Vagadia et al. (2015) state that soya “contains a variety of bioactive anti-nutritional compounds including protease trypsin inhibitors, phytic acid, and isoflavones that exhibit undesirable physiological effects and impede their nutritional quality. Inactivation of these trypsin inhibitors, along with deleterious enzymes, microbes, bioactive components and increasing the protein quality by improving its texture, colour, flavour, functionality and digestibility are the most important factors to be considered in the crucial stage in the manufacturing of soy products.” Are there reasons to be concerned and what can we learn about its history and possible applications in the meat industry?
Historically Valued Plant
Before we break down the concerns raised by Vagadia et al. (2015), it is instructive to know that soya has been consumed in many countries since before recorded history. A rich tradition developed around its use in medicine from antiquity. Duke (1991) showed that a search of his “Medicinal Plants of the World” database (Sept. 1981) indicated that soybeans are or have been used medicinally in China to treat the following symptoms/diseases or for the following medicinal properties (listed alphabetically; Most information from: Li Shih-Chen. 1973. Chinese Medicinal Herbs. San Francisco: Georgetown Press):
Uses in other parts of the world include cancer, and cyanogenetic, shampoo (USA), diabetes (Turkey), soap (Asia), stomach problems (India).
Not only was it recognized as a superfood in many parts of the world, but it was celebrated for its medicinal value. Looking at the factors of concern raised by many, we begin by looking at the most well-known concern factor of its role as a trypsin inhibitor.
The German physiologist Wilhelm Kühne (1837-1900) discovered trypsin in 1876. It is an enzyme that cleaves peptide bonds in proteins (serine protease) and is therefore essential in digestion. It is found in the digestive system of many vertebrates, where it hydrolyzes proteins. (Kühne, 1877) Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen, produced by the pancreas, is activated. (Engelking, 2015) A trypsin inhibitor (TI) is then something (a protein) that reduces the biological activity of trypsin and as such have a negative effect on nutrition by impairing the digestion of food.
The concern about soya’s trypsin inhibitors is of no real concern to us. It turns out that trypsin in humans is more resistant to inhibition than is the trypsin of other mammalian species. “The effect on human trypsin of soybean trypsin inhibition in soy protein does not appear to be a potential hazard to man. Therefore, the elimination of STI does not seem to be necessary for humans.” (Flavin DF, 1982)
“In animal diets, however, pancreatic toxicity must be considered whenever soybean protein is utilized. Soybeans should be treated to increase their nutritional benefits and decrease any animal health risks. This will ensure healthy control subjects in laboratory situations and avoid misinterpretation of pathologic data.
The treatment suggested is heat since heat will destroy most of the soybean trypsin inhibitors. Additional supplementation is required following heat treatment for amino acids such as methionine, valine, and threonine; for choline; and for the minerals zinc and calcium. Excessive heat must be avoided since it will decrease the nutritional value of soybean protein and increase lysinoalanine, a nephrotoxic substance.
Finally, the use of STI as a promotor in the study of potential pancreatic carcinogens may prove beneficial for cancer research and might be considered in the future.” (Flavin DF, 1982)
Phytic acid also is suspect due to its inhibitory effect related to nutrition. Anderson (2018) states “It is a unique natural substance found in plant seeds. It has received considerable attention due to its effects on mineral absorption. Phytic acid impairs the absorption of iron, zinc, and calcium and may promote mineral deficiencies” (Arnarson, 2018)
As is the case with the trypsin inhibition, the story is a bit more complicated than that because phytic acid also has a number of health benefits.
Anderson writes that “phytic acid, or phytate, is found in plant seeds. It serves as the main storage form of phosphorus in the seeds. When seeds sprout, phytate is degraded and the phosphorus released to be used by the young plant. Phytic acid is also known as inositol hexaphosphate, or IP6. It’s often used commercially as a preservative due to its antioxidant properties.
Phytic acid is only found in plant-derived foods. All edible seeds, grains, legumes and nuts contain it in varying quantities, and small amounts are also found in roots and tubers. The following table shows the amount contained in a few high-phytate foods, as a percentage of dry weight:
As you can see, the phytic acid content is highly variable. For example, the amount contained in almonds can vary up to 20-fold.
Phytic acid impairs absorption of iron and zinc, and to a lesser extent calcium. This applies to a single meal, not overall nutrient absorption throughout the day. In other words, phytic acid reduces mineral absorption during the meal but doesn’t have any effect on subsequent meals. For example, snacking on nuts between meals could reduce the amount of iron, zinc and calcium you absorb from these nuts but not from the meal you eat a few hours later.
However, when you eat high-phytate foods with most of your meals, mineral deficiencies may develop over time. This is rarely a concern for those who follow well-balanced diets but may be a significant problem during periods of malnutrition and in developing countries where the main food source is grains or legumes.
Avoiding all foods that contain phytic acid is a bad idea because many of them are healthy and nutritious. Also, in many developing countries, food is scarce and people need to rely on grains and legumes as their main dietary staples.
Phytic acid is a good example of a nutrient that is both good and bad, depending on the circumstances. For most people, it’s a healthy plant compound. Not only is phytic acid an antioxidant, but it may also be protective against kidney stones and cancer. Scientists have even suggested that phytic acid may be part of the reason why whole grains have been linked with a reduced risk of colon cancer.
Phytic acid is not a health concern for those who follow a balanced diet. However, those at risk of an iron or zinc deficiency should diversify their diets and not include high-phytate foods in all meals. This may be especially important for those with an iron deficiency, as well as vegetarians and vegans.
There are two types of iron in foods: heme iron and non-heme iron. Heme-iron is found in animal foods, such as meat, whereas non-heme iron comes from plants.
Non-heme iron from plant-derived foods is poorly absorbed, while the absorption of heme-iron is efficient. Non-heme iron is also highly affected by phytic acid, whereas heme-iron is not. In addition, zinc is well absorbed from meat, even in the presence of phytic acid.
Therefore, mineral deficiencies caused by phytic acid are rarely a concern among meat-eaters. However, phytic acid can be a significant problem when diets are largely composed of high-phytate foods while at the same time low in meat or other animal-derived products. This is of particular concern in many developing nations where whole grain cereals and legumes are a large part of the diet.” (Arnarson, 2018)
Isoflavones are a class of phytoestrogens — plant-derived compounds with estrogenic activity. Soybeans and soy products are the richest sources of isoflavones in the human diet. (oregonstate.edu)
“Since many breast cancers need estrogen to grow, it would stand to reason that soy could increase breast cancer risk. However, this isn’t the case in most studies.
In a review of 35 studies on soy isoflavone intake and breast cancer incidence, higher soy intake reduced breast cancer risk in both pre- and postmenopausal Asian women. For women in Western countries, one study showed soy intake had no effect on the risk of developing breast cancer.
This difference may be due to the different types of soy eaten in the Asian compared to the Western diet. Soy is typically consumed whole or fermented in Asian diets, whereas in Western countries, soy is mostly processed or in supplement form.
In an animal study, rats fed fermented soy milk were 20% less likely to develop breast cancer than rats not receiving this type of food. Rats fed soy isoflavones were 10–13% less likely to develop breast cancer. Therefore, fermented soy may have a more protective effect against breast cancer compared to soy supplements. Additionally, soy has been linked to a longer lifespan after breast cancer diagnosis.
In a review of five long-term studies, women who ate soy after diagnosis were 21% less likely to have a recurrence of cancer and 15% less likely to die than women who avoided soy.” (Groves, 2018)
From the above notes, it may appear that it is perfectly safe for humans to consume raw soya. There is however one very good reason to cook soya well before it is consumed.
“Soybeans contain lectins, glycoproteins that bind to carbohydrates in cells. This can damage the cells or lead to cell death in the gastrointestinal tract. Lectins may bind to the intestinal walls, damaging the cells and affecting nutrient absorption as well as causing short-term gastrointestinal side effects. Unlike most proteins, lectins aren’t broken down by enzymes in the intestine, so the body can’t use them. Lectins can affect the normal balance of bacteria in the intestine and the immune system in the digestive tract.” (Perkins, 2018)
Dr. Mark Messina discussed the issue with Lectin in soya in a brilliant article entitled “Is Soybean Lectin an Issue?” He writes, “Given all the attention they’re receiving, you might think these proteins are newly discovered, perhaps because of a sudden advance in technology. Given all the concerns being raised about them, you might be thinking of avoiding foods that contain them. If you do, you can pretty much say goodbye to a long list of healthy foods such as legumes (including soy and peanuts), eggplant, peppers, potatoes, tomatoes, and avocados. Despite the hoopla, studies show there is little reason for concern.
Lectins are anything but new to the scientific community. They are a class of protein that occurs widely in nature and have been known to exist in plants for more than a century. Much of the lectin research has focused on legume lectins but these carbohydrate-binding proteins are widely distributed throughout the plant kingdom. The lectin in soybeans was discovered in the 1950s.
In plants, lectins appear to function as nitrogen storage compounds, but also have a defensive role, protecting the plant against pests and predators. They are capable of specific recognition of and binding to carbohydrate ligands. The term lectin (legere = Latin verb for to select) was coined by Boyd circa 1950 to emphasize the ability of some hemagglutinins (lectins) to discriminate blood cells within the ABO blood group system.5-The term lectin is preferred over that of hemagglutinin and is broadly employed to denote “all plant proteins possessing at least one non-catalytic domain, which binds reversibly to a specific mono- or oligosaccharide.”
Orally ingested plant lectins remaining at least partially undigested in the gut may bind to a wide variety of cell membranes and glycoconjugates of the intestinal and colonic mucosa leading to various deleterious effects on the mucosa itself as well as on the intestinal bacterial flora and other inner organs. The severity of these adverse effects may depend upon the gut region to which the lectin binds. Several cases of lectin poisoning due to the consumption of raw or improperly processed kidney beans have been reported.
The lectin content of soybeans varies considerably among varieties, as much as fivefold. However, from a nutritional perspective, it is the amount in properly processed soyfoods that is most relevant. Although there has been a lot of debate about whether even active soybean lectin is harmful, a true pioneer in this field, Irvin E. Liener, concluded that soybean lectin isn’t a concern because it is readily inactivated by pepsin and the hydrolases of the brush border membrane of the intestine. But, others think soybean lectin does survive passage through the small intestine.
Not surprisingly, autoclaving legumes including soybeans completely inactivates lectins. However, foods aren’t typically autoclaved. The most practical, effective, and commonly used method to abolish lectin activity is aqueous heat treatment. Under conditions where the seeds are first fully soaked in water and then heated in water at or close to 100°C, the lectin activity in fully hydrated soybeans, kidney beans, faba beans, and lupin seeds is completely eliminated. Thompson et al. noted that cooking beans to the point where they might be considered edible are more than sufficient to destroy virtually all of the hemagglutinating activity of lectins. More recently, Shi and colleagues23 found that soaking and cooking soybeans destroyed more than 99.6% of the lectin content, which agrees with earlier work by Paredes-Lopez and Harry.
Finally, evidence from clinical trials in no way suggests that the possible residual lectin content of soyfoods is a cause for concern. Adverse effects typically associated with lectin toxicity don’t show up in the hundreds of clinical trials involving a range of soy products that have been published. Not surprisingly, the U.S. Food and Drug Administration recently concluded that soy protein is safe.” (Messina, 2018)
Saponins in Soybeans
Saponins in soya are responsible for the bitter taste, foam-forming, and activities that rupture or destroy red blood cells. Its presence in soya is probably an evolutionary development to protect it against, for example, Callosobruchus chinensis L., a common species of beetle. Its protecting properties can be seen for example by the fact that [certain strains of] the first instar larvae, after burrowing beneath the seed coat, subsequently die without moulting. (Applebaum, 1965)
There are five known soya saponins: Soya sapogenols A, B, C, D, and E. Saponins cannot be inactivated by cooking because cooking doesn’t break down this toxin like it does lectins.” (Perkins, 2018) “Triterpenoid saponins in the mature soybean are divided into two groups; group A soy saponins have undesirable astringent taste, and group B soy saponins have health-promoting properties. Group A soy saponins are found only in soybean hypocotyls, while group B soy saponins are widely distributed in legume seeds in both hypocotyls (germ) and cotyledons. Saponin concentrations in soybean seed are ranged from 0.5 to 6.5%.” (Hassan, 2013)
Bondi and Birk (1966) investigated soybean saponins as related to the processing of petroleum etherextracted meal for feed and to the preparation of soy foods. They found that “soybean saponins are harmless when ingested by chicks, rats and mice even in a roughly threefold concentration of that in a 50% soybean meal supplemented diet.” They are decomposed by the caecal microflora of these 3 species. Their non-specific inhibition of certain digestive enzymes and cholinesterase is counteracted by proteins which are present in any natural environment of these saponins. The haemolytic activity of soybean saponins on red blood cells is fully inhibited by plasma and its constituents –
which naturally accompany red cells in blood. Soybean saponins and sapogenins are not absorbed into the blood-stream (Note: Or perhaps not observed in the bloodstream). It may, therefore, be concluded that haemolysis – one of the most significant in vitro [in glass/test tubes] properties of soybean saponins and others–bears no ‘obligation’ for
detrimental activity in vivo [in living organisms].” (Bondi, et al, 1966)
Birk, et al, 1980, found that “saponins are glycosides that occur in a wide variety of plants. They are generally characterized by their bitter taste, foaming in aqueous solutions, and their ability to hemolyze [break down] red blood cells. The saponins are
highly toxic to cold-blooded animals, their toxicity being related to their activity in lowering surface tension. They are commonly isolated by extraction of the plant material with hot water or ethanol.” (Birk, 1980) Leaching the saponins out of the soybeans, removing the bitter taste. (Perkins, 2018)
Applications and History
Reviewing the history of the development of soya industry in Israel, brought up some interesting perspective on its application in food.
