled “Polenski.”
(5) Qualitative and quantitative techniques for measuring nitrite and nitrates in food has been developed in the late 1800’s. (Deacon, M; Rice, T; Summerhayes, C, 2001: 235, 236). The earliest test for nitrites is probably the Griess test. This is a chemical analysis test which detects the presence of organic nitrite compounds. The Griess reagent relies on a diazotization reaction which was first described in 1858 by Peter Griess.
Schaus and others put the year of the discovery by Griess as 1879. According to him, Griess, a German Chemist used sulfanilic acid as a reagent together with α-naphthylamine in dilute sulfuric acid. In his first publication, Griess reported the occurrence of a positive nitrite reaction with human saliva, whereas negative reactions were consistently obtained with freshly voided urine specimen from normal individuals. (Schaus, R; M.D. 1956: 528)
(6) “The typical aroma, texture and taste of these products are denatured and deaminated protein skeletons, and some oxidised fat (some of which are very pleasant and called in German “genuss saeure”, “enjoyable” acids, or food acids.” (private correspondence with Dr. Melette, 2017)
References
Aulie, R. P.. 1970. Boussingault and the Nitrogen Cycle. Source: Proceedings of the American Philosophical Society, Vol. 114, No. 6 (Dec. 18, 1970),pp. 435-479
Published by: American Philosophical Society
Cressy, D. 2013. Saltpeter. Oxford University Press.
Cressy, D. Saltpetre, State Security, and Vexation in Early Modern England. The Ohio State University
Crookes, W. 1868/ 69.The Chemical News and Journal of Physical Science, Volume 3. W A Townsend & Adams.
Deacon, M; Rice, T; Summerhayes, C. 2001. Understanding the Oceans: A Century of Ocean Exploration, UCL Press.
Dunker, CF and Hankins OG. October 1951. A survey of farm curing methods. Circular 894. US Department of agriculture
Frey, James W. 2009. The Historian. The Indian Saltpeter Trade, the Military Revolution and the Rise of Britain as a Global Superpower. Blackwell Publishing.
Jones, Osman, 1933, Paper, Nitrite in cured meats, F.I.C., Analyst.
Drs. Keeton, J. T.; Osburn, W. N.; Hardin, M. D.; 2009. Nathan S. Bryan3 . A National Survey of Nitrite/ Nitrate concentration in cured meat products and non-meat foods available in retail. Nutrition and Food Science Department, Department of Animal Science, Texas A&M, University, College Station, TX 77843; Institute of Molecular Medicine, University of Texas, Houston Health Science Center, Houston, TX 77030.
Kocher, AnnMarie and Loscalzo, Joseph. 2011. Nitrite and Nitrate in Human Health and Disease. Springer Science and Business Media LLC.
Lady Avelyn Wexcombe of Great Bedwyn, Barony of Skraeling Althing
(Melanie Reasbeck), Reviving the Use of Saltpetre for Refrigeration: a Period Technique.
Mauskopf, MSH. 1995. Lavoisier and the improvement of gunpowder production/Lavoisier et l’amélioration de la production de poudre. Revue d’histoire des sciences
Newman, L. F.. 1954. Folklore. Folklore Enterprises Ltd.
Polenske, E. 1891. About the loss of nutrional value which the beef suffers by curing, as well as about the changes of nitric acid in the brine. Releases of the Chemical Laboratory of the Imperial Health Office. In German: “Arbeiten aus dem Kaiserlichen Gesundheitsamte , 7. Band, Springer, Berlin 1891, S. 471–474”
Smith, Edward. 1876. Foods. D. Appleton and Company, New York.
The Wichita Daily Eagle (Whichita, Kansas), 3 September 1890, page 5.
Many years ago people used saltpeter to cure meat. I wondered what it was and who was the first to link saltpeter to nitrite formation in curing brine and meat and ultimately the creation of nitric oxide which cures meat. This is the story.
Background
Edward Smith says in his book that “the art of preserving meat for future use, with a view to increase the supply and lessen the cost of this necessary food (meat), is of very great importance to [England] and all the available resources of science are now engaged in it.” (Smith, 1876: 22)
He lists the main ways that this is bring done as “by drying, by cold, by immersion in antiseptic gases and liquids, by coating with fat or gelatin, by heat, salted meat and by pressure.” (Smith, 1876: 22 – 38) All have their benefits and disadvantages and interestingly enough, they are still all being used to this day and unique products have developed around each of these.
Edward Smith says that pork is particularly prized over beef and mutton because of the “taste, but chiefly perhaps [due] to the universal habit among the peasantry of feeding pigs, which has descended from Saxon times. Moreover, there is a convenience in the use of it, which does not exist with regard to beef and mutton, for in such localities the pork is always pickled and kept ready for use without the trouble of going to the butcher, or when money could not be spared for the purchase of meat.” Pigs proved to be an equally prized meat in the new world due to the “ease with which pigs are bred and reared, and the meat preserved, whilst there is great difficulty in obtaining a sufficient number of persons, in a thinly populated country or a small village, to eat a sheep or ox whilst meat is fresh. (Smith, 1876: 59)
“Bacon is made when cuts from the pig is preserved by salt and saltpeter.” (Smith, 1876: 64). This gives bacon its characteristic pinkish/ redish colour, a nice flavour, and it lasts a long time before it tastes “off”.
A typical curing mix that was used during the late 1800 to the middle of the 1900’s for dry cured bacon was a mix of 10 pounds salt, 3 pounds of brown sugar, 6 ounces of black pepper and 3 ounces of saltpeter. They use 10 pounds of this mixture per 100 pounds of meat. (1, 2)
Dr. Ed Polenski (3)
The power of saltpeter is the fact that it contains nitrogen. The two substances that contains nitrogen most familiar to us are saltpeter and ammonia. The nitrogen in saltpeter and ammonia makes it very reactive, giving it an explosive power. In saltpeter it has a particular effect on blood, explaining the fact that it gives cured meat its pinkish/ reddish colour. Nitrogen comes into our world through plants that take it from the air and use it as food, thus making it part of the plant’s structure. This is why saltpeter is a great fertilizer.
Dr. Ed (Eduard) Polenski (1849-1911) was a chemists at the Imperial Health Office in Berlin, Germany. He was born in Ratzebuhr, Neustettin, Pommern, Germany on 27 Aug 1849 to Samuel G Polenski and Rosina Schultz. Eduard Reinhold Polenski married Möller. He passed away in 1911 in Berlin, Germany. (Ancestry. Polenske)
The Imperial Health Office was established on 16 July 1876 in Berlin,focusing on the medical and veterinary industry. At first it was a division of the Reich Chancellery and from 1879, fell under the Ministry of the Interior. In 1879, the “Law concerning the marketing of food, luxury foods and commodities” was adopted, and the Imperial Health Office was tasked with the responsible for monitoring compliance with it. Established in 1900, the Reichsgesundheitsrat supported the Imperial Health Office in its tasks. (Wikipedia. Kaiserliches Gesundheitsamt)
In 1891 Dr. Polenski made a remarkable discovery when he discovered nitrite in the brine and the meat (4). The next few years saw this knowledge being harnessed by industry and advanced upon by science as they worked out that it is indeed the nitrite doing the curing work (through NO) and developed methods of accessing nitrite directly in curing brines. This sped up curing from 21 days to curing in a few hours. On farms, long curing is less of a problem, but for a commercial curing operation, it means that you keep large stocks of bacon that are in the process of curing.
In an experiment Dr Ed mixed saltpeter and salt as his curing brine. He tested for nitrite. (5) Nitrite and saltpeter are closely related, but it is has different properties. Saltpeter is sodium or potassium or calcium, combined with nitrogen and three oxygen atoms with an extra electron, called nitrate. Nitrite is the same as nitrate, but it lacks one oxygen atom.
He had a hunch about nitrate after work that was recently done in the 1880’s on conversion of nitrates to nitrites in soil and water through bacteria. He tested for nitrite in the brine and meat and there was nothing present.
He then left the brine and the meat in brine for a week. The meat started curing as expected. He again tested for nitrite and as he suspected, nitrite was present.
What is Saltpeter?
For many years we did not know what saltpeter is composed off. We knew what one could do with it. It is a salt that is used for explosives, meat curing, to fertilize crops, cool beverages and lately even as a heart medicine.
At a few places, some peoples of the ancient world cured their meat with saltpeter and enjoyed its reddening effect, it’s preserving power and the amazing taste that it gave. It was however, not widely used until the 1700 when it became more widely used and by 1750, its use was probably universal in curing mixes.
These ancients could not tell if saltpeter occurred naturally or was it something that had to be nourished or cultivated by humans. When they managed to get hold of it, they wondered how to take the impurities out of the salt which gave inconsistent curing results.
People were baffled by its power. Almost every great civilization used it in one way or the other. Romans used it to cure meat as early as 160 BCE. The Chinese and Italians used it to make gunpowder. There is a record of gunpowder being used in India as early as 1300 BCE, probably introduced by the Monguls. It was used since ancient times as medicine and as fertilizer. (Cressy, David, 2013: 12) Saltpeter was used in ancient Asia and in Europe from the 1500’s to cool beverages and to ice foods. (Reasbeck, M: 4) The first reported references to the characteristic flavor of cured meat produced by the addition of saltpeter during meat preservation and curing were made as early as 1835. (Drs. Keeton, et al; 2009)
One magical substance achieved all these amazing results, saltpetre! Some speculated that it contained the Spiritus Mundi, the ‘nitrous universal spirit’ that could unlock the nature of the universe!
Peter Whitehorney, the Elizabethan theorist who wrote in 1500’s said about saltpeter, “I cannot tell how to be resolved, to say what thing properly it is except it seemeth it hath the sovereignty and quality of every element”. Paracelsus, the founder of toxicology who lived in the late 1400’s and early 1500’s said that “saltpeter is a mythical as well as chemical substance with occult as well as material connections.” The people of his day saw “a vital generative principle in saltpetre, ‘a notable mystery the which, albeit it be taken from the earth, yet it may lift up our eyes to heaven’” (Cressy, David, 2013: 12)
From the 1400’s to the late 1800’s scientific writers probed the properties of this magical compound. “Saltpeter encompassed the “miraculum mundi”, the “material universalis” through which ‘our very lives and spirits were preserved. Its threefold nature evoked ‘that incomprehensible mystery of … the divine trinity,’ quoting Thomas Timme who wrote in 1605, in his translation of the Paracelsian Joseph Duchesne. “Francis Bacon, Lord Chancellor and Privy Councillor under James I, described saltpeter as the energizing “spirit of the earth.”” (Cressy, David, 2013: 14)
“Robert Boyle who did experiments trying to understand saltpeter found it, ‘the most catholic of salts, a most puzzling concrete, vegetable, animal, and even mineral, both acid and alkaline, and partly fixed and partly volatile. The knowledge of it may be very conductive to the discovery of several other bodies, and to the improvement of diverse parts of natural philosophy” (Cressy, David, 2013: 14)
Saltpere is found around the world, but nowhere in bigger and better volumes and quality as in India. Here they mined saltpeter from the earth and thousands of small villages are engaged in its production. (Crookes, W. 1868/ 69: 153) In countries such as these, with a warm climate and high rainfall, “ammonia resulting from the putrefaction and decay of nitrogenous materials is washed into the soil by rainfall, to be oxidized by bacteria, yielding nitrate. . . In India, saltpeter is leached from the ground as sheets of water left by monsoon flooding evaporate. A crust of saltpeter, including mineral salts, spreads across the ground, and can be dug up and refined into pure potassium nitrate.” (Frey, James W. 2009)
It was this vast quantities of Indian saltpeter and the European and English desire to get their hands on it that resulted in the establishment of the East Indian Companies in England and Holland. The Dutch East Indian Company, in turn, established Cape Town and in a way, we can say that Cape Town exist because of the saltpeter trade. It was in the first place not used to cure meat, but in the production of gunpowder and as a fertiliser to increase crops to feed the ever growing population of the world. It was the arms-race of the 16th 17th and early 18th century and the desire of all great nations.
Its not only mined from the earth, but it also grows like fungus on the walls of cellars and around toilets. (Drs. Keeton, et al, 2009: 6) (6) It seems as if it occurs wherever urine and dung occurs such as in bat caves. Peter Whitehorn, the Elizabethan theorist said that saltpeter ‘is a mixture of many substances, gotten out of fire and water of dry and dirty ground.’ “It could sometimes be found as an efflorescent or ‘flower that growth out of new walls, in cellars, or of that ground that is found loose within tombs or desolate caves where rain can not come in.’ But saltpeter could also be nourished or encouraged to grow by adding ‘the dung of beasts’ to the earth. A distinction was made between ‘natural saltpeter’ which only needed to be scraped from walls, and ‘artificial saltpeter’, which required digging and refinement. The two kinds ‘partook of the very same virtue’ (according to Whitehorn, relaying Biringuccio) except that some /beasts, converted into earth, in stables or in dunghills of long time not used”. (Cressy, David, 2013: 16)
In Germany they developed technology whereby they created their own saltpeter. The average German farmer was so skilled in its production that Germans authors, writing about it did not even bother to give the detail of its production. The German method centered around the use of niter beds (managed heaps of vegetable matter mixed with excrete and dung) created by farmers from which niter rich material was removed and saltpeter extracted.
The best description of its production in Europe from the mid to late 1500’s came to us from Lazarus Ercker (1530-1594), chief master of the mines of Emperor Rudolph II in Bohemia. He wrote arguably the most detailed account on the production of saltpeter in ‘The right and most perfect way of the whole work of saltpetre’. A German translation appeared in Prague in 1574 and in Frankfurt in 1580. (Cressy, D. Saltpetre, State Security, and Vexation in Early Modern England: 5)
Still, despite the impact of the renaissance and tremendous advances in fields of biology and the natural sciences, people could only appreciate saltpeter by what it did without any understanding of how it worked. (Cressy, D. Saltpetre, State Security, and Vexation in Early Modern England: 5)
In the late 1770’s a chemical instructor said about saltpeter, “‘we are much in the dark as to the origin and generation’ of saltpeter, though we knew it to be ‘found among earth and stone that have been impregnated by animal and vegetable juices susceptible of purification, and have long been exposed to air. . . . It is the product of the elements deposited in the bosom of the earth, and may not be improperly called the universal and unspecific mercury”. (Cressy, David, 2013: 14)
“Written knowledge of saltpeter filtered into England in 1540 with Vannoccio Biringuccio’s De la pirotechnia. This work was eventually translated into English and included accounts of the making of explosives. (Cressy, David, 2013: 14) Saltpeter being one of the main ingredients in gunpowder.
In England they harvested saltpeter earth and extracted it from the niter enriched soil. Saltpetermen scoured the English countryside and dug up any place where the ground could have been impregnated with animal and human urine and dung. Saltpetermen received authority from the king to dig up any soil from which saltpeter could be extracted to the great frustration of the people of England. Their work and the irritation it brought to the English people became a political issue during the time when England was a monarchy and after the civil war. Dove coves or pigeon houses were favourite sites because of their concentration of the sheltered droppings. “A skilled prospector would know how to soil rich saltpeter for ‘by the taste of the tongue it may be felt if it be biting, and how much”. (Cressy, David, 2013: 16)
In 1588 a man by the name Lucar wrote in Collequies Concerning the Art of Shooting in Great and Small Peeses of Artillerie, ““digging the earth out of floors in cellars, vaults, stables, ox-stalls, goat or sheep cotes, pigeon house, or out of the lowermost rooms in other houses.” This reflect the practice in Tudor England’s roving saltpetermen.” (Cressy, David, 2013: 17)
Barrels full of dung rich earth would be set on a framework so that water introduced at the top would trickle down to a catchment tube at the bottom. Further refinement took place through filtration. The whole process would take a week or more. (Cressy, David, 2013: 17)
In general, Europe and England struggled to produce enough saltpeter. After 1850’s the East Indian Company solved the supply problem of Saltpeter by importing it from India where it occurred naturally and was also efficiently produced. (Cressy, David, 2013: 25) Some of the saltpeter were imported in a refined state and some to be refined in England.
Trade in saltpeter from India to London, Amsterdam, Lisbon and Stockholm and Copenhagen dominated. Saltpeter was one of the largest commodities by volume for the Dutch East Indian Company. (Frey, James W. 2009.) (7) Its ships that sailed past our Cape Town brought vast quantities of unrefined saltpeter to be sold to England and European countries.
The state of ignorance as to the workings of saltpeter continued until in France, Antoine Lavoisier wrote in 1777 his groundbreaking works Instruction sur l’établissement des nitrières et sur la fabrication du salpêtre, and Publiée par ordre du roi, par les Régisseurs généraux des Poudres & Salpêtres where the link with nitrogen was made. The breakthrough came in 1770 when he analysed nitric acid and its connection with saltpeter. (Mauskopf, MSH. 1995: 96)
Lavoisier is the father of industrial chemistry. By the time of his death a good understanding of saltpeter’s chemical origin had been achieved. (Mauskopf, MSH. 1995: 116) The mystery was unraveled (8). The mysterious compound – potassium nitrate. It is the nitrate in Saltpeter that Dr. Ed Polenski’s speculated, is turned into nitrite through bacterial action that is ultimately responsible for Nitric Oxide (NO) production and the curing of meat.
Conclusion
Saltpeter’s mysterious composition was unlocked by Lavoisier. This, together with discoveries in the 1880’s about the conversion of nitrite to nitrate and nitrate to nitrite by ground and water bacteria lead to Dr. Polenski’s speculation that nitrite may be created in a mix of saltpeter which is potassium nitrate. He tested for it. His hunch was right. This simple discovery later precipitated an avalanche of academic discoveries about nitrate, nitrite, nitric oxide and the mechanisms behind curing.
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Fact Check
We strive for accuracy and fairness. If you see something that doesn’t look right, contact us at talk2earthwormexp@gmail.com!
(1) A survey was done in the US in the 1950’s to determine the most common brine mix used for curing bacon at the time. Even though it is 60 years after this letter was presumably written, I include it since methods and formulations in those days seemed to have a longevity that easily would have remained all those years later. The survey was also done among farmers, in an environment where innovation are notoriously slow. (Dunker and Hankins, 1951: 6)
(2) How salty was this bacon in reality? The recipe is used by most US farmers by the 1950’s was 10 lb (4.54kg) salt, 3 lb (1.36kg) of brown suger, 6 ounces (170g) of black pepper and 3 ounces (85g) of saltpeter. 10 pounds (4.54kg) of this mixture per 100 pounds (45.36kg) of meat.
The total weight of dry spices is therefore 6.07kg of which salt is 74% or 3.4kg. This was applied at a ratio of 3.4kg salt per 45kg of meat or 1 kg salt per 13 kg of meat. Not all salt was absorbed into the meat, but the meat was regularly re-salted during then curing time which means that this ratio would be applied many times over before curing was complete. Compare this with the salt ratio targeted by us in 2016 of 25g per 1kg final product, this means that the bacon made with this recipe would be extremely salty, irrespective of the use of sugar to reduce the salty taste. The bacon would have to be soaked in water first to draw out some of the excess salt, before consumed.
(3) Spelling of his surname varies between Polenski and Polenske.
(5) Qualitative and quantitative techniques for measuring nitrite and nitrates in food has been developed in the late 1800’s. (Deacon, M; Rice, T; Summerhayes, C, 2001: 235, 236). The earliest test for nitrites is probably the Griess test. This is a chemical analysis test which detects the presence of organic nitrite compounds. The Griess reagent relies on a diazotization reaction which was first described in 1858 by Peter Griess.
Schaus and others puts the year of the discovery by Griess as 1879. According to him, Griess, a German Chemist used sulfanilic acid as a reagent together with α-naphthylamine in dilute sulfuric acid. In his first publication Griess reported the occurrence of a positive nitrite reaction with human saliva, whereas negative reactions were consistently obtained with freshly voided urine specimen from normal individuals. (Schaus, R; M.D. 1956: 528)
(6) Wall saltpeter (calcium nitrate), formed by nitrifying bacteria and found as an efflorescence on the walls of caves and stables, was gathered in China and India long before the Christian era. (Drs. Keeton, et al, 2009: 6)
(7) “BETWEEN 1601 AND 1801, ships made thousands of voyages carrying goods from Asian ports to the primary European markets for East Indian commodities: Amsterdam, London, l’Orient, Copenhagen, Lisbon, and Stockholm. On average, these Indiamen measured 1,000 tons burden, with approximately 2,830 [m.sup.3] of cargo space. Sixteen percent of this cargo space, according to the normal practice of East India captains, consisted of saltpeter–some 452.8 [m.sup.3] of nitrates, weighing 1.6 metric ton” (Frey, James W. 2009)
The British took over the Subah of Bengal from the VOC in 1757. “The subsequent defeat of a VOC expeditionary force at Bedara in 1759, and the British defeat of the Mughals at Buxar in 1764 secured Company control over Bihar and permitted the monopolization of the saltpeter trade. The significance of these events cannot be underestimated. By seizing Bengal, the British exerted mastery over 70 percent of the world’s saltpeter production during the latter part of the eighteenth century.” (Frey, James W. 2009)
(8) One of Lavoisier’s major achievements of the 1770’s (and the one of particular interest to us) : the analysis of nitric acid.” (Mauskopf, MSH. 1995: 96)
“Lavoisier’s chemical discoveries and reformulation, enabled him to delineate the chemical reaction that produced (explosive) gases : between the nitric acid component of saltpeter and the carbon in the charcoal.” (Mauskopf, MSH. 1995: 105)
He wrote the landmark paper in the spring of 1776 “in which Lavoisier demonstrated that nitric acid was a compound of nitrous gas with the portion of the pure air (la portion la plus pure de l’air) by decomposing the acid into these gases and then reconstituting it from them, and asserted for the first time that this “was a constituent of all acids and a principle of acidity” (la portion la plus pure de l’air). (Mauskopf, MSH. 1995: 107)
“Saltpeter is a “borderline” substance between the organic and the inorganic world. Although clearly a neutral salt like other mineral salts, it only seemed to come into existence in the presence of organic substances in a state of decay. There was therefore
a debate in the century before Lavoisier took up the subject over how this substance originated and whether or not vital processes were essential for its formation.” (Mauskopf, MSH. 1995: 108)
“According to Macquer, three theories were current. The oldest one posited a non-vital origin of saltpeter (or at least of nitric acid) in the air. The other two, formulated in the eighteenth century, related nitric acid’s origin to organic processes. Lemery the Younger
postulated a completely organic origin : nitric acid developed in vegetable and animal substances. The theory of Georg Ernst Stahl, was, in a sense, the mean between the other two vis-a-vis organic and inorganic origins; moreover, it offered a chemical analysis
of nitric acid. To Stahl, this acid was a compound of the universal acid (vitriolic) and phlogiston. Although the source of vitriolic acid lay in the ambient air, this acid could only be converted into nitric acid through the agency of organic putrefaction, which liberated
the necessary phlogiston.”
“The origin and chemical nature of the fixed alkali component were only somewhat less obscure than that of nitric acid. “Fixed vegetable alkali” was one of a class of three alkaline substances (the other two were mineral and volatile alkali) that possessed many
common features. Two of these alkalis (vegetable and volatile) were thought to have organic origins while the mineral alkali, or, at least, its principal salt, common salt, was felt to be, in Macquer’s words, “a production of nature, and […] it does not belong to the plant kingdom or the animal kingdom, it is stored in the class of minerals. It is for this reason that we gave his name alkalile iTAlkali mineral” (une production de la nature, & […] il n’appartient ni au règne végétal, ni au règne animal, on le range dans la classe des minéraux. C’est par cette raison, qu’on a donné à son alkalile nom iTAlkali minéral).
. While alkalis, like acids, were distinct chemical substances operationally, they were not yet ontologically separate (nor would they be fully for Lavoisier).” (Mauskopf, MSH. 1995: 108)
“Lavoisier succeeded both in decomposing nitric acid with mercury into its components gases in succession “the rudy, nitrous gas” and then “the portion of the pure air” (la portion la plus pure de l’air) from the calx of mercury which had formed in the meantime and in reconstituting the acid from just these components gases over water. With this analysis, Lavoisier was moving towards a clear differentiation of acids into chemically distinct species (albeit with a common “acidifying principle”, a point also enunciated in this paper for the first time.” (Mauskopf, MSH. 1995: 108)
“By 1777, Lavoisier had reached the conclusion that the traditional (i. e. Macquerian) view of the role of the wood-ash treatment was indeed correct : it was necessary to employ wood-ash preferably both intermixt with saltpeterish earth and as a lessive in that earth’s first purification. His conclusion was based on systematic study of the tamarisk ash used by Parisian saltpetermen ; the crucial tests were of : 1° washed ash mixed with a) mother liquid of raw saltpeter and b) an artificial liquid of “chalk cham loin cloth” (craie de champagne) dissolved in very pure nitric acid; and 2° the same tests using unwashed ash. In the first set of tests, no saltpeter was obtained; the second yielded 7 ounces. Prior to the reports on the tests, Lavoisier had given the results of his analyses of the Parisian ash itself : he had found various salts including «sélénite», «tartre vitriolé» (selenite, tartar vitriolated) , Glauber salt and common salt.
At first surprised at the production of saltpeter in the second set of tests with unwashed ash, Lavoisier soon produced more tests and a chemical explanation : «… il ne m’était pas possible de douter qu’il ne se fût opéré unedouble décomposition en vertu d’une double affinité; que, d’une part, l’acide vitriolique qui entre dans la composition de ces sels ne se fût combiné avec la terre calcaire de l’eau-mère pour former de la sélénite, et que, de l’autre, l’acide nitreux ne se fût emparé de la base alcaline du sel de Glauber et du tartre vitriolé pour former de véritable sal pêtre.» Translate: “it was not possible for me to doubt that he would have made unedouble decomposition under a dual affinity; that, on the one hand, the corrosiveness acid in the composition of these salts was not combined with the ground limestone mother liquor to form selenite, and, on the other, acid nitrous was not captured the alkali and Glauber’s salt to form tartar Vitriolated real sal Petre”
As confirmation, Lavoisier combined the mother liquids of « very pure » niter with solutions of vitriolated tartar and other vitriolates. In all cases, selenite and a niter of whatever base of the vitriol were formed. He concluded :« // est évident, d’après tout ce qui vient d’être dit, que les cendres qu’on emploie dans la fabrication du salpêtre ne servent pas seulement en raison de la partie alcaline qu’elles contiennent à nu; qu’elles agissent encore en raison de la partie alcaline qu’elles contiennent dans un état de neutralité, et combinée avec l’acide vitriolique. Ainsi, peu importe qu’on emploie, pour décomposer l’eau-mère et pour la convertir en vrai salpêtre, un alcali fixe à nu, ou un sel vitriolique à base d’alcali; l’effet est le même, et l’acide nitreux, dans les deux cas, va chercher de préfé rence l’alcali contenu dans le sel, et en déloge l’acide vitriolique. » Translated: Is clear from all that has been said, that the ashes that employed in the production of not only serve saltpetre because they contain the alkaline part exposed; they act yet because of the alkaline part in a state that they contain neutrality, and combined with the vitriolic acid. Thus, regardless of we used to split water mater and to convert it into real saltpeter, alkali fixed bare or vitriolic based salt alkali; effect is the same, and nitrous acid, in each case, pref fetches ence alkali content in salt, and removes the vitriolic acid.” (Mauskopf, MSH. 1995: 112, 113)
References
Cressy, D. 2013. Saltpeter. Oxford University Press.
Cressy, D. Saltpetre, State Security, and Vexation in Early Modern England. The Ohio State University
Crookes, W. 1868/ 69.The Chemical News and Journal of Physical Science, Volume 3. W A Townsend & Adams.
Deacon, M; Rice, T; Summerhayes, C. 2001. Understanding the Oceans: A Century of Ocean Exploration, UCL Press.
Dunker, CF and Hankins OG. October 1951. A survey of farm curing methods. Circular 894. US Department of agriculture
Frey, James W. 2009. The Historian. The Indian Saltpeter Trade, the Military Revolution and the Rise of Britain as a Global Superpower. Blackwell Publishing.
Jones, Osman, 1933, Paper, Nitrite in cured meats, F.I.C., Analyst.
Drs. Keeton, J. T.; Osburn, W. N.; Hardin, M. D.; 2009. Nathan S. Bryan3 . A National Survey of Nitrite/ Nitrate concentration in cured meat products and non-meat foods available in retail. Nutrition and Food Science Department, Department of Animal Science, Texas A&M, University, College Station, TX 77843; Institute of Molecular Medicine, University of Texas, Houston Health Science Center, Houston, TX 77030.
Kocher, AnnMarie and Loscalzo, Joseph. 2011. Nitrite and Nitrate in Human Health and Disease. Springer Science and Business Media LLC.
Lady Avelyn Wexcombe of Great Bedwyn, Barony of Skraeling Althing
(Melanie Reasbeck), Reviving the Use of Saltpetre for Refrigeration: a Period Technique.
Mauskopf, MSH. 1995. Lavoisier and the improvement of gunpowder production/Lavoisier et l’amélioration de la production de poudre. Revue d’histoire des sciences
Newman, L. F.. 1954. Folklore. Folklore Enterprises Ltd.
Smith, Edward. 1876. Foods. D. Appleton and Company, New York.
Mechanism of meat curing – the wonder of nitrogen
By: Eben van Tonder
4 September 2016
INTRODUCTION
In these articles we examine the mechanics of meat curing so that we can ensure factory conditions and processing steps that favour curing.
In our previous article we set the historical context of our understanding of curing mechanisms as it relates to colour development in cooked cured meat. Here we deal with the reactivity of nitrogen and how it changes into a form that we use in meat curing.
SUMMARY
This article follows the formation of some of the important nitrogen compounds and molecules starting with nitrogen gas in the atmosphere, the formation of nitric oxide, nitrogen dioxide, nitric acid and ammonia. We briefly looks at some of the mechanisms that change nitrogen gas into a usable form for meat curing as well as the reactive nature of nitrogen.
THE REACTIVITY OF NITROGEN
Farmers in the 1880’2 were universally well informed about nitrogen and its value in soil. It is a gas that forms part of our atmosphere. We estimate, at least 4/5th. The rest, roughly 20%, is oxygen. (2) (Marion Record, 1887, p3: About Nitrogen)
An article from the Marion Record in 1887, reminded us that the role and effect of nitrogen in human and animal tissue is relevant, not just to the living but also to pork from which we make bacon. The art of bacon is the art of the manipulation of the properties of meat through nitrogen, sodium and chloride.
The curing of meat revolves around nitrogen and it is helpful to know a bit more about the reactivity of this unique chemical element. It forms the link between fertilizers, food processing and war since the same power fires bullet, provides nutrition to plants and cures meat for future consumption.
NITROGEN GAS (N2)
Nitrogen gas molecule (N2)
Nitrogen was so named by the early chemists as the generator of nitre. Nitre is also called saltpeter.
Nitrogen was independently discovered by two scientists. In 1772, by the Scottish physicist, Daniel Rutherford (Marion Record, 1887, p3: About Nitrogen) and in the early 1770’s by a Swedish chemist, Carl Scheele. “Rutherford named his discovery “noxious air,” because animals were not able to breath in it. Scheele called it “foul air.” (Farndon, J, 1999: 9)
It was Antoine Lavoisier (1743 – 1794) who realized that air was basically a mixture between two gasses, oxygen and nitrogen. He burned mercury in a closed jar and found that a 5th of the air combined with the mercury to form a red powder, mercury oxide. No matter what he did, the rest stayed a gas. Mice died in it and a candle could not burn in it. “Lavoisier decided that air is made of two gases. One, which he called oxygen, was the gas that burned with the mercury. The other he called azote from the Greek for ‘no life.’ It later came to be known as nitrogen, because it can be generated from niter, the common name for sodium or potassium nitrate or saltpeter” (Farndon, J, 1999: 9)
At ambient temperature, the gas, nitrogen, is an inert molecule. It is however one of only two elements that can occur in eight oxidation states, the second one being carbon. (Honikel, 2007)
“The outer shell of five electrons () can take up three additional electrons giving the nitrogen an ‘‘oxidation status’’ as it exists in ammonia () or amines or it can release five electrons forming as it exists in nitrate .” “This is the reason for the variability and wide range of carbon compounds (organic matter) but also for the complexity of nitrogen reactivity. The latter is shown below.” (Honikel, 2007) Below one can see the most important nitrogen compounds in their different states of oxidation.
Oxidation states of nitrogen (Honikel)
It is enlightening to understand one of the ways that nitrogen change from an inert gas to a form that is used as food for plants and from our vantage point, ends up curing meat.
Two of the ways it enters the food chain is through the power of lightning and the small microorganisms. Let’s first look at nitrogen that falls from the skies.
NITRIC OXIDE (NO)
Nitric Oxide (NO)
Nitrogen gas exists as two atoms, tightly bound in one molecule (N2). The bonds between the atoms are so strong that it doesn’t normally react with anything else. Lightning provides enough energy to break these strong bonds which now makes the nitrogen available to react with other elements. (Farndon, J, 1999: 10)
One of these elements is oxygen. When they react, they form nitrogen monoxide (NO). Nitrogen monoxide is a colourless gas, also called nitric oxide or nitrogen oxide. The nitric oxide is heated due to the energy from the lightning flash that created it. (Farndon, J, 1999: 10)
The reaction is written as follows:
N2 (g) + O2 (g) lightning —> 2NO (g)
NITROGEN DIOXIDE (NO2)
Nitrogen dioxide. (NO2)
Other sources of nitric oxide, besides lightning, are certain bacteria and volcanos. (Air Quality Guidelines, 2000: chapter 7). As it cools down, it reacts further with the oxygen molecules around it to form nitrogen dioxide. One nitrogen atom attached to two oxygen atoms forms nitrogen dioxide. “It is a poisonous, brown, acidic, pungent gas”. (Farndon, J, 1999: 12) Nitrogen dioxide is however mainly formed in the atmosphere through it’s a reaction with ozone (O3).
