Nitrite Cured Meat: It’s Fantastic but is it also Bad?

Nitrite Cured Meat: It’s Fantastic but is it also Bad?
By Eben van Tonder
15 February 2021


I started my career in meat curing in 2008 when I founded the South African bacon brand Woody’s and the company Woody’s Consumer Brands with Oscar and Anton. I never imagined that the most exciting journey on earth would follow which I chronicled in Bacon & the Art of Living. I wanted to know as much as possible about the world of curing and the chemical, biological and bacterial reactions that fascinated me. One of the first books I consumed was Ronald Pegg and Fereidoon Shahidi’s work, Nitrite Curing of Meat: The N-Nitrosamine Problem and Nitrite Alternatives.

I delved into the matter with great interest. I discovered that nitrates are present in many vegetables, but they first need to change to nitrites through bacterial action before they change chemically into nitric oxide which then cures the meat. Nitrates are not very toxic, but once they change into nitrite and is fried, their reaction in the stomach is of particular concern.

As I learned more I discovered the importance of cured products in a world before refrigeration. They are extremely effective to protect us against pathogens, including the mother of all pathogens, Clostridium Botulinum. Its protective action extends into the age of refrigeration! Far from a villain chemical, it turns out that nitrite is an amazing compound that naturally occurs all around us and is, amongst others, formed in our mouths when we consume a wide variety of food including fruits and vegetables.

The question is now obvious. We know that adding nitrites to meat is doing a world of good in giving us safe food that lasts long without refrigeration and just happens to also taste delicious but are we causing more harm than good? Should we stop using it if we ingest far more nitrites from some vegetables than from cured meat? How do we evaluate a matter when scientists continually conclude any discussion on the matter with the words “more research on the topic is required?”

When did we realise that nitrite is not only beneficial but under certain conditions may be problematic? What exactly is the concern with its use? How did we end up using this? What physiological role does it play in humans? What benefits do we derive from ingesting it?

I will provide a brief overview. More than this, I use this as a landing page for material on the subject. Some of my consultancy work relates to exactly this topic and proprietary information is therefore restricted with password protection. Why “password” protected? Because the obvious next question is this: “Is there anything we can do to change it?” To manage the negative elements so that it is removed, and the product is wholly healthy! The answer is a resounding YES! But that is proprietary information! 🙂

A. How did we Realise there is a Problem?

What is the actual issue then and how did humans realise that there is a problem?

The Realization of Danger of Nitrites in Cured Meat and The Responses Since 1926

Nitrate was used as a curing agent for many thousands of years. The basic value initially related to the preventing of spoilage and in a world before refrigeration bacon soon became the staple meat source for the masses in a large part of the world. Curing with saltpetre, the common name for nitrate salts, takes about a month and apart from retarding spoilage, it imparts into meat a characteristic pinkish/ reddish colour and a very agreeable cured meat taste. In the 1800s a new method of curing was invented which reduced the time to cure meat considerably. It was called tank curing on account of the tanks that were used to cure the meat in or mild curing due to a reduced need for salt. It was invented in Ireland. When our understanding of chemistry and bacteriology matured, we realised the reason why tank curing sped meat curing up. For curing to take place nitrate (saltpetre) must first be converted to nitrite through bacterial action before it can be changed into nitric oxide which, we discovered, is the real curing molecule. So, nitrate (saltpetre) to nitrite curtesy of microorganisms (bacteria) and nitrite to nitric oxide through is a chemical reaction.

What was achieved through tank curing was that the step of bacteria changing nitrate into nitrite is cut out. Still, we do not add the nitrite directly. It is “added” through fermentation. The old brine is re-used and in doing so, the liquid is replete with nitrite that was already converted from nitrate. This, naturally, speeds the process up by cutting a step out. Before the late 1800’s curers did not have a clue what caused curing apart from saltpetre. They arrived at the process of tank curing through experimentation and observation without any inkling to microorganisms changing nitrate to nitrite.

The curing reaction was being unravelled by scientists late in the 1800s and early in the 1900s. As we learned that going from nitrite to nitric oxide is much quicker than going from nitrate first to nitrite and then to nitric oxide. We also realized that nitrite forms a salt with sodium to create sodium nitrite. Late in the 1800s and early in the 1900s sodium nitrite was being used in the dye industry and chemists stocked it because it became an important medication to treat some blood disorders. Butchers used it as the source of nitrite. It is easier and “cleaner” than the indirect creation of nitrite through fermentation (tank curing or mild curing). Sodium nitrite can be dissolved directly in a brine and will immediately start penetrating the meat and change to nitric oxide.

Tank curing soon lost its place as the quickest way to cure meat in favour of the direct addition of nitrites to curing brines. There was an issue with nitrites though in that most people at this time knew that nitrite was a potent toxin. Understandably, from very early, humans who did not “see” the conversion of nitrate to nitrites and did not understand that nitrites were in any event present in cured meat grappled with the concept of a toxic substance being introduced in food preparations.

During the First World War, curing brines came onto the market which included nitrites. The days of tank curing were numbered, and a controversy was born about how healthy this is. Several investigations were made into the matter. No sooner was the matter of the toxicity of nitrites settled through scientific investigation when another, far more dangerous issue came onto the scene in the 1970s of n-nitrosamines. Let’s run through the chronology of some of the key studies and some of the important ways that governments around the world responded to it.