“Hayes Ashdod was one of Israel’s first company to make foods from soybeans and Israel’s first manufacturer of modern soy protein products. In 1963 the company launched its first product, a soy protein concentrate named Haypro. This product was also the first commercial soy protein concentrate manufactured outside the United States. The main applications for Haypro were as a meat extender.” (Chajuss, 2005)
“In 1966 Hayes Ashdod Ltd. introduced texturized soya protein concentrates under the brand names Hayprotex and Contex. Hayprotex was designed for use mainly as a minced
meat extender, while Contex was designed mainly for vegetarian analogs.” (Chajuss, 2005)
“Concerning early textured soy protein concentrates: Hayes Ashdod introduced Hayprotex and Contex in 1966, and a company we are well familiar with for making nitrite curing of meat commercially available around the world through their legendary Prague Powder, the Griffith Laboratories from Chicago introduced GL-219 and GL-9921 in 1974, and Central Soya introduced Response in 1975.” (Chajuss, 2005)
“In 1969 Hayes started to produce Primepro, a more functional and soluble soy protein concentrate, by further treatment of the aqueous alcohol extracted soy protein concentrate (Haypro), for use as substitutes for soy protein isolates and for caseinates in various food systems, especially in the meat processing industries.” (Chajuss, 2005)
Soya is a tremendous food and protein source. The health concerns are addressed at the manufacturing stage. Application of isolates, concentrates and TVP are multiple. Even today, after being available on the market for so many years, all its various applications in foods have not been exhausted. We are limited only by our imagination and interesting work remains to integrate its use into modern meat processing plants.
Applebaum, S.W.; Gestetner, B.; Birk, Y. 1965. Physiological aspects of host specificity in the Bruchidae–IV. Developmental incompatibility of soybeans for Callosobruchus. J. of Insect Physiology 11(5):611-16. May.
Birk, Yehudith; Peri, Irena. 1980. Saponins. In: I.E. Liener, ed. 1980. Toxic Constituents of Plant Foodstuffs. 2nd ed. New York: Academic Press. xiv + 502 p. See p. 161-182. Chap. 6.
Bondi, A.; Birk, A. 1966. Investigation of soybean saponins as related to the processing of petroleum ether-extracted meal for feed and to the preparation of soy foods, to provide information basic to improving the nutritional value of soybean protein products. Rehovot, Israel: Hebrew University. 80 + xvii p. USDA P.L. 480. Project no. UR-A10-(40)-18. Grant no. FG-IS-112. Report period 1 March 1961 to 28 Feb. 1966. Undated. 28 cm.
Chajuss, D.. 2005. Brief biography and history of his work with soy in the USA and Israel. Part II (Interview). SoyaScan Notes. Feb. 19. Followed by numerous e-mails. Conducted by William Shurtleff of Soyfoods Center.
Duke, J. A. 1991. Research on biologically active phytochemicals in soybeans (Interview). SoyaScan Notes. Oct. Conducted by William Shurtleff of Soyfoods Center.
Vagadia, B. H., Vanga, S. K., Raghavan, V. 2015. Inactivation methods of soybean trypsin inhibitor – A review. Received 14 December 2015, Revised 21 January 2017, Accepted 19 February 2017, Available online 27 February 2017. Elsevier. Trends in Food Science & Technology, Volume 64, June 2017, Pages 115-125
We have progressed in our study of the historical development of the concept of using Nitrogen to determine meat content to the Proximate analysis, and its accompanying use of the Kjeldahl method, the Jones factors and a review of the nutritional importance of the Proximate system. Our study leads us to unexpected places as we are challenged in our views on managing a complex operation like a large food factory.
The history of the development of food analysis goes back to the people we met in our introductory articles in the persons of Baussingault, and Liebig. To the list, we should probably add Sir Humphrey Davey, but Davey held a fundamentally different view of nutrition compared to Liebig and Baussingault. Where these two men held the basis for plant nutrition to be mineral, Davey was in the camp of Albrecht Daniel von Thaer (1752-1828) on the subjected who believed humus to be the foundational principle of plant nutrition. “According to this theory, humus is the main source of plant nutrients, next to the previously recognized role of water, obviously. In Thaer’s opinion, minerals played only a supporting role in providing plants with humic compounds. Therefore, the whole soil fertility depends only on the amount of humus present in it. He presented his views in his work “The Principles of Agriculture”.” (Antonkiewicz and Łabetowicz, 2016)
“The humus theory for plant nutrition was the dominant concept explaining the essence of plant nutrition for tens of years. Von Liebig was the first to explain, through his experimental works, the basics of the problem of mineral plant nutrition. In 1841, a publication entitled “Die Organische Chemie in ihrer Anwendung auf Agrikultur und Physiologie” – “Organic Chemistry in Its Applications to Agriculture and Physiology” was released, with a new theory of mineral plant nutrition. This book opens a new chapter in the development of the science of plant nutrition. It attracted great interest not only in scientific world but also among a lot of farmers. Liebig wrote that not humus but mineral salts (are taken up with water by roots from soil) and carbon dioxide assimilated from air in the photosynthesis process are the direct food for plants. For stable plant yields, soil should be supplied with mineral fertilizers in order to replenish the deficiency of nutrients caused by their removal from the field along with plant yield. Liebig formulated his theory about mineral plant nutrition based on other scientists’ studies, and also through deduction from a chemical analysis of plants. As a chemist and analyst, he conducted many studies on the chemical composition of plants. He determined that plants release carbon, hydrogen, oxygen and nitrogen (which are present in them) during combustion, and composition of the generated ash always includes phosphorus, sulfur, calcium, potassium, magnesium, silicon, and many times sodium.” (Antonkiewicz and Łabetowicz, 2016)
In the end, it was the scientific rigor of Liebig that won the day. Not just his new techniques opened up new discoveries, but also the question if science and practice presented a duality. These two concepts were juxtaposed in the mind of the landowners who saw the views of Liebig and Albrecht Daniel von Thaer as much more than a debate about the essence of plant nutrition. Liebig’s word was scientific and based in a laboratory. Of course, it had to have practical application, but he wrestled with solving fundamental questions first before he moved on to the practical and in many instances, as we know from our own experiences, even the best scientific work don’t always work in practice at the first attempt. Such is the nature of the beast.
Von Thaer, on the other hand, was a consummate pragmatist and by all accounts, a skilled manager. I am impressed by the reported neatness of the workshops on the estates that he was in charge off. Reports have it that they were open for inspection by the public and everything had its place. Thaer’s work, “Principles of Agriculture” contain the result of his experience through a series of years. We can feel his passion and approach in his work. It embraces the theory of the soil, the clearing of land, plowing, manuring, and irrigation, hedges and fences, management of meadow and pasture lands; the cultivation of wheat, rye, corn, oats, barley, buckwheat, hops, tobacco, clover, and all the varieties of grasses; the economy of kine stock, breeding and feeding; the management of the dairy, and the use of manures, and the various systems of cultivation, keeping journals and farm records. In brief, it is a complete cyclopedia or circle of practical agriculture. (Homans, 1857)
These issues that we don’t necessarily see as opposing views today would take on a life of its own in Germany which impacted (determined?) the course of history related to the nutritional sciences and the evaluation of foods.
As Liebig’s approach of rigorous science and experimentation started to dominate, tools were being developed on which more discoveries were predicated. Better techniques were developed, gradually, to separate the food fragments which played a role in nutrition including protein, fat, and fiber. The Liebig/ Dumas method for example, for determining the Nitrogen content in food was developed in 1830 and 1840. The famous Kjeldahl method was published in 1883 and much later the use of the 6.25 conversion number of N to protein would become the more complete Jones numbers. At the dawn of the 20th century, food chemistry was firmly established. (Dryden, 2008) Along with improved techniques and tools, the philosophical wars raged on.
The Proximate Analysis
The German Agriculture Research Stations was a driving force in the development of German farming from the mid-1800s and a model for similar developments around the world. Wilhelm Crusius has it that the first German Agricultural Research Station was created on 28 September 1850 during a banquet honouring Leipzig’s new marble statue of Albrecht Daniel von Thaer. He recalls that several agricultural leaders from the kingdom of Saxony agreed to terms that saw the Möckern estate near Leipzig transformed into an institution to investigate the application of scientific knowledge to agriculture. The Möckern facility is widely believed to be the words first state-supported agriculture research station. It was believed that the Möckern facility represented a fulfillment of Thaer’s vision. He propagated a system of “rational” agriculture. Landowners loved him as they looked for ways to increase their yields through comparative investigations, but was skeptical of what we call research. (Finlay, 1988)
It is generally believed to be Liebig who founded the agriculture research stations, through his 1840 work Chemistry and its application to Agriculture and Physiology. Many suggested that it was the excitement created by this publication around the world, that Germanys research stations were founded upon. It is believed by many that the agricultural research station became a haven for the agricultural chemists. The line of thinking then continues that the Americal Agricultural stations were created based on the German model in the 1870’s and 80’s. Even the notion of research is also linked to Liebig through his famous research laboratory in Giesen. (Finlay, 1988)
A study of the Möckern facility challenge these notions. Fundamental science and agriculture chemistry were not, in fact, initial driving forces behind this first agriculture station. The Saxon officials had praise for Liebig’s recognition of the importance of chemical compounds in plants and animal growth but scorned his insistence on laboratory research. Liebig created a plant manure in his laboratory. It was practically insoluble. A white chemical crust formed over fields in practical demonstrations and his invention was a disaster. Many believe that the creation of the agriculture stations would provide an opportunity to verify such work. They saw a division between science and practice and the stations would be a place to unite these two polar opposites. In the early days of the Möckern facility, scientists and what was called “practitioners” had equal authority. As in America, in Germany, the scientists did not win control over these stations for some time and not after a long and hard battle. (Finlay, 1988)
The German Agriculture Experiment stations became the model for similar stations set up in America. Wilbur Atwater of Connecticut had great admiration for the Möckern station. He got involved in work at another station, the one at Weende. Here they were involved in calorimeter research in the 1860’s and Atwater expended on the research. (Marcus, 2015)
Weende Experiment Station
The physiological chemistry work of Liebig had only an indirect application in agriculture. Wilhelm Henneberg was one of his students who applied his theories and methods directly in agriculture research. This would be one example of the triumph of science and laboratory research and fundamental to our understanding of the current methods for determining meat content. Scientists at these research stations directed the priority of work away from the achievement of immediate practical goals and towards the examination of basic scientific questions. Henneberg became the director at the Agriculture Experiment Station at Weende near Göttingen in 1857. He made a huge contribution to this shift and introduced a program using livestock as experimental organisms, incorporating the methods and instruments that he was introduced to in Munich. Precision and quantification were very important to him. He used instruments like the Petterkoffer respiration apparatus. (Phillips and Kingsland, 2015)
He stressed the importance of controlling environmental variables in laboratory settings and focused on fundamental questions in animal metabolism. His assistant was Frederich Stohmann who helped with the findings of his experiments. They directed the findings at farmers and physiologists, but in reality, made no effort to practically apply the results of their work. (Phillips and Kingsland, 2015)
Henneberg challenged the view of Thaer who emphasised close interaction of science and practice and the integration of plant and animal agriculture. Agriculture sciences rose to great prominence in Germany during this time and animal nutrition was one of its most successful branches. (Phillips and Kingsland, 2015)
Henneberg and Stohmann (1860, 1864) developed a top level, very broad, classification of food components for routine analysis which they devised for animal feed. It is a “partitioning of compounds in feed into six categories based on the chemical properties of the compounds. This analysis was an attempt to duplicate animal digestion. (Artemia)
After extracting the fat, the sample is subjected to an acid digestion, simulating the acid present in the stomach, followed by an alkaline digestion, simulating the alkaline environment in the small intestine. The crude fiber remaining after digestion is the portion of the sample assumed not digestible by monogastric animals. In the proximate analysis of feedstuffs, Kjeldahl nitrogen, ether extract, crude fiber, and ash are determined chemically. The determination of nitrogen allows the calculation of the protein content of the sample. It is important to remember that proximate analysis is not a nutrient analysis, rather it is a partitioning of both nutrients and non-nutrients into categories based on common chemical properties.” (Artemia)
“At that time the nutritionally important components of protein had not been recognized, all neutral fats were considered to be nonspecific sources of energy, and vitamins were unknown. However, the multiplicity of the carbohydrates and the practical difficulties of their separate chemical determination were clearly recognized. These workers believed that for nutritional description the carbohydrates could be grouped into (1) the starches and the sugars, and (2) a coarse fibrous fraction. The latter they isolated as an insoluble residue after boiling the food sample first with dilute acid and then with dilute alkali. These procedures were intended to simulate the acidic gastric digestion and the subsequent alkaline intestinal digestion of ingested food. The insoluble residue they called crude fiber. With analytical figures for ether extract, ash, nitrogen, and crude fiber of a moisture-free food sample, they needed only to convert the value for nitrogen to its equivalent in terms of protein (i.e., N x 6.25), add to this the other three group values, and subtract the total from the original weight of dry sample,
thus by difference to arrive at an estimate of the “soluble carbohydrates.” This fraction they called nitrogen-free extract (NFE).” (Loyed, et al. 1960)
“The majority of foods in human diets, as well as those in the diets of some laboratory animals used in nutrition studies, are so low in crude fiber that this fraction can often be disregarded, and the custom has gradually become general, especially in human nutrition, to omit the crude fiber determination. When this is done it is the total carbohydrate that is estimated “by difference.” (Loyed, et al. 1960)
“Probably because the chief components of nitrogen-free extract (NFE) are sugars and starches, we are prone to forget that this fraction includes all the nonfibrous, ether-insoluble, water-soluble organic materials of the food (or other material analyzed). Thus all water-soluble vitamins must be included in this fraction. Quantitatively, the vitamins are an insignificant part of the NFE, but in any broad charting of the makeup of foods in terms of the Weende partition these vitamins are part of the NFE in the same way that the fat-soluble vitamins are part of ether extract.” (Loyed, et al. 1960)
“Being determined by difference, the figure for NFE is also subject to an appreciable but variable error that may be as large as the algebraic sum of any analytical and/or sampling errors of each of those fractions determined by direct analysis.