Like nitrogen, oxygen occurs as two oxygen atoms, bound in one molecule. Ultra-violet light and lightning cause the two tightly bound oxygen atoms to separate and react, either with other single atom oxygen molecules or with more stable two atom oxygen molecules. In the latter case, three oxygen atoms are bound into one molecule (O3). (3) (Wikipedia, Ozone) It is not very stable and quickly breaks down into one oxygen atom (O) and or two oxygen atom molecules or it reacts with nitric oxide to form nitrogen dioxide. (Huffman, R. E.; 1992: 210) (Air Quality Guidelines, 2000: chapter 7)
The reaction occurs as follows:
NO (g) + 1/2O2 (g) —> NO2 (g)
NITRIC ACID (HNO3)
Nitric Acid (HNO3)
Nitrogen Dioxide (NO2) reacts with more oxygen and rain drops to form nitric acid (HNO3) which falls to earth and enters the soil to provide nutrients for plants. (Ramakrishna, A.; 2014: 14) Nitric acid (HNO3) is also known as aqua fortis and spirit of niter. (Wikipedia, Nitric Acid)
This puzzling phrase, “spirit of” something seems to have been used generally by chemists when they did not really know what it was. The particular phrase, “spirit of niter” was puzzling to even Robert Boyle in the 1650’s and 60’s. (Rattansi, P.;1994: 66)
The reaction occurs as follows:
3NO2 (g) + H2O —> 2HNO3 (aq) + NO (g)
Nitric acid is highly reactive and combines with salts in the soil, converting it to nitrates which in turn become food for the plants. (Ramakrishna, A.; 2014: 14) It is this reaction of nitric acid with salts that create sodium nitrate or calcium nitrate or potassium nitrate that are used as fertilizer or in gunpowder or to cure bacon.
It has been discovered that curing happens much faster if nitrite is used directly. Bacteria are responsible for changing nitrate to nitrite when it is injected into meat as a curing agent, just as it is done by bacteria in soil. Nitrite (NO2–) is the same as nitrate (NO3–), with one less oxygen atom. By using nitrite directly, curing is accomplished much faster since the reduction to nitrite takes time.
AMMONIA (NH3)
Ammonia (NH3)
Nitrogen comes into our lives from the atmosphere, but despite the fact that “nitrogen oxides trapped in rocks and sediments probably represent a larger total quantity of nitrogen, this nitrogen, for the most part, is not accessible to living organisms.” (Igarashi, Y. and Seefeldt, C. L.. 2003) Most nitrogen enters our world through special bacteria that take nitrogen from the atmosphere and combine it with another important chemical element, hydrogen, to produce ammonia. (www.eoearth.org)
There are many bacteria who achieve this conversion through various means, but a common denominator is that they all use the most interesting enzyme, nitrogenase. It is this enzyme that is responsible for changing N2 to ammonia. The general N2 reduction reaction catalyzed by these enzymes is typically presented as follows:
N2 + 8 e− + 16 ATP + 8 H+ → 2 NH3 + 16 ADP + 16 Pi + H2 (Igarashi, Y. and Seefeldt, C. L.. 2003)
This amazing enzyme has the ability to break apart the very strong N2 molecule and form ammonia. “Ammonia is easily manipulated by biological cells and by converting it into ammonium (NH4+) and other compounds such as nitrate and nitrites.” (Dincer, I. and Zamfirescu, C.; 2011: 706) Interestingly enough, a small amount of ammonia is also produced through pressure and energy from lightning. (Krasny, M. E.; 2003: 46)
Bacteria with this remarkable ability are found in fresh water, soil and in seawater. A few of these bacteria live in a special relationship with plants where both benefits in special ways. The bacteria live in the roots and supply the plant with nitrogen. In turn, the plant supplies the bacteria with sugars and other carbon compounds. Examples of these plants are alfalfa, clover, peas, peanuts and beans. (Krasny, M. E.; 2003: 46)
Ammonium (NH4+) is taken up by the plants and incorporated in amino acids, the building blocks of proteins. When animals or humans eat the plants, the nitrogen is taken up in their bodies in the form of amino acids and proteins. (Krasny, M. E.; 2003: 46)
“Similar to Carbon, organic nitrogen is returned to the atmosphere when plants and animals die and are decomposed. Bacteria first break protein and amino acids back down into ammonium.” The process now becomes complicated as some ammonium is taken up again by plants and used by the plants to build amino acids and protein. Some are broken down further by bacteria into nitrite (NO2–)and nitrate (NO3–). Nitrate (NO3–) itself can be taken up directly by the plants. Some of the nitrate are transformed by bacteria into gaseous nitrous oxide (N2O), nitric oxide (NO), or nitrogen gas (N2), which are released into the air. Some nitrate makes its way into streams, lakes and groundwater. (Krasny, M. E.; 2003: 46)
Conclusion
Nitrate, nitrite, nitric acid and nitrous acid take center stage in our chemical sequence development from nitrite to nitric oxide (NO) which now becomes key in the subsequent articles.
References
Air Quality Guidelines – Second Edition. 2000. Published by the WHO, Regional Office for Europe, Copenhagen, Denmark.
Butcher, S. S.. et al. 1992. Global biogeochemical cycles. Academic Press, Inc.
Dincer, I. and Zamfirescu, C. 2011. Sustainable Energy Systems and Applications. Springer Science + BusinessMedia, LLC.
Farndon, J. 1999. The Elements, Nitrogen. Marshall Cavendish Corporation.
Honikel, K-O. 31 May 2007. The use and control of nitrate and nitrite for the processing of meat products. Science Direct. Meat Science 78 (2008) 68–76. Elsevier Ltd.
Huffman, R. E.. 1992. Atmospheric Ultraviolet Remote Sensing. Academic Press, Inc.
Igarashi, Y. and Seefeldt, C. L.. 2003. Nitrogen Fixation: The Mechanism of the Mo-Dependent Nitrogenase. Article from Critical Reviews in Biochemistry and Molecular Biology, 38:351–384. Robert. Taylor and Francis Inc.
Krasny, M. E.. 2003. Invasion Ecology. NSTA Press.
Langa, S. L.. 1999. The Impact of Nitrogen Deposition on Natural and Semi-Natural Ecosystems. Springer Science+Business Media.
Marion Record, Marion, Kansas. Friday, 15 July 1887. About nitrogen, p3
Ramakrishna, A. 2014. Goyal’s IIT FOUNDATION COURSE CHEMISTRY. Roshan Lal Goyal for Goyal Brothersn Prakashan.
Rattansi, P.. 1994. Alchemy and Chemistry in the 16th and 17th Centuries. Kluwer Academic Publishers.
Mechanisms of Meat Curing – From Hoagland in 1914 to Pegg and Shahidi in 2000.
By: Eben van Tonder
14 August 2016
Ralph Hoagland
BACKGROUND AND OVERVIEW
Managing a meat curing operation in Cape Town at Woodys Consumer Brands (Pty) Ltd., the need exist to have a thorough understanding of meat curing mechanisms to ensure that conditions exist to optimise cured colour development, limit bacterial growth and deliver good product flavour and taste.
In the next three articles we look at colour development. This first article sets the historical context by reviewing the 1914 landmark article by Hoagland; we briefly outline the current understanding of cured colour development from the work of Pegg and Shahidi and we overview one mechanism that has recently been described. Overall, we focus on the importance of nitric oxide (NO) in cured colour development for both fresh and cooked cured meat.
INTRODUCTION
The formation of cured meat colour takes place “by the reaction of nitrite with the natural meat pigment myoglobin to form dinitrosyl ferrochrome (DNFH). The pigment, which gives meat its characteristic cured-meat colour, is formed from the meat pigment myoglobin, which consists of an iron porphyrin complex, the heme group, attached to the protein globin. In the presence of nitrite, the bright red nitrosomyoglobin is formed, in which the H2O in the axial position on the heme iron is replaced by nitric oxide (NO). The NO is formed from nitrite by the natural reducing activity of the muscle tissue, which is accelerated by the addition of reductants such as ascorbic acid. In heatprocessed cured meat, the globin has been split off to a heat-stable pink pigment, nitrosyl hemochromogen.” (Soltanizadeh, N., Kadivar, M.. 2012)
This understanding of curing developed over many years with input from a variety of scientists. (The Fathers of Modern Meat Curing) One of these influential minds was Ralph Hoagland. His brilliance is seen in his academic work that helped to shape the meat curing industry. He had wide appeal in academic and industry circles as well as the popular press. He contributed immensely to the developing sciences of nutrition and meat processing with a special interest in pork processing and pork nutrition.
He was the Senior Biochemist, Biochemie Division, Bureau of Animal Industry, United States Department of Agriculture in Chicago who was, at this time, one of the curing centers of the world along with Denmark and Calne, in the United Kingdom where the Harris operation started.
He served as the department head of the Minnesota College of Agriculture (part of the University of Minnesota), appointed in 1909. The College of Agriculture later became the College of Biological Sciences. (http://cbs.umn.edu/ and The Bismarck Tribune; 1912)
In 1908 he published results obtained upon studying the action of saltpeter upon the colour of meat and “found that the value of this agent in the curing of meats depends upon its reduction to nitrites and nitric oxid, with the consequent production of NO-hemoglobin, to which compound the red color of salted meats is due.” He found that “saltpeter, as such, [had] no value as a flesh-color preservative.” (Hoagland, R. 1914)
In 1914 he published, Colouring Matter of Raw and Cooked Salted Meat. Reviewing this article has two important objectives.
1. It shows what was understood by 1914 about meat curing and colour formation in particular. This has important implication for determining an accurate chronology of developments around the direct addition of nitrite to curing brines, such as the invention of Praganda in Prague in 1915 and later, the introduction of Prague Salt in Chicago (The Naming of Prague Salt) where Hoagland worked for a time.
2. It is a novel way for an introduction into meat curing mechanisms and shows the progression in our understanding.
I interject the thoughts of Hoagland from 1914 with quotes on our current understanding by two of the leading scientists on the subject namely Ronald B. Pegg and Fereidoon Shahidi with quotes from their 2000 publication, Nitrite Curing of Meat.
Ronald Pegg is currently a professor at the Department of Food Science & Technology, University of Georgia. A great piece appeared about him in FST News (from the University of Georgia Department of Food Science and Technology). “He is a researcher who feels equally at home in the classroom and the laboratory. In addition to inspiring students with the chemistry of chocolate and coffee, he’s become one of the nation’s most sought-after experts on the nutrient content of food and the bioactive compounds that make blueberries, peanuts and other nutritionally dense superfoods so “super.” Pegg joined the faculty of UGA in 2006. He immediately saw the need for a more hands-on, practical approach to teaching food chemistry. His work with students has earned him Food Science and Technology Outstanding Undergraduate and Graduate Professor awards five times. Pegg has received a major teaching honor from his department, the college or the university every year since 2007.” “In addition to his time in the classroom, Pegg has received accolades from producer groups for his research into bioactive chemistry and the health benefits of pecans, peanuts, peaches and other crops.” (http://www.foodscience.caes.uga.edu/)
His research and publishing partner in Nitrite Curing of Meat is Fereidoon Shahidi. He is a university research professor at the Department of Biochemistry, Memorial University of Newfoundland St. John’s, Canada. This monumental food scientist “has received numerous awards, including the 2005 Stephen Chang Award from the Institute of Food Technologists, for his outstanding contributions to science and technology. Between 1996 and 2006, Shahidi was the most published and most frequently cited scientist in the area of food, nutrition, and agricultural science as listed by the ISI.” (wikipedia.org/wiki/Fereidoon_Shahidi)
THE COLOUR OF FRESH MEAT
Hoagland starts with the colour pigment of fresh meat, oxyhemoglobin. The word itself tells us what it is. Oxy is oxygen, connected to hem which is hamatin or the colouring group and globin, the protein. In Oxyhemoglobin, ogygen is connected to “hemoglobin, which is the protein molecule in red blood cells that carries oxygen from the lungs to the body’s tissues and returns carbon dioxide from the tissues back to the lungs.” (medicinenet)
Hoagland states that oxyhemoglobin, is “part of which is one of the constituents of the blood remaining in the tissues, while the remainder is a normal constituent of the muscles,” and “responsible for the red color of fresh lean meat, such as beef, pork, and mutton.” (Hoagland, R. 1914) Today we know that the colour of fresh lean meat is due to myoglobin, “the pigment in muscle that carries oxygen” (medicinenet), as opposed to protein in the blood.
The reason for using hemoglobin, instead, may have been “a matter of convenience” and “a matter of necessity since myoglobin was not isolated and purified until 1932,” (Theorell, 1932) a full 18 years after Hoagland published. “In spite of the differences between hemoglobin and myoglobin, Urbain and Jensen (1940) considered the properties of hemoglobin and its derivatives sufficiently like those of myoglobin to allow the use of hemoglobin in studies of meat pigments.” (Cole, Morton Sylvan, 1961: 2)
Despite the fact that it is oxymyoglobin that is responsible for the bright red colour of fresh meat, we follow his arguments using oxyhemoglobin since the same mechanisms of colour development applies in both proteins. Pegg and Shahidi uses myoglobin.
Our current understanding: Oxymyoglobin (Mb, bright red, – ferrous state)
Oxymyoglobin is the result of myoglobin’s affinity for and it results in a bright red bloom within minutes of fresh meat’s exposed to air. The reaction is rapid and reversible. The continued red bloom depends on a “continuing supply of .” (Pegg, R. B and Shahidi, F; 2000: 31) This is “because the enzymes involved in oxidative metabolism rapidly use the available .” (Pegg, R. B and Shahidi, F; 2000: 31)
“With time, the small layer of oxymyoglobin present on the surface of the meat propagates downward, but the depth to which diffuses depends on several factors, such as the activity of oxygen-utilizing enzymes (i.e., consumption rate of the meat), temperature, pH, and external pressure. In other words, as air diffuses inward, an and a color gradient are established throughout the meat. Muscles differ in their rates of enzyme activity which, in turn, regulate the amount of available in the outermost layers of tissue. As the pH and temperature of the tissue increase, enzymes become more active and the content is reduced. Consequently, maintaining the temperature of the meat near freezing point minimizes the rate of enzyme activity and the utilization and helps maintain a bright red color for the maximum possible time.” (Pegg, R. B and Shahidi, F; 2000: 31)
THE COLOUR OF CURED MEAT
Generally, Hoagland saw the cured colour of meat as “the same color as the fresh meat.” (Hoagland, R. 1914) There is a difference between the cured colour of fresh meat and the cured colour of cured-cooked meat. He recognised this difference and said that “the red color is not destroyed on cooking, but rather it is intensified.” (Hoagland, R. 1914)
The nature of these two different kinds of colour is the subject of his article, “undertaken for the purpose of obtaining more complete information concerning the color of raw and cooked salted meats.” (Hoagland, R. 1914)
HISTORICAL BACKGROUND
In his historical summary, he lists the following developments that lead up to his own work.
-> Weiler and Riegel
“Weiler and Riegel (1897), in the examination of a number of samples of American sausages, obtained a red coloring matter on extracting the samples with alcohol and other solvents, which color they concluded to be in some manner due to the action of the salts used in curing upon the natural color of the meat. On account of similarity of spectra, this color was considered to be methemoglobin.” (Hoagland, R. 1914)
Our current understanding: metmyoglobin (metMb, brown, ferric state)
Methemoglobin and metmyoglobin actually is the brown colour of meat which develops after meat has been standing for some time. Myoglobin exists within the interior of meat and has a purple-red colour. “This is the colour of Myoglobin” (Pegg, R. B and Shahidi, F; 2000: 31) Reductants generated within a cell by enzyme activity prevents the meat from turning brown, until this is no longer available. The heme iron (in the ferrous state – ) is oxidized to the ferric state () . (Pegg, R. B and Shahidi, F; 2000: 31)
It is generated as follows. The superoxide anion () is removed from the hematin. A water molecule is added. This gives a high-spin ferric hematin. “The ferric ion, unlike its ferrous counterpart, has a high nuclear charge and does not engage in strong bonding. Therefore, metmyoglobin is unable to form an oxygen adduct. (Pegg, R. B and Shahidi, F; 2000: 31)
-> Lehmann and Kisskalt
Lehmann (1899) identified nitrite as responsible for the red colour of meat and not nitrate. Kisskalt (1899) confirmed this and noted that “if the meat was first allowed to stand several days in contact with saltpeter and then boiled, the red color appeared” (Hoagland, R. 1914)
-> John Scott Haldane
John Scott Haldane (1901) made several important observations after an extensive study of the colour of cooked salted meat.
He attributed the colour of cooked salted meat “to the presence of the nitric oxide hemochromogen” (reduced hematin; Fe in reduced ferrous state, ; obtained by boiling oxymyoglobin/ oxyhemoglobin with a reducing agent). (Hoagland, R. 1914) He correctly concluded that nitric oxide hemochromogen is “resulting from the reduction of the coloring matter of the uncooked meat, nitric-oxid hemoglobin (NO-hemoglobin).” Hemochrome can be any of a number of complexes with the iron-porphyrin complex with one or two basic ligands (normally amines).
The terms nitric oxide hemochromogen, nytrosomyochrome, nitrosyl hemochrome, nitric oxide hemochrome, nitric oxide denatured globin hemochromogen, denatured globin nitric oxide ferrohemochrome, pigment of cured, heated meat, all as synonyms to refer to the same thing. (ICMSF; 1980: 140) Chromogen is a substance which can be easily converted into dye or other coloured compound for example through oxidation. Since the 1940’s, the term “hemochrome” (hem and chrome) has been used instead of “hemochromogen” and “parahematin.” “The term “hemochromogen” is associated historically with an erroneous conception of one of these substances as the colored component of hemoglobin. These compounds are in any case not “chromogens” in the chemical sense, i.e., ieuco compounds. The new term has the additional advantage of greater brevity.” (Lemberg, R. and Legge, J. W.; 1949: 165)
Linossier was the first to describe it and produced it by passing nitric oxide through hematin. (Haldane, J. S.. 1901) After careful study and observation, Haldene drew the following brilliant conclusions.
1. “The red colour of cooked salt meat is due to the presence of NO-haemochromogen.” (Haldane, J. S.. 1901)
2. “The NO-haemochromogen is produced by the decomposition by heat of NO-haemoglobin, to which the red colour of unsalted meat is due.” (Haldane, J. S.. 1901)
3. “The NO-haemoglobin is formed by the action of nitrite on haemoglobin in the absence of oxygen, and in presence of reducing agents.” (Haldane, J. S.. 1901)
4. “The nitrite is formed by reduction within the raw meat of the nitre used in salting.” (Haldane, J. S.. 1901)
5. “The nitrite is destroyed by prolonged cooking.” (Haldane, J. S.. 1901)
Our current understanding: nitric oxide hemochrome (Cooked Cured Meats – one nitric oxide molecule per heme).
When heated, NO-myoglobin (nitrosyl myoglobin) is transformed to nitrosyl myocromogen, which is denatured NO-myochromogen. This happens upon thermal processing. The globin unfolds (denatures); the iron atom comes loose from the globin; the unfolded globin folds itself around the heme functional part (moiety) which is the iron-porphyrin complex. This brings about the characteristic reddish-pinkish colour of cooked cured meat. (Pegg, R. B and Shahidi, F; 2000: 42)
By way of application, note that “there is a direct relationship between the concentration of NO-myoglobin in the muscle and the intensity of the cured colour” and NOT the nitrite level. “When muscle tissue are cured with equivalent amounts of nitrite, a more intense cured meat colour is produced in,” for example, corned beef as opposed to ham. “The addition of excess nitrite to that required to fix the pigment does not increase the intensity of the cured meat colour.” (Pegg, R. B and Shahidi, F; 2000: 42) This being the case, it is also true that if the concentration of nitrite and therefore nitric oxide formation is to low, that it will impact colour development.
He mentions Orlow (1903) who stated that “the red color of sausages is due to the action upon the color of the fresh meat of the nitrites resulting from the reduction of the saltpeter used in the process of manufacture.” (Hoagland, R. 1914)
“Humphrey Davy in 1812 (cited by Hermann, 1865) and Hoppe-Seyler (1864) noted the action of nitric oxid upon hemoglobin, but it appears that Hermann (1865) was the first to furnish us with much information as to the properties of this derivative of hemoglobin. He prepared NO-hemoglobin by first passing hydrogen through dog’s blood until spectroscopic examination showed that all of the oxyhemoglobin had been reduced to hemoglobin, then saturating the blood with pure nitric oxid prepared from copper and nitric acid, and finally again passing hydrogen through the blood to remove all traces of free nitric oxid.” (Hoagland, R. 1914)
By the time of publishing this article in 1914, he notes that NO-hemoglobin was mentioned very briefly in most of the texts on physiological or organic chemistry as being a hemoglobin derivative of “but little practical importance.” “Abderhalden (1911) and Cohnheim (1911), however, describe this compound quite fully.” (Hoagland, R. 1914)
Hoagland conducted several further experiments with NO-hemoglobin and outlined it in his 1914 paper.
COLOUR OF FRESH, CURED MEAT
He first deals with the Colour of Uncooked Salted Meats. “To a sample of finely ground fresh beef was added 0.2 per cent of potassium nitrate, and the material was placed in a refrigerated room at a temperature of 34 deg F (1 deg C) for seven days. At the end of that period the meat had a bright-red color, but gave evidences of incipient putrefaction.” (Hoagland, R. 1914) He did the same by curing the meat with nitrite. He correctly concluded that the colour of fresh meat, cured with nitrite, is due to NO-hemoglobin. (Hoagland, R. 1914)
Our current understanding: nitric oxide myoglobin (NOMb, red, ).
“When nitrite is added to comminuted meat, the meat turns brown because nitrite acts as a strong heme oxidant. The oxidizing capacity of nitrite increases as the pH of meat decreases, but nitrite itself may also partly be oxidized to nitrate during curing and storage. Myoglobin and are oxidized to metMb by nitrite. The ion itself can be reduced to . These products can combine with one another to form an intermediate pigment, nitrosylmetmyogloboin ().” (Pegg, R. B and Shahidi, F; 2000: 40)
“Nitrosylmetmyoglobin is unstable. It auto-reduces with time and in the presence of endogenous and exogenous reductants in the postmortem muscle tissue to the corresponding relatively stable Fe(II) form, nitrosylmyoglobin (NOMb).” (Pegg, R. B and Shahidi, F; 2000: 40)
A new suggestion was proposed as a mechanism for the meat curing process by Killday et al. (1988)
“They suggested that is more adequately described as an imidazole-centered protein radical. This radical undergoes autoreduction yielding NOMb, and lacking exogenous reductants, reducing groups within the protein can donate electrons to the imidazole radical.” (Pegg, R. B and Shahidi, F; 2000: 40)
An interesting study by Corforth et al. (1998) strengthened the mechanism posed by Killday et al. (1988). “Cornforth and co-workers examined the relative contribution of CO and towards pink ring formation in gas oven cooked beef roast and turkey rolls. Data showed that pinking was not evident with up to 149 ppm of CO or 5 ppm of NO present in the burning gases; however, as little as 0.4 and 2.5ppm of was sufficient to cause pinking of the turkey and beef products, respectively. Cornforth et al. (1998) proposed that pinking previously attributed to CO and NO gas in ovens is instead due to which has much greater reactivity than NO with moisture at the surface of meats. Their argument was predicated on the fact that NO has a low water solubility unlike that of . Therefore on the basis of this consideration, NO would be an unlikely candidate to cause pink ring, since at the low levels typical of gas ovens or smokehouses, NO would be unable to enter the aqueous meat system in sufficient quantity to cause pink ring at depths up to 1 cm from the surface. On the other hand, reacts readily with water to produce nitrous and nitric acid.” (Pegg, R. B and Shahidi, F; 2000: 40, 42)
“Nitrous acid produced at meat surfaces would be free to diffuse inwards, where endogenous or exogenous meat reductants, including Mb itself may regenerate NO. Nitric oxide binds to MetMb followed by rapid autoreduction to NOMb as suggested by Killday et al. (1988).” (Pegg, R. B and Shahidi, F; 2000: 42)
NOMb is therefore responsible for the characteristic red colour of fresh cured meat before thermal processing. The NOMb pigment can be produced by the direct action of NO on a deoxygenated solution of Mb, but in conventional curing, it arises from the action of nitrite, as stated above. (Pegg, R. B and Shahidi, F; 2000: 42)
Hoagland’s conclusion in his 1914 article is, however, limited to NO formation and its role in cured colour formation. He states that “the evidence is ample to show that the action of saltpeter in the curing of meats is primarily to cause the formation of NO-hemoglobin ; but it is very possible that under certain conditions of manufacture or processing to which salted meats are subject, the NO-hemoglobin may undergo changes.”
COLOUR OF COOKED, CURED MEAT
“Haldane has shown that the red color of cooked salted meats is due to the presence of NO-hemochromogen, a reduction product of NO-hemoglobin to which the color of uncooked salted meats is due.”… “While Haldane’s work seems to show clearly that the color of cooked salted meats is due to NO-hemochromogen, it has seemed desirable to study the subject further and to determine especially if the NO-hemoglobin of uncooked meats be reduced to NO-hemochromogen under other conditions than by cooking. The fact that in the examination of certain uncooked salted meats a coloring matter had been obtained similar to NO-hemoglobin yet not possessing all of the properties of that compound, as has already been noted, led the writer to believe that the coloring matter of some uncooked salted meats might be due, in part at least, to NO-hemochromogen. NO-hemochromogen is but briefly mentioned in the literature. The compound is described by Linossier (1887), Haldane (1901), and by Abderhalden (1911).” (Hoagland, R. 1914)
“The structural relation between NO-hemoglobin and NO-hemochromogen is simple. NO-hemoglobin is a molecular combination of nitric oxid and hemoglobin—the latter compound consisting of the proteid group, globin, on one hand, and the coloring group, hemochromogen, on the other. NO-hemoglobin and NO-hemochromogen differ from each other simply in that one contains the proteid group, globin, while the other does not. Apparently, then, a method of treatment which would split off the globin group from NO-hemoglobin should result in the production of NO-hemochromogen, provided, of course, that the procedure did not in turn change or destroy the NO-hemochromogen produced. As has already been noted by Haldane, it was found that when a solution of NO-hemoglobin was heated to boiling, a brick-red precipitate formed, in contrast to the dark-brown precipitate which formed on heating a solution of oxyhemoglobin or of blood. The brick-red precipitate was filtered off and was then extracted with alcohol, which gave a lightred colored extract showing a spectrum with a fairly heavy band just at the right of the D line. This spectrum corresponds with that of NO-hemochromogen. On standing, the color of the extract faded rapidly.” (Hoagland, R. 1914)
“The evidence seems to show very clearly that the color of cooked salted meats is due to the NO-hemochromogen resulting from the reduction of the NO-hemoglobin of the raw salted meats on boiling.” (Hoagland, R. 1914)
“It is very probable that in the case of meats which have been cured with saltpeter or of meat food products in which saltpeter has been used in the process of manufacture, the reduction of NO-hemoglobin to NO-hemochromogen takes place to a greater or lesser degree, depending upon conditions of manufacture and storage. The two compounds are so closely allied that their differentiation in one and the same product is not a matter of great importance.” (Hoagland, R. 1914)
Our current understanding: Nitrosylmyochromogen or nitrosylprotoheme.
Upon thermal processing, globin denatures and detaches itself from the iron atom and surrounds the hem moiety. Nitrosylmyochromogen or nitrosylprotoheme is the pigment formed upon cooking , and it confers the characteristic pink colour to cooked cured meats.” (Pegg, R. B and Shahidi, F; 2000: 44)
“Although the Cooked Cured Meat Pigment (CCMP) is a heat-stable NO hemochrome as evident by the fact that it doesnt undergo further colour change upon additional thermal processing, it is susceptible to photodissociation. Furthermolre in the presence of oxygen, CCMP’s stability is limited by the rate of loss of NO.
This effect is important if cured meats are displayed under strong fluorescent lighting while they are also exposed to air. Under these conditions, the surface colour of cured meat will fade in a few hours, whereas under identical conditions, fresh meat will hold its colour for a few days.” “A brownish-gray colour develops on the exposed meat surface during colour fading; this pigment, sometimes called hemichrome, has its heme group in the ferric state. The most effective way of preventing light fading is to exclude contact with the cured meat surfaces. It is routinely accomplished by vacuum packaging the meat in impermiable films. If is absent from the package, NO cleaved from the heme moieties by light cannot be oxidized and can recombine with the heme.” (Pegg, R. B and Shahidi, F; 2000: 44)
CONCLUSION
Hoagland and other researchers from that period laid the foundation to much of our current understanding of meat curing by drawing a distinction between fresh cured meat colour and cooked cured colour. The first detailed mechanism in the development of cured meat colour that started to emerge was through the action of nitric oxide. Pegg and Shahidi stated in 2000 that “to form cured meat pigment, two reduction steps are necessary. The first reduction of nitrite to NO and the second is conversion of NOmetMB to NOMb.” (Pegg, B. R. and Shahidi, F.; 2000: 44, 45)
An interesting side note. Hoagland wondered if it is possible to produce the cooked cured colour of meat in another way than curing with nitrite and heat treatment. Pegg and Shahidi has dedicated much work along similar lines – to identify a curing system that will replace nitrite curing. In meat curing, this has always been the holy grail which on the one hand will in all likelihood remain an unattainable concept and on the other hand, as our understanding of nitrite grows, will be deemed unnecessary.
The chemical reaction sequence from nitrite to NO, leading to the formation of NOMb will be described in the next article.
References:
The Bismarck Tribune (Bismarck, North Dakota); 10 July 1912; page 2.
Cole, Morton Sylvan, “Relation of sulfhydryl groups to the fading of cured meat ” (1961). Retrospective Theses and Dissertations. Paper 2402
Haldane, J. S.. 1901. The Red Colour of Salted Meat. Journal of Hygiene 1: 115 – 122
Hoagland, R. 1914. Cloring matter of raw and cooked salted meats. Laboratory Inspector, Biochemie Division, Bureau of Animal Industry. Journal of Agricultural Research, Vol. Ill, No. 3 Dept. of Agriculture, Washington, D. C. Dec. 15, 1914.
Lemberg, R. and Legge, J. W.. 1949. Hematin Compounds and Bile Pigments. Interscience Publishers, Inc.
Soltanizadeh, N., Kadivar, M.. 2012. A new, simple method for the production of meat-curing pigment under optimised conditions using response surface methodology. Meat Science 92 (2012) 538–547 Elsevier Ltd.
Meat curing has been and remains one of the important industries on earth. Not much has been done to trace its origins from antiquity or to chronicle the developments of the last few hundred years. With the blog, The Earthworm Express, I seek to rectify this in terms of the meat industry in general. Understanding the history of a process enables us to understand our current work better. In relation to meat curing, I transformed the articles dealing with this into chapters for my book on the history of bacon or meat curing. It is the first such attempt I am aware of where a serious effort is made to follow all the salient developments related to curing over centuries and even millennia. I place it within the narrative of friends setting up a bacon company during the closing years of the 1800s and the opening decades of the 1900s. Some may find this format irritating, but it was done in an effort to make the work accessible, and, along with the history of meat curing, dwells on the development of the meat trade generally. I cannot help to add a sizable volume of work to the quest of finding purpose in life as meat curing is an all-consuming passion of my life, and it is not possible to deal with the subject matter and not with life that is as rich and full as the subject matter at hand. The book is Bacon & the Art of Living and is available online.
The Curing Process
A modern understanding of the benefits of curing is that it fixes a pinkish-reddish cured meat colour. It endows the meat with unique longevity, even if left outside a refrigerator, many times longer than that of fresh meat. It is powerful enough to prevent the deadly toxin formation by Clostridium botulinum. It prevents the formation of rancidity in fat. It lastly gives meat a unique cured taste.
What is completely mesmerising in meat curing is that the basic process follows physiological processes essential for human life. The fact that humans stuck, as it were, to the evolutionary playbook in its practice of curing in that it mimics these physiological processes to the smallest details is completely astounding! I will write to you separately about how the basic processes in curing are exactly the processes essential for life that happen every moment in our bodies! Far from a villain that causes health trouble, nitrate, nitrite, and nitric oxide are indispensable molecules to life on earth. Of course, its overuse, in proportions greater than what nature dictates, is extremely unhealthy, as we discussed in Chapter 12.06: Regulations of Nitrate and Nitrite post-1920: the problem of residual nitrite. By and large, meat curing is a safe and essential technique for preserving meat.
A friend from New Zealand, Edward De Bruin shares a booklet with me, Methods of Meat Curing, 1951, US Dep of Agriculture. This image comes from this publication with a slightly different description for the last method being “brine cure – pumped” which makes more sense than dry-cured, pumped. That the latter was indeed a category is clear from within the text where they refer to “dry-curing meat with a home mixture and no previous pumping.”
Discovering the mechanics behind meat curing was a slow process that took hundreds of years. (For an overview of some of the people behind the most important discoveries, see The Fathers of Meat Curing.) A survey of farm curing methods conducted in 1951 by the US Department of Agriculture among farmers in the US revealed the following brining methods used:
Dry cure – no pumping,
Brine cure – no pumping (the use of cover brine),
Brine cure – pumped, and
Dry cure – pumped. (Dunker and Hankins; 1951: 4)
We can add the following to this list from 1951.
Sweet Curing (Stitch Pumping with dry curing and with hot smoking)
Mild Curing (the re-use of cover brine with or without stitch pumping, with or without dry salting)
Pale Dry Bacon (Sweet curing with no smoking, only drying)
The direct use of nitrites in curing brines
Grid or Formed Bacon
For a discussion on the mechanics of curing, please review The Curing Reaction.
Salt Only (Dry cure – no pumping – salt only – using a dry rub or brine)
Exactly where salt curing of meat started is an interesting question. There is ample evidence that salt preservation of meat was done from the earliest of times. Despite the fact that there are records of fish being salt-cured in China going back to 2000 BCE and from Egypt and Mesopotamia, the practice is much older.