We picked the investigations into this matter up in 1926 which looked at the matter of nitrite as a toxin. If it was simply a matter of concentration, it would be easily settled because we regularly use substances if food which, in too high dosages can harm or even kill us. Alcohol is a very good example. The way to mitigate the risk is to determine the “safe” levels and to ensure that producers use the appropriate dosages.


A 1926 study by Kerr and co-workers was based on the general knowledge of nitrite’s toxicity and the publics very negative perceptions about it.  In the report, they state that public health was the primary motivation behind the study.  (Kerr, et al, 1926: 543)  I quote from their report.  “The first experiment involving the direct use of nitrite was formally authorized January 19, 1923, as a result of an application by one of the large establishments operating under Federal meat inspection. Before that time other requests for permission to experiment with nitrite had been received but had not been granted. The authorization for the first experiment specified that the whole process was to be conducted under the supervision of bureau inspectors and that after the curing had been completed the meat was to be held subject to laboratory examination and final judgment and would be destroyed if found to contain an excessive quantity of nitrites or if in any way it was unwholesome or unfit for food. This principle was rigidly adhered to throughout the experimental period, no meat being passed for food until its freedom from excessive nitrites had been assured, either by laboratory examination or through definite knowledge from previous examinations, that the amount of nitrite used in the process would not lead to the presence of an excessive quantity of nitrites in the meat. By “excessive” is meant a quantity of nitrite materially in excess of that which may be expected to be present in similar meats cured by the usual process.”  (Kerr, et al, 1926: 543)

The maximum nitrite content of any part of any nitrite-cured ham [was found to be] 200 parts per million. The hams cured with nitrate in the parallel experiment showed a maximum nitrite content of 45 parts per million.”  (Kerr, et al, 1926: 543) The conclusion was that “hams and bacon could be successfully cured with sodium nitrite, and that nitrite curing need not involve the presence of as large quantities of nitrite in the product as sometimes are found in nitrate- cured meats.”  (Kerr, et al, 1926: 545)

Related to the health concerns, the report concluded the following:

  1. The presence of nitrites in cured meats, was already sanctioned by the authoritative interpretation of the meat inspection and pure food and drugs acts sanctioning the use of saltpeter; as shown previously, meats cured with saltpeter and sodium nitrate regularly contain nitrites. (Wiley, H, et al, 1907) (Kerr, et al, 1926 : 550)
  2. The residual nitrites found in the nitrite-cured meats were less than are commonly present in nitrate-cured meats.  The maximum quantity of nitrite found in nitrite-cured meats, in particular, was much smaller than the maximum resulting from the use of nitrate.  (Kerr, et al, 1926 : 550)
  3. The nitrite-cured meats were also free from the residual nitrate which is commonly present in nitrate-cured meats.  (Kerr, et al, 1926 : 550)
  4. On the contrary, the more accurate control of the amount of “nitrite and the elimination of the residual or unconverted nitrate are definite advantages attained by the substitution.  (Kerr, et al, 1926 : 550)

Following further studies, the Bureau set the legal limit for nitrites in finished products at 200 parts per million.  (Bryan, N. S. et al, 2017: 86 – 90) Conventional wisdom that surfaced in the 1920s suggested that nitrate and nitrate should continue to be used in combination in curing brines (Davidson, M. P. et al; 2005:  171) as was the case with the Irish curing method or the tank curing concept of the previous century. Nitrite gives the immediate quick cure and nitrate acts as a reservoir for future nitrite and therefore prolongs the supply of nitrite and ensures a longer curing action.  This concept remained with the curing industry until the matter of N-nitrosamines came up in the 1960s and ’70s, but remarkably enough, it persists in places like South Africa where to this day, using the two in combination is allowed for bacon. More about this later.


The USDA progressed the ruling on nitrate and nitrites further in 1931 by stating that where both nitrites and nitrates are used, the limit for nitrite is 156 ppm nitrite and 1716 nitrate per 100lb of pumped, cured meat.  (Bryan, N. S. et al, 2017: 86 – 90)

1960’s – N-Nitrosamine

Up to the 1960’s the limit on the ingoing level of nitrites was based on its toxicity.  In the late 1950s an incident occurred in Norway involving fish meal that would become a health scare rivalled by few in the past.  1960’s researchers noticed that domestic animals fed on a fodder containing fish meal prepared from nitrite preserved herring were dying from liver failure. Researchers identified a group of compounds called nitrosamines which formed by a chemical reaction between the naturally occurring amines in the fish and sodium nitrite.  Nitrosamines are potent cancer-causing agents and their potential presence in human foods became an immediate worry.  An examination of a wide variety of foods treated with nitrites revealed that nitrosamines could indeed form under certain conditions.  Fried bacon, especially when “done to a crisp,” consistently showed the presence of these compounds. (Schwarcz, J) In bacon, the issue is not nitrates, but the nitrites which form N-nitrosamines.