Variability of average
Weende analysis values
It is appropriate at this point to comment on the errors to be expected in numerical values obtained from the several parts of the Weende analysis. These arise from several sources. Errors in the chemical manipulations-that is, analyst’s errors are usually negligible. Sampling errors, however, are often large because foods and the residues of animal digestion are not usually homogeneous. In addition, different lots of foods called by the same name are seldom identical in “proximate” makeup. Consequently, average composition figures found in tables of food composition are not necessarily applicable to a particular lot of a foodstuff. Nevertheless, it is often more feasible to estimate the protein, or the fat, or the carbohydrate, of some particular lot of a foodstuff by referring to tables of average composition than to obtain specific values by analysis. When average values are used in this way it should be remembered that the composition figures given for natural foods may be subject to coefficients of variation such as those listed in the table below.” (Loyed, et al. 1960)
“For example, if the average crude protein content of corn meal is given in a table as 10%, it is probable that two samples out of three purchased at random would on analysis give values between 9.2 [10 minus 10 (8%)] and 10.8 [10 plus 10(8%)] percent protein (see figure above). Similarly, cornmeal may average 72% NFE, and hence two samples out of three might be expected to give values between 69.8% and 74.2% (that is, 72 ± 3%).” (Loyed, et al. 1960)
This current application of this system of analysis can be summarised as follows:
The moisture content is determined as the loss in weight that results from drying a known weight of food to constant weight at 100 degrees C. This method is satisfactory for most foods, but with a few, such as silage, significant losses of volatile material may take place.
The ash content is determined by ignition of a known weight of the food at 550°C until all carbon has been removed. The residue is the ash and is taken to represent the inorganic constituents of the food. The ash may, however, contain material of organic origin such as sulphur and phosphorus from proteins, and some loss of volatile material in the form of sodium, chloride, potassium, phosphorus, and sulphur will take place during ignition. The ash content is thus not truly representative of the inorganic material in the food either qualitatively or quantitatively. There is incomplete recovery of individual minerals. It is one of the aspects of the proximate analysis, less used in modern food analysis. (hmhub.me) “Ash is a mixture of food minerals. The food Organic Matter (OM) content is (OM = DM – ash) is frequently used as a way of correcting data for mineral contamination, as will happen when measurements are made with grazing animals.” (Dryden, 2008)
The crude protein (CP) content is calculated from the nitrogen content of the food, determined by a modification of a technique originally devised by Kjeldahl over 100 years ago. In this method, the food is digested with sulphuric acid, which converts to ammonia all nitrogen present except that in the form of nitrate and nitrite. This ammonia is liberated by adding sodium hydroxide to the digest, distilled off and collected in standard acid, the quantity so collected being determined by titration or by an automated colourimetric method. It is assumed that the nitrogen is derived from protein containing 16 percent nitrogen, and by multiplying the nitrogen figure by 6.25 (i.e. 100/16) an approximate protein value is obtained. This is not ‘true protein’ since the method determines nitrogen from sources other than protein, such as free amino acids, amines and nucleic acids, and the fraction is therefore designated crude protein. (hmhub.me)
The Dumas method in which a sample is burnt and the N gas released is measured, was developed before the Kjeldahl method but has become popular only following the development of automated methods of carrying out the analysis. The method recovers all the sample N and so may give slightly higher values than the Kjeldahl method, depending on the sample analysed.” (Dryden, 2008)
The ether extract (EE) fraction is determined by subjecting the food to a continuous extraction with petroleum ether for a defined period. The residue, after evaporation of the solvent, is the ether extract. As well as lipids it contains organic acids, alcohol, pigments, fat-soluble vitamins, waxes, as well as fats. (hmhub.me) It is used to isolate lipids for more detailed fractionation into fatty acids and waxes. The EE is, nevertheless, still reported as a measure for total lipid. In the current official method, the extraction with ether is preceded by hydrolysis of the sample with sulphuric acid and the resultant residue is the acid ether extract. (Dryden, 2008)
crude fibre, and
Einhof extracted the fibrous part of food in 1805. His concept of fiber is very distant from our present-day understanding. To him, it was what was obtained after rubbing and washing the food to obtain the residue that is “resistant.” He may have thought that it was not nutritious. Boussingault and Davy specifically stated that it is not since it could not be digested. They had no experimental proof of this. (Dryden, 2008) Henneberg and Stohmann developed a method for analyzing crude fiber in 1859. The carbohydrate of the food is contained in two fractions, the crude fibre (CF) and the nitrogen-free extractives (NFE). The former is determined by subjecting the residual food from ether extraction to successive treatments with boiling acid and alkali of defined concentration; the organic residue is the crude fibre. (hmhub.me)
When the sum of the amounts of moisture, ash, crude protein, ether extract and crude fibre (expressed in g/kg) is subtracted from 1000, the difference is designated the nitrogen-free extractives. The crude fibre fraction contains cellulose, lignin, and hemicelluloses, but not necessarily the whole amounts of these that are present in the food: a variable proportion, depending upon the species and stage of growth of the plant material, is contained in the nitrogen-free extractives. Nitrogen Fee Extracts (NFE) was originally assumed to be mainly soluble carbohydrate and so was expected to be highly digestible. The nitrogen-free extractives fraction is a heterogeneous mixture of all those components not determined in the other fractions. It includes sugars, fructans, starch, pectins, organic acids, and pigments, in addition to those components mentioned above. (hmhub.me)
“Unfortunately, the reagents used to measure crude fibre (CF), may remove up to 60% of the cellulose, about 80% of the hemicellulose and a highly variable (10 – 95%) proportion of the lignin.The NFE contains some of the plant cell wall material an can be less digestible than CF. Besides this, NFE contains all those chemical entities which are not measured by the other methods. NFE is not now used in food analysis.” (Dryden, 2008)
Schematically, it can be represented as follows: (chart by (Dryden, 2008))
This system had a long-lasting effect on our approach to food analysis. We still use Dry Matter as the basis for expressing analytical data in calculating food intake of formulating diets. (Dryden, 2008)
“The chemistry of nitrogen is complex due to the fact that nitrogen assumes several oxidation states (Sawyer et al., 2003). Nitrogen is one of the most important elements for plant nutrition. The compounds of nitrogen are of great worth in water resources, in the atmosphere, and in the life process of all plants and animals. Four forms of dissolved nitrogen are of greater interest: organic, ammonia, nitrite, and nitrate, ordered in an increasing state of oxidation. All these forms of nitrogen, as well as nitrogen gas (N2), are mutually convertible, being components of the biological nitrogen cycle (Pehlivanoglou-Mantas and Sedlak, 2006; Worsfold et al., 2008). It is very important to ascertain the contribution (fractions) of different nitrogen species to the total nitrogen content (Prusisz et al., 2007).
Testing for N
The modern version of the proximate analysis uses mostly the Kjeldahl method of testing for N. Few other companies in history had such a dramatic effect on chemistry in general and food chemistry in particular as the Danish beer producer, Carlsberg. S.P.L. Sørensen was Director of the Carlsberg Laboratory’s Department of Chemistry from 1901 to 1938. In 1909, he developed the pH scale – a method for specifying the level of acidity or alkalinity of a solution on a scale from 0-14 and demonstrated the significance of pH for biochemical reactions, including those involved in brewing. With the invention of the pH scale, Carlsberg could ensure high quality of every beer. The applications of the pH scale have since been countless throughout all fields. (carlsberggroup.com)
It is remarkable that more than 20 years before the pH scale was invented, his predecessor from the same institution invented the definitive measurement for N in protein. Here is the story, told by Sáez-Plaza, et al. in their Overview of the Kjeldahl Method of Nitrogen Determination, Part I and Part II.
“The Danish chemist Johan Gustav Christoffer Thorsager Kjeldahl (1849–1900), Head of Chemistry Department of the Carlsberg Foundation Laboratory of the Danish Brewing Carlsberg Company, introduced a method known later under the eponym the Kjeldahl method that basically is still in use. It was first made public at a meeting of the Danish Chemical Society (Kemisk Forening) held on March 7, 1883 (Burns, 1984; Johannsen, 1900; McKenzie, 1994; Oesper, 1934; Ottensen, 1983, Veibel, 1949). Within the same year, the method was published in the German journal Zeitschrift f¨ur Analytische Chemie (Kjeldahl, 1883a), and written in French and Danish languages in communications from the Carlsberg Laboratory (Holter and Møller, 1976; Kjeldahl, 1883b, 1883c; Ottesen, 1983).” (Sáez-Plaza, et al, 2013)
“Because of the respect that the founder of the laboratory, the Danish brewer J. C. Jacobsen, had for Pasteur and his work for the French wine industry (Burns, 1984), extensive French summaries of the Carlsberg papers were also published. As an extended summary of the Kjeldahl paper appeared in Chemical News in August (Kjeldahl, 1883d), the method was quickly taken up (Sella, 2008). The Analyst first gave details of the method in 1885 “for the benefit of those who may have missed the original paper” (Burns, 1984; Editor of The Analyst, 1885, p. 127), although the method had been briefly mentioned by Blyth (1884), who gave Kjeldahl’s name incorrectly as Vijeldahl. A surprisingly short period went by between the publication of the Kjeldahl method and the appearance of publications effecting further improvements (Dyer, 1895; Hepburn, 1908; Kebler, 1891; Vickery, 1946a), both in Europe and the U.S., due to the tremendous impact that the Kjeldahl work had on others, especially in Germany (McKenzie, 1994).
Most of the earlier contributions were discussed by Fresenius in the Zeitschrift, often to a length of several pages (Vickery, 1946a). Throughout the history of analytical chemistry, none of the methods has been as widely adopted, in so short a time, as the “Kjeldahl Method” for the estimation of nitrogen, as stated by Kebler (1891) at the beginning of an annotation in which he compiled references on the estimation of nitrogen by the Kjeldahl method (some 60) and by all other methods (about 200).” (Sáez-Plaza, et al, 2013)
“The Kjeldahl method was originally designed for the brewing industry as an aid in following protein changes in grain during germination and fermentation (Bradstreet, 1940; Kjeldahl, 1883b); the lower the amount of protein in the mush, the higher the volume of beer produced. It was Berzelius who suggested the use of the word “protein” in 1838 in a letter to Mulder because it was derived from the Greek word meaning “to be in the first place” (Zelitch, 1985). The Kjeldahl protein content is strictly dependent on total organic nitrogen content (Wong et al., n.d.); i.e., protein structure will not interfere
with the accuracy of protein determination.”