Ancients consumed their food raw before it was discovered how to make fire. (How did Ancient Humans Preserve Food?) Even after fire-making was invented and this technology became universally part of human culture, humans only cooked their food intermittently for a very long time. There are cultures to this day that eat raw meat in one form or the other. Besides this, hanging meat to dry in the sun, the wind, or over a fireplace without adding any curing agent such as salt was practised in southern Africa, North America, and Nepal, to mention just a few places that I am personally aware of. It was likely universally practised at some point in the past.
Salt was without question the first curing agent and in all likelihood, salt in the form of seawater. It seems that as people migrated from coastal regions, inland, they developed solar evaporation to extract the salt from seawater along with techniques such as boiling the water off when it became more difficult to access seawater when communities started to settle further away from the coast. It is often claimed that salt did not play a significant role in southern Africa. Nothing could be further from the truth! After a careful investigation of the use of salt for meat preservation in southern Africa, the evidence points to the fact that the power of salt to preserve meat was known by for example the Khoe and the San people, but they preferred to hang meat in the sun and the wind to dry. Still, salt played a significant role in the diets of ordinary people. They understood it and used it! (Salt and the Ancient People of Southern Africa) A direct link can be made to every great civilization that existed in antiquity in the fact that they all knew the value and uses of salt.
China
One of the greatest and oldest civilisations that ever existed (and still exists) is the Chinese! What we know for sure is that salt curing of meat occurred in China from very early on. Flad, et al. (2005) showed that salt production was taking place in China on an industrial scale as early as the first millennium BCE at Zhongba. “Zhongba is located in the Zhong Xian County, Chongqing Municipality, approximately 200km down-river along the Yangzi from Chongqing City in central China. Researchers concluded that “the homogeneity of the ceramic assemblage” found at this site “suggests that salt production may already have been significant in this area throughout the second millennium B.C..” Significantly, “the Zhongba data represents the oldest confirmed example of pottery-based salt production yet found in China.” (Flad, et al.; 2005)
Salt-cured Chinese hams have been in production since the Tang Dynasty (618-907AD). The first records appeared in the book Supplement toChinese Materia Medica by Tang Dynasty doctor Chen Zangqi, who claimed ham from Jinhua was the best. Pork legs were commonly salted by soldiers in Jinhua to take on long journeys during wartime, and it was imperial scholar Zong Ze who introduced it to Song Dynasty Emperor Gaozong. Gaozong was so enamoured with the ham’s intense flavour and red colour he named it huo tui, or ‘fire leg’. (SBS) An earlier record of ham than Jinhua-ham is Anfu ham from the Qin dynasty (221 to 206 BCE).
In the Middle Ages, Marco Polo is said to have encountered salt curing of hams in China on his presumed 13th-century trip. Impressed with the culture and customs he saw, he claims that he returned to Venice with Chinese porcelain, paper money, spices, and silks to introduce to his home country. Polo alleges that it was from his time in Jinhua, a city in eastern Zheijiang province, where he found salt-cured ham. Marco Polo is a controversial figure in that there is great uncertainty if he ever actually undertook the voyages he wrote about. Still, these stories, either first hand from Polo or from someone else who compiled it, the reports certainly had a basis in reality.
The reach of Chinese technology for salt production was impressive. On a trip to New Zealand, I learned that the Māori never developed salt extraction in any form. I did a short review of the colonization of Indonesia and salt extraction technology in an article, “Concerning the lack of salt industry in pre-European New Zealand and other tales from Polynesia and the region.” A brief survey of the history of salt extraction from Fiji, Samoa, New Guinea, Vanuatu, and Taiwan shows the large influence of China on regional salt production technology.
This study also revealed a possible forerunner of more formal salt production around the world, including in China. One of the earliest ways that salt found itself in food preparations was undoubtedly through the fact that seafood was consumed that naturally had added salt which came from the water. Another way would have been if meat was stored in seawater. Immersing carcasses of animals and fish in water would have been one of the earliest forms of preservation and since earliest communities gravitated to coastal regions, salt water would have been used and in addition to seafood which is rich in salt, it would have entered early human culture when food was cooked in seawater. It is likely that carcasses were stored in water at first to hide them from predators and its preserving power would soon have been discovered. Migrating groups would have noticed how seawater preserved meat better and changed (improved) the taste of the meat.
Polynesia
The study of salt in Polynesia shows that as groups migrated inland, away from the sea, saltwater was boiled to evaporate the water and leave the salt as a very basic salt extraction technique. The salt was then traded with the inland communities. This was widely practised in Taiwan until fairly recently. The references to it in Polynesia and Asia offer a suggested progression of the extraction of salt from seawater. Studies from Fiji identified population size, even of coastal communities to be a key driver of salt extraction technology.
It seems that migrants from Taiwan spread their technology throughout the lands of Polynesia. Every evaluation of salt on the islands I looked at supports this. China would undoubtedly have been a key driver in the region in progressing salt extraction technology with Pappa New Guinea playing a large role where a multitude of techniques to extract salt was (and still is) in use. Solar evaporation of seawater, extracting salt through plant material, and burning plants, naturally high in salt are a few of the developments from the region, which all presumably have their roots in the practice of simply boiling seawater; in turn, this was probably a progression of the practice of cooking food in seawater; which, in turn, had its roots in storing meat in saline solutions; which had its roots in simply immersing carcasses in bodies of water for storage. When we are at this point, we are clearly at the very early age of the existence of cognitive modern humans who were cognitively similar to modern humans.
New Zealand
In a discussion with a curator from the Canterbury Museum about the matter of salt production and trade in salt being absent from New Zealand’s ancient history, he drew my attention to the interesting practice of the Maori to slow boil large quantities of shellfish in freshwater. Had they not done so, it would not have been possible to consume large quantities at a time. There seems to be evidence that they did, in fact, consume large quantities of this at a time. It supports the notion that they knew about salt and the possibility exists that this was true across the world from very early. Like the people of southern Africa, people probably knew at least some of the techniques for extracting it, but some local populations, as was the case in New Zealand and many of the southern African populations, may have opted not to use the technology simply because it was not necessary. In the case of the Maori, they definitely knew to remove some of the salt from shellfish before consuming it. They have a word for salt which shows that they definitely knew about its taste. In southern Africa, most would have gotten their salt from meat or milk and when they could only eat plant material, they knew that a bit of salt would cure the ailments which resulted from a lack of salt.
Salt as a condiment
One can not talk about salt curing and not at least make mention of its use as a condiment. Even though too much salt alters the taste negatively, preservation through salt and altering (enhancing) the taste go hand in hand. Evidence is emerging about the use of condiments in food, the earliest discovery so far which dates in Europe going back 6000 years ago in Germany and Denmark. Archaeology magazine (Nov/ Dec 2013) reports that “a team of researchers has found phytoliths, small bits of silica that form in the tissues of some plants, from garlic mustard seeds, which carry strong, peppery flavour but little nutritional value. Because they were found alongside residues of meat and fish, the seed remnants represent the earliest known direct evidence of spicing in European cuisine. According to researcher Hayley Saul of the University of York, “It certainly contributes important information about the prehistoric roots of this practice, which eventually culminated in globally significant processes and events.” (Archeology) Salt would undoubtedly have been part of their arsenal of taste enhancers.
It seems that our relationship with salt has never been static and to this day, it continues to evolve. More importantly, the discoveries in Denmark and Germany bring into focus innovations in the European lands of Germany, Austria, Hungary, the Czech Republic, Switzerland, Denmark, Holland, Belgium, Spain, France, and Poland. Besides these, there is Irland. What was happening in these regions while cities and kingdoms covering Mesopotamia, India, Pakistan, and Nepal were developing salt industries and very sophisticated meat-curing technologies based on salt, nitrate, and sal ammoniac? I am filling in the gaps over the years to come.
The Mechanism of Salt-Curing
For years I never seriously looked at salt-only-curing. Yes, its mechanism is well known, or so I thought! The salt reduced the water in the meat which retards the micro activity and meat breakdown (enzymatic) while L-Arginine slowly oxidises to L-citrulline and nitric oxide and nitric oxide cures the meat.
The booklet that Edward De Bruin, my South African friend living in New Zealand, sent me (Methods of Meat Curing, 1951, US Dep of Agriculture) reported that in a survey done in the early 1950s, it was found that 37 percent of the farmers used dry curing. The curing agent they used was salt only. The author describes it as follows, “a fine grade of sack salt or table salt applied to hams, shoulders, and bacons. All the salt was applied at one time by about one-half of the farmers, 10 pounds (4.5kg) of dry salt per 100 pounds (45kg) of meat being used. The liquid extracted from the meat during cure was not permitted to accumulate. Curing temperatures ranged from 20° to 50° F. (-6°C to 10°C), the average being about 40°F (4°C). Most hams weighed 20lb (20kg), 25lb (11kg), or 30lb (13.6kg) : shoulders and bacons weighed 20lb (20kg) pounds. The hams were cured for 1½ days per pound: shoulders and bacons, 1¾ days. About 50 percent of the farmers smoked their meat. Prior to smoking 3 to 1 days in hickory smoke, the meat was washed. The meat was stored in a dry, cool room with some air circulation. Consumption began immediately after the meat was cured and smoked, although some meat was stored for 9 months.”
The method was simple and effective. It took around 30 days to cure the meat and this was the problem. All subsequent curing methods from time immemorial, which is the subject of this work, were done to reduce this time. With the 20:20 hindsight we have peering back over aeons of time, we realise that what they were looking for was other ways to speed up the production of Nitric Oxide which is the curing molecule with its reddening effect on the meat and its broad spectrum antimicrobial activity.
The earliest progression from salt-only curing was the addition of nitrate directly through saltpetre and the oxidation of ammonium. This article sets out this progression. Following World War 1, nitrite was added directly and right from the start this was controversial. The motivation for the change from nitrate to nitrite was the availability of nitrate in a war situation and secondly, the speed of curing with nitrite curing being much faster than nitrate curing. Since that time, and especially from the 60s and 70s, the curing industry tried to find a system that does not rely on nitrate or nitrite. I believe this was done based on an inadequate understanding of the role of nitrate and nitrite in human health but it’s a discussion for another time. (The Truth About Meat Curing: What the popular media do NOT want you to know!)
When the industry found this to be impossible (curing without nitrate or nitrite), a trend began where some denied its inclusion in meat or at least tried to hide it. They did this by using an ancient method of curing where plants and fruits are used, naturally high in nitrate and nitrite but label declaration legislation does not necessitate you to declare all the chemical species naturally found in the plant matter. So, it is still nitrate and nitrite added to the meat which produces the nitric oxide which cures the meat, but using this strategy, producers did not have to include nitrate or nitrite on their labels.
Using this method of curing results in a healthier product due to the inclusion of minerals, vitamins, antioxidants and other beneficial plant constituents but to claim no-nitrite/ nitrate curing is false. A contemporary example of this may be the recent launch of Woolworths in South Africa.
Woolworths in South Africa launched a range of bacon recently which they claim to be cured without nitrite. They state on their packaging that their bacon is cured “using a combination of fruit and spice extracts without compromising on flavour, texture or colour, and it contains no nitrites.” The question is what “contains no nitrites?” Is it the bacon that contains no nitrites or the curing brine?
Maybe they added these indirectly through plant matter which, in the end, is exactly the same thing as adding it directly with a major difference being that adding it through plant matter makes the process uncontrolled – meaning they can’t control how much they add as opposed to the method of adding nitrate and nitrite directly which enables you to reduce the amount of ingoing nitrate and nitrite to the smallest possible ratio which is the “safest” way of doing it if you believe that nitrates and nitrites are bad for your health (an assumption that I do not subscribe to, see The Truth About Meat Curing: What the popular media do NOT want you to know!) Whatever the consequence of adding it through plant matter, claiming “no nitrites” will be a blatantly false statement and I don’t believe this is what they are doing for one moment.
Of course, the “contain no nitrites” may mean that they took care to remove all residual nitrites from the bacon after it was cured. Residual nitrites are what is left in the bacon after curing. I will argue that nitrates and nitrates is not a big deal (The Truth About Meat Curing: What the popular media do NOT want you to know!) but I understand many consumers still have a negative perception of nitrites and if the products are not formulated right, it poses a problem. Residual nitrites can be reduced dramatically by employing a range of processing techniques and through bacteria. Staphylococcus xylosus and Staphylococcus carnosus have, for example, been shown to be also able to reduce the residual amounts of nitrates and nitrites (Neubauer and Götz, 1996; Gøtterup et al., 2007; Mah and Hwang, 2009; Bosse et al., 2016). Woolworths is a quality-driven company their statement, “contain no nitrites” means that they used nitrates and nitrites but removed any traces of it before its made available for sale, I applaud them for their work! There is a small technical matter related to the chemical generation of nitrate from nitric oxide in a meat system and the fact that nitrite will soon be generated through bacterial action which calls into question if one can call any cured meat system 100% free from nitrites, but that is a question for another forum and it is possible with the right approach.
All this is an example of how the industry is grappling with the fact that nitrates/ nitrites are used. Before any of this became an issue in the world, there was curing with salt only. It would seem to me that at the heart of the entire move away from salt-only-curing was the fact that we fundamentally missed the role of microorganisms with the ability to react with protein and to create nitric oxide which then cures the meat. Well, we “missed” it because it was so hard to see nor did we have the technology to identify and isolate certain bacteria with this ability, nor did we understand what bacteria need to be effective by way of nutrition.
We had glimpses of this from the world of salt-only curing! The mechanisms underpinning salt-only curing are only emerging now as a powerful method to cure meat without the use of nitrate or nitrite, directly or indirectly. Let me say it like this. Now that we are working out the mechanism of salt-only curing, we have discovered ways to do it as quickly as is done with nitrite curing. Despite many years of intense research into meat curing, it is remarkable that we are only now starting to understand how the oldest form of curing works.
Proteins and lipids or fats in meat tissues are degraded mainly by enzymes which are also present in the meat during the ripening of the hams/ bacon but the breakdown of proteins and fat cells is also achieved through bacteria (Flores and Toldrá, 2011) and they play a direct role in curing in salt-only systems. Morita et al. found that Nitric Oxide formed in salt-only curing systems is achieved from L-arginine due to nitric oxide synthase (NOS) in either Staphylococci or Lactobacilli. (Morita et al., 1998 and quoted by Gasasira, et al, 2013) Another study on the production of cured meat colour in nitrite-free sausages by Lactobacillus fermentum showed that nitrosylmyoglobin (a form of the meat protein, myoglobin, formed during curing) could be generated when the bacteria, Lactobacillus fermentum AS1.1880 was inoculated into the meat batter, and the formation of a characteristic pink colour with an intensity comparable to that in nitrite-cured sausage can be achieved using 108 CFU/g of the culture. In other words, bacteria, in a salt-only curing system can directly achieve what nitrite curing would later accomplish.
Despite the fact that even in the 1950s salt-only-curing was the biggest single way that bacon was produced on farms in the USA, I am going to look at two important salt-only-cured hams that have been the subject of research which elucidated the mechanisms underpinning salt-only-curing and to illustrate that the key, understanding the mechanism behind salt-only-curing, is bacteria. Microorganisms drive the process!
Parma ham is traditionally produced using only sodium chloride without the addition of nitrate or nitrite and develops a deep red colour, which is stable also on exposure to air. It has been shown that bacteria are responsible for the creation of nitric oxide without nitrate or nitrite which then cures the hams. Fascinatingly, despite the fact that we know that bacteria are responsible for the creation of nitric oxide which leads to nitrosylated heme pigments, the identity of the pigment of Parma ham has not been established. In one study, the stability of the pigment isolated from two different types of dry-cured ham (made with or without nitrite) was compared to that of the NO derivative of myoglobin formed by bacterial activity. Heme pigment from Parma ham made without nitrite was more stable against oxidation than the pigment from dry-cured ham with added nitrite.” (Møller and Skibsted, 2001) This is a most fascinating discovery! Further, heme pigments extracted from Parma ham and a bacterial (Staphylococcus xylosus) formed NO-heme derivative and have similar spectral characteristics (UV/ vis spectra and ESR).” (Møller and Skibsted, 2001)
In China, Nuodeng ham is a dry-cured ham, traditionally made by Bai ethnic people in the Nuodeng village, Dali, Yunnan Province. As part of the production process, they use mineral-rich local salt reserves, and distilled corn liquor and rely on the favourable climate. From these hams, Kocuria rhizophila was isolated (Shi, 2021) and is probably responsible for the formation of the cured colour.
I can give many more examples. Dry-cured, long-cured or salt-only systems are in part enabled by bacterial action where the meat itself is fermented, nitric oxide is generated and the meat is cured. I return to this subject in the very last section of this article under the heading Bacterial Fermentation Curing. Woolworths in South Africa may very well rely on this mechanism of curing their bacon which is the only system where they can make the claim that nitrite is not present. If one would test their cure or their bacon at any time immediately following curing and in the time that it spends on the retail shelf or in the consumer’s refrigerator and nitrite is found, it will make their claim that no nitrites are present, false.
Besides the option of using plant matter that contains nitrate or nitrite, they could of course create the cured colour with proteins outside the meat environment and infuse these into the meat, which I doubt is what they are doing. They could use nitrite to cure the meat directly or indirectly and add bacteria that eliminates all nitrites post curing which is possible, but I would think improbable. The last option is that they could use nitrites at a level below 10 parts per million which will still cure the meat but is undetected in certain methods of testing for nitrites. The challenge will be that at those low levels, the nitrite offers little protection against dangerous microorganisms but I notice that they add rosemary extract which could bolster this protecting mechanism. If this is what they are doing, it would unfortunately again make their claim of “contain no nitrites“, false. If, and I am by no means suggesting they are doing this, a clue would be if they are very sensitive to environmental exposure to nitrites during production as this could push the levels of nitrite in the bacon into the levels which are “detectable”.
The last option would be “underhanded” and with a company like Woolworths, there is no chance that they employ such a strategy. Friends of mine work in their meat department both in the compliance as well as operational departments and they would never be a party to anything not completely truthful. Well done to Woolworths then on your product which can only be using some form of fermentation.
Bacterial fermentation of meat is probably the closest one will ever get to a no-nitrite system which is a spectacular return to salt-only curing. Working out how to do it is, as the saying goes, the million-dollar question and if Woolworths found the way, I salute you! As far as our consideration of curing systems goes, our first consideration of curing, namely salt-only, will also be our final consideration under Bacterial Fermentation Curing. In between these two is the most fascinating story never told!
Origins of Nitrate/ Nitrite curing
This study of salt also brings me back to my work on nitrite/ nitrate curing which has been a major focus for me over many years. While people living in desert areas would have discovered that certain salts have the ability to change the colour of meat from brown, back to pinkish/ reddish, along with increased preservation power and a slightly distinct taste, coastal dwellers would have observed the same. They would have noticed that seasalt or bay salt have the same ability.
Dr Francois Mellett, the renowned South African food scientist, sent me the following very interesting theory about the earliest discovery of the curing process in private communication between us on the matter. He wrote, “I have a theory that curing started even earlier by early seafarers: when a protein is placed in seawater, the surface amino acids are de-aminated to form nitrite for a period of 4 to 6 weeks. Nitrite is then converted to nitrate over the next 4 weeks. Finally, ammonia and ammoniac are formed from nitrate. It is possible that they preserved meat in seawater barrels and that the whole process of curing was discovered accidentally.”
Millettes’ hypothesis is interesting and I re-state the reactions as follows to clear things up. In the system of meat stored in seawater, deamination will likely happen bacterially (as opposed to autolysis, which is the enzymatic breakdown of proteins). Deamination of amino acids typically produces ammonia. It is then converted bacterially into nitrite and, again bacterially, into nitrate.
I suspect that people discovered this even long before barrels were invented. The use of seawater for meat storage and further preparation was so widespread that it would have been impossible not to have noticed meat curing taking place. If it is generally true that the earliest humans first settled around coastal locations before migrating inland, and if the seaside communities first noticed curing, it would push the discovery of curing many thousands of years earlier than we ever imagined, to a time when modern humans started spreading around the globe. When did it develop into an art or a trade is another question altogether, but I think we can safely push this back to the earliest cognitive and cultured humans whom we would have recognized as thinking “like us” if we could travel back in time and meet them.
We know that dry-curing of pork takes around 5 to 6 weeks under the right conditions and if the meat is not cut too thick. It must be cool enough that the meat doesn’t spoil before it is cured. Even though I now suspect that curing was first noticed by communities living by the sea as I just explained, I suspect that curing salts in deserts were discovered since natural salts always appear as a mix of various salts and under certain conditions, these salt deposits contain small amounts of nitrate salts and ammonium chloride. This would have aided its development into an art by the much larger availability of nitrate and related salts.
I deal with these salts below under separate headings, but the most important two curing salts that appear to us from antiquity are saltpetre (sodium nitrate) and sal ammoniac (ammonium chloride). Both salts were well known in Mesopotamia and references to them appear alongside references to salt curing of fish mentioned earlier and both salts were used in meat curing.
The ancients developed basic techniques of separating out the different salts. In particular, sal ammoniac was by far the more important salt of the bronze age (2000 BCE). It was produced in Egypt and mined in Asia where it occurs naturally. There are features of sal ammoniac that favour it as a salt for people who had the motivation to exploit new lands due to population pressure and climate changes or just curiosity. When the horse was domesticated around 5000 BCE, a food source was needed to sustain humans on long expeditions and I believe sal ammoniac fits the requirement perfectly.
Both salts cure the meat in a week which obviously had huge advantages over salt-only curing. This, I speculate, was the first incentive to change to a dedicated curing salt. Secondly, sal ammoniac, as far as I can find, was globally traded from much earlier on than saltpetre. Ancient Macedonian records indicate that even in 2000 BCE saltpetre was preferred in food over sal ammoniac on account of the better taste of saltpetre.
There is a modern-era example of a curing technique that was good for a time and was then replaced with more agreeable methods as soon as supply lines were established. This technique, I believe, actually existed from very early after the horse was domesticated and was re-introduced by various cultures at various times. One such culture was the Boers, who left the Cape Colony and moved into the interior of South Africa. The technique they used to cure their meat disappeared as soon as conventional supply lines were established.
The technique is curing meat by hanging it over the neck of the horse or placing it under your saddle so that the sweat of the horse cure the meat. (For a discussion on this, see my article, Saltpeter, Horse Sweat and Biltong) My point is that this is a good example of a curing technique that was used for a time only and then disappeared, only to re-appear when conditions required it. Such was the case, I suspect when sal ammoniac was used for a time in curing until the requirement subsided, salt curing became popular again, and much later, economic factors re-introduced an improved curing salt which by this time was saltpetre. The inclusion of saltpetre into curing salt mixes goes hand in hand with its increased availability.
Thomas Thomson, commenting on the the Muslim alchemist who lived in the 700s and 800s says that Geber (Abū Mūsā Jābir ibn Ḥayyān) was as far as he could tell, the earliest to mention saltpeter. In contrast to this, in that time, sal ammoniac “seems to have been quite common in his time.” (Thomson, 1830) Beckmann (1846) suggests that Europe became familiar with sal-amoniac in the 12th century and following.
German and Austrian cookbooks pre-1600s reveal that vegetable dyes were used to bolster colour at this time and speak of curing with salt only. It is well known that the Germans and Austrians were familiar with nitrate curing and, I will argue, they would have been acquainted with sal ammoniac as a curing salt also, but for whatever reason, these fell out of common practice. When the requirements disappeared for nitrate and sal ammoniac curing in the ancient world, the nations of Europe and China reverted to salt curing.
The many references to salt curing are therefore not surprising in the context of a mature and stable society. A record exists from Cato the Elder who described in 160 BCE how a ham should be cured. In his Latin work, De Agricultura (On Farming), this Roman statesman and farmer, gives an ancient recipe for curing pork with salt.
“After buying legs of pork, cut off the `feet. One-half peck ground Roman salt per ham. Spread the salt in the base of a vat or jar, then place a ham with the skin facing downwards. Cover completely with salt. After standing in salt for five days, take all hams out with the salt. Put those that were above below, and so rearrange and replace. After a total of 12 days take out the hams, clean off the salt and hang in the fresh air for two days. On the third day take down, rub all over with oil, hang in smoke for two days…take down, rub all over with a mixture of oil and vinegar and hang in the meat store. Neither moths nor worms will attack it.” (economist.com)
Cato may have imitated a process whereby hams are smoked over juniper and beech wood. The process was probably imported by the Roman gourmets from Germania. (economist.com) It is possible that the process of curing itself was brought to Rome by the military stationed in Germany.
Salt curing remains an important technique for high-end hams and certain bacon. Like nitrite curing, it yields a particular cured colour, but one that is a deeper purple than pink. For the mechanism behind this, refer to a section in my article on the mechanisms of nitrite curing, Bacterial/ Enzymatic Creation of Cured Colour. This is entirely restricted to long-term curing which was the norm at a certain time.
Sal Ammoniac
In 2017 I did an article where I speculated that nitrate curing originated from either the Turpan area in western China or from the Atacama desert in Chile and Peru. In this article, I suggest that nitrate curing of meat is thousands of years old. (Salt – 7000 years of meat-curing) I was working on the assumption that nitrate salts are the only salts that will yield nitrite and nitric oxide, required for meat curing. Between the Atacama desert and Turpan in Western China, Turpan is by far the best candidate for the birthplace of meat curing as it is practised around the world. I recently reviewed further evidence from this area in an article, Nitrate Salts Epic Journey andAnd then the mummies spoke!
In the course of researching the article, I discovered that sal ammoniac was far more vigorously traded than saltpetre in the early Christian era and possibly for thousands of years before that. Fascinatingly enough, I realised that ammonium chloride will, like nitrates, undergo bacterial transformation into nitrites which will then in the meat matrix yield nitric oxide which will cure the meat. I further discovered that it is an excellent meat preservative, even better than nitrates. Turpan is also probably the only place on earth where sal ammoniac and nitrate salts in the form of sodium nitrate occur in massive quantities side by side.
Chinese authors of antiquity are unanimous that sal ammoniac came into China from Turpan, Tibet, and Samarkand, and through Samarkand, it was traded into the Mediterranean along the Silk Road. There are similar records that it was traded from Turpan along the Silk Road through the city of Samarkand which had strong trading ties with the Mediterranean. It all makes for an appealing case for sal ammoniac as the actual curing salt from antiquity that was used in meat curing when the practice spread around the world. There is even a tantalizing link between Turfan and the ancient city of Salzburg in that a very particular stitch was found in jerseys on mummies in Turfan and in salt mines in Salzburg. This leads me to speculate that the trade of sal ammoniac was done into the heart of Western Europe, into what became known as Austria. This leads me to believe that the actual technological progressions may have come from Austria. Whether it was Salzburg or Turfan is not clear. More work remains to be done to gain greater insight.
We are not familiar with this salt in the context of meat curing and it will be in order for me to dwell on the topic a bit. I reviewed modern references dating back to the 1700s, 1800s, and 1900s where it continued to be used in meat preservation in Nitrate Salts Epic Journey. Several minerals exist composed of ammonium (NH4). Ammonium is formed by the protonation of ammonia (NH3). Sal ammoniac is the most well-known and was named by the ancient Romans. They collected this salt which was found around the temple of Jupiter Ammon in Egypt and called it salt (sal) of Ammon (ammonocius). The name ammonia was subsequently derived from it. It forms in volcanic vents and after volcanic eruptions before it has rained which dissolves it. It is highly soluble. It is unique in that the crystals are formed directly from the gas fumes and bypass the liquid phase, a process known as sublimation.
Ammonium readily combines with an acid thus forming a salt such as hydrochloric acid to form ammonium chloride (sal-ammoniac) and with nitric acid to form ammonium nitrate. Recent studies have shown that volcanos release a “previously unconsidered flux of nitric acid vapour to the atmosphere. (Mather, T. A., et al, 2004) It is a fascinating and insightful fact that the Turfan area, both the basin and the mountains are replete with different salts containing nitrogen (nitrate salts and ammonium) any one of which could be used effectively in meat curing.
Sal ammonia was mined from openings in the sides of volcanic mountains where steam from underground lava flows created the ammonium chloride crystals. These were traded across Asia, Europe and India. Massive sodium nitrate deposits occur in the Tarim Basin, the second-lowest point on earth. I then speculate that traders used some of these deposits to forge ammonium chloride since the ammonium chloride crystals did not survive in crystal form on long voyages due to their affinity for water which breaks the crystal structure down. Once this happened, the sodium nitrate and the ammonium chloride look similar in appearance. Due to the fact that it is known that almost all the sal ammonia mined in Samarkand was exported, I deduce that demand outstripped supply and this provided the incentive for such forgery. I find support for the likelihood of such a forgery, not just in the limited supply of sal ammoniac compared to nitrate salts, but also in the fact that mining then sal ammoniac was a seasonal affair and extremely dangerous and a difficult undertaking.
It seems likely that sal ammonia wasthe forerunner of saltpetre as the curing agent of choice. It is composed of two ions, ammonium and chloride. The ammonium would be oxidized by ammonia-oxidizing bacteria (AOB) into nitrites and the well-known reaction sequence would result. (Reaction Sequence)
Not only would it result in the reddish-pinkish cured colour, but it was an excellent preservative. In my personal experience, it is a better preservative than salt and nitrites alone, but more work is needed to confirm this. There is, however some evidence of this fact from history. An 1833 book on French cooking, The Cook and Housewife’s Manual by Christian Isobel Johnstone states that “crude sal ammonia is an article of which a little goes far in preserving meat, without making it salt.” (Johnstone, C. I.; 1833: 412) It is, of course, the sodium which tastes salty in sodium chloride and ammonium chloride will have an astringent, salty taste. I know exactly what ammonium chloride tastes like since it was added to my favourite Dutch candy “Zoute Drop” with liquorice. I believe it was none other than my old friend, Jan Bernardo, who first gave me Zoute Drop. As a boy, I used to ride my bicycle once a month to the only Greek Caffe in Vanderbijlpark, which sold it for my monthly fix. My favourite was the double-strength version called “Dubbel Zoute Drop.”
Subsequent to these discoveries, I did two small tests with sal ammoniac. Refer to The Sal Ammoniac Project. Here I show that sal ammoniac stands up to its reputation as an excellent preservative and definitely cures meat in two weeks at a 5 deg C temperature.
Salt with a little bit of saltpetre
Saltpetre is the curing salt that most of us are familiar with that preceded sodium nitrite as curing agent. By far the largest natural known deposits of saltpetre to the Western world of the 1600s were found in India and the East Indian Companies of England and Holland played pivotal roles in facilitating its acquisition and transport. The massive nitrate fields of the Atacama desert and those of the Tarim Bason were still largely unknown. In 1300, 1400 and 1500 saltpetre had, however, become the interest of all governments in India and there was a huge development in local saltpetre production.
In Europe, references to natron emerged in the middle of the 1500s and were used by scholars who travelled to the East where they encountered both the substance and the terminology. Natron was originally the word that referred to saltpetre. Later, the word natron was changed and nitron was used.
At first, the saltpetre fields of Bihar were the focus of the Dutch East Indian Company (VOC) and the British East Indian Company (EIC). The VOC dominated the saltpetre trade at this point. In the 1750s, the English East Indian Company (EIC) was militarised. Events soon took place that allowed for the monopolization of the saltpetre trade. In 1757 the British took over Subah of Bengal; a VOC expeditionary force was defeated in 1759 at Bedara; and finally, the British defeated the Mughals at Buxar in 1764 which secured the EIC’s control over Bihar. The British seized Bengal and took possession of 70% of the world’s saltpetre production during the latter part of the 1700s. (Frey, J. W.; 2009: 508 – 509)
The application of nitrate in meat curing in Europe rose as it became more generally available. Later, massive deposits of sodium nitrate were discovered in the Atacama Desert of Chile and Peru and became known as Chilean Saltpeter. Curing with this was, as I have said before, only a re-introduction of technology that existed since well before 2000 BCE.
The pivotal area where I believe saltpetre technology spread from across Asia, India and into Europe, is the Turpan-Hami Basin in the Taklimakan Desert in China. Here, nitrate deposits are so substantial, that an estimated 2.5 billion tons exist, comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile. (Qin, Y., et al; 2012) (The Tarim Mummies of China) Its strategic location on the Silk Road, the evidence of advanced medical uses of nitrates from very early on and the ethnic link with Europe of people who lived here, all support this hypothesis.
Large saltpetre industries sprang to the South in India and to the South East in western China. In India, a large saltpetre industry developed in the north on the border with Nepal – in the state of Bihar, in particular, around the capital, Patna; in West Bengal and in Uttar Pradesh (Salkind, N. J. (edit), 2006: 519). Here, it was probably the monsoon rains that drench arid ground and as the soil dries during the dry season, capillary action pulls nitrate salts from deep underground to the surface where they are collected and refined. It is speculated that the source of the nitrates may be human and animal urine. Technology to refine saltpetre probably only arrived on Indian soil in the 1300s. Both the technology to process it and a robust trade in sal ammoniac in China, particularly in western China, predate the development of the Indian industry. It is therefore unlikely that India was the birthplace of curing. Saltpetre technology probably came from China, however, India, through the Dutch East Indian Company and later, the English East Indian Company became the major source of saltpetre in the west.
To the South East, in China, the largest production base of saltpetre was discovered dating back to a thousand years ago. Here, a network of caves was discovered in 2003 in the Laojun Mountains in Sichuan Province – possibly the largest production base of saltpetre in China from 1000 years ago. Meat curing interestingly enough is also centred around the western and southern parts of China. Probably a similar development to the Indian progression.
In China, in particular, a very strong tradition of meat curing developed after saltpetre was possibly first introduced to the Chinese well before 2000 BCE. Its use in meat curing only became popular in Europe between 1600 and 1750 and it became universally used in these regions towards the end of 1700. Its usage most certainly coincided with its availability and price. I have not compared price and availability in Europe with the findings on its use in meat curing which is based upon an examination of German and Austrian kook books by Lauder (1991), but I am confident that when I get to it one day, the facts will prove the same.