This fundamentally sharpened the focus of the work of Kerr and co-workers of the 1920s in response to the general toxicity of nitrites to the specific issue of N-nitrosamine formation. Reviews from 1986 and 1991 reported that “90% of the more than 300 N-nitroso compounds that have been tested in animal species including higher primates causes cancer, but no known case of human cancer has ever been shown to result from exposure to N-nitroso compounds.”  However, despite this, there is an overwhelming body of indirect evidence that shows that a link exists and “the presence of N-nitroso compounds in food is regarded as an etiological risk factor.   It has been suggested that 35% of all cancers in humans are dietary related and this fact should not surprise us.  (Pegg and Shahidi, 2000)

Studies have been done showing that children who eat more than 12 nitrite-cured hot dogs per month have an increased risk of developing childhood leukaemia.  The scientists responsible for the findings themselves cautioned that their findings are preliminary and that much more studies must be done.  It may nevertheless be a good approach for parents to reduce their own intake of such products along with that of their children in cases where intake is high.  (Pegg and Shahidi, 2000)

These studies must be balanced by the fact that an overwhelming amount of data has been emerging since the 1980s that indicate that N-nitroso compounds are formed in the human body.  What is important is that we keep on doing further research on N-nitrosamines and the possible link to cancer in humans.  Not enough evidence exists to draw final conclusions.

1970 – The response to the N-Nitrosamine scare.

Back in the 1970s, so grave was the concern of the US Government about the issue that in the early 1970’s they seriously considered a total ban on the use of nitrites in foods. (Pegg and Sahidi, 2000) The response to the N-nitrosamine issue was to go back to the approach that was implemented following the work of Kerr and co-workers in 1926.

The first response was to eliminate nitrate from almost all curing applications.  The reason for this is to ensure greater control over the curing. Meat processors continued to use nitrate in their curing brines from 1920 until the 1970s. One survey from 1930 reported that 54% of curers in the US still used nitrate in their curing operations.  17% used sodium nitrite and 30% used a combination of nitrate and nitrite.  By 1970, 50% of meat processors still used nitrate in canned, shelf stable.  In 1974 all processors surveyed discontinued the use of nitrates in these products including in bacon, hams, canned sterile meats, and frankfurters.  One of the reasons given for this change is the concern that nitrate is a precursor for N-nitrosamine formation during processing and after consumption.  (Bryan, N. S. et al, 2017: 86 – 90)

The reason for the omission in bacon, in particular, is exactly the fact that the nitrates will, over time continue to be converted to nitrites which will result in continued higher levels of residual nitrites in the bacon compared to if only nitrite is used.  The N-nitrosamine formation from nitrites is a reaction that can happen in the bacon during frying or in the stomach after it has been ingested.  It will not happen from the more stable nitrates.

It has been discovered that nitrate continues to be present in cured meats.  Just as the view that if nitrate was added, no nitrite is present in the brine as was the thinking in the time before the early and mid-1800s, in exactly the same way it is wrong to think that by adding nitrite only to meat, that no nitrate is present.  “Moller (1971) found that approximately 20% of the nitrite added to a beef product was converted to nitrate within 2 hours of processing.  Nitrate formation was noted during incubation before thermal processing, whereas after cooking only slight nitrate formation was detected.  Upon storage, the conversion of nitrite to nitrate continued.  Herring (1973) found a conspicuous level of nitrate in bacon formulated only from nitrite.  As greater concentrations of nitrite were added to the belly, a higher content of nitrate was detected in the finished product.  They reported that 30% of the nitrite added to bacon was converted to nitrate in less than one week and the level of nitrate continued to increase to approximately 40% of the added nitrite until about 10 weeks of storage.  Moller (1974) suggested that when nitrite is added to meat, simultaneous oxidation of nitrite to nitrate and the ferrous ion of CodeCogsEqn (5)  to the ferric ion of metMb occurs.” Adding ascorbate or erythorbate plays a key role in this conversion.  (Pegg and Shahidi, 2000)  The issue is not the nitrate itself, but the uncontrolled curing that results from nitrate and the higher residual nitrites.

Secondly, the levels of ingoing nitrite were reduced, especially for bacon.  The efficacy of these measures stems from the fact that the rate of N-nitrosamine formation depends on the square of the concentration of residual nitrites in meats and by reducing the ingoing nitrite, the residual nitrite is automatically reduced and therefore the amount of N-nitrosamines.  (Pegg and Sahidi, 2000) Legal limits were updated in 1970 in response to the nitrosamine paranoia. A problem with this approach is however that no matter by how much the ingoing nitrite is reduced, the precursors of N-Nitrosamine still remain in the meat being nitrites, amines, and amino acids.

An N-nitrosamine blocking agent was introduced in the form of sodium ascorbate or erythorbate. “There are several scavengers of nitrite which aid in suppressing N-nitrosation; ascorbic acid, sodium ascorbate, and erythorbate have been the preferred compound to date.  Ascorbic acid inhibits N-Nitrosamine formation by reducing CodeCogsEqn (11)  to give dehydroascorbic acid and NO.  Because ascorbic acid competes with amines for CodeCogsEqn (11), N-Nitrosamine formation is reduced.  Ascorbate reacts with nitrite 240 times more rapidly than ascorbic acid and is, therefore, the preferred candidate of the two.  (Pegg and Sahidi, 2000)