As we have mentioned earlier in this article, a drawback of the Kjeldahl method is that it lacks the “analytical selectivity because it does not distinguish protein-based nitrogen from nonprotein nitrogen. Adulteration incidents (e.g., adulteration of protein-based foods with melanine and related nonprotein compounds) exploiting this analytical vulnerability have been recently detected (Breidbach et al., 2010; Levinson and Gilbride, 2011; Moore et al., 2010; Tyan et al., 2009) and are new examples of a problem that dates back to before the Kjeldahl method was introduced (M¨oller, 2010a).” (Sáez-Plaza, et al, 2013)
“The presence of non-protein nitrogen (NPN) compounds in foods (aminoacids, ammonia, urea, trimethylamine oxide) overestimates their true protein content (M¨oller, 2010a; van Camp and Huyghebaert, 1996; Yuan et al., 2010) as derived from the current nitrogen determination methods. Separation of NPN from true protein nitrogen may be carried out by adding a protein precipitating agent such as trichloroacetic acid or perchloric acid (Rowland, 1938a, 1938b). The process conditions applied during protein precipitation, however, affect the composition and the amount of NPN, so it is mandatory to specify the type and concentration of precipitating agents used in each case. Alternative techniques such as dialysis and gel filtration are probably more accurate in removing the NPN fraction (van Camp and Huyghebaert, 1996), but they remain unacceptable for routine analysis. Reviews of NPN determination methods in cow milk, and on aspects concerning the composition of NPN fraction, are given by Wolfschoon-Pombo and Klostermeyer (1981, 1982). The Kjeldahl method measures what is termed total protein (American Jersey Cattle Association, n.d.). The alternative use of true protein (total nitrogen minus the NPN) has been under debate for some years (Grappin, 1992; Harding, 1992; Rouch et al., 2007; Salo-V¨a¨ananen and Koivistoinen, 1996). A fundamental change in milk pricing in the U.S. was introduced January 1, 2000 with the implementation of producer payments in Federal Milk Marketing orders on the basis of the true protein content (American Jersey Cattle Association, n.d.; Stephenson et al., 2004; Zhao et al., 2010).” (Sáez-Plaza, et al, 2013)
“The protein content in a foodstuff is estimated by multiplying the nitrogen content by a nitrogen-to-protein conversion factor, usually set at 6.25 (Comprehensive Review of Scientific Literature . . . , 2006; Mariotti et al., 2008), which assumes the nitrogen content of proteins to be 16%. It is not clear who first reported such a factor for use (Moore et al., 2010). This general conversion factor is used for most foods because their non-protein content is negligible. However, pure proteins differ in terms of their nitrogen content because of differences in their amino acid composition, ranging from 13.4% to 19.3%; different multiplying factors are suitable for samples of different kinds. The factor 5.7 is applied for wheat and 6.38 for dairy products (O’Sullivan et al., 1999) and 6.394±0.004 for cheddar cheese, as shown recently (Rouch et al., 2008). The proximate system where protein is measured as total nitrogen multiplied by a specific factor clearly dominates food composition studies (Greenfield and Southgate, 2003). As a matter of fact, most
cited values for protein in food composition databases derive from total nitrogen or total organic nitrogen values.” (Sáez-Plaza, et al, 2013)
“A large variety of food proteins, either from animals (milk, meat, eggs, blood, fish) or plants (seeds, cereals), is nowadays available in the food industry. The determination of protein in foods and food products has important nutritional, functional, and technological significance (Van Camp and Huyghebaert, 1996). The protein content determines the market value (Krotz et al., 2008; Wiles et al., 1998) of major agricultural commodities (cereal grains, legumes, flour, oilseeds, milk, and livestock feeds). In addition, the quantitative analysis of protein content is necessary for quality control, and also a prerequisite for accurate food labeling (Owusu-Apenten, 2002). Protein analysis is required for a very wide range of animal and human nutrition products. Consumer interest in soy protein products has increased rapidly in Western cultures in recent years. This trend is due in part to the high-quality protein of soy foods and soy protein ingredients and in part to their associated health benefits (Jung et al., 2003); 25 g of soy protein per day may improve cardiovascular health (U. S. Food and Drug Administration, 1999). Consequently, precise determinations of protein content of soy products are very important. Total nitrogen concentration in soils is one of the most frequently measured
nutrients in soil-testing laboratories (Sharifi et al., 2009). Determination of nitrogen content plays a key role in assigning values to insulin reference materials (Anglow et al., 1999). Primarily devised for the determination of protein nitrogen, the Kjeldahl method has been extended to include the determination of various other forms of nitrogen, e.g., in soils, plant materials, biological tissues, and wastewater matrices (Chemat et al., 1998). (Sáez-Plaza, et al, 2013)
“Though the Kjeldahl procedure is hazardous, lengthy, and labor intensive, it has become the industry standard; it remains an accurate and reliable method and is used to standardize other methods (ISO, 2009a, 2011; Orlandini et al., 2009a; Orlandini et al., 2009b; Rayment et al., 2012). Semiautomated or fully automated nitrogen (protein) analysis systems based on the classical Kjeldahl procedure (Rhee, 2001; Wright and Wilkinson, 1993) are preferable in order to cut cost and to save time when a large number of samples need to be analyzed.” (Sáez-Plaza, et al, 2013)
The automation of chemical methods used routinely in research can lead to a considerable saving in time and labor and, thus, efficiency in carrying out a particular piece of work (Davidson et al., 1970; Feinberg, 1999). Automation makes it possible to avoid direct handling of dangerous reagents (Pansu and Gautheyrou, 2006), such as boiling sulfuric acid or concentrated soda. Ferrari (1960) succeeded in automating the Kjeldahl nitrogen procedure, describing the new concept of continuous nitrogen determination. The automated macro Kjel-Foss analyzer was introduced in 1973, with which one can routinely perform 20 analyses/hour (Oberreith and Neil, 1974). Various degrees of automation are available for the Kjeldahl method, including automated digestion and distillation followed by manual titration; fully automated digestion, distillation, and titration; and the use of block digesters and autosamplers for the unattended analysis of a maximum of 60 samples per batch. Semiautomated equipment is available with digestion and distillation determination units at macroscale and microscale from, for example, the manufacturers Bicasa, B¨uchi, Gerhardt, Skalar, Foss-
Tecator, and Velp (Pansu and Gautheyrou, 2006; Pansu et al., 2001). Depending on the analysis procedure used, the scale of operation applied, and the degree of automation installed, the analysis time of the procedure could be further reduced, corresponding to frequencies of analysis up to 20 samples/hour.” (Sáez-Plaza, et al, 2013)
An important feature of the Proximate Analysis is the conversion of measured nitrogen to protein by multiplying total N by a factor to estimate the total protein content. It is still used for its simplicity and relative accuracy. The commonly used factor is 6.25 derived from the fact that protein contains 16% nitrogen. 100/16 = 6.25. Who the first person is to use this factor is not known. N in food can be measured by the Kjeldahl Method (1883) in which protein-N is dissociated from its combination with other elements by digestion in concentrated sulfuric acid (H2SO4) followed by conversion to the hydroxide and subsequent distillation and titration.” (Dryden, 2008)
“Jones, Munsey and Walker (1942) measured the nitrogen content of a wide range of isolated proteins and proposed a series of specific factors for different categories of food. These factors have been widely adopted and were used in the FAO/WHO (1973) review of protein requirements. These are listed in the table below. Several authors have criticized the use of these traditional factors for individual foods (e.g. Tkachuk, 1969). Heidelbaugh et al. (1975) evaluated three different methods of calculation (use of the 6.25 factor, use of traditional factors and summation of amino acid data) and found variations of up to 40 percent. Sosulski and Imafidon (1990) produced a mean factor of 5.68 based on the study of the amino acid data and recommended the use of 5.70 as a factor for mixed foods.
In principle, it would be more appropriate to base estimates of protein on amino acid data (Southgate, 1974; Greenfield and Southgate, 1992; Salo-Väänänen and Koivistoinen, 1996) and these were incorporated in the consensus document from the Second International Food Data Base Conference held in Lahti, Finland, in 1995, on the definition of nutrients in food composition databases (Koivistoinen et al., 1996).
If these recommendations are to be adopted, the amino acid data should include values for free amino acids in addition to those for protein amino acids because they are nutritionally equivalent. The calculations require very sound amino acid values (measured on the food) as discussed below, and involve certain assumptions concerning the proportions of aspartic and glutamic acids present as the amides and correction for the water gained during hydrolysis. Clearly, this approach would not be very cost-effective when compared with the current approach.
At the present time, it is probably reasonable to retain the current calculation method, recognizing that this gives conventional values for protein and that the values are not for true protein in the biochemical sense. However, it is important to recognize also that this method is not suitable for some foods that are rich in non-amino non-protein nitrogen, for example, cartilaginous fish, many shellfish and crustaceans and, most notably, human breast milk, which contains a substantial concentration of urea.
Factors for the conversion of nitrogen values to protein (per g N)*
Meat and fish
Milk and milk products
Rice and rice flour
Rye and rye flour
Barley and barley flour
* (Where a specific factor is not listed, 6.25 should be used until a more appropriate factor has been determined.)
Source: FAO/WHO, 1973.
A number of direct methods for protein analysis have been developed for specific foods based on reactions involving specific functional groups of the amino acids present; these are thus not applicable to the measurement of proteins in general. Such methods include formol titration (Taylor, 1957) and the biuret reaction (Noll, Simmonds and Bushuk, 1974). A widely used group of colorimetric methods is based on reaction with Folin’s reagent, one of the most widely used biochemically in the dairy industry (Lowry et al., 1951; Huang et al., 1976). These methods are most commonly calibrated with bovine serum albumin, which is available at high purity.” (Greenfield and Southgate, 2003)
Nutrient makeup of proximate principles
The Proximate Analysis is not used for deriving nutritional values, but it is still important, before leaving this subject, that we should specifically relate it to several nutrients. “We shall thus also delimit the extent to which the Weende scheme can be expected usefully to describe specific nutrients and groups of nutrients found in the animal body and in its food.” (Loyed, et al. 1960) I quote this from a Loyed, et al. who was published in the 1960. Despite the age of the work, I find it remarkably complete as an introduction to the subject.
“Carbohydrates The total number of edible materials that are carbohydrate by definition is large. There are, for example, a dozen or more that are found in everyday foods, either as one of six or seven “sweet” sugars, or in combinations of them comprising numerous more complex molecules such as the starches, hemicelluloses, or celluloses. The monosaccharide sugars are classified according to the number of carbon atoms in their molecules. Thus there are 5-carbon or pentose sugars, and 6-carbon or hexose sugars. All pentose sugars have the same empirical formula, C5H10O5; the empirical formula for all hexoses is C6H12O6. The complex carbohydrates are merely polymers of the simple sugar units, as (C5H8O4)n or (C6H10O5)n. Cellulose, for example, has been estimated to consist of 1000-2000 hexose units polymerized into the long fibrous chains characteristic of the cellulose structure. The distribution of the carbohydrates between the Weende nitrogen-free extract and crude fiber fractions is shown in the table below.” (Loyed, et al. 1960)
“It will be seen that the carbohydrate portion of our foods and feeds consists either of single 1-carbon or 6-carbon units, or of larger molecules formed by combinations of such structures. Before the larger molecules can be useful in nourishing the body they all must be degraded by enzymes in the digestive tract to their simple 5- or 6-carbon units; or, in the case of cellulose and perhaps of some of the hemicelluloses, to either the 2-, 3-, or 4-carbon molecules of acetic, propionic, or butyric acids, respectively. (These three acids are products of digestion by microflora inhabiting the digestive system of animals, such as herbivores.)” (Loyed, et al. 1960)
“The nutritional significance of the fact that carbohydrates are all assemblies
of 5- or 6-carbon units is that they have potentially about the same energy value, roughly between 3.75 and 4.25 kilocalories per gram of dry substance. Except for small amounts of ribose, carbohydrates can be considered useful primarily as sources of energy. These facts make it clear that even though the carbohydrate portion of a food or a diet is estimated “by difference” in the Ween de scheme of analysis, little, if any, useful information is lost by this group treatment.” (Loyed, et al. 1960)
“The digestible or the metabolizable energy the body ultimately obtains from the nitrogen-free extract, from the crude fiber, or from the total carbohydrate (i.e., the nitrogen-free extract plus the crude fiber) of a food, is a somewhat different matter, since the completeness of the digestion of these two groups of carbohydrates is often appreciably different. This matter will be considered later when the question of digestibility is dealt with. For the moment it will suffice to note that celluloses and hemicelluloses yield less useful energy to nonherbivores than do the carbohydrates of the nitrogen-free extract category.” (Loyed, et al. 1960)
Crude protein Crude protein is also a group name; it refers collectively to the sum of up to 20 nutrients, the amino acids, each of which has one or more specific roles in metabolism. In addition, each of these protein components, if present in excess of that needed for its specific function, may, following absorption, be split into a nitrogen-containing entity NH3 and a deaminized residue, the latter becoming a nonspecific source of energy.” (Loyed, et al. 1960)
“Most of the amino acid residues that can be metabolized for energy contain 3-carbon atoms. In any case, only that fraction of an amino acid that is equivalent to some intermediate in the metabolism of sugars (or of fats) is so used. However, the potential energy in proteins, as measured by their complete combustion in a bomb calorimeter, is considerably greater than that in carbohydrates. This is true because with protein, oxygen is required not only – to oxidize the carbon, but, unlike carbohydrate, is required also to oxidize some of the hydrogen atoms; and the heat of water formation is much higher than that of carbon dioxide. Thus, typical pure proteins yield 5.25-5.75 kilocalories of gross energy per gram.” (Loyed, et al. 1960)
“Nevertheless, the amount of nutritionally useful energy of protein is not greatly different from that of carbohydrate. This is so because the amino group that is split off in the deaminization of each “discarded” amino acid forms urea, which is eliminated in the urine. Urea contains combustible carbon and hydrogen, and this part of the potential energy from protein is lost the body. In humans it amounts to about 1.25 kilocalories per gram of protein so that the maximum usable energy from typical protein does not exceed 5.50 – 1.25 or 4.25 kilocalories per gram; this is usually reduced further by the incompleteness of digestion to about 4 kilocalories per gram. This can be stated in another way: whereas carbohydrate yields to the body, on the average, about 95% of its potential energy, only some 70% of the potential energy of protein can be used to meet energy needs. Protein is obviously not normally the preferred source of energy in nutrition.” (Loyed, et al. 1960)
“Incidentally, crude protein, by itself, describes only the energy of this nitrogenous fraction of foods. Without other information, the figure for the amount of crude protein in a food gives no reliable clue to the makeup of its nutrient units, the amino acids. Of these acids, we shall learn more later. It is sufficient here to tabulate them as some of the nutrients that we must deal with in nutrition (see table below).” (Loyed, et al. 1960)
Lipids, fats, and ether extract “In a beginning course in nutrition there is a tendency to use almost interchangeably the terms lipid, fat, and ether extract. In particular, when we record the total of the ether extractives, We often designate it merely as fat. This rather loose usage of these terms does not often lead us astray, for reasons that will become obvious as one delves deeper into the subject. But it may be well at the outset to define these terms in a more specific way, in order to have a clearer conception of what substances are included in that fraction of the Weende analysis called ether extract.” (Loyed, et al. 1960)
“Lipids Ure naturally occurring substances soluble in organic solvents, such as diethyl ether. A classification of these substances is given in the table below.” (Loyed, et al. 1960)
Calorie value of ether extract “This classification does not include all of the substances that may be found in the ether extract of foods or of tissue of the animal body. In general, the presence of substances other than triglycerides in ether extract dilutes its useful energy. They are mentioned here chiefly to show what a mixture the ether extract of foods may be. In foods of animal origin, such as meat fats, lard, or butter, it may be composed almost entirely of triglycerides. But in foods of plant origin, as much as half the total ether extract may be composed of sterols, waxes, and various other lipids. Since the nonglyceride lipids yield little utilizable energy to animals, the caloric value of ether extract is characteristic of specific foods: a single energy value, such as 9 kilocalories metabolizable energy per gram, while perhaps satisfactory for the fats of animal origin, the refined vegetable oils, or the shortenings prepared from them, is usually too high for the ether extract of foods of plant origin.” (Loyed, et al. 1960)
“The usefulness of the ether extract of the Weende scheme as a source of energy is dependent almost entirely on its total content of triglycerides. Ether extract values by themselves give no indication of the particular fatty acids in the fraction, nor of the amount of nonglyceride lipid. These values, therefore, are only an indication of the energy of a feed, which in turn is subject to considerable variation from one type of feed to another because of the possible variation in the composition of the lipid fraction.” (Loyed, et al. 1960)
Ash-the inorganic nutrients “The Weende analysis includes an inorganic fraction-the total of the noncombustible substances of the material. The quantity of ash in a feed or in some biological product does not of itself give information about any specific nutrient, and frequently the figure is used only to calculate the amount of carbohydrate by difference. The combination of mineral elements found in foods of plant origin is so variable that the ash figure of our analysis is useless as an index of the quantity of any particular element, or even of the total of the nutritionally essential ones. In the case of certain animal products, such as bone, milk, or cheese, whose composition is relatively constant, the approximate quantities of calcium and phosphorus can be predicted from the total ash figure. Thus, so far as useful information about the inorganic nutrients of foods is concerned, the ash figure is merely a starting point for specific analysis for one or another of some 21 to 26 mineral elements required by the body, and for a few about which information may be needed because of their toxic nature.” (Loyed, et al. 1960)
Classification of the nutrients
“To summarize this what we discussed here, the table below identifies the principal nutrients by name and indicates the fractions of the Weende analysis into which they fall.”