The Dutch and English arrived in India after 1600 with the first shipment of saltpetre from this region to Europe in 1618. Availability in Europe was, generally speaking, restricted to governments who, at this time, increasingly used it in warfare. (Frey, J. W.; 2009) This correlates well with the proposed time when it became generally available to the European population as the 1700s from Lauder. I believe that a strong case is emerging that the link between Western Europe and the desert regions of Western China was the place where nitrate curing developed into an art. The exact place, I believe, in Western China is the Tarim depression.
Heuzenroeder (2006) reports that recipes for early ham brines in Germany did not include saltpetre. Remember that the first shipment of saltpetre from India reached Europe only in 1618. Heuzenroeder (2006) reports that recipes for early ham brines in Germany did not include saltpetre. Remember that the first shipment of saltpetre from India reached Europe only in 1618. In Chapter 05.00: Evaluation of Dry Curing with Saltpeter (with and without sugar) under Vegetable Dies we look at the use of plant matter to colour meat during the 1600s. In all likelihood, this had more to do with the nitrates inherent in these plants than the actual colour it provided.
Making ham and bacon without adding saltpetre continues to be a tradition in certain Barossa families and I would suspect them to be using techniques that “unlock” the formation of nitrite which converts to nitric oxide or the creation of nitric oxide directly. “The Hentschke family continued to use a wooden pickle barrel and immerse their bacon and ham in pure salt brine for a week to a fortnight as late as 1939.” The reason for the effectiveness of this method has been discussed under “Origins of Nitrate/ Nitrite curing?” above. Two weeks will be enough time for curing to take place.
Heuzenroeder (2006) says that early in the 1900s many families adopted another method. “Recipes started to appear in woman’s private notebooks for boiling a pickle brine of water, salt, saltpetre, sugar and pepper in a clean kerosene tin, into which the meat was immersed and then kept cool for about three weeks. The Australasian Butchers’ Manual of 1912 advocated this more efficient method also, saying that the old dry-salting process was ‘simply a waste of time.’ The lateral use of the kerosene tin, a common farm commodity, made possible a new technique which must have altered the texture and flavours of the hams considering the difference in saltpetre and salt concentrations between the boiled and the naturally induced brines and the difference in the length of time of immersion.” (Heuzenroeder, 2006) When heated above 300oC, the saltpetre decomposes into nitrite and oxygen. It is then the nitrite that penetrates the meat and is further reduced to nitric oxide which cures the meat.
Placing the meat in the water while it is still warm will speed up the process of diffusing the brine through the meat. It would not have been done if the water was warmer than around 50oC because it would have resulted in the denaturing of the proteins. Boiling water would definitely not have worked. Adding sugar and salt raises the boiling temperature of the water. Whether enough would be added to make a temperature of 300oC possible is debatable. Failing this strategy, the well-known bacterial reduction of nitrate to nitrite would have followed.
Dry curing of meat changed from salt only to a mixture of salt and saltpetre, liberally rubbed over the meat. As it migrates into the meat, water and blood are extracted and drained off. The meat is usually laid skin down and all exposed meat is plastered with a mixture of salt and saltpetre. Pork bellies would cure in approximately 14 days. (3) (Hui, Y. H., 2012: 540)
The Hallstatt Revelations
What I presented thus far has been many years of work. It is here where I have given enough information to step back and ask if the chronology that I presented can be the full picture. Does this “accidental” discovery work? We trace saltpetre and its use from a time when “purifying” it became the main focus as in its unpurified form its usage was very limited. Same thing with sal ammoniac. We pick its usage up in the earliest times following the Dark Ages, but what was the state of play in the Iron Age, the Bronze Age and earlier? Was the “link” between us and that far-distant past really an accident or was it a transition where the “new” was calibrated to a method that served humanity for many hundreds of thousands of years and when we looked for alternatives, we knew exactly what we outcome we were calibrating to?!
In Feb 2024 I was contacted by a researcher from Austria about the link between Australia and the ancient community who lived in the Tarim basin in present-day Western China. She also had fascinating observations about curing vats that have been discovered close to the earliest rock-salt mine in Europe dating back to the late bronze age around 1200 BCE. From the late Bronze Age/ Early Iron Age curing vates in Halstatt, through a high-intensity sharing of information that followed and daily interaction with the data between us, following our cooperation on Hallstatt, a gigantic shift happened in my thinking about the origins of meat curing. Here is how it happened.
I first shared my new theory in Reevaluation of the Discovery of Nitrate and Nitrite Curing. It stems from an uneasiness I had with this whole business of “accidentally” discovering. There were too many things that mitigated against consistent curing results and would have smothered the discovery of meat curing at every opportunity. I needed a powerful curing agent that would have worked every time, in the words of a great South African butcher, and paraphrasing it a bit, the system of curing should have been “Un-mess-up-able” or “unvermurksbar” in German.
What happened is that my European collaborator alerted me to the possible link between animal droppings and the development of the smelting process and in particular the hardening of the blades for which you need nitrogen. It was in considering this that the broader realisation emerged of what the level of sophistication in the manipulation of animal dung and urine must have been. By today’s analysis of poultry droppings, the usage in steel smelting does not work, but the folklore is so specific about it that I started looking at ways that the droppings could be “enhanced.”
A breakthrough came when I saw that this “enhancement” was done in Egypt. If I take the enhancement of animal dung in Egypt into account – suddenly it worked. More than worked! Ample carbon to fuel the furnace and for reducing metal oxides to pure metal. The high nitrogen content helps to create a reducing atmosphere, preventing oxidation during smelting. It improves the smelting efficiency and metal purity, contributing to better quality iron and steel. The relatively high phosphorous content increases steel hardness. Besides these, dung acts as a binder and flux and the ash residue from burnt dung serves as an insulating material, helping to retain heat within the smelting furnace. Generally, dung, when used in combination with other fuels like charcoal or wood, helps in controlling the aeration and combustion process. The structure of dung allows for a more controlled burn, ensuring a steady temperature during smelting. (from my notes in A Newspapers Record and Old Chemistry Textbooks References on Use of Urine and Dung in Antiquity with Traces in Old but More Recent Usages)
Chemically, urine works extremely well as a preservative and to create nitrite for curing. The conversion of ammonia to nitrite and then to nitrate is facilitated by bacteria through processes called nitration and nitrification. Ammonia-oxidizing bacteria (AOB), converts ammonia into nitrite (NO2-). These bacteria are commonly found in various environments, including soil and water, and can exist on the surface of the meat or in the storage environment.
Urine contains urea, which bacteria convert to ammonia and carbon dioxide. This ammonia can further undergo nitrification, where bacteria convert it to nitrite and then to nitrate. The presence of ammonia-oxidizing bacteria (AOB) in meat or in the environment helps facilitate this process. Ammonia acts as a curing agent, preserving the meat and inhibiting the growth of spoilage organisms.
The hypothesis I propose about the use of urine in curing meat highlights the ingenuity of ancient practices in food preservation. It was translated into alchemy and traditional medicine where urine was often used for its chemical properties, including its high ammonia content, which was harnessed for various purposes.
It seems then to me that people from antiquity became extremely skilled in managing human and animal excrement, both urine and droppings or manure. Its properties were understood for tens of thousands or you’re, possibly over 100 000 years. As with anything deer to humans, it was incorporated into our stores, our religion and our general cultural practices. We used in, or at least tried to use it, in everything from meat preservation to medicine.
Through careful observations of the natural world, humans realised that there is a link between urine and a salt that came to be known as saltpetre (a salt of nitrate) and a link between droppings and sal ammoniac (ammonium nitrate) was made in the human mind. We tried to work out what the link was, but mostly people did not concern themselves with the “why”. They were focused on the “how”. What started as a very tentative project, humans became better at creating nitrate salts from urine and dung and sal ammoniac from dung.
We incorporated both the original inspiration of dung and urine into the emerging system of alchemy. So strong were its presence and so absolute its domination in the ancient world that even when we got better at making saltpetre ourselves and sal ammoniac, not even these two salts could dethrone the position of permanence that dung and urine had in alchemy and the many religious practices that incorporated its use.
This picture emerged out of the preponderance of evidence I considered over the last 20 years in trying to understand the origins of the art of meat curing. What seems to have happened is that people would make pits in the ground to store their meat, just as they would place them in bodies of water to protect them from predators. We learned that such pits were constructed in clay soil that can hold moisture and if we add urine and dung and possibly salt and water to the pits before we cover it, that enigmatic forces which we know are reactions by chemistry, bacteria and enzymes in the meat, had the effect on the meat that on the one hand it cured it and on the other hand it fermented it.
This then takes me to the curing vats in Hallstatt. (see The Hallstatt Curing Method) “The first log construction was uncovered in 1877 as a result of a landslide and excavated in the following year. The second log construction was dug up by Friedrich Morton in 1939 and is characterized by double walls sealed with clay daub. Because of the numerous everyday items found in them, they were at first thought to be dwellings dating to the Celtic (or Late Iron Age) period. Later, they were considered to have been basins for collecting natural brine. But the interpretation continued to alter. In the 1990s, radiocarbon analyses showed that the basins were much older than assumed.” Reschreiter, H. – Kowarik, K. – Loew, C.)
“The analyses showed that they were dated to the 13th/12th century BC, that is to the Bronze Age. Excavations conducted in the High Valley on behalf of the Natural History Museum, Vienna, in 1993 and 1994 led to a reinterpretation of the structures. Archaeologists found a large number of animal bones, mainly from pig; these were subjected to archaeozoological analysis at the Natural History Museum, Vienna. Their construction indicates large-scale meat processing in the Salzbergtal valley with a production volume above and beyond the meat requirements of the inhabitants living in the settlement(s) in Hallstatt.” (Reschreiter, H. – Kowarik, K. – Loew, C.)
In my article, The Hallstatt Curing Method, I deliver into the possible chemical reactions that would have occurred and either urine was directly added to the curing vats or through the process of deamination which we discussed earlier based on the theory of Milette, or through autolysis (the enzymatic breakdown of the proteins), ammonia would have been created which would have been changed bacterially into nitrite if the water was turned or if it was hung in the mine shafts for drying. A whisk was found in one of the curing vats that could have served the purpose of churning the brine/ meat to “airate it” or mix something like urine into it.
The fact that we are in my estimation discussing very specific bothering techniques and curing practices from Celtic times in Austria dating back to at least 1200 BCE is volcanic! The fact that we can project back into the furthest part of antiquity is beyond comprehension!
Another ancient method of curing was plant-based curing. (Ancient Plant Curing of Meats) This curing method relied on the natural nitrate content of certain plants and I use the Turkish Pastirma as an example of this system. Meat is coated with plant matter, replete with nitrates. The nitrates are converted to nitrites by bacteria, facilitating the curing process. However, the nitrate content in plants varied significantly depending on environmental factors such as growing conditions, season, time of day, and harvest time. This variability likely resulted in inconsistent outcomes, making plant-based methods. This is similar to the results that would have been experienced if desert salts were used that would have been heavily “contaminated” with other salts and minerals, also resulting in inconsistent curing. Both systems would have been far less reliable compared to urine-based curing. Urine would have been the far more consistent option and a much better general preservative!
I did a reevaluation of my work on plant-based curing that interestingly enough also probably originated around the Black Sea area where much of the meat inventions took place. I tried to ascribe an order of magnitude to the likelihood that curing was discovered from salts of the earth or from plant matter or from the use of urine. The complete work can be found at Ancient Plant Curing of Meats. Here is my conclusion.
Urine-Based Curing: High consistency and efficacy due to the relatively stable ammonia content. Order of magnitude: 10³ (consistent and effective).
Plant-Based Curing: Variable consistency due to fluctuations in nitrate content influenced by environmental factors. Order of magnitude: 10² (inconsistent and less reliable).
Nitrate Salts and Sal Ammoniac: Moderate consistency, with variability due to contaminants and natural variations in composition. Order of magnitude: 10² (more consistent than plants but less so than urine).
It was therefore important for me to first deal with sal ammoniac and to take the thinking to its conclusion that curing of meat started with the accidental discovery of these salts and rubbing plants with plant matter that naturally contains nitrate. In my research over the years, I often read warnings by prominent scholars in ancient chemistry and archaeology who warned that it would be wrong to apply our current understanding of saltpetre or sal ammoniac to historical settings because of the extremely inaccurate and ineffective ancient purifying techniques used. So much so that scholars disregard that ancients called the different salts and simply gave it their own interpretation based on what the sal was supposed to have done. Thinking back, I always took note of these warnings and then conveniently “disregarded” them. When an alternative system of curing emerged, from tentative work I’ve done on the use of bodily fluids in meat preservation and when I realised that using urine as the ammonia source to cure the meat, it all started to fall in place and instead of ignoring the very tentative nature of ancient salt technology, I could embrace it and suddenly it becomes a pillar in the theory of urine-based curing that dominated curing and preservation in antiquity.
There are other aspects to this that I have to develop better. Ammonia itself would have played a decisive role in my investigation in curing. The practice of burying meat in pits for storage, fermentation, curing and later cooking is one of the next subjects for me to explore and I will certainly add my discoveries here. I already have a wealth of source data on the subject.
Let us now return to the chronology of our historical review of curing to the time when saltpetre was the key curing agent.
Salt, Saltpeter, and Sugar
A friend from New Zealand, Edward De Bruin shares a booklet with me, Methods of Meat Curing, 1951, US Dep of Agriculture. This image comes from this publication which beautifully gives a visual representation of the inclusion rates of the various ingredients in use in the 1950s.
The addition of sugar which favours the reduction of nitrate to the active agent nitrite became common practice during the 19th century.” (Lauer K. 1991.) At first, it was added to reduce the saltiness of the meat and make it generally more palatable. Curers soon discovered that when sugar is added, the meat cures faster and the colour development is better.
Science later revealed that the sugars contribute to “maintaining acid and reducing conditions favourable” for the formation of nitric oxide.” (Kraybill, H. R.. 2009) “Under certain conditions reducing sugars are more effective than nonreducing sugars, but this difference is not due to the reducing sugar itself. The exact mechanism of the action of the sugars is not known. It may be dependent upon their utilisation by microorganisms or the enzymatic systems of the meat tissues.” (Kraybill, H. R.. 2009)
Ralph Hoagland, Senior Biochemist, Biochemie Division, Bureau of Animal Industry, United States Department of Agriculture, discovered that saltpetre’s functional value upon the colour of meat is its reduction to nitrites and the nitrites to nitric oxide, with the consequent production of NO-hemoglobin. He showed that the reactant is nitrous acid () or one of its metabolites such as nitric oxide ().
He wrote an important article in 1921, Substitutes for Sucrose in Cured Meats. Writing at this time, this formidable meat scientist is ideally placed to comment on the use of sugar in meat curing in the 1800s since the basis of its use would have been rooted in history.
He writes about the use of sugar in meat curing in the USA and says that it is used “extensively.” He reveals that according to government records, 15,924,009 pounds of sugar and 1,712,008 pounds of syrup, totaling 17,636,017 was used in curing meats in pickle in establishments that were inspected by the US Government, in 1917. If one would add the estimated use of sugar in dry cures in the same year, he placed the usage at an estimated total of 20,000,000 pounds. This estimate excludes the use of sugar in meat curing on farms. (Hoagland, 1921.)
Hoagland says that the functional value of sugar in meat curing at this time (and probably reaching back into the 1800s) was entirely related to product quality and not preservation. “Sugar-cured” hams and bacon were viewed as being of superior quality. He states that a very large portion of bacon and hams produced in the USA are cured with sugar or syrup added to the cure. The quantity of sugar used in the curing mix is so small that it does not contribute to meat preservation at all. “Meat can be cured in entire safety without the use of sugar, and large quantities are so cured.” (Hoagland, 1921.)
The contribution to quality that he speaks about is probably related to both colour and flavour development. The colour development would have been related to the formation of the cured colour of the meat (The Naming of Prague Salt) as well as the browning during frying.
The role of sugar in bacon curing of the 1800s when saltpetre was used was elucidated in 1882 by Gayon and Dupetit, studying and coining the term “denitrification” by bacteria. The process whereby nitrate is changed to nitrite is through the process of bacterial denitrification. They demonstrated the effect of heat and oxygen on this process and more importantly for our present discussion, “they also showed that individual organic compounds such as sugars, oils, and alcohols could supplant complex organic materials and serve as reductants for nitrate.” (Payne, 1986)
Denitrifying bacteria are facultative anaerobes, that is, they will only use nitrate () if oxygen () is unavailable as the terminal electron acceptor in respiration.” “The is sequentially reduced to more reduced forms although not all bacteria form gas. ” “Many bacteria can only carry out the reduction of to , and this process is referred to as dissimilatory nitrate reduction. There is also evidence emerging that certain bacteria can denitrify, even if is present. (Seviour, R. J., et al.. 1999: 31)
(Seviour, R. J., et al.. 1999: 31)
“The rate of denitrification is affected by several parameters including temperature, dissolved oxygen levels and the concentration and biodegradability of carbon sources available to these cells” (Seviour, R. J., et al.. 1999: 223) Examples of such carbon sources are sugar, oxygen and plant oils.
In the 1800s when the use of saltpetre was at its pinnacle, the use of sugar with saltpetre had then a much more prominent role in that it energizes denitrification bacteria which results in an increased rate of nitrate reduction to nitrite and therefore would speed up curing with saltpetre and result in a better overall curing process. Today, with the widespread use of sodium nitrite in curing brines, certain denitrifying bacteria is one mechanism for NO formation which directly leads to better curing. The use of sugar or dextrose in bacon production in the modern era has more to do with the browning effect through the well-known Millard reaction to give fried bacon a nice dark caramel colour when fried.
Double Salting
In order to dry the meat quicker, a practice developed to salt it multiple times. During the first salting, meat juices are pulled from the meat. This was cleared away and a second “salting” was administered. Later on, several “saltings” were administered. Right here from the southernmost point of the African continent comes a great illustration of this from the early 1700s which then, easily extends back several hundred years.
Remember that the settlement which became Cape Town was in the first place set up as a refreshment station for the Dutch East Indian ships that rounded the African continent en route to India from Amsterdam. It became a stop-over for any friendly ship and Cape Town soon got the name of Tavern of the Sea. Here the summers are extremely hot from December to March or mid-April. Winter starts when the first Arctic cold fronts arrive in April and lasts till at least September. From September to December, it’s technically summer, but it’s often very cold and rainy with intermitted very hot spells. This means that April to August would be the only four months to properly cure meat which was very important for the Cape economy as it would be sold to passing ships. The pressure would have been relentless to find ways to cure meat in the other months also. This is then the background to the account of multiple saltings.
Upham reports on the following course of events from 1709. A detailed treatment of the reference can be seen atSaltpeter, Horse Sweat and Biltong. What was happening in the sweltering heat of March in Cape Town was that meat that was salted for sale to ships was off. A certain Michiel Ley then suggested that the meat should be salted in a two-step process. In other words, salt it and let it lay for a couple of days, giving time for blood and meat juices to be drawn out. Then, give it a second salting. Lay originally came to the Cape as a soldier employed by the Dutch East Indian Company but he changed his occupation to that of a master butcher. Certainly, this was his trade which he received in Europe.
An extract from 28 March 1709 from a Broad Council Meeting at the Cape of Good Hope gives us the rest of the story. It is clear from the entry that they were under pressure to supply due to both supply and increased demand. They noted, “Not one hardly offered himself for the supply of dried or smoked meat. Only 2,500 or 3,000 Ibs. were offered – a quantity very little among so many vessels. The necessity of supplying the ships properly is re-iterated.” The reason for the short supply was the prices offered by the Company which were too low and consequently the farmers were reluctant to sell.
The small quantity of meat that they received was itself unsuited for sale. They minuted that the “Governor and flag officers inspect some meat salted 8 days ago by the contractor Husing. The lean parts were found good, but the thick parts already spoiling“.
Michiel Ley came up with a plan that was accepted. “Decided that the treat should first lie some days in the brine to draw out the blood, and after that placed in new salt. That was not the idea of Husing but of his fellow contract or Michiel Ley. The former believed that the meat should be left in its first salt and not pickled beforehand; And was prepared to guarantee supply remaining good.” This dispute clearly shows that double salting was by no means an accepted technique in the 1600s and early 1700s.
The decision was made. “Decided, however, to adopt the plan of double salting, recommended by Ley; Husing ordered to supply in that manner; “Meervliet” having brought sufficient casks for the purpose. Ley to supply his share according to his plan. Company to supply the pepper.” The meat which was previously salted by Husing was also given over to Ley. “Decided to take over for the Company, the meat already salted by Husing. The good portions to be distributed among the crews, & the tainted ones among the slaves …”
So it happened that Lay was contracted to supply all the meat required by the Company together with Willem Basson, Jan Oberholster, and Anthony Abrahamsz. The issue of the supply of meat was major and shaped the immediate political landscape of the colony. Remember that we said that the prices offered by the Company for meat were too low and the farmers refused to sell. South Africans are well familiar with the fact that Van der Stell was recalled and that Adam Tas was involved in the saga. Adam Tas was one of these farmers and he took it upon himself to collect signatures for a petition against the governor at the Cape. Governor Van der Stel was eventually recalled to Holland. Van der Stel’s reply to the petition against him was a document drafted by him in his defence and signed by among others Ley and Oberholster. The four partners requested that their meat contract be cancelled which was granted and it was taken over by Claas Henderiksz Diepenaar. Adam Tas was locked up in the Castle’s notorious dungeon and finally, Van der Stel was recalled to Holland in 1708. The meat contract was the issue at the heart of Van der Stel’s recall. (Linder) Ley acted as one of Van der Stel’s representatives to finalize the sale of his assets. (Stamouers)
Notice the black pepper which was added. The reason for this was probably to keep flies and other insects away.
Brine-soaking (brine cure – no pumping)
Brine-soaking followed dry-salt-curing. Note that dry or wet curing is defined by what the meat is left in to cure and not what is applied to the meat. Wet brine curing is still relatively slow and meat pieces are placed in a mixture of salt, saltpetre, and water. It is important to take temperature into account since spoilage may occur before the brine had a chance to penetrate the meat. (Hui, Y. H., 2012: 540) Here the temperature is very important and is the reason why curing was only done in the winter months.
An 1830 description of a “wet cure” survived where a farmer describes the dry cure method as “tedious.” He credits Europe as the birthplace of the wet-cure method. One of the benefits of this simple system is that it can be used for mutton and beef also. The downside is that it is more expensive than dry-cure, but the wet cure could be re-used and taking everything into account, would work out cheaper in the long run than dry-cure. (The Complete Grazier, 1830: 304) It seems then that wet-curing was invented in the late 1700s or early 1800s.
This re-using of the brine would turn out to become the cornerstone of the industrial revolution for bacon curing and the country credited for this development is Ireland. Before we get to that, we have to first look at barrel pork.
Barrel pork
Barrel pork was an easy way to cure pork that involved liquid brine. It had the benefit that it could be put in barrels, loaded onto a wagon or a ship for transport and cure in transit. It could also be stored in the cure which would render it safe from flies and other insects. References to it show that it was practised already by the second half of the 1700s and well into the 1800s.
In the 1800s, this was the main way that the packing plants in the USA exported pork to England as bacon. There are many accounts in newspapers of the time where advice is given to the bacon producers on how to make sure that the meat arrives in England unspoiled. One of the main points was the importance of using good, new wood for the barrels.
A 1776 description is given on how barrel pork was produced. “After the meat has cooled < probably after the hair was removed >, it is cut into 5 lb. pieces which are then rubbed well with fine salt. The pieces are then placed between boards a weight brought to bear upon the upper board so as to squeeze out the blood. Afterward, the pieces are shaken to remove the surplus salt, [and] packed rather tightly in a barrel, which when full is closed. A hole is then drilled into the upper end and brine is allowed to fill the barrel at the top, the brine being made of 4 lb. of salt (1.8kg or 10%), 2 lb. of brown sugar (0.9kg or 5%), and 4 gallons of water (15L or 84%) with a touch of saltpetre. When no more brine can enter, the hole is closed. The method of preserving meat not only assures that it keeps longer but also gives it a rather good taste.” (Holland, LZ, 2003: 9, 10)
Again, notice the brine make-up of salt, saltpetre, sugar mixed with water. The role of the sugar was to break the hard salt taste.
Barrel pork would remain an important curing method throughout the 1700s and would make a spectacular return almost 100 years later when pressure pumps were introduced to inject the brine into the meat through needles. A plank would be run across the barrel opening. The meat is placed on the plank for injection with between one and three needles. The three needles are fed brine through a hand pump that pumps brine directly from the barrel. The barrel is half-filled with brine. After the meat has been injected, it is pushed off the plank to fall into the brine, which acts as a cover brine. It would remain in the cover brine for the prescribed time before it is removed and smoked.
The invention of Mild Cured Bacon by William Oake
Ham press from the 1910s
Sometime before 1837, William Oake, a chemist from Ireland, invented Mild Cured Bacon. (William Oakes Mild-Cured Bacon and Mild-Cured Bacon and the Curers of Wiltshire) This was the first major development in curing technology following barrel curing. The essence of mild curing is the continued reuse of the old brine. Oake was investigating what was responsible for the preservation power in the salt/saltpetre mix. He correctly concluded that salt plays a very limited role in preservation and today we know that its main function in old dry curing systems was to reduce the moisture in the meat and thus lowering the water activity. He also found no great preserving power in saltpetre but he knew that “nature” provided somehow a preserving power to the meat. The final power behind the reuse of the old brine took the rest of the 1800s to work out and was probably done in Denmark or definitely in Wiltshire. It was known at this time that the reuse of old brine had a large benefit and we know that this probably came to England from the German region of Westphalia. (William Oakes Mild-Cured Bacon) So, at this time, there was a practice in England to reuse brine twice. One would cure the meat with the liquid brine, boil it to “clean it”, and re-use it a second time. (For a full discussion on this, see William and William Horwood Oake)
After a careful and detailed investigation of the curing techniques used in Westphalia, I came to the realisation that this, the key feature of William Oake’s Mild Cures system was a progression of a system developed years earlier, not in Westphalia but in the Russia of Catherina the Great! She (or someone in Russia or even possibly in her court) happened upon the idea that since salt is a scarce and very expensive commodity, as was the case in Russia at that time, a way to re-use, not the brine but the salt would be to boil the brine down after it was used, add sugar, saltpetre and salt to it with fresh spring water. The brine was called the Empress of Russia’s Brine and for a comprehensive discussion on the link between this brine and Westphalia, see Westphalia Bacon and Ham & the Empress of Russia’s Brine: Pre-cursers to Mild Cured Bacon. The clue to the close connection between a knowledge of this brine, possibly through Westphalia and Northern Ireland where William Oake invented mild-cured bacon is discussed in great detail in Mild Cured Bacon.
William Oake, a trained chemist must have worked out that boiling the brine was not necessary which is the only substantive change he made to the method of Catherina the Great! Oake’s major contribution was to look at the full process and reorganise it in a way that makes sense in a factory environment. He industrialised bacon production. He also realised that the brine can be used many more times than only twice and boiling it was not necessary. His work made great bacon affordable and available to the general public. His system incorporated the following elements.
Lightly salting the meat to draw out the blood on the concrete factory floor
Tanking or brining (stacking and pickling) for 7 days which involved sprinkling the bottom of the tank where the meat would be cured with salt. Stack the flitches on the bottom. Lightly sprinkle saltpetre over it with sugar and salt. The next layer of flitches is stacked on top of the first but done crosswise. This is again sprinkled exactly as was done with the first and so it is repeated till the tank is full. A lid is now placed inside the tank with an upright on top and pickle is poured into the tank. The lid and upright serve the purpose of keeping the bacon sides submerged. The pickle is made as follows: To every 10lbs. of salt we add 8lbs. of dark-brown sugar; 1 lib. of spice, and 1/2lb. of sal-prunella.” Sal prunella a mixture of refined nitre and soda. Nitre is refined saltpetre used in the manufacturing of explosives. Saltpetre plays a very important role as does the grade of saltpetre used. It is important to turn the meat over after forty-eight hours into another tank. The meat that was on top is placed at the bottom of the next tank. Salt, sugar, and saltpetre are again used exactly as it was done during the first salting. Now the real trick comes in. The same pickle is used!”
Maturing/ Resting and Drying for 21 days. After seven days the flitches are removed and stacked on the floor putting some salt between each layer. Be careful not to stack it higher than four sides deep, until it has been on the floor for some days when it should be turned over, and stacked higher each time until the fourth week from the day it went into the tanks; the bacon will then be cured.”
Washing, drying, trimming and smoking. Place the bacon in tanks of cold water. Here it is soaked overnight. The next morning we wash them well with a brush. Whether smoking is done or not after tank curing the meat should be rinsed off and dried before ageing or maturation. The reason for this is that the meat pores should be closed leading to a hardening of the surface and a considerable reduction in the drying rate. The meat is trimmed and hung till it is properly dried. It is then smoked.
Two aspects should be noted. One is the rigid stepwise process which addresses efficiency, speed and hygiene and the second is the re-use of the old brine. Oakes’ genius was combining existing curing steps in a new way and the quality of his brine. His lasting contribution is, however, without any doubt, the creation of the live brine system which became the cornerstone of tank curing.
His use of sal prunella was, however a setback. Its inclusion in brine systems was nothing novel by 1830 with reference to its inclusion dating back to the 1700s. I suspect that sal prunella was for the most part not manufactured exactly as the intention was by heating saltpetre to boiling point which would have resulted in the formation of nitrite. It was heated and sulphur was added which resulted in saltpetre and sulphate. I suspect that the sulphate had an antimicrobial effect on the microbes who was supposed to convert the nitrates to nitrite, resulting in this conversion not taking place. I know this from the fact that the bacon lasted longer than traditionally cured bacon and the bacon was pale. The characteristic pinkish/reddish colour did not develop. The sulphites provided good antimicrobial protection along with the hygienic system of Oake’s, but no meat curing as we would define it today. (Mild-Cured Bacon and the Curers of Wiltshire) Mild Cured bacon was sold till after World War 1. It took many years to get rid of sal prunella in the cure and revert back to saltpetre only. It is, however clear that William Oake pioneered the repeated reuse of the old brine. Some companies reused the brines for decades. (William Oakes Mild-Cured Bacon)
The system was next adopted by the Danes. The year was 1880. Denmark is a tiny nation. To remain competitive, they realised years earlier to learn as much as they can from other nations and peoples and adapt. Every industry in Denmark was constantly looking at where new discoveries were being made and how they could adopt and adapt them.
Denmark had large dairy farmers and a sizable pork industry developed from the by-products of dairy farming. It was very simple and profitable. Raise pigs on the byproducts from milk and sell them to England and Germany. Someone from the pork industry learned about the new mild cured bacon produced in Ireland. They tried many times to send people to learn the techniques, but the Irish were careful not to employ the young Danish men who were sent over for employment in the large bacon plants in Ireland. They needed an opening in the Irish market to learn their techniques. Such an opening was presented through industrial action by the Irish workers. The thing about Ireland is that the workers often go on strike and how they are treated by the companies they work for is often very harsh. Those on strike do not get paid and stand a large chance to be laid off.
In 1880 there was a strike among butchers in the Irish town of Waterford. Some shrewd members of the Danish pork processing guild happened to be in Ireland at that time, in Waterford, and at the promise of lucrative employment in Denmark managed to persuade a number of the striking men to return with them to Denmark. In Denmark, they quickly arranged for them to train the Danish butchers. Mild Cured Bacon became the new Danish bacon.
Sweet Cured Bacon by C & T Harris (Dry-salt-curing in combination with injection)
In Calne, a small settlement in Wiltshire, England, the firm C & T Harris was becoming the world leader in producing exceptional mass-produced bacon. For a complete discussion, please read Sweet Cured Harris Bacon!
Their invention was very similar to the general method of William Oake’s Mild Cured Bacon with the notable exception of the re-use of the old brine. Very importantly, they hot-smoked their bacon after curing. Even more important was the fact that this invention in the 1840s used stitch pumping. Stitch pumping itself was invented around this time and it allowed for much quicker curing of the meat which together with hot smoking cut the curing time down and was a major improvement on the taste. It was not a hard salted taste, but a mild cure taste, and from there the name.
It seems that the basic distinguishing between dry and wet curing is not based on whether injection is applied or not, but the state of the salts that the meat is left in, even after it has been injected with a brine (mixture of salt and water). So, if it is packed in a dry mix, it is dry curing and if it is soaked in a brine, it is wet curing.
It was reported by some bacon curers that they used the dry-curing in conjunction with injection. In this case, the meat is injected with approximately 10% saturated brine solution, and the injected meat is then treated the usual way in the application of dry-salt-cure. There is a record showing that C & T Harris (Calne) used injection with their bacon from 1843. After it was dry-cured, the meat was smoked at a temperature of not higher than 38 degrees C (100 degrees F) in order to prevent nitrate burn which presents itself as green spots that appear on the meat. In the report, mention is also made that care should be taken if these products are stored to prevent damage from insects such as cheese skippers, mites, red-legged ham beetles, and larder beetles. (Hui, Y. H., 2012: 540) The result was sweet cured bacon!
The Injection of Meat
A short review of the invention of the practice of brine injection with needles is appropriate at this time. The practice started as a way to preserve cadavers. I remember an account I read of how Von Hombult and Guthrie went from house to house after a particularly heavy thunderstorm buying up the corpses of the deceased for their own medical studies. Before the age of refrigeration, preserving human remains to study the makeup of the human body would have received considerable attention and this was the first area where injection of meat was done for the purpose of preservation.
The link between meat preservation for sustenance and meat preservation for the study of anatomy is, as the link between meat injection and the medical establishment, one that is abundantly obvious if you just think about it for a minute, but not necessarily the first connection you make when you look at the different disciplines separately. The man who took front and centre stage in the development and progressed the practice of injecting preserving fluids into dead animal muscles for the purpose of preservation was Morgan.