More detailed studies identified the following factors to influence the level of N-nitrosamine formation in cured meats.  Residual and ingoing nitrite levels, preprocessing procedure and conditions, smoking, method of cooking, temperature and time, lean-to-adipose tissue ratio, and the presence of catalyst and/ or inhibitors.  It must be noted that in general, levels of N-nitrosamines formation have been minuscule small, in the billions of parts per million, and sporadic.  The one recurring problem item remained fried bacon.  In its raw state bacon is generally free from N-nitrosamines “but after high-heat frying, N-nitrosamines are found almost invariably.”  One report found that “all fried bacon samples and cooked-out bacon fats analyzed” were positive for N-nitrosamines although at reduced levels from earlier studies.  (Pegg and Sahidi, 2000)

Regulatory efforts since 1920 have shown a marked decrease in the level of N-nitrosamines in cured meats, even though it is still not possible to eliminate it completely.  “Cassens (1995) reported a marked decrease (approx 80%) in residual nitrite levels in of US prepared cured meat products from those determined 20 years earlier; levels in current retail products were 7 mg/kg from bacon.”  This and similar results have been attributed to lower nitrite addition levels and the increased use of ascorbate or erythorbate.  (Pegg and Sahidi, 2000)

Despite the actions of governments and the curing industry, consumer demand has grown over the years to eliminate nitrites in food. Evidence has started to emerge that links the prevalence of colon cancer, for example, not just to the use of nitrites but to the use of saltpetre or the far less toxic cousin of nitrite called nitrate. Much of the evidence is either anecdotal or indirect but it is sufficient to fuel public suspicion and legitimate industry concerns.

B. Can’t we just Remove the Nitrites?

What is clear from our survey above is that it is a technical and complex field. Can we not just remove the nitrites and sell nitrite-free bacon? When we talk about nitrite-free bacon, it is important to know exactly what we are talking about. The term can imply several things.

– Is the Problem Synthetic Nitrites Only (I.e. Sodium Nitrite Added Into the Brine)?

Is it that no synthesized nitrite must be used in the curing of the meat? Tank curing or fermented nitrate containing plant juices would then be an appropriate curing procedure. Celery and other plants are filled with nitrates which are part of plant nutrition, absorbed from the soil through the roots. Certain spice companies started using these plant extracts and then through a process of fermentation, allowed microorganisms to reduce the nitrite to nitrate like what was done in tank curing using old brine and they sold the plant extracts to be added to the meat as an ingredient. They called it a “natural curing agent” but in my opinion, they were actually deceiving the public. After the bacterial fermentation, the plant juices were now filled with nitrates. They cleverly circumvented the requirement to declare the use of nitrites in the curing process and in reality, nitrites were still present, now in usually much larger quantities as was the case using sodium nitrite.

– Is the Problem All Nitrites in the Brine and Meat, Including Either Sodium Nitrite or Nitrite that Formed Through Bacterial Action, Either through Reduction or Oxidation or Chemically and Irrespective of the Source?

Nitrite-free bacon can mean that no nitrites should be used in the curing process added directly or generated indirectly. Indirectly it can be generated through fermentation but there are other sources of nitrite which forms as a result of the decomposition of meat. In long-term curing, for example, the same colour, even a better taste and longer shelf life is achieved by the use of salt only. I mention this because it introduces a very important issue. For curing to take place, you don’t actually need nitrate or nitrite. You need nitrogen. The nitrogen must then react with oxygen to create nitric oxide (NO) which is a gas! Nitrate and nitrite are only the nitrogen source! Once Nitric Oxide is created, it must react with the meat proteins, myoglobin.

As the proteins of a dead animal or other constituents of meat are being broken down, nitrogen is made available and in long term curing, certain processes are involved and one of them is the combination of the nitrogen molecule, made available through decomposition, with an oxygen molecule and curing takes place if the overall destruction of the meat is managed through the removal of water which retards (even stops) the action of microorganisms and favours the effect of enzymes.

So, this can be done completely without any outside source of nitrogen but the process is very slow and there is no way that the world demand for cured meat will be satisfied through this. It will also be extremely expensive due to the weight loss involved in removing the moisture. No matter how you look at it, nitrogen must be accessed somehow, or it is not curing.

It is extremely important to know that curing is something that happens to the meat itself and it mimics a natural, biological process of nitric oxide being formed in our bodies. The meat protein in either its oxygenated state or with a nitric oxide molecule presents red. This is an extremely important concept to understand. Curing is a characteristic of meat itself and is a natural process. It is NOT the imposition upon the meat of a colouring agent. The fact that nitrogen is used in curing is completely consistent with natural biological processes. Even the reduction and interaction of nitrate and nitrite, including the chemical reduction to nitric oxide, is a biological process, essential to life!

I give one example from a review article by Shiva (2013). I anticipate that very soon consumers may demand food with high nitrate (NO3-) in a swing in perceptions of these molecules which will in all likelihood be driven by people who regularly work out. Shiva summarizes this work as follows. “Nitrite dependent inhibition of ccox also potentially regulates responses to physiological hypoxia (the absence of enough oxygen in the muscles), such as that present in the muscle during exercise. Larsen and colleagues recently demonstrated that ingestion of NO3- (nitrate) decreased whole-body oxygen consumption during exercise without changing maximal attainable work rate in human subjects.” Directly as a result of this work, several booster supplements are currently on the market and sold in gyms and health shops around the world containing nitrates.