“The table makes it clear that the Weende analysis does not describe nutrients individually; when this is necessary, some other scheme of description must be used. But, in spite of limitations, the Weende analysis is the basis for the everyday chemical description of foods, body tissues, and excreta that are of concern in such calculations as the estimation of digestibility and utilization of foods and the establishment of feeding standards for all animal species.” (Loyed, et al. 1960)
The young man who took over from me as production manager at Woody’s Consumer Brands has a saying that managing a production department of a meat factory is a team sport. On the one hand one needs the experienced manager’s approach of Albrecht Daniel von Thaer. On the other hand, I know from first-hand experience the financially devastating effect if a management team gets a call on a scientific matter related to meat science wrong. Managing a large food manufacturing concerns is the job of an experienced team, not a lone ranger or a single night in shining armour and discipline in science and discipline in management has equally valid places.
A week ago an old friend visited from the United States and as we discussed these matters he commented that no matter what detours we take, we seem to always get back to clear management principles laid down by people like Peter Drucker. The study of the development of the proximate analysis and the examples of marrying good management and science as exemplified in the life of Carlsberg come to us through our analysis of the history of what led us to our current day determination of meat content in formulations. It is a subject so rich. We gain from it on every level.
For part 6, click on
Counting Nitrogen Atoms – The History of Determining Total Meat Content (Part 6): (being written)
Bacon and the art of living is a study in the birth of the elements of bacon curing. Neither the chemical reactions, nor the different mechanical processes are simple. Everything about bacon is complex and beautiful. One of the most amazing stories within the grand story of bacon, is the story of sodium nitrite.
Pork is changed into bacon by the reaction of nirtrite (NO2-). With salt, it is the curing agent. The meat industry uses nitrite in the form of an ionic compound, sodium nitrite. It is sold as Quick Cure or Insta’ Cure, Prague Salt, Prague Powder or simply Pink Salt or Curing Salt. It is coloured pink to distinguish it from ordinary salt (sodium chloride). Every spice company sells it. It is the essential ingredient in the meat curing process.
Meat changes colour from the red fresh meat colour to an unappetising brown colour within days. (1) If one injects nitrite into the meat or rubs a mixture of salt and a small percentage of nitrite onto it, the meat will develop an appatizing reddish/ pinkish fresh meat colour (Hoagland, Ralph. 1914) and a characteristic cured taste. It will retain this colour for weeks and months if packed in the right conditions. (1) Nitrite provides an indispensable hurdle against a particularly nasty food pathogen, clostridium botulinum. It also endows the meat with a distinct cured taste.
During ages past, it has however not been nitrite that was added to meat to accomplish this, but its cousin, nitrate (NO3-). They may be cousins, but are very different in characteristics. Nitrate takes several weeks or even months to cure meat where nitrite accomplishes the same task in 12 hours. How the change happened from using nitrate or salpeter in meat curing to nitrite is an epic story.
This article tracks the migration of the meat industry from the use of saltpeter (potassium or sodium nitrate) as curing agent to sodium nitrite. It gives an overview of the scientific discoveries which started to reveal the mechanisms of meat curing. This understanding lead to the realisation that a direct application of nitrite as the curing agent will be vastly superior to the use of saltpeter (nitrate).
This was a dramatic discovery since in the late 1800’s and early 1900’s, the world saw nitrite as a dangerous drug at best and a poison that polluted drinking water and cause death of cattle. Using this directly in food and meat curing was unthinkable.
Sodium nitrite was available in this time for application in the coal-tar dye and medical industries. Science and engineering have however not worked out its large scale production in a way that will make it a commercially viable proposition for direct use in meat curing from a price and availability perspective.
World War One provided the transition moments required to change everything. Germany invested heavily in nitrogen related technology for the war. The most organised scientific and engineering environment on the planet in the early 1900’s focused its full attention on overcoming the manufacturing challenges in the service of the manufacturing of munitions. It also required this technology to overcome the challenge of being cut off, as a result of the war, from the natural sodium nitrate deposits in Chili that it required as fertilizer to drive its enormous agriculture sector during the war. At the same time, the use of saltpeter in meat curing was prohibited under the leadership of Walther Rathenau so that the valuable nitrate could be reserved for manufacturing of munitions.
This prohibition, I believe, was the initial spark that caused butchers to change to the use of sodium nitrite. At the same time, sodium nitrite was being produced in large volumes since it had, in its own right, application in the manufacturing of explosives. Health concerns and probably the need to have it reserved for munitions, lead to a ban, similar to nitrate, on its use in meat curing. So, World War One solved the scientific challenges of large scale manufacturing of sodium nitrite, the engineering challenges of building production facilities and provided the impetus for the meat industry to change by banning the use of saltpeter in meat curing. The ban was lifted after the war.
Following the war, Germany had to find markets for its enormous war time chemical stock piles. One of the ways it “sold” sodium nitrite was as a meat curing agent based on its inherent benefits of curing consistency and the vastly shorter curing time required.
It was introduced to the world mainly through the Chicago based firm, Griffith Laboratories, who imported it as Prague Salt from Germany and later improved on it by fusing the sodium nitrite to sodium chloride and sold it as Prague Powder.
Early humans to Polenski (1891)
Early humans did not know they added nitrate to the meat. A mixture of salt and a small amount of saltpeter was used to cure meat in order to preserve it and to retain the fresh meat colour.
Saltpeter is found naturally around the world in typically dry areas. Deposits exist in India, China, Mexico, the USA, and the Middle East. Despite its wide occurrence, the concentration of natural saltpeter is low. (Whittaker, CW, 1932: 10)
Saltpeter is also made by human effort. Europe, particularly Germany and France, Great Britain, India and the United States all acquired the technology to produce satpeter. (Van Cortlandt, P, 1776: 7, 8)
In South Africa, saltpeter deposits are found in the Griquatown beds of the Transvaal geological system. It extends from just South of the Orange River Northwards to the Kalahari Desert and then Eastwards into the Old Transvaal from Zeerust to Polokwane. The nitrate deposits occur in the middle portions of these beds, in softer and more decomposed shale. These South African reserves have fortunately never been mined even though it was used on a small scale to make gunpowder for the old Boer government. (Whittaker, CW, 1932: 10)
Saltpeter was at the heart of the arms race of the middle ages. It was used mainly in gunpowder, but as the worlds population grew, it became indispensable as a fertilizer and for curing meat. (See Bacon and the art of living, chapters 2, 3 and 4)
The French chemist, Antoine Lavoisier worked out its chemical composition. It is an ionic compound consisting of the metal potassium and its power is nitrate. Potassium Nitrate. (Mauskopf, MSH. 1995: 96) Trade in Saltpeter around the world was done through companies such as the Dutch East Indian Company (Dutch abbreviation, VOC) who traded it for its main use as an ingredient in gunpowder. It was by volume one of the largest commodities traded by the Dutch East Indian Company who set up the trading post in 1652 that became Cape Town.
Major developments shifted the balance of power away from Indie, China and home grown saltpeter production to South America where huge deposits of sodium nitrate were discovered that would become the principal source of the worlds nitrate for much of the 1800’s.
A popular legend tells the story of the discovery by two Indians in the Atacama desert in the South of Peru. According to the legend, after a hard day’s work, they camped in the Pampa and started a campfire to warm themselves. All of a sudden the ground started to burn and they ran away, thinking that they have seen the devil. They reported the event later to a priest in Camina who returned to the site. He had it analysed and found it to contain sodium nitrate (the same power as potassium nitrate, but linked to another common metal). The priest, according to the story, threw the rest of the soil in the courtyard of his house and saw the plants grew vigorously. He recommended the soil as an excellent tonic for the plant kingdom. (Wisniak, J, et al., 2001 :433)
So was discovered the enormous sodium nitrate deposits of the Atacama desert. The fertilizer properties of the salt was known long before the 1600’s. There are references to saltpeter and the nitrate ground in 1604. During the time of the Spanish Conquest, in the 1700’s, miners working in the South of Peru realised that gunpowder could be manufactured from the material in the soil instead of potassium nitrate. (Wisniak, J, et al., 2001 :433)
A report published in 1803 by Juan Egana, Secretary of the Royal Court of Mines in Chile showed the Huasco region is “covered in a large part by a crust of niter salt, well crystallized, and several inches thick” (Wisniak, J, et al., 2001 :434)
The region was developed and by 1850 exports reached 24 000 tons/ year. In 1910 it was 2.4 million tons per year and by 1916, 3 million tons per year from 97 plants. (Wisniak, J, et al., 2001 :434)
By the beginning of the 1900’s the country buying the largest quantity of the Chilean saltpeter was Germany (Wisniak, J, et al., 2001 :434) who used it aggressively in their agriculture sector as fertilizer.
There is a close correlation between sodium and potassium nitrate. Its difficult to distinguish between sodium and potassium nitrate just by tasting it. Scientists were able to distinguish between the two compounds from the mid 1600’s and knew that sodium nitrate had a much greater ability to attract water (Whittaker, CW, 1932: 3). This made sodium nitrate a much better curing agent than potassium nitrate.
Nitrite was described in 1864 by the English Physiologist, B. W. Richardson. He outlined how to manufacture it and its chemical properties. (Wells, D. A., 1865: 233) Much earlier, in 1777 the prolific Swedish chemist Scheele,working in the laboratory of his pharmacy in the market town of Köping, made the first pure nitrite. (Scheele CW. 1777) He heated potassium nitrate at red heat for half an hour and obtained what he recognized as a new “salt.” The two compounds (potassium nitrate and nitrite) were characterized by Péligot and the reaction established as 2KNO3→2KNO2+O2. (Péligot E. 1841: 2: 58–68) (Butler, A. R. and Feelisch, M.)
The technology existed in the 1800’s to not only produce potassium nitrate (salpeter) and nitrite, but to also test for these.
Remember that curing up till 1890 has been attributed to saltpeter (potassium nitrate) or Chilean saltpeter (sodium nitrate). In 1891 a German food scientist, Dr Ed Polenski, working for the German Department of Health made an observation that would change the world while studying curing brines. When he tested the curing brine made from saltpeter and salt, days after it was made, he found nitrite to be present. This was surprising since saltpeter is potassium or sodium nitrate, not nitrite.
Dr Ed speculated that the nitrate (NO3-) was changed into nitrite (NO2-) through bacterial action, a reduction step between nitrate and nitrite that was well understood by this time. He had a hunch that nitrite is responsible for curing of meat and not the nitrate directly, as was previously thought.
From Polenski (1891) to WWI (1914 to 1918)
Following Dr Ed’s observations in 1891, considerable resources from around the world were dedicated to understand the chemistry of meat curing.
When World War One broke out, the concept of nitrite as curing agent (as opposed to nitrate) was firmly established.
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 accepted fact by the outbreak of World War One (Hoagland, Ralph. 1914)
Readers who dont have an interest in the detailed description of the key discoveries may want to skip over the rest of this section altogether or glance over it generally. The goal of the section is to give the reader a sense of how firmly and universally the concept of nitrite as the curing agent was established by 1914. In the midst of the technical names and jargon, don’t lose the sense of the universal interest. The 1700’s, 1800’s and beginning of the 1900’s was a time when the average person was as interested in chemistry as we are today about communication and information technology.
The difference between nitrates and nitrites, for example, was taught in school curriculum. An article appeared in the Daily Dispatch in Brainerd, Minnesota in the 20’s, that gives as an example of a diligent high school student, that he or she would know the difference. (The Brainerd Daily Dispatch (Brainerd, Minnesota). 17 January 1923. Page 3.)
Following Dr. Polenski’s observation, the German scientist, Notwang confirmed the presence of nitrite in curing brines in 1892, as observed by Dr Polenski, 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.
Karl Bernhard Lehmann (September 27, 1858 – January 30, 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. (Lee Lewis, W., 1925: 1243)
In the same year, another German hygienists, K. Kisskalt, confirmed Lehmann’s observations but proved that the same red colour resulted if the meat was left in saltpeter (potassium nitrate) for several days before it was cooked. (Lee Lewis, W., 1925: 1243)
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 (Hoagland, Ralph. 1914).
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. (Lang, M. A. and Brubakk, A. O. 2009. The Haldane Effect)
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. (Lang, M. A. and Brubakk, A. O. 2009. The Haldane Effect)
“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)
An interesting anecdote is told about him from the time when he was studying medicine in Jena. He apparently carefully observed the amount of beer being drunk, noting that the students on the average drank about 20 pints per evening.” (Lang, M. A. and Brubakk, A. O. 2009. The Haldane Effect)
Before we look at Haldene’s contribution, let us re-cap what has been determined thus far.
Polenski and Notwang discovered that nitrite were present in a mix of saltpeter and salt, after a while, even though no nitrite were present when the brine was mixed.
Karl Bernhard Lehmann linked nitrite conclusively with the reddening effect of fresh meat that was boiled in a nitrite and water solution with some free acid. He also showed that this does not happen if fresh meat is placed in saltpeter and water solution and boiled immediately. K. Kisskalt showed that the same reddening occurred if fresh meat is left in saltpeter for some time.
K. B. Lehmann managed to “isolate” the colour by dissolving it in ether and alcohol and analyze it spectroscopically.
What S. J. Haldele did was to apply 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). (Lang, M. A. and Brubakk, A. O. 2009: 119)
Nitrite is further reduced to nitric oxide (NO) by bacteria or enzymatic reactions and in the presence of muscle myoglobin 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. (Lang, M. A. and Brubakk, A. O. 2009: 119)
This is how he did it. He concluded (1901) that its red colour is due to the presence of the nitricoxid hemochromogen resulting from the reduction of the coloring matter of the uncooked meat, or nitric-oxid hemoglobin (NO-hemoglobin). (Hoagland, Ralph. 1914)
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. (Hoagland, Ralph. 1914)
Haldene 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. (Hoagland, Ralph. 1914)
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. Hoagland conclusively shows that saltpeter, as such, has no value to preserve the fresh colour. (Hoagland, Ralph, 1914: 212)
The reason why the knowledge did not translate to a change in curing brines was very simple. The technology and infrastructure did not exist to produce enough nitrite commercially to replace saltpeter. This means that to produce nitrite was very expensive.