Morgan’s Patent
It was a certain Mr Morgan, in England, who had a significant impact on popularising the technique of injecting a liquid brine into the meat in the first place. The motivation was to increase the rate of curing by getting the brine faster into the meat in order to reduce the time required for processing which became the basis of sweet-cured bacon.
In temperatures above 20 deg C, pork spoils in three days. By injecting a liquid brine into the meat at evenly spaced intervals, the brine diffuses more quickly through the meat. Morgan’s interest was the preservation of meat generally but included meat preservation for long sea voyages before the advent of refrigeration and not the curing of meat by farmers.
We encountered Mr Morgan in the work of Edward Smith, Foods, (1873). Smith wrote that “Mr Morgan devised an ingenious process by which the preserving material, composed of water, saltpetre, and salt, with or without flavouring matter, was distributed throughout the animal, and the tissue permeated and charged. His method was exemplified by him at a meeting of the Society of Arts, on April 13, 1854, when I [Edward Smit was] presided.” (Smith, 1873)
He describes how an animal is killed in the usual way, the chest opened and a metal pipe connected to the arterial system. Brine was pumped through gravity feed throughout the animal. Approximately 6 gallons were flushed through the system. Pressure was created to ensure that it was flushed into the small capillaries. Smith reported overall good results from the process with a few exceptions. He himself seemed unconvinced.
An article appeared in the Sydney Morning Herald that mentions Dr Morgan and his arterial injection method. An important observation from the article is the date of 1870. By this time, he is referred to as “Dr Morgan”, cluing us in about the timeline of Morgan’s life.
A second observation is a drawback of the system. The article states that “salting is the most common and best-known process of preservation (of meat), the principal modern novelty being Dr Morgan’s plan of injecting the saline solution into the arterial system – the principal objection to which has been that the meat so treated has been over-salted.” (Sydney Morning Herald, 1 March 1870, p 4) The brine mix that Mr Morgan suggested was 1 gallon of brine, ¼ to ½ lb. of sugar, ½ oz. of monophosphoric acid, a little spice and sauce to each cwt of meat. (Smith, E, 1873: 36)
Seventeen years after Smith met Morgan at the Society of Arts meeting, in 1871, Yeats reported that a certain “Professor Morgan in Dublin, proposed a method of preservation by injecting into the animal as soon as it is killed, a fluid preparation, consisting, to every hundredweight of meat, of one gallon of brine, half a pound of saltpetre, two pounds of sugar, half an ounce of monophosphoric acid, and a small quantity of spice.” (Yeats, J, 1871: 225)
The plan was widely tested at several factories in South America and by the Admiralty, who had reported that they had good results from the technique. (Yeats, J, 1871: 225, 226) It was in all likelihood the same Morgan that Smith reports on who, by 1871, became a professor in Dublin. Notice, as a matter of interest that he used the same basic brine mix of salt, water, saltpetre, sugar, monophosphoric acid and spices. This, together with the similarity in surname makes it quite certain that Mr Morgan, Dr Morgan and Prof. Morgan are the same person. In itself, this is an example of perseverance! In 1854 his arterial injection was met with scepticism whereas Yeats reports in 1871 that the Admiralty viewed his improved method.
Was this Morgan’s Invention?
The concept of arterial injection was not new. By the time Morgan demonstrated it to the Society of Arts, on April 13, 1854, it may have been as old as 150 years, used for embalming corpses for the purpose of medical studies. This invention is credited by some to the Dutch physician, Frederik Ruysch (1638 – 1730). He injected a preservative chemical solution, liquor balsamicum, into the blood vessels, but his technique remained largely unknown for some time. (Bremmer, E.; 2014)
British scientists who used arterial injection and from whom Morgan could have learned the system were the Hunter brothers William (1718–1783) and John (1728–1793) and their nephew, Matthew Baillie (1761–1823). The injection was into the femoral arteries. They all injected different oils, mainly oil of turpentine, to which they added Venice turpentine, oil of chamomile, and oil of lavender. Vermillion was used as a dye to create a more life-like skin colour, but would also have added preservation to the final solution. (Bremmer, E.; 2014)
There is a reference from 1837, on an essay delivered on the operation of poisonous agents upon the living body by Mr John Morgan (1797 – 1847), F.L.S Surgeon to Guy’s Hospital. (1837; Works on Medicine) The same publication contains an article by Dr Baillie, M.D. on the morbid anatomy of some of the most important parts of the human body. John Morgan was undoubtedly well familiar with arterial injection. Not only due to the fact that he was a contemporary of Baillie, but he was also a demonstrator of anatomy at the private school near Guy’s Hospital. (livesonline.rcseng.ac.uk/) The late 1830 article that is referenced means that it fits the timeline perfectly for a late 1830 or early 1840 technology transfer for the use of the same general technique of injecting preserving fluids into the meat of a pigs carcass which presumably became stitch pumping, a precursor for Morgans invention.
John Morgan is in all likelihood the father of Dr John Morgan (Circa 1863), who was a professor of anatomy at the University of Dublin. A process of arterial injection is described that was used by Dr John Morgan from the University of Dublin. ” John Morgan, a professor of anatomy at the University of Dublin in Ireland, formally established two principles for producing the best embalming results: injection of the solution into the largest artery possible and use of pressure to push the solution through the blood vessels. He also was among the first to make use of a preinjection solution as well as a controlled drainage technique. Morgan’s method required that the body be opened so the heart was visible, then an 8-inch pipe was inserted into the left ventricle or aorta. The pipe was connected to yards of tubing ending in a fluid container hung above the corpse. The force of gravity acting on the liquid above the body would exert about 5 pounds of pressure, adequate to the purpose of permeating the body.” (Wohl, V.) This process described here is applied, not to the preservation of animal carcasses, but for embalming a human body! It is, however, the exact same process that he demonstrated years earlier in London to Smith at the Society of the Arts meeting on 13 April related to carcass preservation.
From the process description, it is clear that we have identified Morgan, father of the arterial injection method in meat curing as Dr John Morgan, professor of anatomy at the University of Dublin, son of John Morgan, Surgeon to Guy’s Hospital. The original inventor of the system was the Dutch physician, Frederik Ruysch and the application was embalming.
Henry Denny and the claim of a Return to Dry Salting
No review of curing history will be complete without mentioning the legendary Henry Denny and the equally legendary company founded by him.
Ireland in the first half of the 1800s was a fertile field for innovation. An excellent example is found in the person of Henry Denny. Part of his remarkable legacy is a firm that once was the largest bacon producer in Europe, Henry Denny & Sons. Henry was born in Waterford, Ireland in 1790.
Denny started out as a provisioner merchant in Waterford. The first reference to him as a bacon merchant comes to us from 1846. In 1854 he started using ice in bacon curing which allowed him to cure meat all year round like his colleagues in Calne. The bacon he cured was also referred to as mild cured bacon and a patent was granted in 1857 on his process. Like the process invented by C & T Harris, which they called Sweet Cured Bacon, Henry’s process used much less salt. The priority for inventing the first mild cured system, however, goes to William Oake from Ulster whom we know invented this at around the time when Denny had his merchant business or shortly after this and well before Denny entered the pork processing trade.
Henry’s curing system is described in Geocaching where the post seems to be a copy from another work that is unfortunately not referenced and all my attempts to locate the original publication have been in vain. The author describes it as follows: “Until the early 19th century, pork was cured by soaking large chunks of the meat in barrels of brine for weeks. Shelf life was poor, as often as the inside of the chunks did not cure properly, and meat rotted from the inside out. Henry Denny and his youngest son Edward Denny introduced a number of new innovations – he used long flat pieces of meat instead of chunks; and they dispensed with brine in favour of a dry or ‘hard’ cure, sandwiching the meat in layers of dry salt. This produced well-cured bacon with a good shelf life and revolutionised Ireland’s meat industry. Irish bacon and hams were soon exported to Britain, Paris, the Americas and India“.
Reference is made to the fact that Denny invented several curing techniques and if the description given is correct, it would be one of several inventions. Taken at face value I doubt the superiority of his system over Oakes’ invention. It also comes so late in terms of dates that I seriously doubt if this could be the patent that was awarded in 1957. By this time meat injection was already well established which solved the shortcomings of William Oakes’ invention in his mild cured system of simply filling the curing tanks with brine to diffuse into the meat “naturally.” If this was in fact the patent that was granted in 1857, it would represent a serious step backwards.
The greatest contribution to this review article of Denny is the fact that he acquired a meat curing company in Denmark in 1894. The reference is Lets-Look-Again which also seems to quote an uncredited source. They make a statement that this purchase “introduced Irish meat curing techniques to Denmark.” I have over the years come across several authors who made the same claim that the Irish meat curing system was introduced to Denmark in the late 1800s after an Irish firm acquired a Danish processing company. They never gave the name of the Irish firm in question. The end of the 1800s is, however, the wrong time for the introduction of the Irish system to Denmark. By this time it was already well established in Denmark and the likely transfer of the technology to C & T Harris took place from Denmark either at this time (closing years of the 1800s) or in the opening few years of the 1900s. For this reason, I never used the reference but I was always curious about who the Irish firm was, wrongly credited for the transfer of the technology to Denmark. Now I know and for this reason, as well as the widespread nature of the erroneous claim, I include it here.
Denny was undoubtedly a creative man. He is credited with the invention of the pork rasher. Geocaching quotes an unnamed source that “the rasher (a piece of bacon to be cooked quickly or rashed) was reportedly invented in 1820 by Henry Denny, a Waterford butcher who patented several bacon curing techniques still used to this day.” It must be mentioned that Denny’s career only started in 1820 but that was not as a butcher. It was as a merchant and he entered the pork processing business only in 1854. There could still be credibility to the claim which I base on the widespread nature of the story in Ireland. Maybe he was a young man with unusual interest and creativity in selling pork at his trading business. The claim may however be apocryphal.
Related to the inventions of Henry Denny in bacon curing in particular, is there any clue as to what this may have been exactly? It was when I studied the life of another man who claimed to have invented a unique curing system, the Dutch Orthodox Jewish bacon curer Aron Vecht, that I discovered the great contribution to the art of curing made by Denny. One aspect of pork curing that I overlooked for years was the importance of singeing. It is exactly in this area where Henry Denny made his greatest contribution to curing.
Singeing pork was nothing new. Removing the hair off the carcass and retaining the “rind” was done with straws for centuries. The old method is beautifully illustrated by Тихомир Давчев in their set of photos featured below.
Henry Denny automated this process. He re-looked at the process in light of the latest industrialised equipment available. One publication from 1866 describes it as follows. “Each pig is hoisted by the hind leg, it is hooked on to a lever, which suspends the animal head downwards, and its throat is slit with a sharp knife; the blood caught in a receiver flows into an external tank, from whence it is carted away. The leg is then fixed to a hook, which slides on a round iron bar placed overhead on an incline. A push of the hand sends the dead pig with railway speed to the singeing furnace, a distance of 30 to 50 feet. Here it is taken by a crane, placed on a tramway, and run into the furnace, where the flame impinges on it, and in a moment all the hair is removed. The carcass is re-hooked by the leg, passes into another room, where it is disembowelled, the entrails being transferred to an underground region or be dealt with. The head is next removed, and then the backbone is cut out, thus dividing the carcass into two flitches, which pass, suspended on the round bars and without handling, into the cooling room, where it hangs until the meat is firm.” (Fraser’s Magazine for Town and Country, Vol. LXXIV July to December 1866)
Molander (1985)
His fame was in the first place due to his invention of the automated process of pork singeing. He may have, of course, also called his process “mild cured” as with the aid of refrigeration he would have obtained the same result as did William Oake who actually invented the original mild cured process.
Was this disingenuous for him to also have called it “mild cured”? I think not. It illustrates the inherent problem in using the result of the process (i.e. milder bacon) as the name of your product. If the result is the same but a different process was used to arrive at it, how would the consumer know (or care)! From a trademark perspective, it makes it tricky since the words seem to be difficult to protect as it would be the general way people would refer to the bacon, not heavily salted. It is like trying to trademark the phrase “well cooked.”
The Dutch Orthodox Jew, Aron Vecht and His Secret Curing System
If we have spoken about Henry Denny, we most certainly have to stop for a minute and look at Aron Vecht who essentially copied the system of Denny and passed it on as his own invention.
Dr James Anderson told me in New Zealand that Vecht claims that worldwide “only five firms possessed the right to use [his secret]’ one of which was his own, the London-based Inter-Marine Supply Company. This means that William Oake’s company, Oake-Woods in Dorset was by far the most widely used curing system under a patent of the time. Still, what Vecht created was impressive.
Vecht took out patents in 1894 in New Zealand related to the singeing of pigs and the preservation of meat. His method of preservation was called the “Vecht Mild Cure Process.” He masterfully tied the patent was tied to his own bacon brand, York Castle. The patents were presumably owned by his business in New Zealand which he had with William Stokes called the Christ Church Meat Company, Ltd. An interview with Vecht in New Zealand from 1894 reveals that the essence of Vecht’s curing system was in fact the system of William Oake and Mild Curing (Interview with Aron Vecht 1894) to which he added the singeing of pigs. Like Oake, Vecht used known systems and fused them to create his own unique curing system. Like the original Mild Cured system, Vecht used sal prunella and his bacon was pale. (Interview with Aron Vecht 1894) This was, however, not the full extent of his system. To this, he added refrigeration!
From a lawsuit following his death related to the York Castle trademark in New South Wales, Australia, we get insight into how he managed his intellectual property. The trademark and his secret method of curing went hand-in-hand. Only the Vecht Mild Cure Process could be used to produce the York Castle brand of bacon. Vecht would receive monetary compensation for every pig so cured in a territory.
When refrigeration was introduced into international trade, its impact on meat quality was an unknown. People opted for the less harsh conditions of chilling temperatures and tried to avoid freezing the meat. A drawback of mild cured bacon is that it did not last on long sea voyages under chilled conditions. The English market has, by the time Aron Vecht arrived on the scene, became used to mild cured bacon as opposed to heavy salted which was the kind of meat produced under the Rapid Cure process of Robert Davison. An attempt was made to use the sea voyage for the curing to take place and to pack the pork on ice. Famously the Harris brothers of Calne were involved in exactly this scheme. The Waikato Argus who reported on this in 1901 said that the lowering of the temperature below 32o Fahrenheit (0o C) has ‘invariably faded the flash into a pale, unpleasant colour and alienated the affections of the British matron.” If they achieved the cured colour as we are used to it today, what could have happened is that they meant that lowering it to 0o C was ineffective in securing a good product that would arrive in London. At chilling schilling temperatures, when the meat has not been heated through hot smoking, the curing colour, resulting from the effect of nitric oxide on the meat proteins, giving it a bright pinkish/ reddish appearance would be reversed. If, however, the meat is frozen, such reversal would not take place. The meat would then be smoked when it arrived at its destination and the colour would be “fixed” through the unfolding of the proteins. They, however, had pale meat, to begin with. (Interview with Aron Vecht 1894)
The Waikato Argus reported on this progression by Vecht as follows: “Now, however, by what may be called a triumph of transit and cure, a most promising and important trade has begun between New Zealand and England. By employing the Vecht curing process, a New Zealand firm is shipping pigs from that distant colony, placing them in refrigerators with a temperature of 20o Fahrenheit (-6o C), and curing them here on the banks of the Thames with apparently perfect success.”
It was not well understood at the time and it was incorrectly believed that the method of sterilisation of the meat which was part of the Vecht process was responsible for preventing the cured colour from fading. What is true is not that it would have prevented the cured colour from fading, but that it would have stopped bacterial and enzymatic action which spoiled the meat and degraded the meat quality and this would undoubtedly also have affected the meat colour, even though it was by no means the only reason why the colour faded.
The article reported on this as follows. “This success is obtained by first treating the carcase*, before they leave New Zealand, by the Vecht curing process, which allays the action of the cold, and so sterilises the flesh as to prevent the changes which have hitherto interfered with the successful curing at Home of what is grown abroad.”
The Waikato Argus which we quoted above related to the use of temperature and the curing of meat made also provides us with another very valuable bit of information related to the trading of bacon cured with the Vecht method. It reported that “Messrs Trengrouse and Co., who are colonial shippers on a huge scale and the British agents of Armours, of Chicago, are encouraging this new process, and prophesy for it a vast influence on the bacon trade.” The mention of the agents of the legendary firm of Phil Armour is of extreme interest as is the link between Armour’s company and the propagation of Vecht’s method of curing. Armour was the pioneer of freezer technology for the distribution of meat in America and owned probably the largest curing works in Chicago in the world. Vecht was an expert in the refrigeration of meat in particular. Phil Armour was carefully plotting his way to introduce sodium nitrite directly as a curing brine but not wanting to be left out of the huge and lucrative international bacon trade, must have seen Vecht as a brilliant ally to secure bacon for his own trade while avoiding the expensive curing systems such as Auto Cure which Armour knew would be replaced by the direct addition of nitrite to curing brines.
– Messrs Trengrouse and Co
I told you that the one interesting aspect of Vecht was his method of curing. I referred you to the Waikato Argus which did an article on his life from where we got the all-important information on the temperature during the shipment of the meat. The same article mentions that Vecht’s products were sold through the firm of Messrs Trengrouse and Co.. They are described as colonial shippers on a huge scale and the British agents of the Armour Packing Company from Chicago, who are encouraging his new process. This brings us to the next fascinating aspect of this remarkable man’s life namely his link to the legendary provisions and general commission merchants of Messrs Trengrouse and Co.
The firm was officially called Trengrouse, H & Co., and was described as “Provision Agents and General Commission Merchants” Their address was 51, 55, Tooley Street, London, S.E. The firm was established in 1875 by Henry Trengrouse and his brother, who retired in 1908. They had agents in Liverpool, Manchester, Bristol, Cardiff, Melbourne, Sydney, Brisbane, Dunedin, (N.Z.), Monte Video, Buenos Ayres and they specialised in butter, cheese, bacon, eggs, and canned goods. They claim to have pioneered the trade in New Zealand and Australia in dairy products. Most important for our purposes is that they were the agents for Armour & Co. from Chicago and by 1914 they have been Armour’s agents for upwards of thirty years. (1914 Who’s Who in Business) This means that Phil Armour probably set them up himself and dealt directly with them. Phil passed away at the turn of the century.
The grandfather Henery Trengrouse after whom he was named was a legendary figure in his own right. He devoted his life to the invention of a number of methods to improve safety aboard ships after he witnessed the sinking of a ship with a tragic loss of life close to his home town when he was a young man. (5) Adventure and perseverance ran in the family and, I am sure, accounted for their success in no small way!
– International Bacon War: Quest for Supremacy
I thought it important to deal with Vecht, Trengrouse, and Denny in relation to each other since it speaks to the state of international competitiveness of the newly emerging superpower of the United States relative to the diminishing influence of England. We must not lose sight of the fact that Vecht’s process was a short-lived attempt by the Dutch (Vecht) and the Americans (Armour) to wrestle away control of the international bacon market from the British.
Over the years I have always wondered why Phil Armour did not try and assert his influence on the lucrative bacon trade not just through exports to Britain (which they did on a large scale), but in the international bacon trade. I never came across them in almost 10 years of research apart from sending bacon from the USA to England. This all changed with the mail from Dr Anderson and looking into the life and career of Vecht.
I speculate that their agents found an ideal ally in the Dutch curer, Aron Vecht. Vecht combined several known (and patented) curing processes, created his own version of mild cure, ostensibly predicated upon the use of refrigeration, and an invention by the Irish firm of Henry Denny that automated the singeing process of the carcass. I suspect his allegiance with Armour either led him to become an expert in the newly developing art of refrigeration or he was already interested in this before he came into contact with the Armour Meatpacking company in Chicago. His curing process would have suited Armour in that it was far less capital intensive than Dorset based firm of Oake-Wood’s autocue and despite not being as fast in curing as was accomplished with the autocue equipment, it was a progression on the mild curing process of the inventor of the original process, William Oake, father of the Oake who was a partner in Oake-Woods.
The link with a unique bacon brand is a stroke of genius and something, I am sure, that was carefully deliberated. Before this time, bacon was differentiated by the particular method of curing. As I explained at the start, these would have been dry-cured, sweet-cured, mild-cured, pale-dried, or auto-cured. There is evidence of Harris going after people using the name “pale dried bacon” but the advent of refrigeration, effectively levelled the playing field as many options became available to produce bacon with far less salt than was traditionally done under the dry-cured system.
Another very important point about Armour must be made. A few years ago, I came across a reference to a secret trial in the use of sodium nitrite done at a packing plant in Chicago. The year was 1905. This was done before its use was legal in any country on earth. I speculated that it was carried out by Phil Armour as very few people would have had the audacity to have tried it. I reported on this experiment in an article and shortly after this all references to it were removed from the publications I cited and I could not get hold of the source documents. I know the author of the article where this reference appeared. He is a prominent person in a leading role in European meat-curing circles and I understand why this reference was removed.
This is pure speculation on my part, but it has a tone of credibility. I think that Armour or Armour with the key meatpackers in Chicago of Gustav Swift, and Edward Morris jointly performed the trial. I wrote extensively about this in The Direct Addition of Nitrites to Curing Brines – The Spoils of War. The experiment would have been spectacularly successful and I believe was done on the back of experiments done in German agricultural research centres for years before 1905.
With them having known about the work on nitrites, I believe the process of Vecht suited Armour well as a kind of a “placeholder” without engaging a firm like Oake-Woods and locking them into the Auto Curing system which was the leading system internationally at the time as far as it being patentable and indeed, it was the most widely used international patented system of the late 1800s and early 1900s.
There is an “air” of the thinking of Armour, Swift and Morris in the preamble to a meat science group formed by them, also in the early 1900s where their mission was stated as being “to reduce steers to beef and hogs to pork in the quickest, most economical and the most serviceable manner.” The process they had in mind here was nitrite curing.
It was a key turning point in the history of curing and the Americans spectacularly took the lead when, following the First World War, Griffith, the American Chicago-based company became the evangelist of the direct addition of nitrite to curing brines, a riveting saga which I uncovered and wrote extensively about in the article which I just now sited. So, anticipating what is to come in the direct addition of nitrites to curing brines, there would have been no point in investing in any of the “indirect curing processes” of the English, Danes, or the Dutch. There is evidence that the Chicago meatpackers were preparing for this curing revolution for a number of years and the Griffith Laboratories was an important participant who had to be ready to handle the PR of what was to come. They have undoubtedly taken careful note of public perception related to nitrites and had to be careful how they introduce the matter to the public. Besides this, they had to ensure that using nitrites directly in meat curing was legalised. All this was carefully orchestrated and it completely explains why they never fully committed to curing systems that dominated through the rest of the world prior to 1905. Supporting the Vecht system would have been a perfect “placeholder.”
Was the use of the curing technique of Vecht as deliberate as I present it here? I suspect it but have no direct evidence to that effect. Is it a likely scenario, taking the full spectrum of information from that time into account? I believe so! At least it warrants keeping the possibility in mind as we progress our efforts to understand the grand story of the development of bacon!
Drying and Smoking of Bacon
Another aspect of bacon processing that we have not considered thus far is the drying and smoking of bacon. The oldest reference I can find of the smoking of bacon is a statement by the Scottish farmer, Robert Henderson that he created his own very simple design for a smokehouse in 1791. (Robert Henderson and the Invention of the Smokehouse) What is interesting about his account is that it deals with the establishment of the pork trade in Scotland.
Henderson recalls that in 1766 pigs were brought into Annandale in Scotland for the first time. Farmers bought them more out of curiosity than to make a profit. The pigs were small with bristles on their back. Between 1775 and 1780 both bacon flitches and hams became a considerable trade in this part of Scotland. By 1790 the pork trade was well established with buyers travelling throughout the region to buy pigs. Several markets were established for pigs. One such market was established at Dumfries where the Annadale curers meet the Galloway farmers. Events allowed Robert a birds-eye view on the birth of an industry!
Robert Henderson was a formidable pork trader. He distributed the carcasses among the farmers to dry and smoke them in the farmhouses. In one season he would cure no less than 500 animals in this way. He wrote, “I practised for many years the custom of carting my flitches and hams through the country to farm-houses and used to hang them in their chimneys and other parts of the house to dry, some seasons to the amount of 500 carcasses.”
The system was accompanied by many difficulties. For starters, he often had to provide his own wood for hanging the flitches and hams on. This was only the start of the trouble. He wrote, “for several days after they were hung up, they poured down salt and brine upon the women’s caps, and now and then a ham would fall down and break a spinning wheel, or knock down some of the children; which obliged me to resort to the shop to purchase a few ribbons, tobacco, &c. to make up peace.”
The biggest problem of this system is related to weight loss. Henderson wrote, “there was a still greater disadvantage attending this mode; the bacon was obliged to hang until an order came for it to be sent off, which being at the end of two or three months, and often longer, the meat was overdried in most places and consequently lost a good deal of weight.”
In 1811 Henderson noted that this was still the way that bacon was cured in large quantities in Dumfriesshire. He lamented the fact that people are slow to abandon old ways of doing things in favour of better alternatives.
Robert Henderson claims that twenty years earlier, in 1791, he designed a simple, dedicated smokehouse for smoking hams and bacon. This simple statement would become my earliest reference to a smokehouse. He describes it as being twenty feet square (1.8m2) with walls about seven feet (2.1m) high. Each wall allowed for 6 joints. Twenty-four flitches can be hung together in a row without them touching. Each one of the flitches was resting on a beam. There are five rows, allowing for a total of 120 flitches in the smokehouse. The flitches were hung between 21/2 to 3 feet (900mm) from the floor which is covered with sawdust of five or six inches (100 to 150mm), kindled at two different sides. (Henderson, 1811)
The door is kept closed with a small hole in the roof for ventilation. Bacon and hams smoked in this smokehouse were ready for dispatch within eight to ten days. An advantage of this system is that there is only a little loss in weight. (Henderson, 1811)
So, the system was that the bacon was kept in the salt-house till an order is received. At this point, it was moved to the smokehouse for drying and smoking before it was dispatched to the client. (Henderson, 1811)
During this time, the invention of the smokehouse by Robert Henderson had a dramatic impact on the quality of the bacon. One of the consequences of too much drying is very salty meat since water escapes, but salt is left in the meat.
This invention was “in the air” already since Henderson’s 1791 invention of the smokehouse. Losing weight results in more salty bacon as a large weight loss reduces the volume of meat to salt, making the remaining meat saltier. Smoking, at this time, was exclusively cold smoke.
Apart from better-tasting bacon, there was a significant reduction in cost. Henderson wrote that he “found the smoke-house to be a great saving, not only in the expense and trouble of employing men to cart and hang it through the country, but it did not lose nearly so much weight by this process.”
It is extremely unlikely that Robert Henderson was the first or only person who did away with the farmhouse-drying/ smoking of hams and bacon and opted for a built-for-purpose smokehouse. The following hundred years would see a plethora of ideas being shared and taken up by various companies and individuals, many claiming priority for their invention or progression. It is possible to get close to the people who pioneered these different progressions based on the dates for their inventions but if we are ever able to identify the very first person related to each invention is highly unlikely. It is, however, fascinating how close we can get to the first instance of an invention or progression.
It is interesting that the 1791 reference of Henderson (when he first designed his smokehouse) is still the earliest reference we can find anywhere to smokehouses. Following the indirect reference of Henderson, the next reference I was able to find was a 1796 reference to a smokehouse being part of an estate for sale. (The Philadelphia Inquirer, 1796) Several advertisements for properties in Pennsylvania with smokehouses on occurred in the 1790s and into the early 1800s. There is an 1813 reference to a smokehouse by a reader who complains that his measures against insects are not working. (Buffalo Gazette, 1813)
The author elaborates on the experience of his teacher who warned him about damp which leads to bitter-tasting bacon. He uses an interesting phrase to describe Mr A of Baltimore namely a man who “followed smoking for gain.” He is therefore squarely set in a commercial mindset.
The author continues. “one good fire per diem will smoke the pieces exactly in the same time they were salted viz. hams 4 weeks, shoulders 3 weeks, other pieces in two. When the bacon is smoked and all returned to the smokehouse, a floor, if not laid before should now be laid on the joist; by this means rats will be prevented from descending on the bacon, and the heat of the sun will be moderate so that the bacon will not drip in the summer heats. Darkness and coolness are necessary to preserve the bacon from flies – it may there hang in perfect safety till wanted!” (Newbern Sentinel (New Bern, North Carolina), 1820)
The fact that smokehouses were a new progression in the 1840s is seen from a newspaper report from Northern Ireland in 1841. The article points out that due to the misconstruction of the smokehouse and because the surface of the meat is not properly wiped dry and there is still saline matter on the outside of the meat, these cause the meat not to dry out but remain moist. Because of this a “pyroligneous acid taste and smell” is left on the meat.
The author gives the requirements for a good smokehouse:
it should be perfectly dry;
not warmed by the fire that makes the smoke;
the fire shall be sufficiently far from the meat so that any vapour from the smoke shall be “thrown off” and may be condensed before reaching the meat;
yet, close enough to prevent flies, mice, etc from feasting on the meat.
The art of building a proper smokehouse was still being disseminated through the British Isles by 1841. Not only in Britain but also in Germany smokehouses were not universally used to smoke bacon. The same article refers to smoking meat in Westphalia. Smoking Westphalia hams was done at this time in “extensive chambers in the upper stories of high buildings, some of four or five stories.”
In the constructions in Westphalia, the fire was made in the cellar and the smoke directed to the meat through pipes in which the heat was absorbed and the moisture removed. The smoke was dry and cool when it came into contact with the meat. The meat is, in this way, perfectly dried and had a flavour and a colour far superior to meat smoked in the “common method.” (Belfast News-Letter, 1841) Westphalian bacon and hams were notorious for what was later referred to as cold smoking. For a detailed discussion on this, see Westphalia Bacon and Ham & the Empress of Russia’s Brine: Pre-cursers to Mild-Cured Bacon.
The strict aversion to heat of any kind in the smokehouse would not last and subsequent authors and experts found that a bit of heat produces a better environment for drying (less moist).
There is a reference from Lancaster Intelligencer (Lancaster, Pennsylvania), 1833 which states that during smoking the smokehouse should be warm but after smoking, it should be cool and dark. This “heating” of the smokehouse is an interesting reference and was by no means universally practised as we saw from the construction of the smokehouses as described from Westphalia. Another report from 1840 states that the smokehouse should be of a moderate temperature. The purpose is given as it will prevent dampness on the meat. (New England Farmer, 1840)
Heuzenroeder (2006) reports that the Westphalia method of cold smoking became the norm in Germany. “German hams were smoked, often in a series of ingenious smoking chambers or racks high up inside the chimney cavity to hold the smallgoods. Every house in growing German cities in the 1800s had smoking chambers on an upper floor with cool smoke ducted from fireplaces in rooms below. Old farmhouses devoted much space to smoking meat. The Brandedburgisches Freilichtmuseum, Altranft, Germany, has restored a farmhouse with a traditional Schwarzeküche or “black kitchen,” where the entire room in the centre of the house contains the cooking hearth. Above the whole room rises the interior of the chimney with hooks and rods for smoking meat. Notes on the restoration website say that this was the typical structure of a middle-sized Brandeburg farmhouse before 1800. (Heuzenroeder, 2006)
The Harris operation would progress this concept years later when they invented pale dried bacon where the bacon is dried in specially constructed ovens but not smoked (Harris Bacon – From Pale Dried to Tank Curing!)
– Smokehouse as the Storeroom for Finished Bacon
One system of storing the bacon was to keep it in the salt house till its sold. Then, smoke it and dispatch it to the client. Another system was to use the smokehouse as the storeroom for finished bacon. The system described in Winchester, Tennessee in 1856 calls for the bacon to be removed from the curing vats and the salt to be scraped off. Rub the bacon all over with hickory ash and hang it up for smoking, hock down. Smoke moderately for four weeks with only two fires a day made from hickory chips. On about the 1st of March, take them down, rub them with hickory ash again and hang them again. Here they remain the whole year. It makes an interesting comment that if little green mould appears on the outside of the bacon, it only ensures against spoilage. (The Home Journal (Winchester, Tennessee), 1856)
The hams and bacon can be wrapped in cotton bags for storage during the summer. Before use, dip the bag in strong salt brines to protect against insects. The next season, while bacon and hams are being smoked, hang the cotton bags in the middle of the smokehouse. The smoke will preserve the cotton.
During the summer, the bacon should not be hung against the roof, due to the heat, but in the middle of the smokehouse where it is cooler. The smokehouse should be dark, and in the summer, the ventilation holes must be closed to keep insects and rodents out.
– Was this customary in Wiltshire in the 1840s?
In asking this question, we look one more time at the possible nature of sweet-cured bacon invented by Harris in the 1840s. (Sweet Cured Harris Bacon) An article from the Yorkshire Herald and the York Herald (1840) reports on the following method of curing used in Hants, Wilts, and Somerset.
The pork is singed by packing straw around the carcass and burning the bristles, and hair off. Scalding tends to soften the meat and this method ensures the meat is left firm. The carcass is left to cool after which it is cut into flitches and salted and treated with saltpetre. The flitches are left for two to three weeks and turned three to four times. They are then wiped dry and suspended over a chimney over a wood or turf fire to dry out. A note is made that coarse sugar is used in Hampshire bacon but not in Wilts and Somerset. Hampshire bacon is imported with its particular flavour by the wood and turf smoke. During smoking, the flitches must be taken down and inspected for bacon-fly.
The 1840 newspaper report does not claim to be exhaustive, but it nevertheless creates the picture of a simple non-industrialised process and most certainly there is no mention of a dedicated smokehouse or salt house. In a dedicated butcher shop, as was run by the Harris family, one would expect a smokehouse and a curing room.
We dealt with the mild cured system of William Oake in great detail (William Oakes Mild-Cured Bacon) and since he invented what later became known as tank curing, it is important that we reference his system again.