Shiva continues, “This increase in exercise efficiency, which was associated with augmented plasma NO2- levels, has now been corroborated by a number of studies in various exercise models. While the underlying mechanism of this beneficial effect is not completely elucidated, a decrease in the rate of oxygen consumption due to proton leak and state 4 respiration in the skeletal muscle of subjects receiving NO3- was reported.” (Shiva, 2013)

Right there, the entire matter is resolved and in a few short years, the public will demand more nitrates in meat (and by implication, nitrite also)! 🙂 🙂

Furthermore, not only is the reaction of nitrite to nitric oxide not foreign in our physiology, the reaction of nitric oxide with myoglobin is an extremely important physiological reaction that is mimicked in curing. Jens Moller and Leif Skibsted write that “Nitrosylmyoglobin (MbFeIINO), the NO complex of iron (II) myoglobin, as formed in meat products, has now also been observed in vivo in rats. MbFeIINO thus seems important in controlling radical processes associated with oxidation”. (Møller and Skibsted, 2002)

The issue is that our best available source of nitrogen is through nitrite and nitrite itself but is both beneficial and problematic at the same time.

The fact that the reaction of oxygen (O2) and Nitric Oxide are both matters that all butchers work with daily is important. None of these reactions is “unnatural!” This is seen in the colour of fresh meat and cured meat. I dedicated a chapter to it in Bacon & the Art of Living, called Fresh Meat Colour vs Cooked Cured Colour.

I plan to do much more work about the physiological reason why nitric oxide fits onto the colouring site of a protein apart from the short quotes above, but I will deal with this separately and update this section with a link reference.

– If the Meat itself Does Not Change Colour (Curing), is the use of External Colourant Permitted/ Desirable?

There is another way of achieving a red colour in meat which we alluded to and that is through an artificial process that involves the use of an external colourant. Legally there are colourants that are allowed in meat, but how will consumer groups respond to this? This is not something natural and inherently part of meat itself. It is an external colourant that is brought to bear upon the meat matrix. This is even more objectionable to some than nitrite and the extreme objection against it goes back to the start of the meat trade where butchers used to disguise old and sometimes putrid meat as fresh by colouring it with an external colourant.

– Is the Real Issue Actually Residual Nitrite That We Must Eliminate? (I.e., Not Ingoing Nitrite but Nitrite Left in Meat After Curing)

Another possible meaning of nitrite-free bacon refers not to the fact that nitrite was somewhere involved in the supply of the nitrogen source to form nitric oxide, but the real meaning may refer to the question of whether any nitrite is left in the product when the consumer fries it in the pan. It is after all not the initial source of the nitrogen atom, which is the real issue, but how much nitrite is left after the meat has been cured. This is what is referred to as residue nitrite. The other question which goes hand in hand with this is to what degree can the consumer be guaranteed that no appreciable amount of nitrite is left in the product he buys?

– Is The Objective to Eliminate All Manipulation of Colour (Natural or Artificial) and Resign Ourselves to Selling Brown Bacon and Hams (uncured, salted only)?

A final solution for some is to simply omit accessing nitrogen in any shape or form altogether and not be concerned about the brownish colour that develops. I have over a few years followed the work of a New Zealand company, interestingly enough also called Woody’s who follow this approach and I am amazed at the success they have had with their brand positioning. Good old strict hygiene is used to sort shelf-life issues out and they educate their customers that the browner bacon is actually healthier bacon. The brown bacon they sell becomes a source of comfort for their clients. If this is advisable as a universal approach to bacon or ham is debatable in a world where not everybody shares the strict attention to detail of this company, but I applaud them for their honesty and the practical way in which they have dealt with this thorny issue (see Woody’s Free Range Farm) In the end, I feel much of the problems are self-inflicted in a world where bacon flitches are no longer wrapped in cloth, palletized and shipped any longer.

By William James Topley – This image is available from Library and Archives Canada under the reproduction reference number PA-026092 and under the MIKAN ID number 3424485

How to Explain it?

As you can see from this short overview, the matter is not simple but the fact that there is an issue to address is clear. For myself, I am satisfied that in the minuscule levels that nitrite is used and remains present in bacon and hams, these products are completely safe to eat. The consumer is, however, also not wrong to be concerned about the matter. The problem is that the explanation above is already so technical – who can follow this? Let alone a dissertation by Dr Sebranek or Dr Møller, two of the world authorities on the subject. If anybody must understand what they are saying before one can decide which bacon is healthy and not and which brine to use or not, only a handful of people will ever make a meaningful determination on the matter. This business of reduction and oxidation, bacterial, enzymatic reactions are all very confusing for people without an advanced degree in chemistry, like me. The only way that I could make any sense of it was to follow the story right from the beginning. As it unfolded. And what a story it turned out to be!

C. Review: How did we get here?

I will tell the story, at least the parts that are pertinent to the discussion about nitrite, from a series of articles I did on the subject over a few years and from extracts of a book I wrote about the history of bacon called Bacon & the Art of Living. One article where I deal with the full sweep of its history is Bacon Curing – a Historical Review.

Before we jump into the detail, let’s establish a timeline. Broadly speaking the development of bacon curing to where we are with the direct addition of nitrite to curing brine can be divided into the following timeline.

  • The Prehistory of Bacon Curing experimenting with various salts (sodium chloride, sal ammoniac, nitrate also called saltpetre) From antiquity to the end of the 1500s.

  • Saltpetre gained popularity as it becomes widely available as a vitalizer, an ingredient in gunpowder and as medication. 1600 to 1800.