There were some attempts to capitalise on the knowledge gained. 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)
Saltpeter can only effect the colour of the meat if the nitrate in the saltpeter is reduced to nitrite. 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)
The fear of nitrites
The lack of a large scale production process for sodium nitrite and the engineering to build these plants were however not the only factors preventing the direct use of sodium nitrite in meat curing brines. As one review literature from the late 1800’s and early 1900’s, one realises that a major hurdle that stood between the use of sodium nitrites in meat curing was the mistrust by the general public and authorities of the use of nitrites in food. The matter relate to the high level of toxicity of nitrite, a matter that will be dealt with separately in Bacon and the art of living.
The first recorded direct use of nitrite as a curing agent was in 1905 in the USA where it was used in secret. (Katina, J. 2009) The USDA finally approved its use as a food additive in 1906. (porkandhealth) This did not mean that the public would accept it.
Sodium Nitrite started to be used in this time as a bleach for flour in the milling industry. Several newspaper articles reveal public skepticism and the great lengths that the scientific community and industry had to go to in order to demonstrate its safety as a bleaching agent for flour. An article appeared in The Nebraska State Journal Lincoln, Nebraska on 29 June 1910 entitled, “All for bleached flour. No harm can come from its consumption says experts”. The article deals with a federal court case about the matter and interestingly enough, it seems from newspaper articles that the government was opposing its use. Many other examples can be sited.
There is a 1914 reference in the London Times that shows the general view of nitrite as not just restricted to the USA. The article appeared on 9 June 1914 and a reference is made to sodium nitrite where it is described as “a dangerous drug with a powerful action on the heart.” (The London Times. 1914. Page 118) The reference was to the use of nitrite for certain heart conditions.
It is interesting that sodium nitrite did not find an immediate application in the meat industry, even after it was allowed in 1906 in the USA.
In my view, this points to problems surrounding availability and price. If the issue was the public perception alone, this could have been overcome with a PR campaign by the meat industry as was successfully done by the milling industry.
On 13 Dec 1915 George F. Doran from Omaha, Nebraska, filed an application for a patent for a curing brine that contained nitrites. His application strengthens the evidence that it was not the knowledge of nitrite and its role in curing that was lacking, but availability and price. He states the objective of his patent application to “produce in a convenient and more rapid manner a complete cure of packing house meats; to increase the efficiency of the meat-curing art; to produce a milder cure; and to produce a better product from a physiological standpoint.”
One of Doran’s sources of nitrite is “sterilized waste pickling liquor which he [I have] discovered contains soluble nitrites produced by conversion of the potassium nitrate, sodium nitrate, or other nitrate of the pickling liquor when fresh, into nitrites. . .” “Waste pickling liquor is taken from the cured meats. Nitrites suitable for use in carrying out the present invention may be produced by bacterial action from nitrates and fresh pickling liquor by adding a small percentage of old used pickling liquor. The bacteria in old pickling liquor are reducing bacteria and change nitrates to nitrites.” (Process for curing meats. US 1259376 A)
The use of old pickle has been described much earlier than Doran’s patent. His usage of old pickle when he understood the reduction of nitrate to nitrite and nitrite’s role in curing along with the fact that sodium nitrite was available can point to only one reason – price. It comes 10 years after sodium nitrite was first tested in curing brines for meat and shows that it has never become the curing agent of choice most probably due to limited availability and price. Much more about this later.
The postWWI era (1918 and beyond)
After WWI something changed. Saltpeter (potassium or sodium nitrate) has been substituted by the direct addition of nitrite to the curing brines.
The question is who pioneered this. Why and how did sodium nitrite production become so commonplace that it became available to bacon curing plants around the world?
Industry developments like this do not happen “by itself.” Someone drives it in order for it to become general practice in an industry.
Chilean Saltpeter is a good case in point. Even though natural sodium nitrate deposits were discovered in the Atacama desert, it took a considerable effort on the side of the producers (mainly the Chilean Government) to work out the benefits of sodium nitrate and to market it to the world. It is, for example, famously reported that the first shipment to Britain was dumped in the sea before the ship docked on account that the cargo attracted customs duty and the ships owners could not see any commercial application for sodium nitrate. (2)
In the same way, the direct application of nitrite in curing brines must have been driven by someone.
The Griffith Laboratories, Inc.
The Chicago based company of Enoch Luther Griffith and his son, Carroll Griffith started to import a mixture of sodium nitrite and salt as a curing substitute for saltpeter from Germany in 1925. The product was called Prague Salt (Prague Powder, 1963: 3)
The Griffith Laboratories (3) played a key role in marketing the new curing brine in the USA. They took the concept of the Prague Salt (sodium nitrite) and in 1934 announced an improved curing brine, based on the simple use of sodium nitrite, where they fuse nitrite salt and sodium chloride in a particular ratio. They called it Prague Powder. Their South African agents, Crown Mills (4), brought the innovation to South Africa. (Prague Powder, 1963: 3, 4)
It is fair to assume that if Prague Salt was being sold to Griffith in the 1920’s, the German producers must have sold it to other countries and companies around the world also.
The benefits of Prague Salt and later Prague Powder over Saltpeter is dramatic. Prague Salt (sodium nitrite) does not have the slightly bitter taste of saltpeter (Brown, 1946: 223). It allows for greater product consistency since the same percentage of nitrate was not always present in the saltpeter and the reduction of nitrate to nitrite takes longer or shorter under various conditions (Industrial and Engineering Chemistry, December 1925: 1243). The big benefit was however in the curing time required. Instead of weeks or even months that is required with saltpeter, curing could now be done in days or even hours with sodium nitrite. (The Food Packer, 1954: 64) From there, brand names like Quick Cure or Instacure.
This means that we have narrowed the time line for invention of Prague Salt (Sodium Nitrite) to between 1914, the beginning of the Great War and 1925 when Griffith imported it from Germany.
However, a document, published in the USA in 1925 shows that sodium nitrite as curing agent has been known well before 1925.
The document was prepared by the Chicago based organisation, The Institute American Meat Packers and published in December 1925. The Institute started as an alignment of the meat packing companies set up by Phil Armour, Gustavus Swift, Nelson Morris, Michael Cudahy, Jacob Dold and others with the University of Chicago.
A newspaper article about the Institute sets its goal, apart from educating meat industry professionals and new recruits, “to find out how 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 document is entitled, “Use of Sodium Nitrite in Curing Meats“, and it it is clear that the direct use of nitrites in curing brines has been practiced from earlier than 1925. (Industrial and Engineering Chemistry, December 1925: 1243)
The article begins “The authorization of the use of sodium nitrite in curing meat by the Bureau of Animal Industry on October 19, 1925, through Amendment 4 to B. A. I. Order 211 (revised), gives increased interest to past and current work on the subject.”
Sodium Nitrite curing brines would therefore have arrived in the USA, well before 1925.
It continues in the opening paragraph, “It is now generally accepted that the salpteter added in curing meat must first be reduced to nitrite, probably by bacteria, before becoming available as an agent in producing the desirable red color in the cured product. This reduction is the first step in the ultimate formation of nitrosohemoglobin, the color principle. The change of nitrate to nitrite is by no means complete and varies within considerable limits under operating conditions. Accordingly, the elimination of this step by the direct addition of smaller amounts of nitrite means the use of less agent and a more exact control.”
Griffith describes the introduction and origin of Prague Salt and later, Prague Powder as follows in official company documents:
“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.)
The World War One link
The tantalizing bit of information from Griffith sets World War One as the background for the practical and large scale introduction of direct addition of nitrite into curing brines through sodium nitrite.
There has to be more to the reason for saltpeter being replaced by sodium nitrite as curing agent than the reasons given by Griffith. For starters, the meat industry has always been under pressure to work fast with less people due to pressure on profit margins. The need to cure meat quicker due to short manpower and time as a result of the war could not be the full story.
The World War One link from Griffith does not give all the answers, but it puts the introduction of sodium nitrite to meat curing between 1914 and 1918, at least 7 years before Griffith started to import Prague Salt.
A document from the University of Vienna would fill out the story. According to it, saltpeter was reserved for the war effort and was consequently no longer available as curing agent for meat during World War One. (University of Vienna). It was reserved for the manufacturing of explosives, and for example, the important industry of manufacturing nitrocellulose, used as base for the production of photographic film, to be employed in war photography. (Vaupel, E., 2014: 462) It gets even better. Not only did the prohibition on the use of saltpeter expand the information from Griffith as to why people started using sodium nitrite (macro movements in culture does not take place because of one reason only), but it provide a name to the prohibition.
In August 1914, the War Raw Materials Department (Kriegsrohstoffabteilung or KRA) was set up under the leadership of Walther Rathenau. It was Rathenau who was directly responsible for the prohibition on the use of salpeter. (5) He therefore is the person in large part responsible creating the motivation for the meat industry in Germany to change from saltpeter to sodium nitrite as curing medium of choice for the German meat industry during Wold War One.
Walter Rathenau’s actions may have motivated the change, but it was the developments in synthesizing ammonia, sodium nitrate and sodium nitrite which provided the price point for the compound to remain the curing agent of choice, even after the war and after the prohibition on the use of saltpeter was lifted.
One ofthe most important scientific riddles to be solved in the late 1800’s/ early 1900’s was how to produce ammonia and its related chemicals from atmospheric nitrogen. Sir William Crookes delivered a famous speech on the Wheat Problem at the annual meeting of the British Association for the advancement of Science in 1898.
In his estimation, the wheat production following 1897 would seriously decline due to reduced crop yields, resulting in a wheat famine unless science can step in and provide an answer. He saw no possibility to increase the worlds wheat yield under the prevailing agricultural conditions and with the increase in the world population, this posed a serious problem. He said, “It is clear that we are taxed with a colossal problem that must tax the wits of the wisest.” He predicted that the USA who produced 1/5th of the worlds wheat, would become a nett importer unless something change. He pointed to the obvious answer of manure, but observed that all available resources are being depleted fast.
Sir William saw a “gleam of light in the darkness” and that “gleam” was atmospheric nitrogen. (Otago Witness. 3 May 1900, Page 4)
It was the German Chemist, Fritz Harber who solved the problem, with the help of Robert Le Rossignol who developed and build the required high pressure device to accomplish this. (www.princeton.edu)
In 1909 they demonstrated that they could produce ammonia from air, drop by drop, at the rate of about a cup every two hours. “The process was purchased by the German chemical company BASF (a coal tar dye supplier), which assigned Carl Bosch the difficult task of scaling up Haber’s tabletop machine to industrial-level production.Haber and Bosch were later awarded Nobel prizes, in 1918 and 1931 respectively, for their work in overcoming the chemical and engineering problems posed by the use of large-scale, continuous-flow, high-pressure technology.” (www.princeton.edu)
“Ammonia was first manufactured using the Haber process on an industrial scale in 1913 in BASF’s Oppau plant in Germany.” (www.princeton.edu)
It was the vision and leadership of Walther Rathenau, the man responsible for restricting the use of saltpeter, that drove Germany to produce synthesized Chilean Saltpeter. He saw this as one of the most important tasks of his KRA. He said: “I initiated the construction of large saltpeter factories, which will be built by private industries with the help of governmental subsidies and will take advantage of recent technological developments to make the import of saltpeter entirely unnecessary in just few months“. (Lesch, J. E., 2000: 1)
Fritz Harber was one of the experts appointed by Rathenau to evaluate a study on the local production of nitric acid.
During World War One production was shifted from fertilizer to explosives, particularly through the conversion of ammonia into a synthetic form of Chile saltpeter, which could then be changed into other substances for the production of gunpowder and high explosives (the Allies had access to large amounts of saltpeter from natural nitrate deposits in Chile that belonged almost totally to British industries; Germany had to produce its own). It has been suggested that without this process, Germany would not have fought in the war, or would have had to surrender years earlier.” (www.princeton.edu)
So it happened that Germany became the leader in the world in synthesised sodium nitrate production and it effectively replaced its reliance on saltpeter from Chile with sythesised sodium nitrate, produced by BASF and other factories.
So, as a result of the First World War, sodium nitrite was produced at levels not seen previously in the world and in large factories that was build, using the latest processing techniques and technology from a scientific and an engineering perspective. Sodium nitrite, like sodium nitrate was being used in the production of explosives. Nitroglycerin is an example of an explosive used extensively by Germany in World War One that uses sodium nitrite in its production. (Wikipedia.org. Nitroglycerin and Amyl Nitrite)
Sodium nitrite and the coal-tar dye industry
The importance of the manufacturing cost of nitrite and the matter surrounding availability can be seen in the fact that sodium nitrite has been around since well before the war. Despite the fact that it was known that nitrite is the curing agent and not nitrate, and despite the fact that sodium nitrite has been tested in meat curing agents, probably well before the clandestine 1905 test in the USA, it did not replace saltpeter as the curing agent of choice. My hunch is that it did not enter the meat industry as a result of cost.
The technology that ultimately is responsible for synthesising Chilean Saltpeter and made low cost sodium nitrite possible was being incubated in the coal-tar dye and textiles industry and in the medical field. The lucrative textiles and dye industry was the primary reason for German institutions of education, both in science and engineering to link with industry, resulting in a strong, well organised skills driven German economy. For example, “Bayer had close ties with the University of Göttingen, AGFA was linked to Hofmann at Berlin, and Hoechst and BASF worked with Adolph Baeyer who taught chemists in Berlin, Strasbourg, and Munich.” (Baptista, R. J.. 2012: 6)
“In the late 1870s, this knowledge allowed the firms to develop the azo class of dyes, discovered by German chemist Peter Griess, working at an English brewery, in 1858. Aromatic amines react with nitrous acid to form a diazo compound, which can react, or couple, with other aromatic compounds.” (Baptista, R. J.. 2012: 6)
Nitrous acid (HONO) is to nitrite (NO2-) what nitric acid (NO3) is to nitrate (NO3-).