The first major difference with what we have seen so far relates to drying. Instead of hanging the bacon to dry, Oake used pressure when he re-stacked the flitches after curing, on a dry floor. The weight of the bacon is incrementally increased as the flitches are re-stacks with the ones at the bottom now on the top and by stacking them higher and higher every time it is restacked while always rotating the position of the meat pieces.
Oake called for a quick smoking of the bacon. According to his system, between twenty-four and forty-eight hours will suffice to properly smoke the bacon if the weather is suitable, after which it may be packed and forwarded to market.” His smokehouse design is in line with what we have looked at thus far. He also used cold smoke.
Pale Dried Bacon and Wiltshire Cure or Tank Cured Bacon
The next major development in curing also came from C & T Harris (Calne). Pale Dried Bacon was invented by them just before they adopted tank curing. It was invented under John Harris in Calne in the 1890s. It is basically the same as Sweet Cured Bacon but instead of hot smoking the bacon, it was dried in special drying rooms and not smoked. The bacon was therefore pale on the outside of the flitches but it was properly dried. From there the name Pale Dried Bacon.
It was just after this, at the closing years of the 1800s or the very first few years of the 1900s that tank curing technology was transferred from Denmark to Calne in Wiltshire. The technology of mild cured bacon of Oake, invented in Ireland, adopted by the Danes finally spread to Calne, Wiltshire and became the famous British Wiltshire bacon curing or Tank curing in the closing years of the 1800s or early 1900s. For a detailed discussion, please refer to Harris Bacon – From Pale Dried to Tank Curing.
Wet-curing in combination with injection (brine cure – with pumping)
The first cooperative bacon-curing company was started in Denmark in 1887. It was seven years after the visit to Waterford in Ireland in 1880 “taking advantage of a strike among the pork butchers of that city, used the opportunity to bring those experts to their own country to teach and give practical and technical lessons in the curing of bacon, and from that date begins the commencement of the downfall of the Irish bacon industry. . . ” (Tank Curing was invented in Ireland)
It means that the Danes had the technology and when the impetus was there, they used the technology. The impetus, as we already said, was the outbreak of swine flu which saw a ban on Danish pork. They had no choice but to change their export from live pigs to bacon. The detailed description of Oakes invention and his process came to me through an Australian publication from 1889. It means that Ireland not only exported the mild cure or tank curing technology to Denmark but also to Australia, probably through Irish immigrants during the 1850s and 1860s gold rush, between 20 and 30 years before it came to Denmark. Many of these immigrants came from Limerick in Ireland where William Oake had a very successful bacon-curing business. Many came from Waterford. A report is given in The Journal of Agriculture and Industry of South Australia, edited by Molineux, General Secretary of Agriculture, South Australia, Volume 1 covering August 1897 – July 1898 and printed in Adelaide by C. E. Bristow, Government Printer in 1898. Apart from giving the complete system as invented by Oake and crediting him for the invention, it also sites one company that used the same brine for 16 years by 1897/ 1898 which takes tank curing in Australia too well before 1880 which correlates with the theory that immigrants brought the technology to Australia in the 1850s or 1860s.
One further note about the invention of tank curing by Oake from Ireland. He was a chemist and his invention had as much to do with the brine makeup as it had to do with the fact that tanks were used. Morgan’s work, already cited in great detail here, shows clearly that curing brine was a priority in Ireland in the mid-1800s. The possibility that Oake and Morgan interacted and possibly influenced each other is a tantalizing likelihood that emerges from the data.
The original founders of the St. Edmunds Bacon Factory are shown in this old print of the laying of the factory’s foundation stone in 1911.
It was Denmark, however, who continued to expand on the tank curing system, or mild cured system, as it was called, using a combination of stitch pumping and curing the meat in curing tanks with a cover brine. (Wilson, W, 2005: 219) Brine consisting of nitrate, salt, and sugar was injected into the meat with a single needle attached to a hand pump (stitch pumping). Stitch pumping was either developed by Morgan, whom we looked at earlier, or became the forerunner of arterial injection which is solely credited to Morgan.
The meat was then placed in a mother brine mix consisting of old, used brine, and new brine. The old brine contained the nitrate which was reduced through bacterial action into nitrite. It was the nitrite that was responsible for the quick curing of the meat.
The Auto Cure System and the legendary Oak Woods & Co. Ltd. Bacon Curer
The auto cure system is an excellent example of the fact that the power of the used brine was known and who else to have invented it than the son of the man who pioneered the live brine system, namely Willaim Oake!
William Horwood Oake set his curing operation up in Gillingham, Dorset with partners. It eventually became the famous Oak’ Woods & Co Ltd. Oake invented the system which was eventually in use in England, Sweden, Denmark, and Canada. William Harwood Oake passed away on 28 September 1889 in his late 40s and Evan R Down took over the running of the company. There is a report that they exported their technology to New Zealand and South Africa also. They patented it around the world and licensed its use to companies in different countries. Down became the driving force for international expansion on the back of solid patents. The Danes paid a £4,000 annual royalty for the use of the system which was probably applied in many factories across Denmark. They became the premium representation of Wiltshire bacon meaning the curing of whole bacon sides.
The process is as follows. The pig is slaughtered in the usual way and the sides are trimmed and chilled. After chilling, it is laid out in rows on a sort of truck that exactly fits into a large cylinder of steel 32 feet long, 6 feet in diameter, and which will hold altogether 210 sides. When the cylinder is filled, the lid, weighing 3 ½ tons (7000lb. Danish) is closed and hermetically sealed by means of hydraulic pumps at a pressure of 3 tons to the square inch.
A vacuum pump now pumps all the air out, which creates a vacuum of 28 inches. It takes about an hour to pump all the air out. The brine channel which leads to the brine reservoir, holding around 6000 gallons of brine is now opened. The brine rushes into the chamber and as soon as the bit of air that also entered has been extracted again, the curing starts. It happens as follows.
The brine enters the cylinder at a pressure of 120 lbs. per square inch. It now takes between 4 and 5 hours for the brine to enter the meat completely through the pores, which have been opened under an immense vacuum. When it’s done, the brine runs back into the reservoir. It is filtered and strengthened and used again.
An advantage of the system is given that the bacon can then be shipped overseas immediately. The time for total process is around three days. On day 1 the pig can be killed, salted on day 2, and packed and shipped on day 3.
There are two brine reservoirs. The one is used with a stitch pump to inject brine into the sides as usual before they are placed in the cylinder and the second tank is used. The largest benefit of this system is the speed of curing and many people report that the keeping quality of the bacon and the taste are not the same as bacon cured in the traditional way.
For a full discussion on the father-son duo of William and William Horwood Oake and their inventions, see William and William Horwood Oake.
American Rapid Curing
Auto Curing was, however, only a progression of the Rapid Curing system developed in America.
Clues as to the possible origin of the American report come to us from an 1848 report in the Sydney Morning Herald. The author begins his explanation of a certain American curing system with an interesting statement. He says that “they (we) desire considerable satisfaction in promulgating the discoveries and inventions of our fellow labourers in the field of science, no matter whether they be transmitted to us from the shores of the Neva or the banks of the Mississippi, and we, therefore, hasten to lay before our agricultural friends an important American invention, which promises to with the greatest benefit in a particular branch of the domestic economy, as well as in a commercial point of view, and which we are certain requires only to be generally known to be usually adopted.” (Sydney Morning Herald, 1848) In this, the author is completely right that adopting and adapting inventions are, for the most part not very difficult. It clues us into something of the possibility that Auto Curing may well be an improvement of an American invention.
The author then turns his attention to a certain Mr Davison. Setting the 1848 report in the Sydney Morning Herald aside for a moment, we see if we can find evidence of who this Mr Davison was. A stunning description is given by Paul (1868) who records that Mr Robert Davison attended the food committee meeting as a member of the Institution of Civil Engineers, in order to give information on the subject of desiccation as a preservative process which he studied since 1843. So, here we have Mr Davison’s first name given as Robert. He was an engineer by profession and he has been studying preservation since 1843. It definitely looks like the right man!
Paul (1868) gives us more information. He was not originally from the USA but resided in London. He writes that Robert was of No. 33, Mark Lane, in the City of London, Civil Engineer, and James Scott Horrocks, of Heaton Norris, in the County of Lancaster, registered a patent for improvements in the means of conveying and distributing or separating granular and other substances.” The patent was sealed.
Paul then explains the basis of Robert’s method of preservation being through heated air and using the newly emerging science of creating a vacuum. “The importance of hot blast had been discovered in the melting of metals, and it occurred to him that impelled currents of hot air might be advantageously applied to other processes of manufacture, especially as a purifying and desiccating process. In reference to its application to the purification of brewers’ casks, the question arose, in the first instance, as to the effect it would have upon the strength of the wood.” Here we pick up the similarities of Oake’s Auto Cure system with treating wood. “He (Robert) experimented on the subject and found that, so far from deteriorating the wood, it gave increased strength to it to a large extent. He saw that impelled currents of hot air were a valuable thing that had been overlooked, and he then turned his attention to the desiccation (the preservation of food by removing moisture) of vegetable and animal substances.
The key first observation is that his interest was in the removal of moisture and the application of heated air. You may very well wonder how on earth he brought those two together, but hang on. He did it in an interesting way. Paul (1868) writes that “he was successful in the first instance in desiccating potatoes and other table vegetables, which were preserved for a very long time; and he afterwards operated upon a quantity of rump steaks, and by depriving them of all their moisture, they were preserved in a perfectly sweet and wholesome condition for several months.” So far it sounds like standard drying and hot air would not be required. In fact, any air velocity would aid the evaporation process as is done today with fans, for example, in producing biltong. But using hot air, which is moved around sounds very similar to what we use in smoking/ drying cabinets today where the air is indeed warm.
For all South African biltong lovers and American Jerky fans, he reveals something extraordinary. Paul (1868) writes that “at the time he was engaged in these experiments an intelligent young man, brother-in-law to Dr Livingstone. . .” Dr Livingston was of course the famous African explorer missionary who resided at the Cape for some time and laboured mostly in Botswana. He had an intimate knowledge of indigenous drying practices and the value of salt.
Paul (1868) continues describing the relationship with the brother-in-law of Livingston and Robert. He does not focus on information about the indigenous practice from Southern Africa but from North America, even though I am absolutely certain that he would have informed Robert about the drying techniques in Southern Africa also. He mentions that Livingston’s brother-in-law was “then his pupil, mentioned to him that he was doing by an artificial process precisely what the North American Indians did with their buffalo meat and venison by the natural heat of the sun in preserving their provisions, and at the same time, he gave him an extract from Catlin’s work on the subject. The Indian method of drying their meat was to cut it up into thin strips, which were hung upon the branches of trees for several days in the heat of the sun. The moisture was entirely evaporated. The meat was then stowed away and would keep good for years. Salt they never used, notwithstanding the country, abounded with it. What the Indians did by natural means, he did by artificial, by the employment of impelled currents of heated air. He cooked some of the steaks desiccated by this process three or four years after they had been operated upon, and they were perfectly good and retained their flavour. After it had been soaked in water the meat recovered nearly its original bulk. In the process of desiccation, nothing but the water was removed, the albumen being all retained in the meat.” (Paul, 1868)
Take special note of his views on the nature of what causes spoilage in meat and vegetables. “By depriving them of all their moisture, they were preserved in a perfectly sweet and wholesome condition for several months.” Mr. Davison said that “he had not entertained the idea of preparing meat in this way (through drying) for the tables of the gentry, but his idea was to have the meat cut into thin slices, thoroughly dried, and packed away for use as we should biscuits. In this way, he thought an excellent article of food might be prepared for shipping purposes and for the poorer classes.” Not only is it clear that he targeted the moisture of the meat but also his method of work required cutting the meat into smaller cuts and inserting it into the apparatus manually which is similar to what the Indians (and the tribes of Southern Africa) did in cutting the meat into strips before hanging it.
“Mr Davison remarked that three or four years ago an article appeared in the Times, expressing a hope that some plan would be devised for desiccating meat in a better manner than had hitherto been done. The results of the process he had described were decidedly superior to any charqui (drying of meat) that he had seen. He had long since parted with the last portion of the steaks he had experimented upon. The apparatus for desiccation was at present largely in use for other purposes, such as the seasoning of the wood, the purifying of casks, &c. It was extensively used for the former purpose in the royal dockyards. He had no doubt he should be able to make the experiment for the satisfaction of the Committee and should have great pleasure in doing so at the earliest opportunity. The heat of the air in his experiments was 180°, but he believed the desiccation would be effected equally well at a temperature of 120° when the albumen would not be coagulated.”
Let’s now park Davison’s views of preservation which we know he worked on since 1843 for a minute and return to the Sydney Morning Herald’s 1848 article. Davison is described as, “prior to his present occupation, was long connected with the manufacture of salt.” We also learn that he resided in South America for a time, in a country “with greater capacities for the production of the hog and the ox” and his attention was turned to the preservation of meat. Mr Davison drew upon his knowledge of salt and after much investigation invented a method of curing that will sound very familiar to us. He is described as possessing an “inventive genius,” well educated and assisted in the matter of science by Dr Lardner, “whom he consulted upon his arrival in the United States.” (Sydney Morning Herald, 1848)
So, we learn that he did travel to the United States and there he solicited the assistance of a certain Dr Lardner. He was an authority on the subject of steam engines and the application of steam in industry.
Peters (1846) describes the system as follows: “The apparatus is very simple, consisting of a cylinder made airtight. It has a “mouthpiece” through which meat is loaded into the machine and closed with a lid that is screwed onto the machine. The lid has two air vents which are opened and closed by screws. Next to the machine is a large wooden vat holding the brine, connected to the machine through a pipe and elevated higher than the cylinder. A lifting pump circulated the brine from the cylinder back to the vat.” I imagine it looking something like the apparatus at the top of the three above which were associated with Auto Curing.
“Meat is cut and placed into the cylinder. Brine is allowed to fill the cylinder which is then closed. Brine is now pumped back into the vat till all the brine is out and a vacuum is formed in the cylinder with the meat pieces in. Blood, air, and gasses are thus removed from the meat also. Brine is now run back into the cylinder. The air vents are opened and the liquid brine expels all air from the vessel. As soon as the vessel is full, the air vents are closed again, the brine is pumped into the vat again and the meat is left in a vacuum. Again, blood, air, and gasses are pumped out. The cycle is repeated. The initial intervals between the cycles are short but eventually, as all the blood, air and gasses have been removed from the meat, the brine is allowed to remain in the cylinder for as long as between 6 and 8 hours. The entire process is completed in about 12 hours.”
It is here where the explanation or the link that Davison found with meat curing and preservation moves from the factual to the fanciful. He believed that the blood, air, and gasses in the meat created some kind of a “resisting power” to the brine which had to seep into the meat. The blood had an affinity for the brine and left the meat for brine to fill it. The pressure created by the elevated brine created relative pressure greater than the gasses and air. When the meat is under vacuum, the reporter writes that the meat is “swollen, its fibre distended and pores open and it readily admits the brine even at the pressure of the mere quantity of brine which the cylinder will hold.” One atmosphere was sufficient and where double and triple were used, it would respectively close and completely close the pores.
So, he abandoned the use of hot air and instead used a vacuum and the pressure of the brine. Whether his explanation is accurate or not, his invention worked. The process cures the meat in hours as opposed to weeks and he patented it. The process is named Rapid Cure.
This means that Mr Davison’s invention or the application of a vacuum and pressure in curing has priority in terms of the Oake Woods invention which is a progression of the Davison invention. In all likelihood, what Ewart refers to in his 1878 publication is the American invention that was widely in use in America. The key object of the invention was the speed of curing and not the production of mild cured bacon as was the case with the Oake Woods patent.
The primary method of obtaining “mild cured bacon” from the USA was through the addition of sugar. Ewart writes that “it should, however, be stated, that American bacon, in its several forms of flitch, roll, and ham, and any of them of small and moderate weights, are also mildly cured in which sugar is in a considerable proportion an ingredient in the curing mixture used; and the article when so prepared is deservedly held in the highest esteem.” (Ewart, 1878)
Ewart also reports the formation of a bluish-green mould upon the flesh-cut portions of the flitches and hams from bacon or ham that are “perfectly cured and becomes thoroughly dried.” He states that the mould “most effectually prevents the rusting of the fat on these parts.” (Ewart, 1878)
It is clear that Aoto Cure for the meat industry is a progression of Rapid Cure, developed by Mr. Robert Davison which had huge success in the USA. Auto Cure quickly developed an impressive list of countries that participated in the technology.
Tank Curing
For a detailed treatment on tank curing or Wiltshire curing, please refer to The Wiltshire Cut.
Denmark was, as it is to this day, one of the largest exporters of pork and bacon to England. The wholesale involvement of the Danes in the English market made it inevitable that a bacon curer from Denmark must have found his way to Calne in Wiltshire and the Harris bacon factories. The tank-cured method, as it became known, was adopted by C & T Harris (Calne). The fact was that it was already in Wiltshire in the company Oake’ Woods & Co. Ltd.. Why it took C & T Harris till the second half of the 1800s to incorporate it into their processes is a good question to which I don’t have the answer yet.
A major advantage of tank curing, as it became known in England, is the speed with which curing is done compared with the dry salt process previously practised. Wet tank curing is more suited for the industrialisation of bacon curing with the added cost advantage of re-using some of the brine. It allows for the use of even less salt compared to older curing methods. One of the biggest advantages was, however, the increased curing speed as nitrites were used which were already converted from nitrates through bacterial fermentation.
The question comes up if we have corroborating evidence that Denmark imported the Irish technology in 1880. Clues to the date of the Danish adaption come to us from newspaper reports about the only independent farmer-owned Pig Factory in Britain at that time, the St. Edmunds Bacon Factory Ltd. in Elmswell. The factory was set up in 1911. According to an article from the East Anglia Life, April 1964, they learned and practised what at first was known as the Danish method of curing bacon and later became known as tank-curing.
A person was sent from the UK to Denmark in 1910 to learn the new Danish Method. (elmswell-history.org.uk) The Danish method involved the Danish cooperative method of pork production founded by Peter Bojsen on 14 July 1887 in Horsens. (Horsensleksikon.dk. Horsens Andelssvineslagteri)
The East Anglia Life report from April 1964, talked about a “new Danish” method. The “new” aspect in 1910 and 1911 was undoubtedly the tank curing method. Another account from England puts the Danish invention of tank curing early in the 1900s. C. & T. Harris from Wiltshire, UK, switched from dry curing to the Danish method during this time. In a private communication between myself and the curator of the Calne Heritage Centre, Susan Boddington, about John Bromham who started working in the Harris factory in 1920 and became assistant to the chief engineer, she writes: “John Bromham wrote his account around 1986, but as he started in the factory in 1920 his memory went back to a time not long after Harris had switched over to this wet cure.” So, late in the 1800s or early in the 1900’s the Danes imported the Irish system and practised tank-curing which was brought to England around 1911. The 1880 date fits this picture well.
It only stands to reason that the power of “old brine” must have been known from early after wet curing and needle injection of brine into meat was invented around the 1850s by Morgan. Before the bacterial mechanism behind the reduction was understood, butchers must have noted that the meat juices coming out of the meat during dry curing had special “curing power.” It was, however, the Irish who took this practical knowledge, undoubtedly combined it with the scientific knowledge of the time, and created the commercial process of tank curing which later became known as Wiltshire cure.
Why the system was brought over from Denmark when William Harwood Oake’s dad invented the system in Ireland remains a very good question. It is almost impossible to speculate on what exactly was happening in the Harris, Oake ‘ Wood & Co Ltd and in the St. Edmunds Bacon Factory Ltd., but I have a suspicion that Oake Wood was completely focused on their auto cure system in the 1890s and early 1900s and other companies were looking for a less expensive and equally efficient system which the Danish tank curing offered them. I can on the one hand understand why competitors were reluctant to buy into the Oake Wood system of auto curing and on the other hand, why Oake ‘ Woods was reluctant to sell it to strong opposition.
What we know for certain is that tank curing undoubtedly developed from the Oake Woods factory in Gillingham, Dorset, and “diffused” into Wiltshire. It was probably independently incorporated into the Harris operation as was the case with the St. Edmunds Bacon Factory Ltd who both claim to have received the technology from Denmark.
Multi-Needle Injection and Vacuum Tumbling and The Direct Addison of Nitrites to Curing Brine
Multi-needle injector, C & T Harris (Calne) Ltd. C 1960
The composition of the brine changed around 1915 with the direct addition of sodium nitrite. For a thorough discussion on this revolutionary development, see,
Where tank curing used the fermented brine which after fermentation contained nitrites, despite the fact that only nitrates were added to the brine, to begin with, along with salt and sugar, nitrites became widely available through pharmacies at this time as it was used in treating certain heart-related ailments. Nitrites were now being included directly into curing brines, bypassing the fermentation step.
Multi-needle injectors and vacuum tumblers became commonplace in any met curing operation. It is generally accepted that these developments took place in the mid to late 1900s, but an interesting US patent (number 23,141) was awarded to L. M. Schlarb from Allegheny, Pennsylvania on 3 June 1901 directly related to injection and vacuum machines for meat curing. (Journal of the Society of Chemical Industry; 1902: 269)
The process is described as “injecting brine and carbon dioxide under pressure into the meat by means of suitable needles connected to a tank containing the brine and carbon dioxide, the pressure in the tank being about 2 atmospheres.” The nozzles it talks about may be the three-needle injectors that were used until the middle of the 1900s and the unique aspect of the patent was the use of brine in conjunction with carbon dioxide. (Journal of the Society of Chemical Industry; 1902: 269)
The next bit is fascinating as it is possibly the earliest recorded date of the use of a vacuum machine in meat processing. The patent is described in a journal article as “the meat is now placed in a vessel from which the air is exhausted, and brine is then allowed to flow in. The meat is allowed to remain in the brine for about 10 hours, and may then be subjected to the action of carbon dioxide under pressure.” If one removes the presence of carbon dioxide, it is then reasonable to assume that a vacuum machine has been in use in one shape or another to facilitate the diffusion of brine into meat, as early as 1901. (Journal of the Society of Chemical Industry; 1902: 269) The process was, however, not new as auto-curing was already in use in the second half of the 1800s in many countries across Europe.
Over the next 60 years, the multi-needle injector became bigger, with more needles until the present machines were being produced from the mid-1900s. Tumbling machines, as we know it today has been in use since the early 1970s.
Current Developments
Three major developments are currently taking root across the globe and the last one has the potential to change the way that bacon is being cured. One is a return to fermented brines where a natural carrier of nitrates is used as the start of brine preparations. A starter culture is then added to this “carrier” which will be something like celery powder or beetroot, high in nitrates and specially grown with high nitrate content in the soil. Salt and phosphates, where permitted, are added along with reducing and non-reducing sugar to complete the modern curing brines. This seems like a new curing system, but as we have seen, it is the resurrection of a curing method probably as old as humanity itself. Leafy green vegetables, spices, and many other plants are replete with nitrates and have been used in various forms to cure meat for millennia.
The second important development in commercial curing plants of the last decade is undoubtedly the introduction of what we call the grid system. According to this method, grids or bacon moulds are used to give the bacon a regular shape. The meat is normally wrapped in banking paper or some film before it is placed in the moulds and in one form or the other, an enzyme, Transglutaminase, is added to the product. The main purpose of this is to achieve higher slicing yields, but in reality, it also accounts for lower smoking losses. A detailed treatment of this method can be found at The Best Bacon System on Earth. I am inviting producers who are interested to interact with me on the process as long as developments will be used for our mutual benefit.
The third new development is about to make its entrance onto the bacon curing scene and it is this discovery that makes me particularly excited to be right at the forefront of the investigations and attempts to understand it and commercialise it. It is the use of bacteria that has the ability to oxidise certain nitrogen-containing components in meat to create nitric oxide directly which then cures the meat. Let’s spend some time looking at this development.
Bacterial Fermentation Curing
In a 2017 review I did on the curing reaction, Reaction Sequence: From nitrite (NO2-) to nitric oxide (NO) and the cooked cured colour, I quoted Morita et al. as referenced by Gasasira (2013), who found that nitric oxide (NO) formation in nitrite-free system is achieved from L-arginine due to nitric oxide synthase (NOS) in either Staphylococci or Lactobacilli. (Gasasira, et al, 2013) The nitric oxide-producing enzyme in cells is called nitric oxide synthase (NOS), which converts L-Arginine into L-Citrulline and nitric oxide (NO).
This simple statement opens up the world as far as nitrite-free curing is concerned. I was doing a review of this matter again on the night of 24 June 2022 when the gravity of the work of Morita (1998) on the subject dawned upon me. I re-looked at the 2017 reference I made and thought about the implications. During the last year, I focused my own efforts on an enzymatic solution for the oxidation of nitrogen in L-Arginine by the application of extracted enzymes. The cost of these oxidizing enzymes was however prohibitively expensive and after consulting with Novozymes on the matter, I realised that the direction was unfruitful.
For the first time ever, I personally considered the use of bacteria to deliver the oxidation and found the species of staphylococcus most likely to be involved in the process. The earliest work on the subject I discovered was indeed Morita (1998), but his work was on low-pH salami. Li (2011) seems to be one of the earliest researchers to have noticed the formation and identification of nitrosylmyoglobin by certain Staphylococcus species in raw meat batters and suggested a potential solution for nitrite substitution in meat products. Again, I noticed that in 2017 already, I quoted Møller and Skibsted (2001), who observed that “Parma ham is traditionally produced using only sodium chloride without the addition of nitrate or nitrite and develops a deep red colour, which is stable also on exposure to air. The identity of the pigment of Parma ham has not been established, but bacterial activity has been explored as responsible for transformation into nitrosylated heme pigments. In one study, the stability of the pigment isolated from two different types of dry-cured ham (made with or without nitrite) was compared to that of the NO derivative of myoglobin formed by bacterial activity. Heme pigment from Parma ham made without nitrite was more stable against oxidation than the pigment from dry-cured ham with added nitrite.” (Møller and Skibsted, 2001)
They observed that “Heme pigments extracted from Parma ham and a bacterial (Staphylococcus xylosus) formed NO-heme derivative had similar spectral characteristics (UV/ vis spectra and ESR). ESR spectroscopy of heme pigment isolated from salami inoculated with bacteria had NO in a predominant pentacoordinate NOheme environment, whereas MbFeIINO, formed from nitrite and ascorbate, exclusively showed hexacoordinated iron, a difference which could be due to the decrease in pH during fermentation.” (Møller and Skibsted, 2001)
In Europe, Commission Regulation [EU], 2011, The conclusion was drawn that Staphylococcus xylosus has been shown to convert metmyoglobin to nitrosomyoglobin in a culture medium in salami (Morita et al., 1998) and in raw meat batter (Li et al., 2013, 2016), without the addition of nitrate or nitrite.
NO production has been suggested to be linked to NO synthase (NOS) activity. Alderton (2001) also concluded that NOS catalyzes the production of NO from L-arginine and was initially described in mammals (Alderton et al., 2001).
The all-importantquestion of whether nitric oxide without nitrite will facilitate the inhibition of Clostridium botulinum was answered by Reddy by pointing out that NO2– is not the inhibiting factor against c. botulinum, but NO. He writes, “Vegetative cells of Clostridium botulinum were shown to contain iron-sulfur proteins that react with added nitrite to form iron-nitric oxide complexes, with resultant destruction of the iron-sulfur cluster. Inactivation of iron-sulfur enzymes (especially ferredoxin) by binding of nitric oxide would almost certainly inhibit growth, and this is probably the mechanism of botulinal inhibition by nitrite in foods.”
This all places us in a uniquely exciting time, but much work must be done. For example, NO3-, NO2- and NO are like the Christian concept of the Father, the Son and the Holy Spirit in that where you have one, you are likely to find the other. If we then cure meat without nitrites and nitrites develop post-curing, did we solve the matter? The second question is that knowing the facts that I just presented by no means results in a curing system that can be used in a commercial curing operation. What I just gave you have been available in the literature for a decade and a half. It is nothing new to science. Obstacles such as shelf life and colour stability pose daunting challenges, and researchers are working tirelessly to solve the challenges.
In South Africa, the master curer, Richard Bosman, and I partnered to take up the challenge with arguably one of the leading researchers in the world of nitrite curing from an esteemed American University. With partners in Europe, we are starting our own attempt to crack the riddle, and we are energised by existing work that has been done by our European partners. I am myself under restrictions by NDAs in terms of making anything public that is not in the public domain, and both Richard and I will remain bound by relevant agreements and collaborations, yet what has been in the public domain must be noted in a review of curing systems.
Richard and I are very aware that it took two world wars and the efforts of the Griffith Laboratories in Chicago to change the world from NO3- curing to NO2- curing. Only lab work will not spread the gospel, nor will the simple facts that I stated above about the role of microbes in the generation of NO, which cures the meat, lead to a curing system that actually works.
There is an altogether different matter to consider and that is the avalanche of recent work conclusively showing the essential role of nitrite, nitrate and nitric oxide in human physiology. An understanding is emerging that these compounds are not inherently either good or bad for humans or other mammals. In fact, they are essential. Certain conditions, as it were, tip the scale for them to be either destructive or immensely constructive in essentially contributing to our health. Apart from nitrite-free curing, or, I should rather say, parallel to this, we have made it our goal to understand what these factors are and incorporate them into our food systems and we are developing a number of novel ways that we believe it can be done.
Especially related to this section, frustratingly for readers, I do not provide all the references below (work in progress)- I realise this, and as I find time to return to this, I will provide all references and cross-check how I use them. I will confirm that all the references I give are actual work by the quoted scientists, or are they stating facts that they have not verified themselves. I have to ask everybody to forgive me for this approach, as research is not my primary occupation. I actually earn my living through meat processing and do this work in the minutes I am free in the day. As I always do, I will provide the full set of references and verify every comment over time. Accuracy is of the highest importance to me and so if you spot any misquotes, please mail me at ebenvt@gmail.com. There is enough work done, however, on the subject by others to present the general case and explain the direction of our future efforts along with a wide scope of international collaborators.
The N-Nitrosamine Controversy and the discovery of the Physiological importance of Nitrite: Towards Bacon as a Superfood
No survey of meat curing will be complete without a brief mention of the N-Notrosamine issue and the subsequent discovery of the physiological importance of nitric oxide, together with nitrate and nitric oxide to our physiology. In my book on the history of meat curing, which is, in a way, a detailed treatment of this paper, I devoted the closing four chapters to the matter. I refer the reader to them.
This review is done from the perspective of a commercial high-throughput bacon plant. It, however, paints a rich picture and most of what is regarded as “artisan” today has been the way that large throughput factories of yesteryear have done it. In years to come, how bacon was cured even when we embarked on our current bacon project in 2008 will be regarded as “artisan curing” as we have seen the transition to moulds or grid curing over the last 10 years.
I vividly remember my first introduction to the fascinating world of meat curing when I used Prague Powder (invented by Griffiths) and embarked on a quest to find the origins of the name. Over the intervening 24 years, I have been constantly busy trying to understand the curing of meat and I have a sense that we stand at the dawn of significant breakthroughs in terms of our understanding of the natural world and the amazing cycles that govern it. Such a fundamental system is what we see at work in meat curing.
(c) Eben van Tonder
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Yeats, J. 1871. The technical history of commerce; or, Skilled labour applied to production. Cassell, Petter, and Galpin
These are the men who laid the scientific foundation that resulted in the change from the use of saltpeter to sodium nitrite in meat cures. Initially, the reactions of nitrite and nitric oxide () were studied separately until Haldane showed that nitrite only had value as the initiator of a reaction sequence that produce nitric oxide ().
Note that hemoglobin is used in the early studies. The reason is “mostly a matter of convenience” and “a matter of necessity since myoglobin was not isolated and purified until 1932 (Theorell, 1932).” “In spite of the differences between hemoglobin and myoglobin, Urbain and Jensen (1940) considered the properties of hemoglobin and its derivatives sufficiently like those of myoglobin to allow the use of hemoglobin in studies of meat pigments.” (Cole, Morton Sylvan, 1961: 2)
These are the pioneers of our current understanding of the chemistry of curing.
HUMPHREY DAVY
Humphrey Davy (1778 – 1829) in 1812 (cited by Hermann, 1865) and Hoppe-Seyler (1864) was the first to note the action of nitric oxid upon hemoglobin. (Hoagland, R.; 1914: 213)
HERMANN
Hermann (1865) studied the properties of the compound formed in the reaction between hemoglobin and nitric oxide.
He showed the spectrum of oxyhemoglobin and NO-hemoglobin. “The blood saturated with nitric oxid was found to be darker in color than either arterial blood or that saturated with carbon monoxid.” (Hoagland, R.; 1914: 213)
GAMGEE
On 7 May 1868, Dr. Arthur Gamgee from the University of Edinburgh, brother of the famous veterinarian, Professor John Gamgee (who contributed to the attempt to find ways to preserve whole carcasses during a voyage between Australia and Britain), published a groundbreaking article entitled, “On the action of nitrites on the blood.” He observed the colour change brought about by nitrite. He wrote, “The addition of … nitrites to blood … causes the red colour to return…” Over the next 30 years, it would be discovered that it is indeed nitrites responsible for curing and not the nitrates added as saltpeter.
POLENSKI
It fell upon a German researcher, Dr. Ed Polenske (1849-1911), working for the Imperial Health Office in Germany, to make the first discovery that would lead to a full understanding of the curing action. He prepared a brine to cure meat and used only salt and saltpeter (nitrates). When he tested it a week later, it tested positive for nitrites.
The question is where did the nitrites come from if he did not add it to the brine to begin with. He correctly speculated that this was due to nitrate being converted by microbial action into nitrite. He published in 1891.
NOTHWANG
Following Dr. Polenski’s observation, the German scientist, Nothwang confirmed the presence of nitrite in curing brines in 1892 but attributed the reduction from nitrate to nitrite to the meat tissue itself. The link between nitrite and cured meat colour was finally established in 1899 by another German scientist, K. B. Lehmann in a simple but important experiment.