  • William Oake invented Tank Curing/ Mild Curing around 1832 (aged 25) – an Indirect Addition of Nitrite to Curing Brines.

  • Dr. Ed Polenski’s Article on Nitrite in saltpetre brines, 1891.

  • The academic work of German and English researchers identifying Nitrate and Nitric Oxide as the curing agents. Notwang (1892), Lehmann (1899), Kiskalt (1899), Haldane (1901).

  • The work of Ladislav Nachmullner and the first curing brine containing sodium nitrite (1915).

  • The Impact of the First and Second World War in changing the indirect use of Nitrites to the direct addition of nitrites to curing brines.

  • The Griffith Laboratories as evangelists of the direct addition of nitrites to curing brines. Prague Salt (1925).

  • “Houston, we have a problem!” The n-nitrosamine problem and the response of the curing industry and world governments, late 1950s.

  • Must we Remove Nitrite from Food or Manage it?

D. Why do we use it at all?

Its anti-microbial ability now becomes important, especially as it relates to C Botulinum. Nitrite as a key hurdle in botulinum prevention remains relevant. I looked at the most important microorganism in a 2015 article, Clostridium Botulinum – the priority organism

The Anti-Microbial Efficacy of Nitrite

In 2015 I had the privilege to interact with Dr R. Bruce Tompkin on the issue of the antimicrobial efficacy of nitrate and nitrite. Dr Tompkin was one of the founders of the HACCP system. We had some correspondence about the possibility of replacing nitrite as a hurdle and his insights are still helpful to this day. For this, I will be eternally grateful. It was written before I discovered that tank curing came from Ireland and there are other sections where my understanding evolved. I nevertheless share it with you as I wrote five years ago. I am thankful for experts from around the world who continue taking the time to give input not just on the matter of nitrite replaces, but on a wide array of meat and processing-related subjects. I can honestly say that if you do not know in our trade you do not want to know! (or you have been so busy that there was no time to find out!) 🙈🙈 Which I fully understand!! 🤣🤣

I looked at this issue in 2015 in an article, Concerning Nitrate and Nitrite’s antimicrobial efficacy – chronology of scientific inquiry.

E. Further Work on Nitrite Free Bacon and its role in Human Physiology


I have no doubt that this matter can be resolved scientifically. In terms of marketing, this can be done in a way that the consumer will be fully in-step, all the way and is taken along, not left behind or feel that half-baked ideas are thrust down his/her throat. This work is important, not just for the uncompromising drive to better and healthier food, but for the overall quest to be better in every way! To offer safe and delicious food should be the desire of every food producer on earth. Anything less both in terms of taste, quality, and safety is a crime! In this work, I can end with a quote from no finer man than Nelson Mandela who said that “what counts in life is not the mere fact that we lived. It is what difference we have made to the lives of others that will determine the significance of the life we lead!”


Jens K. S. Møller and Leif H. Skibsted. 2002. Nitric Oxide and Myoglobins. Chemical Reviews 2002102 (4), 1167-1178DOI: 10.1021/cr000078y

Chapter 12.03: The Direct Addition of Nitrites to Curing Brines – the Master Butcher from Prague

Introduction to Bacon & the Art of Living

The story of bacon is set in the late 1800s and early 1900s when most of the important developments in bacon took place. The plotline takes place in the 2000s with each character referring to a real person and actual events. The theme is a kind of “steampunk” where modern mannerisms, speech, clothes and practices are superimposed on a historical setting.  Modern people interact with old historical figures with all the historical and cultural bias that goes with this.

The Direct Addition of Nitrites to Curing Brines – the Master Butcher from Prague

September 1959

Dear Tristan,

The Father/ Son Example from New York

I received your previous mail with great excitement. Your account of Henry Hudson’s exploration around the New York area, what became known as Hudson Bay and the Hudson River is riveting! I am so glad you go to exhibitions such as these! It broadens our horizons! You know that we get to read newspapers from around the world in our Cape Town library. Last Monday I went into the city and spent the day at the library and the archives. I made this clipping from the Troy Record for you advertising the exhibition you visited in Amsterdam.


From the Troy Record, Troy, New York, 27 March 1959.

The story is epic. How an Englishman was employed by the Dutch East Indian Company to find the rumoured northeast passage to Cathay via a route above the arctic circle. He landed in North America in 1609 where he explored the regions around New York looking for a Northwest Passage. His exploits became the basis for a Dutch Colony that was later established here and the Hudson River was named after him.

He was back in 1611, this time on behalf of the English East Indian Company but his voyage ended in a mutiny by his crew when, after a long winter, they were eager to return to Europe when Hudson wanted to press on with his trip. In the end, Hudson, his teenage son John, and seven crewmen (all men who were either sick and infirm or loyal to Hudson) were forced into a small shallop (a name used for several types of boats and small ships) and left behind. The small vessel tried to keep up with the large ship but they hoisted another sail and left the small boat behind. Hudson, his son and the others left behind were never seen again.

It can, on the one hand not imagine a more desperate situation than to be left behind with your son when he will either see his dad dying at the hand of hostile locals or by the challenges of nature. If the son did not see his father suffering these, it was surely the father who saw his son dying. Yet, I can not help but notice that he took his son with him on his exploration! That reminds me of us!