According to K. H. Saunders, a chemist at Imperial Chemical Industries, Ltd., Martius was the chemist to whom the introduction of sodium nitrite as the source of nitrous acid was due. (Saunders, K. H., 1936: 26)
The economic imperative
The simple fact is that ammonia can be synthesized through the direct synthesis ammonia method at prices below what can be offered through Chilean Satlpeter. (Ernst, FA. 1928: 92 and 100) Sodium Nitrite can be supplied at prices below Chilean saltpeter and this made sodium nitrite the most effective curing agent at the lowest price since World War One.
As an example of the cost differences, the price of Nitric Acid (HNO3) from direct synthesis in 1928 was $23.60 per ton HNO3 plus the cost of 606 lb. of NH3 by-product and from Chilean Nitrate at $32.00 per ton of HNO3, plus the cost of 2840 N NO3 by-product. (Ernst, FA. 1928: 112)
The advantage of scale and technology
By 1927, Germany was still by far the worlds largest direct syntheses ammonia producer. Production figures of the year 1926/ 1927 exceeded Chilean saltpeter exports even if compared with the highest levels of exports that Chilean saltpeter ever had in 1917. A total of 593 000 tons of nitrogen was fixed around the world in 1926/27. Of this figure, Germany produced 440 000 tons or 74%. The closest competitor was England through the Synthetic Ammonia and Nitrates Ltd. with a total capacity of 53 000 tons of nitrogen per year. (Ernst, FA. 1928: 119, 120)
In the USA 7 direct synthesis plants were in operation with a combined capacity of 28 500 tons of nitrogen per year. (Ernst, FA. 1928: 120)
Supporting evidence from the USA
The thesis that before the war, the production of sodium nitrite was not advanced enough for its application in the meat industry (resulting in high prices and low availability) is confirmed when we consider the situation in the USA.
The first US plant for the fixation of atmospheric nitrogen was build 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. The imports referred to, was as a result of Germany selling their enormous stockpiles of sodium nitrite at “below market prices” and not directly linked to a lower production price in Germany, even though this was probably the case in any event. ( The Cincinnati Enquirer ( Cincinnati, Ohio), 27 September 1923. Page 14.)
The Vienna University document indicate that the fast curing of sodium nitrite was recognised and the ban was lifted when the war ended. It was this fact that Griffith picks up on in their literature.
This is how it happened that sodium nitrite replaced saltpeter as curing salt.
The ban on the use of saltpeter for non military uses by Walther Rathenau is the likely spark that caused butchers to look at alternative curing systems. A known alternative was sodium nitrite. Despite a similar ban on the use of nitrite, later imposed for concerns over the safety of nitrite in meat and because sodium nitrite was also used to produce explosives, it was available in such large quantities around Germany that it was possible to defy the ban.
The likely consequence of the developments surrounding the production of atmospheric nitrogen is that sodium nitrite was being produced at prices that was previously not possible. These prices, combined with the volume of sodium nitrite now available made it a viable proposition to replace saltpeter in meat curing and to remain the curing brine of choice, following the war.
(1) “The red color of fresh lean meat, such as beef, pork, and mutton, is due to the presence of oxyhemoglobin, a 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. When fresh meat is cooked or is cured by sodium chloride, the red color changes to brown, owing to the breaking down of the oxyhemoglobin into the two constituents, hematin, the coloring group, and the protein, globin.
On the other hand, when fresh meat is cured by means of a mixture of sodium chloride and a small proportion of potassium nitrate, or saltpeter, either as a dry mixture or in the form of a pickle, the red color of the fresh meat is not destroyed during the curing process, the finished product having practically the same color as the fresh meat. Neither is the red color destroyed on cooking, but rather is intensified.” (Hoagland, Ralph. 1914)
(2) The first export of salitre (sodium nitrate) was authorised by the Chilean government in March 1830 and went to the USA, France, and to Liverpool. It is the latter shipment which failed and was thrown overboard. Different sources give different reasons for the action. One, that price was not attractive, another, that the excise duties were to high, and a third that the Port captain did not allow the boat to come in because it was carrying a dangerous load. A few farmers in Glasgow received a few bags. They used it as fertalizer and reported a three fold increase in crop yield. (Wisniak, J, et al. 2001: 437)
(3) Steve Hubbard, Vice President, Global Marketing and Innovation at Griffith Laboratories Worldwide, Inc. graciously provided me with much of the information from company documents.
(4) Crown Mills was bought out by Bidvest and became Crown National.
(5) The first War Raw Materials Department (KRA) in Germany was created (KRA) in mid-August 1914, as suggested by Walther Rathenau. (Vaupel, E. 2014: 462) Walter was the son of the founder of AEG and “one of the few German industrialists who realized that governmental direction of the nation’s economic resources would be necessary for victory, Rathenau convinced the government of the need for a War Raw Materials Department in the War Ministry. As its head from August 1914 to the spring of 1915, he ensured the conservation and distribution of raw materials essential to the war effort. He thus played a crucial part in Germany’s efforts to maintain its economic production in the face of the tightening British naval blockade.”
Baptista, R. J.. 2012. The Faded Rainbow: The Rise and Fall of the Western Dye Industry 1856-2000. From: http://www.colorantshistory.org/files/Faded_Rainbow_Article_April_21_2012.pdf
Brown, Howard Dexter et al. 1946. Frozen Foods: Processing and Handling
Butler, A. R. and Feelisch, M. New Drugs and Technologies. Therapeutic Uses of Inorganic Nitrite and Nitrate From the Past to the Future. From: http://circ.ahajournals.org/content/117/16/2151.full
Determination of nitrite in meat products. University of Vienna, Department of Analytical Chemistry, Food Analytical Internship for nutritionists.
Ernst, FA. 1928. Fixation of Atmospheric Nitrogen. D van Nostrand, Inc.
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.
Hwei-Shen Lin. 1978. Effect of packaging conditions, nitrite concentration, sodium erythrobate concentration and length of storage on color and rancidity development of sliced bologna. Iowa State University Digital Repository @ Iowa State University
Katina, J. 2009. Nitrites and meat products. Czech Association of Meat Processors. http://www.cszm.cz/clanek.asp?typ=5&id=1136
Lang, M. A. and Brubakk, A. O. 2009. The Haldane Effect. The American Academy of Underwater Sciences 28th Symposium.Dauphin Island
Lee Lewis, W. December, 1925. Use of Sodium Nitrite in Curing Meat. Industrial and Engineering Chemistry.
Lesch, J. E.. 2000. The German Chemical Industry in the Twentieth Century. Kluwer Academic Publishers.
Mauskopf, MSH. 1995. Lavoisier and the improvement of gunpowder production/Lavoisier et l’amélioration de la production de poudre. Revue d’histoire des sciences
Otago Witness. 3 May 1900. Sir William Crookes and the wheat problem. Issue 2409, Page 4, from: http://paperspast.natlib.govt.nz/
Péligot E. 1841. Sur l’acide hypoazotique et sur l’acide azoteux. Ann Chim Phys.; 2: 58–68.
Prague Powder, Its uses in modern Curing and processing. 1963. The Griffith Laboratories, Inc.
Process for curing meats. US 1259376 A
Redondo, M. A.. 2011. Effect of Sodium Nitrite, Sodium Erythorbate and Organic Acid Salts on Germination and Outgrowth of Clostridium perfringens Spores in Ham during Abusive Cooling. University of Nebraska – Lincoln.
Salem, H. et al. 2006. Inhalation Toxicology, Second Edition. Taylor & Francis Group, LLC.
Saunders, K. H. The Aromatic Diazo-Compounds and their technical applications. Richard Clay and Company.
Scheele CW. 1777. Chemische Abhandlung von der Luft und dem Feuer. Upsala, Sweden: M. Swederus.
The Brainerd Daily Dispatch (Brainerd, Minnesota). 17 January 1923. Page 3.
The Food Packer. Vance Publishing Corporation. 1954
The Indiana Gazette, 28 March 1924
The Indiana Gazette. 28 March 1924.
The Nebraska State Journal Lincoln, Nebraska. Wednesday, June 29, 1910. All for bleached flour. No harm can come from its consumption says experts. Page 3.
The Times (London, Greater London). 8 June 1914. Adulteration. Examples of fraudulent manufacture. Page 118
The Times (London, Greater London). 1 May 1919. Government Property for by direction of the Disposal Board. Explosives and Chemicals. Prices were coming down in 1920, as reported in The Cincinnati Enquirer ( Cincinnati, Ohio), 2 July 1920. Page 17.
Van Cortlandt, P, et al. 1776. Essays upon the making of salt-petre and gun-powder. Published by order of the Committee of Safety of the colony of New-York.
Vaupel, E. 2014. Die chemische Industrie im Ersten Weltkrieg
Krieg der Chemiker. Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Wisniak, J, et al. The rise and fall of the salitre (sodium nitrate) industry. Indian Journal of Chemical Technology. Vol. 8, September 2001, pp 427 – 438.
Wells, D. A. 1865. The Annual of Scientific Discovery, Or, Year-book of Facts in Science and Art for 1865. Gould and Lincoln.
Whittaker, CW, et al. July 1932. A Review of the Patents and Literature on the Manufacture of Potassium Nitrate with notes on its occurrence and uses. United Stated Department of Agriculture. Miscellaneous Publications Number 192.
It is Christmas today. I hope you received the gifts I’ve sent you and the letters I’ve sent to each one of you. I write with mixed feelings and great affection.
I miss Cape Town and I miss Table Mountain. It’s summer back home and you have the most beautiful days of the year. The sun and the festive atmosphere make one forget about the wind and the rain of the winter that sometimes persists up till new years day. Mostly, the days in December are glorious! We always do a long hike on boxing day and new years eve. This year I’m missing it, but next year we will do it again.
I am also excited because I think back today about all that I have learned. That curing bacon, like living life, is indeed an art that is worth cultivating. Paying close attention to how it has been done and the traditions that brought us to this place is not intended as a burden. It increases the pleasure of its consumption!
Christmas in Copenhagen in unlike any I could have imagined. For starters, it snows! The home is cozy and friendly!
Juleaften, as they call Christmas eve is the mots important time of the Christmas celebration. The entire family is together. Like we do it at home, great food and family are the focal point of the celebration. (Wikipedia. Culture of Denmark)
Andreas’ dad told me that after the industrial revolution of the 1860’s, Wood-fired ovens and meat grinders became common items in Danish household and a whole new range of foods started to dominate the Christmas supper. (Madadpakjan-sunshine, Traditional Danish Food).
Andreas’ mom prepared the dish in their wood-fired oven, the same way as my mom and you, Ava do. She selected a pork roast for last night.
Andreas brought home from Jeppe’s factory a joint of pork from the neck with the rind still on. He cut through the rind to the meat in narrow, long strips. His mom then rubbed salt and pepper onto the joint and inserted bay leaves into the cuts and roasted it in a hot oven.
The dish was served with boiled and caramelized potatoes (brunede kartofler). These she specially prepared by melting sugar in a frying pan over strong heat, adding a clump of butter, and allowing a portion of small round peeled potatoes to bathe in the mixture until they become richly browned or caramelized. She also served red cabbage (rødkål) with slices of apples. (Wikipedia. Flaeskesteg)
You would have loved it!
Last night was my chance to tell a few stories. It was snowing and the discussion around the table turned to the matter of using ice to preserve food and why we have difficulty curing bacon in South Africa. I think I finally know why Oscar and my attempt to cure bacon did not work.
Edward Smith in his book, Foods, that you are familiar with at this point, listed cold in 1876 as one of the ways to preserve food.
For him refrigeration was mainly the supply of ice. Remember that the challenge in the 1800’s was to supply enough food for the old world and a solution was to import food from the new. Apart from the long voyage from the new world to the old, the fact is that new worlds have warm climates.
Smith says that the “real difficulty is to provide a sufficient quantity of ice at the ports of South America and Australia.” (Smith, Edwards, 1873: 25) of course, one solution was to load a ship with enough ice to make the journey to the new world, load the meat and transport it back to the old world, still under refrigeration of the ice.
This would be very costly though and Smith stays that “so long as our supplies of meat are from hot climates the expense will be a serious impediment to such a commercial enterprise.” He suggested that countries with cold climates should either start producing meat for the old world or “by storing large quantities of ice in an economical manner at the ports of other meat-producing countries” (Smith, Edwards, 1873: 25, 26) such as Australia.
He refers to the work of Messrs. Nasmyth of Manchester who “produced machines on the patent of M Mignot, by which 50 lbs. of ice may be made per hour at the cost of condensing and then rerafying air, ” (Smith, Edwards, 1873: 26)
Andreas knows a lot about the development of refrigeration. He has been to London and many American cities.
Apparently, ice houses started to be build in the northern hemisphere on the property of wealthy owners from the 1700’s. These were generally brick-lined pits, build below the ground where ice from surrounding lakes were stored. (Dellino, C, 1979: 2) This concept of this natural refrigeration was first described by Frederic Tudor (1783 – 1864). (Kha, AR, 2006: 26)
In the 1800’s commercial cold storage facilities were being build at harbors in America and Europe, mainly for the storage of carcasses, fruit and dairy products. The ice was cut from frozen ponds, lakes or rivers in the winter and stored in the heavily insulated ice house. (Mfo.me.uk, Harris) (2) It is no wonder that Smith equated refrigeration to the production of ice!
As Smith observed, this was obviously not an option for the warmer climates of the new world from the Southern Hemisphere. It never gets cold enough in Cape Town for any ice to form.
From what Andreas told me, it is clear that the seeds for solving the refrigeration problem were planted and in the 1600’s, the Englishman Robert Boyle (1627 – 1691) showed that water under pressure have a reduced boiling temperature. (3) (Kha, AR, 2006: 26)
The mathematics Professor, Sir John Leslie (1766 – 1832) at Edinburgh university in Scotland created ice in his laboratory by absorbing water from a water container with sulfuric acid , thereby producing a vacuum in the closed container. The vacuum in turn caused the saturation temperature of the water producing the vapor to be low enough to form ice.