LEHMANN
Karl Bernhard Lehmann (1858 – 1940) was a German hygienist and bacteriologist born in Zurich.
In an experiment he boiled fresh meat with nitrite and a little bit of acid. A red colour resulted, similar to the red of cured meat. He repeated the experiment with nitrates and no such reddening occurred, thus establishing the link between nitrite and the formation of a stable red meat colour in meat.
K. B. Lehmann made another important observation that must be noted when he found the colour to be soluble in alcohol and ether and to give a spectrum showing an absorption band just at the right of the D line, and a second band, often poorly defined, at the left of the E line. On standing, the color of the solution changed to brown and gave the spectrum of alkaline hematin, the colouring group.
KIßKALT
In the same year, another German hygienists, one of Lehmann’s assistants at the Institute of Hygiene in Würzburg, Karl Kißkalt (1875 – 1962), confirmed Lehmann’s observations and showed that the same red colour resulted if the meat was left in saltpeter (potassium nitrate) for several days before it was cooked.
HALDANE
The brilliant British physiologist and philosopher, John Scott Haldane weighed in on the topic. He was born in 1860 in Edinburgh, Scotland. He was part of a lineage of important and influential scientists.
J. S. Haldene contributed immensely to the application of science across many fields of life. This formidable scientist was for example responsible for developing decompression tables for deep sea diving used to this day.
“Haldane was an observer and an experimentalist, who always pointed out that careful observation and experiments had to be the basis of any theoretical analysis. “Why think when you can experiment” and “Exhaust experiments and then think.” (Lang, M. A. and Brubakk, A. O. 2009. The Haldane Effect)
S. J. Haldele applied the same rigor to cured meat and became the first person to demonstrate that the addition of nitrite to hemoglobin produce a nitric oxide (NO)-heme bond, called iron-nitrosyl-hemoglobin (HbFeIINO).
Haldane showed that nitrite is further reduced to nitric oxide (NO) in the presence of muscle myoglobin and forms iron-nitrosyl-myoglobin. It is nitrosylated myoglobin that gives cured meat, including bacon and hot dogs, their distinctive red color and protects the meat from oxidation and spoiling.
This is how he discovered it. Remember the observation made by K. B. Lehmann that the colour of fresh meat cooked in water with nitrites and free acid to give a spectrum showing an absorption band just at the right of the D line, and a second band, often poorly defined, at the left of the E line.
Haldane found the same colour to be present in cured meat. That it is soluble in water and giving a spectrum characteristic of NO-hemoglobin. The formation of the red color in uncooked salted meats is explained by the action of nitrites in the presence of a reducing agent and in the absence of oxygen upon hemoglobin, the normal coloring matter of fresh meats. He showed that the redox reaction occurs in meat during curing (1901).
Haldane finally showed the formation of nitrosylhemochromogen from nitrosylhemoglobin (nitrite added to hemoglobin) when thermal processing has been applied and identified this as the pigment responsible for the cooked cured meat colour. He attributed this formation to NO-hemoglobin denaturing into two parts namely hemin (the colouring group) and the denatured protein (1901).
HOAGLAND
Ralph Hoagland, Senior Biochemist, Biochemie Division, Bureau of Animal Industry, United States Department of Agriculture, published an article in 1914, Coloring matter of raw and cooked salted meats. In this article, he shows that nitrite as curing agent was a known and in theory an accepted fact by the outbreak of World War One.
Ralp Hoagland (1908) studied the action of saltpeter upon the colour of meat and found that its value as an agent in the curing of meats depends upon the nitrate’s reduction to nitrites and the nitrites to nitric oxid, with the consequent production of NO-hemoglobin. The red colour of salted meats is due to this compound and that the nitrite anion is not the reactant. He showed that the reactant is nitrous acid () or one of its metabolites such as nitric oxide ().
Hoagland conclusively shows that saltpeter, as such, has no value to preserve the fresh colour.
Cole, Morton Sylvan, “Relation of sulfhydryl groups to the fading of cured meat ” (1961). Retrospective Theses and Dissertations. Paper 2402
Hoagland, R. 1914. Cloring matter of raw and cooked salted meats. Laboratory Inspector, Biochemie Division, Bureau of Animal Industry. Journal of Agricultural Research, Vol. Ill, No. 3 Dept. of Agriculture, Washington, D. C. Dec. 15, 1914.
At our pork processing plant in Cape Town, Woody’s Consumer Brands, we use Prague Powder to cure the meat. I wondered where the name comes from and a fascinating journey started.
Prague Salt and its later version of Prague Powder are meat cures that contain sodium nitrite, a revolutionary development which transformed the cured meat industry. The name Prague Salt is closely tied with the direct addition of nitrite in curing brines. The one story is the story of the other.
From the outset, a word of caution. This is the background to the enigmatic name, Prague Salt. The historical context in Germany, Prague and in the USA are considered between the middle of the 1800 to the 1920’s, related to sodium nitrite. It does not deal with the safety of nitrite in foods. An extraordinary amount of data on nitrites became available since 1925 which form the basis of every government on earth and the Wold Health Organisation’s decisions to allowing its use in the curing of meat. A full overview of these considerations will be presented in a future article.
With that cautionary, let us begin.
In order to understand what Prague Salt is and why it is so important for meat curing we begin with an overview of the curing process.
Meat curing is a complex process where brine ingredients react with each other and with the meat which is made up of “water, proteins, lipids, carbohydrates and inorganic, non-protein compounds containing nitrogen and trace amounts of vitamins. (Pegg, B. R. and Shahidi, F.; 2000: 23) Each reaction is governed by many and complex factors and mechanisms, some of which are still not clearly understood by modern science.
Curing is a fascinating process. A modern understanding of the benefits of curing is that it fixes a pinkish-reddish cured meat colour. It endows the meat with unique longevity, even if left outside a refrigerator, many times longer than that of fresh meat. It is powerful enough to prevent the deadly toxin formation by clostridium botulinum. It prevents rancidity in fat. It lastly gives meat a unique cured taste.
Discovering the curing process and the mechanics behind it was a slow process that took hundreds of years. The object was the preservation of meat for future consumption. Bacon and other cured products, properly prepared, have, however, always been a delicacy as it remains to this day. Today, taste and a visual appeal probably dominates, but ask any outdoor’s person and they will tell you that preservation for future consumption is still a huge factor in the immense popularity of cured meats.
Before the 1600’s meat preservation was done with salt only. Vegetable dyes were used to bolster colour. (The history of curing) A few people added a little bit of saltpeter (potassium nitrate) to the salt for “cured colour development.” This practice gained momentum from the year 1700. By 1750, the trend turned into the norm, being practiced almost universally. During the 1800’s sugar was added to the mix. This, with the exception of phosphates which have been added since the mid-1900’s, is very much the same process as we follow today. (Ladislav NACHMÜLLNER vs The Griffith Laboratories)
On 7 May 1868, Dr. Arthur Gamgee from the University of Edinburgh, brother of the famous veterinarian, Professor John Gamgee (who contributed to the attempt to find ways to preserve whole carcasses during a voyage between Australia and Britain), published a groundbreaking article entitled, “On the action of nitrites on the blood.” He observed the colour change brought about by nitrite. He wrote, “The addition of … nitrites to blood … causes the red colour to return…” (Gamgee, A; 1867 – 1868; Vol. 16, 339-342) Over the next 30 years, it would be discovered that it is indeed nitrites responsible for curing and not the nitrates added as saltpeter.
It fell upon a German researcher, Dr. Ed Polenske (1849-1911), working for the Imperial Health Office in Germany, to make the first discovery that would lead to a full understanding of the curing action. He prepared a brine to cure meat and used only salt and saltpeter (nitrates). When he tested it a week later, it tested positive for nitrites. (Polenske. E. 1891)
The question is where did the nitrites come from if he did not add it to the brine to begin with. He correctly speculated that this was due to nitrate being converted by microbial action into nitrite. He published in 1891. (Polenske. E. 1891)
Karl Bernhard Lehmann and Karl Kißkalt discovered in 1899 that nitrite is responsible for the reddish color of dry cured meat. It was John Scott Haldane who showed in a 1901 article that the cured meat colour is due to a nitrosylheme complex. (Concerning the direct addition of nitrite to curing brine) (Hoagland, Ralph. 1914) [1]The heme part of the meat protein is where the colour is generated through the presence of an Fe ion and nitrolsyl refers to a non-organic compounds containing the NO group. In the protein, nitric oxide is bound to the Fe ion through the nitrogen atom. Therefore the term, nitrosylheme complex.
The change of nitrate into nitrite through bacterial action takes weeks. If a salt, like sodium nitrite, is used instead of saltpeter, curing is accomplished in days or even hours (if a heating step is applied to the meat before it is smoked).
The only aspect in curing that is time-consuming is however not the bacterial reduction of nitrates to nitrites. The change from nitrite into a form that reacts with the meat protein and produce the nitric oxide coupling with the Fe ion is also not instantaneous. The rate of reaction is slow.[2] It is not like mixing sugar into coffee. An analogy is if you put sugar in your coffee and have to wait twelve hours and reheat it in the microwave before you can taste sweetness.
When the brine enters the meat, the anion is formed and a very small amount of nitrite (less than 1% of the total nitrite) forms the neutral nitrous acid (). It is nitrous acid that is responsible for the formation of nitrosating compounds which is the ultimate reaction of joining nitric oxide to an organic compound, in this case, the myoglobin protein (resulting in a nitroso derivative). (Sebranek, J. and Fox, J. B. Jn.. 1985)
The first step in the reaction sequence of creating such a link between myoglobin and niric oxide is the formation of nitrous acid (). From nitrous acid, the neutral radical, nitric oxide is formed directly as well as a variety of nitrosating species or molecules that create such a nitrite-oxygen pair of atoms to link to an organic structure like a protein. [3][4] (Sebranek, J. and Fox, J. B. Jn.. 1985)
This reaction takes time and its rate is dependent on the pH of the meat it is injected into, the temperature of the meat and the brine and the concentration of nitrite. Curing then happens when the nitric oxide reacts with iron which is part of the meat proteins, myoglobin. [1]
The concentration of nitrous acid is very low in meats. This means that the potential for nitrite to change into nitric oxide to react with the meat protein is very low. In general, nitrite is readily reduced by endogenous reductants in the meat to form nitric oxide. (Toldr, F.; 2010: 180) [5]The reduction of nitrous acid can be sped up by adding a “reducing agent” to the brine mix. (Pegg, B. R. and Shahidi, F.; 2000: 39) (the presence of table salt also speeds up the conversion of nitric oxide, but this matter is for another article)
One such reducing agent, introduced to brine cures in the 1800’s, is sugar. [6] Sugar was added originally to reduce the salty taste of the meat. Curers noticed that if sugar is added with saltpeter to the brine mix, the meat cures slightly faster and with better colour development. (The history of curing) In the 1920’s, ascorbate or its isomer, erythorbate became the magical reducing agent [7] , but this too is the subject for another article.
If saltpeter is used as principal curing ingredient, adding sugar favours the proliferation of bacteria that reduces nitrate to nitrite. It, therefore, speeds up the curing process.
Better colour development is due to the action of reducing sugars (such as brown sugar) to create a reducing environment in the meat which encourages the reduction of nitrous acid to nitric oxide (Kim-Shapiro, D. B. et al. 2006). [6] (The history of curing)
This was then the understanding of meat curing by the beginning of the 1900’s. Scientists knew that adding nitrite directly to the meat would dramatically speed up the curing process, but working out how to do it and navigating through the complex maze of public perception and legal restraints would be another matter altogether.
Changing from saltpeter to the direct addition of nitrite in curing brines has not been easy to accomplish. In 1925, a curing brine was imported into the USA by the Chicago-based firm, the Griffith Laboratories. It was a crude mechanical mix of sodium chloride (table salt) and sodium nitrite. They called it Prague Salt. It arguably became the most successful curing brine of the early 1900’s.
The name fascinated me. Especially after an internet search where I learned that nobody really had a clue where the name came from. The Griffith Laboratories documents state that the product was imported from Germany (Ladislav NACHMÜLLNER vs The Griffith Laboratories), but I was unable to find a curing brine from the 1920’s that was produced and sold in Germany called Prague Salt. I found no reference to Prague Salt at all before 1925, in Germany or any other country for that matter.
If it was not called Prague Salt in Germany, why would Griffith call it that? I wondered if the fact that “Prague” is used in the name had any definite link to Prague, even if it was produced in Germany. Is there a link and if so, what and possibly, who is that link? Is there any significance to the “Salt” in Prague Salt? Similar curing brines of the time was not called “salt.” Is this just coincidence or is there more to this?
I started to unravel the history of the direct addition of nitrite to curing brines. Tantalizing possibilities of what was behind the name, Prague Salt, developed. The answers are conjecture, but as you will see, they naturally flow from concrete facts. The conclusions are presented here, in part, to allow others to contribute and bring evidence to the table that will prove the contrary or confirm my hypothesis. As new information comes to light, this article will be amended. What I discovered makes for one of the greatest stories of our age.
The Danes took the development where nitrites are directly applied to curing, in one very particular direction. They invented the “mother brine” cure. The English imported this Danish invention as early as the 1910’s and called it tank curing. Tank curing later became the famous Wiltshire curing process. (The Mother Brine and C & T Harris and their Wiltshire bacon cure)
In this process, a nitrite and salt brine is prepared and injected into meat. The brine that inevitably runs out of the meat (exudate) contains nitrate that has been turned into nitrites by bacterial action. When the meat is finally removed for smoking, the leftover brine is collected. It now contains nitrites.
The next batch of meat is injected with fresh salt and nitrates and placed in a tank with the old brine which contains nitrites. The old brine that is re-used is called the mother brine. This method is particularly effective in terms of final product quality due to the action of enzymes, but again, the subject is for another article.
There was another easier option in the early 1900’s. Nitrites were already being used in a large, industrial process since the end of the 1800’s in the form of sodium nitrite. This made it generally available.
Sodium nitrite was used in the production of azo dyes. It was available in every country and city where there was a large dye industry. This was part of the new and booming new industry of coal-tar dyes. The late 1800’s and early 1900’s was the birth of the age of chemistry and chemical synthesis, a development that directly resulted from the dye industry. (Concerning Chemical Synthesis and Food Additives)
A direct consequence of this development (chemical synthesis) was the creation of new preservatives and colourants which flooded the market and offered to improve food safety through chemical means. In reality, it became a way to disguise inferior products. There was an uproar from consumers around the world and governments reacted by introducing food legislation. (Concerning Chemical Synthesis and Food Additives)
Unscrupulous producers cheated the public but many food scientists and producers had noble intentions. Populations in Europe and the UK were booming and the race was on to find a way to feed them from produce from the new world. Chemical preservation was one of the options of making it possible to supply the old world with meat from the new. This was before refrigeration solved the problem definitively, early in the 1900’s. (Ice Cold Revolution) The general public’s perception about sodium nitrite was, however, that it was part of the chemicals dye industry and that it had no place in food preparations.
There were nevertheless early scientific flirtations with the use of sodium nitrite in meat. A laboratory in Germany, founded by C. R. Fresenius, records in 1848 experiment with sodium nitrite to preserve meat. (Ladislav NACHMÜLLNER vs The Griffith Laboratories)
An article appeared in the Sydney Morning Herald on 1 March 1870 where it lists the methods of preserving canned meat in use at that time. Included in the list of “antiseptic agents” are “sulfurous and nitrous acids, sulphites and nitrite. (It also lists sodium and “other substances having a special affinity for oxygen.”) It was explained that “these agents are not applied to meat itself, but are used simply to absorb oxygen unavoidably left within the tins and pores of the meat.” As far as the preservation of fresh meat is concerned, the world saw it as a race between the use of chemicals or cold. (Sydney Morning Herald, 1 March 1870, p4)
The major obstacle standing in the way of a chemical solution was perception. Those of the general public and the governments of the world alike.
Between the mid 1800’s and early 1900’s, industry and informed members of the public knew nitrite as an ingredient in medication [8] (Vaughn E, et al.;2010; Jul–Aug; 18(4): 190–197) and sodium nitrite as an intermediary in the chemicals dye industry. (Concerning Chemical Synthesis and Food Additives) Most people, however, knew nitrite as a toxic chemical that kills livestock and people if the drinking water has even small traces of it. Such was the concern that nitrite levels in drinking water were reported in local newspapers every week to alert the public to possible contamination. It is, therefore, no wonder that the public and authorities were very skeptical about its use in food.
At the beginning of the 1900’s, science developed a detailed understanding of the chemistry of curing which clearly showed the priority of nitrites in curing. In contrast to this, the general public and their elected officials were against the direct use of nitrites in food. As is many times the case, the scientific understanding was not general knowledge yet.
We now delve deeper into the story and zoom in on developments in three parts of the world, Prague, Germany and in the USA, Chicago. Events, dates, and places will start to overlap and two processes will become very important, the electric arc method of extracting nitrogen from the atmosphere and the Haber process.
As we do so, it is important to understand one more point in chemistry namely the close proximity of nitric oxide (), nitrous acid (), nitric acid (), nitrite (), nitrate () and ammonia (). All have a nitrogen atom as part of either the molecule or the ion. The Haber process yields ammonia () and the electric arc process, either nitrous acid () or nitric acid (). From any of these, nitrite () can be formed. (Webb, H. W.; 1923)
PRAGUE 1800 – 1920 – Food innovation, industrial leadership and the availability of nitrite
Prague, Logansport Pharos Tribune, 19 Oct. 1895
Germany’s neighbor and ally in World War One, the Austro-Hungarian Empire with the key cities of Prague, Vienna and Budapest, in the late 1800’s and early 1900’s led the world in many respects in matters pertaining to science and technology. In Bohemia and regions surrounding Prague the industries were leading Europe in innovation. (Turmock, D.;1989: 40) It was reported that in many respects, industry in this region surpassed Germany.
A huge textile industry developed in Vienna. In Prague, cotton printing became the dominant industry with the accompanied dyes industry. Bohemia, in general, had well-developed textile manufacturing. (Hiemstra-Kuperus, E. 2010) This means that by the early 1900’s, sodium nitrite was available in and around the city of Prague.
Prague and surrounding areas were not just a consumer of chemicals. The scientific and industrial environment was sophisticated and advanced and they produced many of the chemicals for their industry themselves, primarily in support of the textile printing industry. The point is that we when we deal with the people in Prague, we are talking about people who understood chemistry (my personal experience is that this is still the case to this day).
D. Hirsch, for example, established his factory in Prague to “provide acid for calico printing in 1835.” F. X. Brosche supplied printing inks, paint, and pharmaceuticals. The first major chemicals producer in the area was Johann David (J. D.) Starck had a sulfuric acid plant near Zwittau (now Svitavy in the Czech Republic), 183km to the east of from Prague, in 1810.
Between 1810 and 1850, J. D. Starck expanded into a multi-plant operation manufacturing a variety of products including phosphates at Kaznau (now Kosnejov, in the Czech Republic), 109km South West of Prague. He was big enough to own his own source of coal from the Falknov (Sokolov) basin. (Turmock, D.;1989: 39) It all supports a picture of sodium nitrite being readily available in Prague as part of the chemicals associated with the dying and textile printing industry. [9] More than that, the Bohemian people proofed to be innovative and capable in matters pertaining to chemistry.
At the end of the 1800 and beginning of the 1900’s, Prague was a fertile breeding ground for industrial and food innovations. A case in point is the phenomenal success of Pilsner named after the city of Pilsen (Plzen). The innovation was the application of steam power to the production of chilled lager. It was an important improvement on the old processes and helped the town of Pilsen to become one of the great European beer producers. (Turmock, D.;1989: 40)
Another Bohemian innovation was the invention of the sugar beet refining process through diffusion to produce refined sugar. “The diffusion process was discovered in Seelowitz (Zidlochovice) in Moravia by J. Robert, the son of the founder of the first sugar beer factory in the Czech lands.” Within a few years, 25 other factories converted to this process and sugar refining machines were being exported to Germany and France. The Prague-based engineering firm of C. Danek (founded in 18540) was particularly successful. (Turmock, D.;1989: 40)
The kingdom boasted the most sophisticated food industry with a very strong scientific backing from the local academia in Prague. Under their leadership, the first food code in industrialized Europe was created, the Codex Alimentarius Austriacus, which is the basis for international food legislation to this day. (The Life and Times of Ladislav NACHMÜLLNER – The Codex Alimentarius Austriacus) It also became the first country in the world to specifically allow the use of sodium nitrite in food, before Germany and the US.
Not just was Prague and the Bohemian people leading the world in food innovation and food science and chemistry, but the existence of large food industries created an environment where other food industries would benefit, for example, the meat industry. (Turmock, D.;1989: 39, 40)
The ether around Prague and the Bohemian people was right for a company or an individual to step forward and take up the challenge to work out the details of how to use sodium nitrite directly in meat curing.
Into this advanced and scientifically and industrially mature environment, Ladislav Nachmullner was born on 2 April 1896. (Eva’s Beloved Dad)
In 1912, the Bohemian boy, Ladic (Ladislav) NACHMÜLLNER was 16 years old. His dad tragically burned to death four years earlier, in 1908, when his clothes caught fire in his home. His mother had just passed away from tuberculosis and as the oldest child, the responsibility fell on him to care for his siblings.
Ladic got an opportunity to learn the art of meat curing to provide for his siblings in a land where chemistry was well understood, salts were of a high quality, sodium nitrite was widely available and there was an appetite for and a culture of innovation in food production. He was taught the art of curing by a well known butcher, Josef Pazderky from Praha, almost 600km from Prague. He was an unusually gifted young man who learned fast and an illustrious career followed.[10] At the young age of 19 he invented Praganda, which would become the most successful curing brine of its day, containing sodium nitrite. This was the year 1915 when he also started writing his book on Praganda.
How his invention happened is not known, but possibly very early in his employment he was introduced to the use of sodium nitrite for meat curing. Ladic himself gives important clues.
He says that he discovered the power of sodium nitrite through “modern-day professional and scientific investigation.” He probably actively sought an application of the work of Haldane. Ladic quotes the exact discovery that Haldane was credited for in 1901 that nitrite interacts with the meat’s “hemoglobin, which is changing to red nitro-oxy-haemoglobin.” This must have made a profound impression on him which explains why he never forgot it. If it was not him personally, it must have been his mentors in Prague who decided to start experimenting with sodium nitrite to develop a meat curing brine.
The “modern day professional investigations” that he spoke off would have been the input of master butchers who was not primarily interested in a quicker process, but in a better end product. Saltpeter is potassium nitrate. The butchers did not like it due to the slightly bitter taste of potassium. Butchers who used Ladic’s brine would later put signs in their shop windows that their meat is free of saltpeter.
Another point that Ladic specifically addressed in his nitrite-based brine is the use of as little nitrite as possible. This shows an advanced understanding of the chemistry or curing and an ability to apply this to his trade.
His fame as curer spread and he received employment offers from more countries. He moved to Austria and then, Switzerland for the duration of the war.
He received offers for management positions from all over Germany, France, England, Holland, Switzerland, Romania, Yugoslavia , Poland and as far afield as America and China.
He says that he invented Praganda in 1915 (when he was 19 years old) and at a time when the use of nitrites in food was not legal in Germany.
We know that it was not legal in Germany before August 1914 when Walther Rathenau who created the War Raw Materials Department (Kriegsrohstoffabteilung or KRA) restricted the use of saltpeter to military purposes only and the use of nitrites in food were allowed. Germany again banned its use some time during the war. The concession on sodium nitrite’s use in food was reversed after an accident in Leipzig where sodium nitrite was mistaken for table salt and 34 people died. (Concerning Nitrate and Nitrite’s antimicrobial efficacy – chronology of scientific inquiry) This must then have happened some time in 1915.
The impression one gets from reading his life story through the writings of his daughter Eva, is that he probably learned the basics of nitrite curing early on and this “paid his way” on many travels through Europe. Along the way, he must have continued to refine and perfect his formulations and solve the many challenges of using such a potentially dangerous chemical. (For a detailed analysis of the technical challenged facing him and how he dealt with it, see Ladislav NACHMÜLLNER vs The Griffith Laboratories.)
His move to Switzerland for the remainder of World War One is of interest. In Switzerland, the Polish chemist, Prof. Mościcki of the University of Freiburg, invented a process to use atmospheric nitrogen to produce both nitric and nitrous acid (US patent US1097870) in 1901 through the use of an electric arc in a closed container. (cesa-project.eu)
In 1910, a factory opened in Switzerland, Chippis, in Wallis canton,where the world’s first nitrous acid was produced using Prof. Mościcki’s electric arc process. (cesa-project.eu) This means that a factory producing nitrite was in operation in the same country where Ladislav lived, during the war.
It is equally important that Prof. Mościcki opened another factory in Poland during the War, the Azot nitrogen factory near Jaworzno. (cesa-project.eu) Jaworzno is less than 460km from Prague.
From the evidence of his life, handed down to us by his daughter, Eva, he returned to Prague from Switzerland in 1929 and set up his first outlet where he sold Pragnada and ham moulds which he invented.
It makes Prague the center of the development to add sodium nitrite directly to meat, other than canned meat.
(All information and pictures about Ladislav Nachmüllner and Praganda, from Ladislav Nachmüllner vulgo Praganda. Nachmüllnerová, Eva, Editor, 2000, Translated by Monica Volcko)
The history of Ladislav Nachmuller not only points to the first commercial curing brine containing nitrites, but also to the use of pure salt from the regions surrounding Prague. Using the correct salt was very important to Ladislav. The area around Prague, like the neighbor to the north, Poland, were famous for the production of high-quality salt. Ladislav procured salt from various mines, including from the salt producer, Solivary Prešov. He gives the requirement for good salt as pure, clean, and “regular salt.” This mine delivered on this requirements.
Mining at Solivary Prešov started as far back as the 13th century. The salt was produced from “brines” (water saturated with a salt solution) where the water was evaporated. First in pans and then in boiling rooms. The final result was good quality NaCl (table salt) which has been popular among butchers in the area on account of its purity. (From private communication with the museum curator, Prof. Marek Duchoň)
Historical records inform us that the salt production exceeded local consumption, which points to the fact that the salt from Solivary Prešov was widely traded. The technology used in producing the salt was sophisticated. (http://www.stm-ke.sk/)
An interesting fact, relevant to our current discussion, is that the mine produced its own sodium nitrite since 1945. It falls outside our time of interest and the production has since the been discontinued, but the fact that producing sodium nitrite was fairly “widespread” and the technology, common in the area is fascinating. (From private communication with the museum curator, Prof. Marek Duchoň)
Sodium nitrite, produced at Solivary in 2007.
This is a key fact in piecing together why it was “natural” to call the sodium nitrite/ sodium chloride mix that Griffith imported into the USA, Salt from Prague. The region was indeed famous for its salts.
GERMANY 1910 – 1920 – the race to access atmospheric nitrogen
Austerity for the middle class in Germany during the Great War.
By the end of the war, the largest stockpiles of nitrite in the history of humanity up to that point were in Germany. It was created by the most productive chemicals industry in the world.
By the end of the 1800’s it became apparent that the world’s growing populations will not be fed unless atmospheric nitrogen can be harvested. Solving the problem of how to do this became one of the biggest priorities of science.
After an intense search and various processes tested on an industrial scale, including the electric arc method, the German chemist, Fritz Harber finally solved the problem with the help of Robert Le Rossignol who developed and build the required high-pressure device to create ammonia. It would be the most productive system ever developed to fix atmospheric nitrogen.
The process was first demonstrated in 1909. The German Dyes manufacturer, BASF acquired the technology and under the leadership of Carl Bosch, the first Haber-process factory went into operation in Oppau, Germany in 1913. (Concerning the direct addition of nitrite to curing brine),
As a direct consequence of this development, Germany was no longer reliant on saltpeter from Chili (sodium nitrate) as fertilizer to feed its massive agriculture industry. Another consequence of the Haber-process is that it made World War One possible on an industrial scale. Nitrogen is key in ammunition production. Germany and its allies could escalate the war to a never before seen level.
There are good examples of Germans toying with the use of nitrite in food, even before the war. The German scientist, Glage (1909) wrote a pamphlet where he outlines the practical methods for obtaining the best results from the use of saltpeter in the curing of meats and in the manufacture of sausages. (Hoagland, Ralph, 1914: 212, 213)
Glage gives for the partial reduction of the saltpeter to nitrites by heating the dry salt in a kettle before it is used. It is stated that this partially reduced saltpeter is much more efficient in the production of color in the manufacture of sausage than is the untreated saltpeter. (Hoagland, Ralph, 1914: 212, 213)
This means that by the 1910’s, German scientists tried to solve the problem by still using saltpeter as starting point to the reaction but getting to a reduced state faster. The line of thinking of using nitrate as the starting point was finally perfected by the Danes who allowed the reduction to take place at the normal pace.
It was however not before BASF’s new Haber process came into operation that sodium nitrite became generally and cheaply available. Solving the problem by using sodium nitrite was now a serious possibility. The Great War provided the environment to “motivate” an entire industry to change from saltpeter to sodium nitrite when saltpeter was suddenly not available for curing, survival was linked to speed of curing and public perceptions were put aside.
By 1909, the world production of inorganic nitrogen by the electric arc method and some miscellaneous processes were standing at a combined 3000 metric tons. The Haber process was not invented yet. One year after Ladic started working as a meat curer, by 1913, the arc and miscellaneous processes yielded 18 000 metric ton and the Haber process, 7000 metric tons.
By 1917, the arc and miscellaneous processes delivered 30 000 metric ton and the Haber process, 100 000 metric tons. This was 5 years after Ladic learned the art of curing and possibly started using sodium nitrite in meat curing. Over this five years, he has seen a dramatic increase in the availability of nitrite and therefore a reduction in nitrite prices.
In 1920, the Haber process delivered a staggering 308 000 metric ton of nitrogen, compared to the 33 600 metric tons of the arc and miscellaneous processes. (Scott, E. Kilburn. 1923; : 859–76)
World War One broke out on 28 July 1914 and lasted until 11 November 1918. When the war ended, Germany had huge stockpiles of sodium nitrite (along with many other war-chemicals). They had to pay a massive war debt and raise the German economy from the dead. These were desperate times and Germany threw its full energy and industriousness behind this effort. The effort focused on the lucrative market of the USA.
The drama of the sale of German nitrites played itself off in the USA and particularly in Chicago. This directly led to the creation of Prague Salt.
We begin our US story by looking at public and government views on nitrite. During the 1910’s, the USA wrestled with the question whether nitrites in food constitute adulteration and it’s consideration created its own epic drama.
Vastly opposing views were held in relation to preservatives and colourants generally. Prof. Julius Hortvet, a chemist at the Minnesota Dairy and Food Commission said in an address delivered on 16 July 1907, at the Eleventh Annual Convention of the Association of State and National Food and Dairy Departments, in Jamestown, “Some state laws go so far as to inflict fine and imprisonment for making an article appear better than it really is.”
He presented the opposing view when he said that he believes that “if we must have legislation in regards to this, it would be wiser to reserve it and punish the man who did not make his food product as attractive as possible.” (American Food Journal; 1907)
In his speech, he made the following prophetic comment about saltpeter which in years to come would become one of the dominant arguments for the use of nitrite in foods. He said that “we know..that certain substances, as salt and saltpeter, have caused death from the effects of large doses.” He then draws a brilliant comparison between these products and alcohol when he said that ” alcohol is classed as a poison.” His point was that what is good for alcohol, which is a poison if consumed in high concentrations and large volumes, should be good for saltpeter (i.e. limit the amount of nitrate and nitrite in foods instead of banning it altogether, as is the case with alcohol). “In short,” he said, “the whole question sometimes is relative.” (American Food Journal; 1907)
He was “not contending that certain articles commonly used in…food may or may not under certain circumstances act as a poison.” He was “simply defending… against two possible evils: first, the addition to…food of any substances that will tend to augment the possibilities of harm arising from our daily diet.”
His second point sounds like one directed to the use of nitrite and its medicinal use when he said that “he is secondly defending against,” the addition to … foods of substances having therapeutic or even toxic properties by persons unqualified to prescribe such substances.” (American Food Journal; 1907) He is possibly tripped up by a lack of scientific understanding about nitrites at the time, but his cautionary note is commended.
In the 1910’s, the US Department of Agriculture had the right to promulgate “standards of purity for food products and to determine what are regarded as adulteration therein.” (American Food Journal; 1907 vol 2 no 2, 15 Feb 1907, p43 ) Whether these standards would become law was an open question at this stage. If there was a dispute about a substance, it was heard by a special organ of the US Department of Agriculture, the Referee Board of Consulting Scientific Experts, created in 1908.
The battleground about the use of nitrites itself was not the meat industry. It seems that the meat industry considered and possibly used it in secret. The battle played out in its use as a bleaching agent in flour. The controversy came to a head in a landmark court case in 1910.
The Millers were infuriated because the attorney general opted for a jury trial instead of . referring the matter to the Referee Board of Consulting Scientific Experts. (Chicago Daily Tribune ; 7 July 1910; Page 15) I can only suspect that he was himself against the use of nitrites in food and probably did not want scientists to decide.
A court case was brought by the US Federal Government against the Mill and Elevator Company of Lexington, Nebraska. The charge was that they adulterated and misbranded flour and sold it to a grocer in Castle, Missouri.