The events transpired in the 1600s which is where I want to pick up the story of the art of bacon. I am very thankful that I am able, through the technology of writing, drawings, and pictures, to share my adventure with you and your sister. I enjoy the fact that my voyage of discovery involves all the senses. It challenges and engages my entire being, mind, and soul! The quest is not only bacon but life itself and the crown of life most certainly, is not the places I visited and the many things I learned, but Minette! How thankful am I that we walk this amazing path together and with you guys!

Prague 1

Prague, photo by Dawie Hyman

This is one of the most important letters I have written to you from the time I spent at Calne. Within the greatest inventions of meat curing systems, this is the next major drumbeat since the invention of Tank Curing.

The Progression of Curing Systems

Please allow me to very briefly review the major movements in the history of curing systems.

– Dry Cured Bacon

Dry-curing is the system of bacon curing which existed for hundreds of years and included only dry ingredients and later dry ingredients with wet brine added (Chapter 02: Dry Cured Bacon)

– Mild Cured Bacon

The honour for the industrialisation of the bacon curing process goes to William Oake from Northern Ireland who invented mild cured bacon sometime before 1837. (Chapter 09.01 – Mild Cured Bacon)

– Sweet Cured Bacon

The next major movement came by the initiative of the Harris bacon operation in Calne, Wiltshire. Invented by Harris in Calne, early in the 1840s, mild cured bacon exploited new opportunities brought about by stitch pumping, a new invention which was taking the bacon world by storm. (Chapter 10.02 – Sweet Cured Harris Bacon)

– Pale Dried Bacon and Wiltshire Bacon or Tank Cured Bacon

Pale dried bacon was invented under John Harris in Calne in the 1890s. Wiltshire bacon curing or Tank curing was invented in Calne in the closing years of the 1800s or early 1900s. (Chapter 10.06: Harris Bacon – From Pale Dried to Tank Curing!)

– The Direct addition of Nitrite

The next major development related to the direct addition of nitrites to curing brines. This was in turn made possible through the availability of sodium nitrite in pharmacies as a heart medication. The man with the vision and the scientific background to bring such a transformation about was the master butcher from Prague, Ladislav NACHMÜLLNER. He invented the first curing brine legally sold containing sodium nitrites in 1915 in Prague. The system was made popular around the globe by the Griffiths Laboratories. My next two letters deal with this monumental progression!

Meat Curing: 1600 to 1910: Reviewing what we knew.

Prague 2

Prague Breakfast by Dawie Hyman

In Europe, before the 1600s meat preservation was done mostly with salt only. Colour in meat was important from antiquity because a reddish appearance denotes freshness. People looked for ways to manipulate meat colour for a long time, probably since meat was sold or traded. In the 1600s vegetable dyes were used to bolster colour. (The history of curing) A few people added a little bit of saltpetre (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 as Salpeter became universally available as a result of its military application and as fertilizer and the quality and purity improved. During the 1800s sugar was added to the mix. This, with the exception of ascorbic acid and phosphates that have been added since the mid-1900s, 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 saltpetre.

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 saltpetre (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 colour 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 saltpetre, 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 produces 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 before you can taste sweetness.

When the brine enters the meat, the anion CodeCogsEqn (17) is formed and a very small amount of nitrite (less than 1% of the total nitrite) forms the neutral nitrous acid (CodeCogsEqn (19)). 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 nitric oxide is the formation of nitrous acid (HNO2). 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 1800s, is sugar. [6] Sugar was added originally to reduce the salty taste of the meat. Curers noticed that if sugar is added with saltpetre to the brine mix, the meat cures slightly faster and with better colour development. (The history of curing) In the 1920s, ascorbate or its isomer, erythorbate became the magical reducing agent [7], but this too is the subject for a future letter.

If saltpetre 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)

Investigating Two Sources of Nitrite’s

Prague 3

Prague Supper by Dawie Hyman

This was then the understanding of meat curing by the beginning of the 1900s. 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.

The Irish and later the Danes took the development where nitrites are directly applied to curing, in one very particular direction. They invented the “mother brine” cure. The concept of re-using the old brine and meat juices was a well-known practice in many regions of the world from early on. Butchers worked out that it speeds up curing, even long before the term nitrite was coined. It was the Irish who invented a system to exploit the mother-brine approach on an industrial scale. The Danes got the technology from Ireland and I, after studying under Uncle Jeppe and Andreas in Denmark taught the system to John Harris in Calne. They called it tank curing which is a method of allowing bacteria to reduce saltpetre to nitrites and the nitrites to be added back into bacon brine after it was boiled to kill the bacteria. The net result is that nitrites were produced through bacterial means and the nitrites were used to cure the meat much quicker than could ever be done with saltpetre alone. (The Mother Brine and C & T Harris and their Wiltshire bacon cure)

There was, however another readily available source of nitrites which became the focal point of meat curers in Germany, Austria, Hungary and in the USA. Nitrites were already being used in a large, industrial process since the end of the 1800s 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 1800s and early 1900s 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)

There were 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)

PRAGUE 1800 – 1920 – Food innovation, industrial leadership and the availability of nitrite

Germany’s neighbour and ally in World War One, the Austro-Hungarian Empire with the key cities of Prague, Vienna, and Budapest, in the late 1800s and early 1900s 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, the 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 1900s, 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 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 who 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 showed themselves to be innovative and capable in matters pertaining to chemistry.