The government seized as evidence 625 sacks of flour from the grocer. The court case lasted five weeks. The case was brought by the government under the pure food and drug act of 1906. (Chicago Daily Tribune ; 7 July 1910; Page 15) This is an act “for preventing the manufacture, sale, or transportation of adulterated or misbranded or poisonous or deleterious foods, drugs, medicines, and liquors, and for regulating traffic therein, and for other purposes.” (www.fda.gov)
The government contended that “poisonous nitrites are produced in the flour by bleaching.” They did not share the view of Prof. Julius Hortvet that we looked at earlier who said that these matters are relative to the amount of the substance used since alcohol is also a poison if used in the right quantity. The Federal Government said that “any amount of poison introduced into food is an adulteration.” (Chicago Daily Tribune; 7 July 1910; Page 15)
The issue was that as much as 80% of the flour produced in the USA during that time was bleached with a nitrogen peroxide process. Flour naturally has a creamy tint. The cheaper the grade, the more creamy it is. In ages past, flour was bleached simply by age. The chemical bleaching process with nitrogen peroxide instantly changes the yellowest flour whiter than the highest grade. The process results in residue traces of nitrous and nitric acid being left in the flour which produce nitrites and nitrates. (Chicago Daily Tribune ; 7 July 1910; Page 15)
The defense argued that “nitrates (and nitrites) were present in such small quantities that no man could eat enough bread at one time to be poisoned by them.” (Chicago Daily Tribune; 7 Jul 1910; Page 15) The government contended that “if this view were upheld by the courts all foodstuffs manufactured could introduce quantities of poison into their products, infinitely small in each case, but devastating in their cumulative effect.” (Chicago Daily Tribune, 7 Jul 1910, Thu, Page 15) (The arguments will be analysed and an overview will be given of how the international food industry answered it in the years following 1910 in a separate article)
This was a case of huge importance to the industry as can be seen from the list of people called upon by the defense. Pierce Butler of St Paul acted as special attorney for the defense. (Chicago Daily Tribune; 7 Jul 1910; Page 15) Whether he still had the position in 1910 when the case was heard must be verified, but he was a lawyer of such stature that in 1908, Butler was elected President of the Minnesota State Bar Association. From 1923 to 1939 he served as Associate Justice of the Supreme Court of the United States. (saintpaulhistorical.com)
Apart from Butler, “a large staff of distinguished lawyers fought for the company who’s flour was seized, and for the millers of Nebraska, the millers of Kansas, and the company who makes the bleaching machines. Among the experts who testified were all the toxicologists who testified in a previous landmark case (the Swope case), professors of chemistry and medicine from twenty universities, doctors, bakers, millers, and housewives.” (Chicago Daily Tribune; 7 Jul 1910; Thu, Page 15)
After seven hours of deliberation, the jury returned a verdict in favour of the government upholding the charge that the bleached flour was both adulterated and misbranded. (Chicago Daily Tribune; 7 Jul 1910; Thu, Page 15)
It is fair to conclude that by 1910, nothing was more sensitive in food production than the presence of nitrites and the use of sodium nitrite in food was highly controversial.
In the early 1900’s, in Chicago, the powerful meat packing companies set up by Phil Armour, Gustav Swift and Edward Morris were all looking for ways to reduce steers to beef and hogs to pork in the quickest, most economical and the most serviceable manner.” (The Indiana Gazette. 28 March 1924).
The earliest reference to a test of meat curing with sodium nitrite in the USA places a secret experiment conducted where sodium nitrite was used to cure meat in 1905. [11] This was probably done in Chicago. When the “Pure Food and Drug Act and Meat Inspection Act” of 1906 was promulgated, it made the use of sodium nitrite in food illegal. It was not specifically forbidden, but the act was applied, for example in the 1910 court case we just looked at, in such a way that it was seen as making its use in food illegal.
During the 1910’s a very interesting article appeared in Chicago that places a company with the technology to produce sodium nitrite in the same city. It appeared in the American Food Journal of 15 February 1907 entitled “Cheap Nitrogen.”
It said that a Chicago-based company was producing nitric acid by the electric arc method invented by Prof. Mościcki of the University of Freiburg, Switzerland, that we looked at before. The method, in reality, was able to produce both nitric and nitrous acid (US patent US1097870) and dates back to 1901. (cesa-project.eu) The article states that the process made its production “cheap enough to be commercially applicable.” (American Food Journal. Vol 2. No 2. 15 Feb 1907, p29) The entrepreneur behind this company was William M. Thomas, who set an experimental plant up in Marshfield Avenue, Chicago. His main goal was probably to produce fertilizer. (Chicago Sunday Tribune, Nov 10, 1907)
We have already referred to the electric arc method several times. Mościcki, the inventor of the process was the former assistant to Józef Wierusz-Kowalski (1896), professor of physics, and rector (provost) at Albert-Ludwigs University in Freiburg, Switzerland.
Prof Mościcki was an interesting person. After a very successful academic career and a career as an inventor, he became the 3rd president of the second Polish Republic. He was in office from 4 June 1926 to 30 September 1939. Another interesting fact relates directly to his invention is that in Bern, Switzerland, his patent application was handled by none other than Albert Einstein.
“In 1905 Einstein Prof Mościcki’s special arc furnace which employed a rotating electric arc and was used for the production of nitric (and nitrous) acid…” ” The field generated by an electromagnet was used to rotate the arc. The 26-year-old physicist (Einstein) and the still young (38) but already renowned inventor and scholar (Prof Mościcki’s) met and discussed the patented idea. Einstein was curious to know why an electric arc changed its orientation in a magnetic field.” Prof Mościcki’sbecame a successful businessman in Switzerland. (Zofia Gołąb-Meyer Marian. 2006) [12]
When we looked at the career of Ladic Nachtmullner, we have seen that the first production of nitrous acid in Switzerland was in 1910, during World War One based on the invention of Prof Mościcki. This happened “immediately after his procedure was patented.” “A factory was opened in Chippis in Wallis canton, Switzerland.” “In the subsequent years, this procedure was substantially perfected and nitrous acid could be supplied not only to Switzerland but also to neighbouring countries.” (cesa-project.eu)
What is interesting in relation to Chicago is that the American Food Journal article says that the Chicago company was already in production by 1907 manufacturing nitric acid “in a small way” from free nitrogen, using the technology invented by Mościcki’s. (American Food Journal. Vol 2. No 2. 15 Feb 1907, p29)
In the USA the fixation of atmospheric nitrogen was a priority and they knew the lagged behind Germany. The first US plant for the fixation of atmospheric nitrogen was built in 1917 by the American Nitrogen Products Company at Le Grande, Washington. It could produce about one ton of nitrogen per day. In 1927 it was destroyed by a fire and was never rebuild. (Ernst, FA, 1928: 14)
An article in the Cincinnati Enquirer of 27 September 1923 reports that as a result of cheap German imports of sodium nitrite following the war, the American Nitrogen Products Company was forced to close its doors four years before the factory burned down. We will consider America’s response to these cheap imports momentarily. ( The Cincinnati Enquirer ( Cincinnati, Ohio), 27 September 1923. Page 14.)
We can conclude then with great certainty that there was at least one company in Chicago by 1907 that could produce sodium nitrite. Was this venture funded by the meat packing companies? It is a question for further discovery. A much larger project got under way in 1917, but by 1923, the USA was not in a position to supply material quantities of sodium nitrite.
At the end of World War One, England had its own stockpiles of nitrite to dispose of.
Sodium nitrite in the UK appeared for sale in an advertisement in the Times of London on 1 May 1919, 6 months after the armistice. (The Times, London)
The stockpile of the English was dwarfed by what was available from Germany. The German Government did not wait long before they started selling their war stockpile. An article appeared in The Watchman and Southron on 19 Feb 1921 and shows that German goods, especially chemicals have been making its way to the USA in such quantities that it was seen as a threat to the local industry.
Our three worlds of Germany, Prague, and the USA now merge.
The Detroit Free Press (Detroit, Michigan) reported on 14 Jan 1921 that “large stocks of imported sodium nitrite are offered at extremely low prices by agents of German manufacturers.”
Some of the tactics used by Germany to get goods into the USA, including goods subjected to presidential restrictions, were to import goods through the “concealment of the origin of shipment.” German chemicals, subject to such restrictions have been making their way into the USA “appearing as having been shipped from Switzerland, Italy and elsewhere. “Also, there has been extensive smuggling.” The article states that the German plans to sell their products in the USA and economic domination have been made as early as May 1919. (The Watchman and Southron, 19 Feb 1921, page 3)
Great emphasis is placed on sodium nitrite. The author of an article that appeared in The Watchman and Southron, 19 Feb 1921, misread its importance when it was reported that “sodium nitrite would seem to be of minor importance.” “Since the first of the year (Jan 1921), the Germans have glutted the American sodium nitrite market, threatening to destroy the hitherto prosperous American industry, and no relief has yet been obtained through the war trade board.” (The Watchman and Southron, 19 Feb 1921, page 3)
In April 1921, the call made in February for greater control over the import of sodium nitrite was answered when the war trade board in the USA placed an embargo on the importation of Sodium Nitrite. In the future, it could only be imported under license.
An article that appeared in the Detroit Free Press, 22 April 1921, reported that the goal of the embargo was to “check the heavy imports from Germany and Norway which have swamped the market in the country and reduced prices to a level below the cost of manufacture in the United States. (Detroit Free Press, 22 Apr 1921, Page 18)
On 7 May 1924, The Indianapolis News, reports that the tariff for importing sodium nitrite was increased by a massive 50% from 3 cent a pound to 4.5 cent per pound. This was the maximum duty permitted under the Fordney-MacCumber tariff act. The additional duty was levied in response to a petition filed by the American Nitrogen Products Company of Seattle, Washington. (Detroit Free Press, 22 Apr 1921, Page 18)
In June it is reported that the measures were effective and that sodium nitrite prices were increasing. (Detroit Free Press, Detroit, Michigan, 11 June 1921, p4)
GERMAN SODIUM NITRITE APPEARS AS CURING AGENT IN THE USA – ingredients for deceit
Union Stock Yard, Chicago, USA, C 1920
Then arrived 1925 and everything seems to change as sodium nitrite became available through the Griffith Laboratories in a curing mix for the meat industry. They described Prague Salt and how they came upon the concept in official company documents as follows, “The mid-twenties were significant to Griffith as it had been studying closely a German technique of quick-curing meats. Short on manpower and time, German meat processors began curing meats using Nitrite with salt instead of slow-acting saltpeter, potassium nitrate. This popular curing compound was known as “Prague Salt.” (Griffith Laboratories Worldwide, Inc.)
In Canada, Prague Salt was classified as food adulteration. A progress report from the Canadian department of agriculture in 1925 lists the fact that “one sample of ” Prague ” salt” was tested and it was found to contain “5.87 % of potassium nitrite.” It calls it an adulteration. (Progress Report for the Years Canada. Dept. of Agriculture. Division of Chemistry, 1912)
In 1925 in the USA however, the fortunes of nitrite seem to change overnight. If the courts continue to find against the use of an ingredient in food that is seen as a food adulteration, the easiest way to solve the problem is to change the law.
In Oct 1925 the American Bureau of Animal Industries legalised the use of sodium nitrite as a curing agent for meat.
In December of the same year (1925) the Institute of American Meat Packers, created by the large packing plants in Chicago, published the document. The use of sodium Nitrite in Curing Meats.
A key player suddenly emerge onto the scene in the Griffith Laboratories, based in Chicago and very closely associated with the powerful meat packing industry. In that same year (1925) Hall was appointed as chief chemist by the Griffith Laboratories and Griffith started to import a mechanically mixed salt from Germany consisting of sodium nitrate, sodium nitrite and sodium chloride, which they called “Prague Salt.”
Probably the biggest of the powerful meat packers was the company created by Phil Armour. More than any other company in that time, Armour’s reach was global. It was said that Phil had an eye on developments in every part of the globe. (The Saint Paul Daily Globe, 10 May 1896, p2) He passed away in 1901 (The Weekly Gazette, 9 Jan 1901), but the business empire and network that he created must have endured long enough to have been aware of developments in Prague in the 1910’s and early 20’s.
Could one of the offers of employment that Ladislav received before 1926 have been from Armour or one of the other meat packers in Chicago?
Griffith Laboratories is formed in the year following the armistice in 1919. This is the same year when the United Kingdom starts selling its sodium nitrite stockpile. Two years later, even cheaper German and Norwegian sodium nitrite start arriving in the USA. In response to this, import duties are levied against German sodium nitrite.
By April 1921, the import duties have been bolstered by a blanket embargo on importing sodium nitrite, except where a special permit is granted. In 1924, the tariffs on sodium nitrite is increased by 50% to the maximum allowed level permitted under the law. By this time, the use of sodium nitrite in curing brines were in all likelihood the norm in Chicago and the 50% increase would have impacted on the bottom line of these companies.
Is it possible that by calling it the curing mix from Germany, Prague Salt, did Griffith sidestep the import tariff and the required permit for importing sodium nitrite completely? My thesis is that it is entirely possible. Even probable. It may have misrepresented the content in Prague Powder (mislabeling) as well as misrepresenting the country of origin.
When Phil Armour passed away, his personal fortune was estimated at $50 000 000. This is almost $1,500,000,000 in 2016. So powerful were the packing companies that US anti-trust legislation was created to break these companies up. The point is that big money was at stake and big influence on parts of the American government.
Is it possible that Prague Salt is no more than clever name given to a curing brine? Taking the full weight of the historical context of events in Prague, Germany and the USA into account in the 1910’s and 1920’s; particularly the severe measures to keep German sodium nitrite out of the USA, with the last blow being dealt, in 1924; understanding the extreme pressure on the packing houses to deliver huge volumes of bacon faster, I seriously doubt it.
The issue is not so much that nitrite was a controversial chemical. This only helped to drive its use underground. The main issue was that German sodium nitrite was not welcome in the USA and the US plants were nowhere near the level of the German plants in efficiency and low cost product output.
It seems that the name, Prague Salt, was crafted to misrepresent the country of origin and possibly its real composition. Importing salt was no problem. There is a possibility, of course, based on the popularity of salt from Bohemia, and the fact that we know it was widely exported, including to Germany, that the original mix done in Germany, could even have been done with actual salt from Prague with German sodium nitrites added.
Whether this was so or not, the name had enough of a basis in reality in Ladislav Nachtmullner, Praganda and the famous salts from Prague to get it past the customs officers at the American harbours and into the meat packing plants of Chicago and later, around the world.
The fact that it was tested in Canada and found to contain nitrite shows that this was not something that was declared at borders, at least in one of the event of the import into Canada and even though this does not prove that it was done in the US also, it at least build the case for the theory that it was imported into the US without a disclosure of its nitrite content at the borders.
Prof. Julius Hortvet, in his address in Pittsburgh, had these prophetic concluding remark about the future of science in the food industry. He said that “…it is imperative that the use of colouring matter should be kept under intelligent control. Regulations of the food industries will in future depend more than ever before on the results of scientific investigations, and the laboratory will become the dominant factor in the shaping of food standards and food laws.” (American Food Journal; 1907)
The legal status of nitrites as food additive was clarified in 1925 through proper legislation, based on Prof. Hortvet’s principal of “intelligent control” when science decided the matter and it was taken out of the hands of “the court of popular opinion.” However, the involvement of the packing plants and Griffith in everything that happened in 1925 raises suspicion of collusion with the US government.
The real hero in the story is the master butcher from Prague who through practical application and the exact scientific inquiry that Prof Hortvet spoke about, developed the first commercially successful curing mix, Praganda. Unknowingly, he became the central figure in the saga about the naming of Prague Powder and the worldwide phenomena of the direct addition of nitrites to curing brines.
Finally, there is the Griffith Laboratories. It seems as if how Prague Salt came into the USA was possibly not above board. They did however became central around the world in making the direct addition of sodium nitrite through Prague Salt and later, Prague Powder a worldwide phenomenon.
Understanding this grand story, helps us to understand ourselves and the technology we use and to apply our trade with greater skill through knowledge. Much gratitude must be shown to these legendary companies and individuals.
The meat colour generally “changes” (either red, purple or brown), based on how many electrons are spinning around the iron atom which is part of myoglobin. Nitric oxide stabilizes or fixes the myoglobin colour through a reversible chemical bond. It does not colours the meat. (Pegg, B. R. and Shahidi, F.; 2000: 23 – 45) This is an important point to remember because, in the consideration of the use of nitrite in meat, nitrite can not be viewed as a meat colourant. BACK TO POST
2. Rate of reaction.
The reaction of nitrite in meat is slow, in part due to the very small quantity used in the curing brine. The rate of reaction, as always, depends on the concentration of the reactants, the pH and temperature. BACK TO POST
3. Nitrosating species from nitrous acid.
“The first step in the reaction sequence beginning with nitrous acid is the generation of either a nitrosating species or the neutral radical nitric oxide (NO).” (Sebranek, J. and Fox, J. B. Jn.. 1985)
The following list gives the relative reactivities of various nitrosating species, species 1 being the strongest and species 5 being the weakest.
Species 1:
Source: “From smoke which has many other phenolic compounds”
Species 2:
Source: From curing salt
Species 3:
Source: Found in the air.
Species 4:
Source: Nitrous acid anhydride
Species 5:
Nitrose derivatives of citrate, acetate, sulphate, phosphate.
Sources: Cure ingredients, weakly reactive under certain conditions.
I excluded those found under very acidic conditions. (Comparison by Sebranek, J. and Fox, J. B. Jn.. 1985) BACK TO POST
4. The term “nitrite”
“The term nitrite is used generically to denote both the anion, , and the neutral nitrous acid , but it is the latter which forms nitrosating compounds.” (Comparison by Sebranek, J. and Fox, J. B. Jn.. 1985) BACK TO POST
5. Reducing agents in the meat system.
One such mechanism for the conversion of “nitrite to nitric oxide in meat is by oxidation of myoglobin to metmyoglobin (brown coloured meat; Fe3+). This oxidation-reduction coupling produces both nitric oxide and metmyoglobin. It has been suggested by Kim et al. (2006) that metmyoglobin can be converted back to deoxymyoglobin through metmyoglobin reducing activity (MRA), a reaction facilitated by lactate. It is the enzyme activity of LDH that helps convert lactate to pyruvate and produce more NADH. Hendgen-Cotta et al. (2008) suggested that deoxymyoglobin can convert nitrite to nitric oxide and the generation of more deoxymyoglobin is likely to result in more nitric oxide (NO) from nitrite and less residual nitrite.” (Mcclure, B. N.; 2009: 28)
Several specific biochemical reducing systems have been the subject of intense investigation as far as their importance in the development of cured meat colour are concerned.
“Endogenous compounds such as cysteine, reduced nicotinamide adenine dinucleotide, cytochromes and quinones are capable of acting as reductants for NOMb formation (Fox 1987). These reductants form nitroso-reductant intermediates with NO and then release the NO to Mb, forming a NOmetMb complex that is then reduced to NOMb. In model systems, the rate limiting step in the production of NOMb was the release of NO from the reductant-NO complex (Fox and Ackerman 1968). Several researchers have investigated the effects of endogenous muscle metabolites including peptides, amino acids, and carbohydrates on the formation of NOMb. Tinbergen (1974) concluded that low-molecular-weight peptides such as glutathione and amino acids with free sulfhydryl groups were responsible for the reduction of nitrite to NO, wich is subsequinrtly complexed with Mb to produce NOMb. Similar work by Ando (1974) also suggested that glutathione and glutamate are involved in cured-meat colour formation. Depletion of these compounds in meat via oxidation occurs with time, but reductants such as sodium ascorbate or erythorbate are added to nitrite-cured meats before processing to ensure good colour development (Alley et al. 1992) The role of reductants in heme-pigment chemistry is somewhat ambiguous, but they can promote oxidation and even ring rupture under certain conditions. Thus to form cured meat pigment, two reduction steps are necessary. The first reduction of nitrite to NO and the second is conversion of NOmetMB to NOMb.” (Pegg, B. R. and Shahidi, F.; 2000: 44, 45) BACK TO POST
6. Sugar as reducing agent.
“Sugars itself does not reduce dinitrogen trioxide in the way that ascorbate or erythorbate does, but it contributes to “maintaining acid and reducing conditions favorable” for the formation of nitric oxide.” (Kraybill, H. R.. 2009)”Under certain conditions reducing sugars are more effective than nonreducing sugars, but this difference is not due to the reducing sugar itself. The exact mechanism of the action of the sugars is not known. It may be dependent upon their utilization by microorganisms or the enzymatic systems of the meat tissues.” (Kraybill, H. R.. 2009) BACK TO POST
7. Ascorbate or erythorbate supplements sugar.
An excellent reducing agent was discovered in the 1920’s when ascorbate was isolated. As early as 1927, two German chemists, J. Tillmans and P. Hirsch (1927) observed that there is a correlation between the reducing capacity of animal tissue and their vitamin C content. (Concerning the Discovery of Ascorbate) . It reacts so aggressively (effectively) with nitrite, that a less effective, but more manageable cousin (an isomer of ascorbate), erythorbate turned out to be the most practical to use in curing brines along with nitrite and salt.
Ascorbate (vitamin C) reacts so aggressively (effectively) with nitrite, that a less effective, but more manageable cousin (an isomer of ascorbate), erythorbate turned out to be the most practical to use in curing brines along with nitrite and salt.
The old curing brines of the 1800’s consisting of saltpeter (nitrate), sugar (create reducing conditions) (6) and salt are, therefore, equivalent to the current curing brines of nitrite (being added directly), erythorbate (reducing agent) and salt. The same general functionality at vastly reduced curing time.
Today, nitrate is still being added to many curing brines as a reservoir for future nitrite as bacteria continues to change nitrate into nitrite. This bolsters the residual nitrite levels in cured meat which is important since it was found that nitrite has a unique anti-microbial function in cured meat, in addition to its function of fixing the cured colour and contributing to the cured taste. It is unique in the sense that it is the most effective chemical control against a highly lethal pathogen, clostridium botulinum. (Concerning Nitrate and Nitrite’s antimicrobial efficacy – chronology of scientific inquiry)
Table salt remains the most important curing agent, but salt alone will not give the cured colour or taste and will not, on its own, be effective against clostridium botulinum. Sugar is still being used in many brines today, mostly to enrich the taste profile and to create browning during frying, especially in bacon. Its contribution to reducing conditions is now secondary and since the addition of ascorbate or erythorbate. Saltpeter has been replaced by sodium nitrite. BACK TO POST
8. Nitrite as medicine.
“The organic nitrite, amyl of nitrite, was initially used as a therapeutic agent in the treatment of angina pectoris in 1867, but was replaced over a decade later by the organic nitrate, nitroglycerin (NTG), due to the ease of administration and longer duration of action.” BACK TO POST
9. Azo dye and textile colouring in 1895.
“Dyeing with Diazotised Dyestuffs
All the diazotised dyestuffs belong to the substantive group, and therefore, all that has been said with regard to these dyestuffs and their manner of application applies to the former also. In the majority of instances, however, the dyeings obtained direct are not sufficiently fast to be usable in that condition. Nevertheless, they can be converted into fast dyeings — provided the dyestuff contains free amino groups — by diazotising, followed by developing or coupling. The chemical reactions and method of procedure are just the sam.e as in the case of cotton.
In practice, the diazotising is effected in the following manner : —
The dyed and rinsed silk is entered at once into the cold diazotising bath and is worked about constantly for fifteen to thirty minutes. For each 100 parts of silk, the bath contains 3 parts of sodium nitrite dissolved in 1500-2000 parts of cold water, 8-10 parts of crude hydrochloric acid (20° Be.) being added. The operation must be conducted in wooden vats, metal vessels or fittings (lead excepted) being unsuitable. At one time, ice was used for cooling during the process, but this has been given up in favour of water at ordinary temperature, and in some cases, e. g. diazo indigo blue, the bath may be allowed to rise to 20-30° C. As a rule, the diazotisation will be complete in fifteen minutes, though some dyestuffs take longer and have to be left in the nitrite bath for half an hour. The goods are centrifuged or squeezed, contact with metal being avoided. A lead-lined hydro-extractor may be used, or else the goods must be wrapped in packing-cloth.
The intermediate diazo compound formed on the fibre is very unstable and sensitive to light, especially direct sunlight. The operation must, therefore be carried on in a shady room, and care be taken to prevent any part of the diazotised goods from getting dry, or streaks and spots will be formed in the coupling stage. The diazotised material is rinsed and then immediately entered in the developing bath. The nitrite baths will keep for a considerable time, and can be freshened up for use by the addition of one-third the original amounts of nitrite and acid. During the whole process the bath should smell strongly of nitrous acid. In the case of light shades the bath may be weaker in nitrite and acid.” (Ganswindt, A; 1895: 98, 99) BACK TO POST
10. The Professional Career of Ladic
After his apprenticeship he worked in several factories in Praha (Kracik, Beranek, Ugge-Sitanc and Miskovsky) as an assistant. His first work as a specialist in his field was with A. Chmel, Fr. Hlousek in Paha, Fr. Strnad in Lazne Luhacovice, and later in Germany, at the factories of Josef Sereda, Fr. Seidl, Zemka and Leopold Fisher in Berlin.
He worked as a “cellar man” at Josef Cifka, Vaclav Miskovsky in Praha, Kat. Rabus & Son in Zagreb, Jugoslavia,
Later he worked as a Foreman (Workman Leader) for the companies, Fr. Maly, Vacl. Havrda, A. Kadlec in Praha and Alexander Brero, Hard a/Bodensee Vorarlbersko and, in the end, he worked as a “Quick Production Specialist” for the export of hams for Carl Jorn A.-., Hamburg, Germany, Herrmann Spier, Elberfeld, Westfalsko, Karl Frank, Urach b/Stuttgart, Wurttemberg, A. Brero & Co, St. Margrethen, Switzerland. BACK TO POST
11. The secret 1905 curing test with sodium nitrite.
Upon inquiry, the author of the article who mentioned it explained that the article was not intended for wide circulation and it lacks verification of the source. I, therefore, do not cite the reference, but I want to mention it. Circumstantial evidence makes such a test in 1905 very likely plus, the date was probably not conceived out of thin air.
I mention it for several reasons. Firstly, circumstantial evidence makes such a test in 1905 very likely plus, the date was probably not conceived out of thin air. Secondly, the fact that the reference can not be verified fits the image of the meat curing industry at that time as a secretive fraternity, especially in light of the enormous amounts of money at stake on the one hand and on the other, both the public and governments negative perceptions about chemical preservatives generally and nitrite in particular at this time. Verifiable references from this time are almost completely missing from historical records and conclusions are left, in large part, to inference. Thirdly, I mention the 1905 US test because the person who wrote the article is a well-known and highly respected figure in the modern, international meat curing industry. If anything, I trust his instincts that there is enough to the date for him to have mentioned it in an article. BACK TO POST
12. Prof. Mościcki
“As a young student of chemistry in St. Petersburg, Russia, Mościcki was an active socialist. Later, back in Poland, he participated in a failed attempt on the life of the tsarist governor of Warsaw. In 1892, he was threatened with arrest and escaped to London where he met Józef Piłsudski, who was to become one of the most important people in Polish history. In 1920, Marshal Piłsudski led the forces that defeated the Soviet army at the Battle of Warsaw. This and subsequent battlefield successes led to Poland’s victory in the Polish/Soviet war and saved weakened by WWI Europe from the threat of Soviet conquest. After Piłsudski engineered a coup d’etat in Poland, Ignacy Mościcki was asked to become the president. He gave up his academic positions and served as president of the Republic from 1926 until the outbreak of the WWII in 1939. Among his other titles, Mościcki is known as the father of the chemical industry in Poland. A town in southern Poland (Mościce) is named after him. And one of his many patent applications was studied by a young technical expert, Albert Einstein, in Bern, Switzerland.” (Zofia Gołąb-Meyer Marian. 2006) BACK TO POST
Gamgee, A. 1867 – 1868. Researches on the Blood. On the Action of Nitrites on the Blood. Proceedings of the Royal Society of London. Vol. 16 (1867 – 1868), pp. 339-342. Published by: Royal Society.
Ganswindt, A. 1895. Dyeing. Silk , Mixed silk fabrics and artificial silks. Translated from German by Charles Salter. Scott, Greenwood & Son.
Griffith Laboratories Worldwide, Inc. official company documents.
Hoagland, Ralph. 1914. Coloring matter of raw and cooked salted meats. United States Department of Agriculture. National Agricultural Library. Digital Collections.
Hiemstra-Kuperus, E. 2010. The Ashgate Companion to the History of Textile Workers, 1650–2000. Ashgate Publishing, Ltd.
The Indiana Gazette, 28 March 1924
The Indianapolis News, 7 May 1924, Wed, Page 1
Jones, G. 1920. Nitrogen: Its Fixation, Its Uses in Peace and War. The Quarterly Journal of Economics. Vol. 34, No. 3 (May, 1920), pp. 391-431. Oxford University Press.
Kim-Shapiro, D. B., Schechter, A. N., Gladwin, M. T. 2006. Unraveling the Reactions of Nitric Oxide, Nitrite, and Hemoglobin in Physiology and Therapeutics. Arteriosclerosis, Thrombosis, and Vascular Biology. Published online before print January 19, 2006.
Kraybill, H. R.. 2009. Sugar and Other Carbohydrates in Meat Processing. American Meat Institute Foundation, and Department of Biochemistry, The University of Chicago, Chicago, Ill. USE OF SUGARS AND OTHER CARBOHYDRATES IN THE FOOD INDUSTRY. Chapter 11, pp 83–88. Advances in Chemistry, Vol. 12. Publication Date (Print): July 22, 2009 . 1955
Ladislav Nachmüllner vulgo Praganda Nachmüllnerová, Eva. OSSIS,2000
Mcclure, B. N.; 2009. The effect of lactate on nitrite in a cured meat system. Iowa State University.
Packer, L. 1996. Nitric Oxide, Part 1. Academic Press.
Pegg, B. R. and Shahidi, F. 2000. Nitrite Curing of Meat. Food & Nutrition Press, Inc.
Polenske. E.. 1891 Works from the Imperial Health office, Volume 7, Springer, Berlin, S. 471-474
Progress Report for the Years Canada. Dept. of Agriculture. Division of Chemistry.
Sebranek, J. and Fox, J. B. Jn.. 1985. A review of nitrite and chloride chemistry: Interactions and implications for cured meats. J. Sci. Food. Agric. 1985, 36, 1169 – 1182.
Scott, E. Kilburn. 1923. “NITRATES AND AMMONIA FROM ATMOSPHERIC NITROGEN. Lecture I”.Journal of the Royal Society of Arts 71 (3702). Royal Society for the Encouragement of Arts, Manufactures and Commerce: 859–76. http://www.jstor.org/stable/41356346.
Sullivan, G. A., 2011. “Naturally cured meats: Quality, safety, and chemistry”. Graduate Theses and Dissertations. Paper 12208.
Sydney Morning Herald on 1 Mar 1870 (p4)
The Times, London, Greater London, England, 1 May 1919, Page 18
Toldr, F.. 2010. Handbook of Meat Processing. John Wiley & Sons Inc.
Turmock, D.. 1989. Eastern Europe: A Historical Geography 1815-1945. Routledge
Vaughn E. Nossaman, Bobby D. Nossaman, Philip J. Kadowitz; Cardiol Rev. Author manuscript; available in PMC 2011 July 1; Published in final edited form as: Cardiol Rev. 2010 Jul–Aug; 18(4): 190–197. 10.1097/CRD.0b013e3181c8e14a
The Watchman and Southron, 19 Feb 1921, Sat, First Edition, page 3
The Weekly Gazette, 9 Jan 1901, Wed, Page 3
Webb, H. W.. 1923. Absorption of Nitrous Gasses. Edward Arnolds & Co, London.
Zofia Gołąb-Meyer Marian. 2006. Albert Einstein and Ignacy Mościcki’s, Patent Application. Smoluchowski Institute of Physics, Jagellonian University, Cracow, Poland
Images
Image 1: Old Prague: Old Prague Logansport Pharos Tribune Sat Oct 19, 1895
Image 2: Ladislav Nachmüllner from Ladislav Nachmüllner vulgo Praganda Nachmüllnerová, Eva. OSSIS, 2000.
Image 3: Ladislav Nachmüllner from Ladislav Nachmüllner vulgo Praganda Nachmüllnerová, Eva. OSSIS, 2000.
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![IMG_0134[1].JPG](https://i0.wp.com/earthwormexpress.com/wp-content/uploads/2017/03/img_01341.jpg?resize=700%2C700&ssl=1)
) can take up three additional electrons giving the nitrogen an ‘‘oxidation status’’ 
as it exists in ammonia (
) or amines or it can release five electrons forming 
as it exists in nitrate 
.” “This is the reason for the variability and wide range of carbon compounds (organic matter) but also for the complexity of nitrogen reactivity. The latter is shown below.” (Honikel, 2007) Below one can see the most important nitrogen compounds in their different states of oxidation.
, bright red, 
– ferrous state)
ferric state)
) is removed from the hematin. A water molecule is added. This gives a high-spin ferric hematin. “The ferric ion, unlike its ferrous counterpart, has a high nuclear charge and does not engage in strong 
bonding. Therefore, metmyoglobin is unable to form an oxygen adduct. (Pegg, R. B and Shahidi, F; 2000: 31)
are oxidized to metMb by nitrite. The ion itself can be reduced to 
. These products can combine with one another to form an intermediate pigment, nitrosylmetmyogloboin (
).” (Pegg, R. B and Shahidi, F; 2000: 40)
towards pink ring formation in gas oven cooked beef roast and turkey rolls. Data showed that pinking was not evident with up to 149 ppm of CO or 5 ppm of NO present in the burning gases; however, as little as 0.4 and 2.5ppm of 
was sufficient to cause pinking of the turkey and beef products, respectively. Cornforth et al. (1998) proposed that pinking previously attributed to CO and NO gas in ovens is instead due to 
) or one of its metabolites such as nitric oxide (
) if oxygen (
) is unavailable as the terminal electron acceptor in respiration.” “The 
, and this process is referred to as dissimilatory nitrate reduction. There is also evidence emerging that certain bacteria can denitrify, even if 
is formed and a very small amount of nitrite (less than 1% of the total nitrite) forms the neutral nitrous acid (
). From nitrous acid, the neutral radical, nitric oxide is formed directly as well as a variety of nitrosating species or molecules that create such a nitrite-oxygen pair of atoms to link to an organic structure like a protein. 
), nitrite (
) and ammonia (
). All have a nitrogen atom as part of either the molecule or the ion. The Haber process yields ammonia (