At the end of the 1800 and beginning of the 1900s, 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 in 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 only 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 Master Butcher from Prague

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 high quality, sodium nitrite was widely available and there was an appetite for and a culture of innovation in food production.

Ladic knew sodium nitrite well from his father who was a glassmaker. Even as a boy, he would have been exposed to it. His father encouraged him never to enter the glassmaking profession and he instead chose curing as a way to provide for his siblings. 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.

Ladic knew sodium nitrite well. The seemingly boring facts of the early experiments on curing and the confirmation through science that it was indeed nitrite responsible for curing and not saltpetre was cutting edge technology of the time and the scientific findings were reported upon in many publications and newspapers of the time. Ladic must have been an unusually gifted and curious person and he read these reports with great attention, realising that he may have the answer to a much faster and more controlled way of accessing nitrite namely through the direct addition of sodium nitrite to the curing brine.

He wrote 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 were not primarily interested in a quicker process but in a better end product. Saltpetre 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 saltpetre.

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. The little nitrite would still cure the meat much faster than even the mild cured techniques as the Irish called it or the tank curing technology as the English referred to it.

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 saltpetre to military purposes only and the use of nitrites in food was 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 sometime 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 challenges 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. (

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. ( 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. ( 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.

The Salts from Prague

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 neighbour to the north, Poland, was 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 these 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. (

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 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)

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.

A Fork in the Road

Ladislav’s invention was a fork in the road for nitrite technology. A new and “more direct” way of getting nitrite in the curing brine was developed. It is not surprising that it happened in the part of the world where nitrogen technology was best understood and where people were mesmerised through the opportunities created by the science of chemistry. It challenged the Irish mild cured system and the Danish and English Tank curing systems, as they called the mild cured process, by offering an even faster curing solution and one which is “safer”. The exact quantity of nitrites added can be much better controlled with this new system and when it comes to a substance such as nitrite that is poisonous in too high dosages, being able to control the amount of ingoing nitrite into the meat is very important.

Almost concurrent with Ladislav’s invention was events in Germany that brought about a wholesale conversion of German meat curers to this new and faster technology. Its getting time for Minette and my hike down to the promenade where we plan to do a 15km this afternoon. Caring for the body is just as important as caring for the mind.

I am glad you are getting out and seeing exhibitions in this great city where you find yourself! Learn as much as you can while you live in Amsterdam!

Lots of love from Cape Town,

Dad and Minette.

Further Reading

Difference between Fresh Cured and Cooked Cured Colour of Meat.

Mechanisms of meat curing – the important nitrogen compounds

Reaction Sequence: From nitrite (NO2-) to nitric oxide (NO) and the cooked cured colour.

The Naming of Prague Salt

Tank Curing Came from Ireland

The Mother Brine


(c) eben van tonder

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1. The colour changes in meat.

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.

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.

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:

NO smoke

Source: “From smoke which has many other phenolic compounds”

Species 2:

CodeCogsEqn (55)

Source: From curing salt

Species 3:

CodeCogsEqn (57)

Source: Found in the air.

Species 4:

CodeCogsEqn (22)

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)

4. The term “nitrite”
“The term nitrite is used generically to denote both the anion,

CodeCogsEqn (17)

, and the neutral nitrous acid

CodeCogsEqn (19)
, but it is the latter which forms nitrosating compounds.” (Comparison by Sebranek, J. and Fox, J. B. Jn.. 1985)

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, which is subsequently 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)

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)

7. Ascorbate or erythorbate supplements sugar.

An excellent reducing agent was discovered in the 1920s 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 1800s 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 continue 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.

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 directly 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 every 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 fiber 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 into 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


Ladislav Nachmüllner vulgo Praganda. Nachmüllnerová, Eva, Editor, 2000, Translated by Monica Volcko

1907. American Food Journal. Volume 2.Chicago Daily Tribune, 7 Jul 1910, Thu. P15Chicago Sunday Tribune, Nov 10, 1907, The Cincinnati Enquirer ( Cincinnati, Ohio), 27 September 1923. Page 14

The Detroit Free Press (Detroit, Michigan) reported, 14 Jan 1921, p 16Detroit Free Press, Detroit, Michigan, 11 June 1921, p4

Detroit Free Press, 22 Apr 1921, Fri, Page 18Ernst, FA. 1928. Fixation of Atmospheric Nitrogen. D van Nostrand, Inc.

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 1924The 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,2000Mcclure, 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. 471-474Progress 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.

The Saint Paul Daily Globe, 10 May 1896,


Journal of the Royal Society of Arts 71 (3702). Royal Society for the Encouragement of Arts, Manufactures and Commerce: 859–76.

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 18Toldr, F.. 2010.

Handbook of Meat Processing. John Wiley & Sons Inc.Turmock, D.. 1989.

Eastern Europe: A Historical Geography 1815-1945.

RoutledgeVaughn 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, PolandImages


1: Old Prague: Old Prague Logansport Pharos-Tribune Sat Oct 19, 1895Image

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.Image

4: Sodium nitrite, photos by Prof Duchon.Image

5: Germany.

Image 6 and 7: Notice of sale by UK government: The Times, 1 May 1919, Thu, Page 18Image 8: Union Stock Yard, Chicago. The Modern Packing House. 1905, 1921. Nickerson & Collins.