Dr William Cullen at Glasgow University observed in 1755 showing that an isolated water container dropped in temperature during evaporation. In 1871 Thomas Masters in England demonstrated an ice cream maker where a temperature of close to freezing point can be obtained if a brine mix of salt and ice is used. (Kha, AR, 2006: 26)
The American Charles E. Monroe of Cambridge, Massachusetts, demonstrated a food cooler that effected cooling through the evaporation of water through the porous lining of the refrigerator. (2) (Kha, AR, 2006: 26)
M. Howell observed in 1755 that air leaving a pressurized air line cooled when it escaped. A patent, based on this observation, was granted to Dr. John Gorrie (1803 – 1855) for the first machine to work successfully on the air refrigeration cycle. (Kha, AR, 2006: 26)
In 1824 Ferdinand P E Carre showed that ammonia could reach much lower temperatures than water when boiled at the same pressure. (4) (Kha, AR, 2006: 26)
Refrigeration was “in the air” in the 1800’s. It was just a matter of time before this was being done successfully in our homes, at harbours, meat markets and on ships.
It is doubtful that David Graaff kept abreast of all the particular developments in refrigeration that Andreas is telling me about. The practically minded man that I know, and without having talked to him about this, my guess is that he paid close attention to the development of freezing technology generally. In particular, the race to apply it to ships in order to transport frozen meat successfully from Australia to England and the creation of refrigerated railway car’s. This affected him directly, after all, and I am sure he noticed the commercial opportunity immediately.
He no doubt took careful notice of the development in England where the railways were using refrigerated cars for transporting perishable goods. Cold storage works were springing up in docklands and markets from Auckland and Buenos Aries, London, Antwerp and Chicago. (Brooke Simons, P, 2000: 22)
One year after he was appointed manager of Combrinck & Co, he noticed the docking of the Dunedan. This was the first successful shipment of meat between Australia and England. David was consumed by the quest to make Cape Town a world class city generally and by making Combrinck & Co a world leader in the supply of meat. (Brown, R.) It is only to be expected that David must have identified the creation of large storage works in Cape Town and across Southern Africa and linking these by the equipping of railway cars with refrigeration as a priority and something that he could be instrumental in. He had the background and the means to effect this.
I would expect that one of the things that was on his mind as the Dunedan docked was the question: why is the beef not being transported from South Africa? A much closer source than Australia and why are we not setting up a network to support similar distribution across Africa?
Where our current quest is discovering the art of preserving pork through the curing process and creating of the worlds best bacon, David was looking at solving the problem of preserving meat for later use by the application of refrigeration.
He set out in the 1880’s on a world journey to investigate refrigeration and to familiarise himself with every aspect of the meat trade in England and in the USA. In Chicago he looked at the most modern systems of meat packing. As soon as he returned to Cape Town, he set out to apply refrigeration to Combrinck & Co. (Brooke Simons, P, 2000: 22, 23)
Great business leaders often capitalist in areas where they already have a presence. Combrinck & Co was best positioned to take advantage of refrigerated railway car’s and cold storage works. A Scotsman, Sir Donald Currie, the owner of the Castle Line of mail ships, servicing the line between South Africa and Great Britain, was best positioned to capitalise on the transport of meat between South Africa and England. (5) Currie’s first ship with a refrigeration facility was Grantully Castle which set sail from Cape Town on 13 February 1889 with 15 tons of grapes. The experiment with grapes was a disaster, but David was ready with a supply of a far more durable product to ship under refrigeration. Meat! (Brooke Simons, P, 2000: 23)
There is a very specific application of refrigeration to the production of bacon.
Remember that I told you how Oscar and myself tried to cure our own bacon on his farm in the Potchefstroom district and how, when we ate it, the meat was off? I think that I finally have the answer why this happened.
It was August 1890 when we tried to make our own bacon based on what we were told by an old Danish spice trader in Johannesburg. August is the last official winter month in Potchefstroom, but its already warm during the days with temperatures reaching as high as 25 deg C and sometimes even higher.
We thought that the curing salt would prevent the purification of the meat, but the fact is that pork takes approximately 7 days to cure properly. Whether wet or dry cure is used, the brine must have sufficient time to permeate the joint in order for it to do its preserving work. Pork goes off quicker than beef or lamb. If it has not been cured, it will be off within 3 days under warmer conditions like we have in Potchefstroom.
The only way that this can be done in our warm climate is under constant refrigeration. This is also the reason that it is good for us to focus on the curing of bacon and possibly other pork cuts and not on cold storage refrigeration as David is doing. Our investment is in the process of curing and not in large scale storage or transportation. Donald Currie and David Graaff have already staked these claims. We have neither the money, not the time to compete against them. Since they are not experts in the curing and processing of pork, this is an area where we can steak our claim with a great likelihood of success for our venture.
The fact that David is about to build a new, much bigger storage works in Cape Town will be to our advantage since we can use this as refrigerated storage for our carcasses as well as for our bacon, before it is sold to ships and clients throughout South Africa.
Not just have I received a letter from David, informing us that he is interested in discussing our venture when he visits Denmark early in 1892, but I have also received a telegram from Oscar that he will be visiting at about the same time.
I have mailed both and asked if we can combine their visits. I believe Oscar and David will have much to discuss on the trip and will find great pleasure in each others company since they are of similar personalities.
We will need some form of refrigeration at our factory in Cape Town, but not to the size as David is building. David and Oscar will have many practicalities to discuss.
Another lesson that I have learned is that we can look at cooking methods and technology that are generally available to households and build the products that we produce around these technology.
Take as an example the meat that Andreas’ mom prepared for Christmas. I see a clear trend that people have less and less time to prepare dishes that were prepared by our grandparents in the home. Ovens are also becoming generally available to households in Cape Town and this opens up the opportunity for preparing roasts.
If we can prepare neck joints with the skin on and cut in the same way as Andreas did, in narrow lines, cut through the rind and fat, to the meat and we can rub salt and spices onto the meat in the same way as the housewife would do, people who dont have as much time as our grandparents did will support us.
This level of curing and preparing of meat is something that David and his Combrinck & Co never had to do. They are used to supplying basic joints to clients throughout the Cape Town and surrounding area. It is here that Oscar and I intend specializing and being different.
Here is my Christmas promise to you. In two years time, this time, I will be in Cape Town and Oscar, I and the Woody’s team will make you a Prague Ham.
I have learned that we will be in the business of creating the exceptional for people from all walks of life. The fact that they will eat our food is a sacred trust.
The Christmas lunch is coming up. I cant wait to see the magic that Andreas’ mom has prepared for us. My sadness of missing you is balanced by the excitement to share with you everything that we are learning.
(1) Ice Cold in Africa is the title of a book by Phillida Brooke Simons, on “The history of the Imperial Cold Storage & Supply Company Limited” which was taken over by Tiger Brands in October 1989. ICS dates its official foundation to Wednesday, 19 February 1902 when it was legally registered in Pretoria. The company’s origins were much older. It was in 1868 when a Swiss-born butcher names Othmar Bernard Scheitlin handed the over his business which he owned since 1849 to his foreman Jacobus Combrinck. The business became Combrinck & Co and dominated the meat trade in Cape Town Peninsula. When Jacobus retired, he handed over the reigns to David Graaff who was his foreman, just as he has been to Mr Scheitlin.
During the 1880’s David Graaff traveled extensively throughout Europe and the USA to familiarise himself with among other, developments in refrigeration.
Upon his return refrigeration chambers were constructed on the premises of Combrink & Co., thus bringing refrigeration to Southern Africa.
Combrink and Co was transformed into the Imperial Cold Storage & Supply Company Limited who later changed its name to ICS.
By the time that ICS lost its independance, ICS had over 100 subsidiaries as well as branches all over South Africa. (Brooke Simons, P, 2000: 7, 22, 27)
This chapter is named in honour of the work of Phillida Brooke Simons who has been responsible for many other books, including ones on South African architecture. She was the editor responsible for retelling the story “Jock of the Bushveld” by Sir Percy Fitzpatrick.
One obituary reads: “A distinguished Honorary Life member of the Historical Society of Cape Town, Phillida Audrey Fairbridge Brooke-Simons died on 29 July 2013 and we remember her with deep affection in this memorial to her life and work. Her contribution to historical literature was considerable, particularly in recording the history of the old buildings in the Cape and the lives of those who have contributed to progress in South Africa.” (Sabinet.co.za)
(2) My grandparents used a similar system on their farm Stillehoogte in Fredefort district. The “cooler” had two layers of bricks. Between the inner and the outer was a layer of insulation of anthracite. The outer layer was “staggered”. Water dripped over the outer part of the wall to affect refrigeration on the inside.
They continued using the system, well after they got electricity on the farm.
To the right of the cooler, my grandfather, Eben Kok is looking through his binoculars. He was sitting like that many afternoons to see who was driving over his motor-gates (motorhekke). He had signs put op next to the gates “privaat motorhek/ private motor gate”. The idea was that only his family could use these gates. The rest of the people had to use the traditional gates. He passed away when I was either 7 or 8.
(3) The French meat processing equipment producer Lutetia used the same basic principle discovered by Robert Boyle in their thawing massager/tumbler (patent 92-07091).
Under pressure, the temperature of steam, injected into a chamber drops and thawing of meat is effected without cooking and therefore denaturing the meat proteins.
Lutetia describes their invention as follows: “Defrosting is obtained by injecting expanded steam into the massager previously put under vacuum. At low pressure, the steam condenses on the surface of the food at low temperature. So, at 50mbar, the steam condenses at 33°C which is insufficient to lead to coagulation on the surface of the meat. The steam can come from a LUTETIA steam generator or from the factory boiler via the LUTETIA client kit. In order to reduce the humidity level, the massager drum may be fitted with a double envelope fed with a tepid mixture of mono-propyl glycol and water. In order to accelerate the heat transfer and to homogenise the defrosting, the blocks of meat may be passed through the block breaker before defrosting.” (http://de.lutetia.fr/equipement.php?id=7)
(4) In 1930 the Crosley system of refrigeration, based on Carre’s cycle was widely sold in the US. (Kha, AR, 2006: 26)
(5) In 1891 the Lions (the British Isles) became the first team to tour South Africa. (Wikipedia. Currie Cup). The team was entertained on the voyage to South Africa by Donald Currie himself. It was the maiden voyage of his most recent steam boat. In Currie’s luggage was a golden cup which he planned to present to the team who performed best against the touring Lions. The tourists were to strong for the locals and the trophy went to Griqualand West who lost by the smallest margin, 0-3. (Joffe, E, 2013: 99)
In 1892 the cup became known as the Currie Cup, presented to the winner of a fiercely contested local tournament. The inaugural Currie Cup tournament was held in 1892 with Western Province earning the honour of holding it aloft as the official first winners. (Wikipedia. Currie Cup)
Brooke Simons, P, 2000, Ice Cold in Africa, Fernwood Press.
Brown, R. Design Dissertation Report. http://issuu.com/archirube/docs/designreportprint2/1#
Dellino, C. 1979. Cold and Chilled Storage Technology. Blackie Academic and Professional.
Joffe, E. 2013. Before Mandela’s Rainbow. Author House
Kha, AR. 2006. Cryogenic Technology and Applications. Elsevier, Inc.
It is autumn. It mirrors my mood as I am writing to you today. As much as I am excited every Monday morning about what is on the menu that week, I am also frustrated because I know that I must get done here so that I can get home. The value in knowledge is not in the knowing, but in the doing.
Everything that I know and learn must translate into products that are sold to consumers who are willing to pay for the goods. If this does not happen, I am no more than a man engaged in mind games. What I learn and the skills I acquire must change into profit for a business.
On the other hand I also know, as another good friend that I met in Denmark has told me, if I have 5 years left on earth and I have to do something new, it will be best if I spend the first four years preparing for it.
Working through the complexities of the matters at hand will have a reward in my life, but also in yours if you would choose to follow on this exciting path. It really seems like the most complicated industry in the world.
Every day is spent on solving a giant mathematical equation.
The friends name is Martin Sauer. His dad has been in the pork business all his life and has travelled extensively through Africa. I was telling Martin one day all that Jeppe and Andreas has been teaching me. Martin laughed and said that I will spend a lifetime on these matters and must not try and remember everything. When I get back home I will have ample time to go over my notes. More than this, I may learn many new things that may seem to contradict some of the things that I’ve learned. I am looking forward to meet his father because I heard that he met Livingston.
It was a strange thing that Martin told me. The thing about learning things that may seem contrary to what I was taught at first. What was even stranger was that the following Monday, Jeppe told me that this was true when it comes to saltpetre and nitrite. Remember that I told you that it is the key ingredient in curing bacon?
This statement is not entirely accurate. The real magical ingredient in bacon is salt!
So opened up to me another vast world. The world of salt.
At night, after supper, we still read Foods by Edward Smith, written in 1867. He writes, “the oldest and best known preserving agent is salt, with or without saltpetre.” (Smith, E, 1867: 34) (1)
Remember the quote from the American Encyclopedia of 1858. It said 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) (1)
So Jeppe started last Monday, during my lunch time lessons to discuss the matter of salt. As was the case with saltpetre, a world started to open up for me that I did not know existed.
That white substance that I used so many times back in Cape Town and now, here in Denmark, without giving a second thought as to the nature and the power inherent in it.
As I could have guessed, the story of the use of salt goes back much further even than the story of humanity.
It is likely that the Neanderthals (2), some 125 000 years ago, that ancient and extinct subspecies of homo sapiens (Wikipedia, Neanderthal) were the first to use salt to preserve meat. They probably prepared and stored food “at locations near readily available salt and may well have learned to preserve food with it.” (Bitterman, M, 2010: 16).
There is evidence that using salt to preserve has been practiced since before the last ice age, some 12 000 years ago. Salt deposits in the hills of Austria and Poland, the shores of the Mediterranean and Dead Sea, the salt springs and sea marches across Europe and Asia would have provided salt to cultures across the world. (Bitterman, M, 2010: 16) To this list I can add the great salt pans and salt springs across our great African land.
It is doubtful that the use of the salt was very sophisticated.
The next step in the development of the technique of preserving meat was curing (2). Adding salt to meat evolved into an art.
A Dutch legend says that the curing of herring was invented by Willem Beukelsz around the early 1300’s. Whether this is entirely true or not, we know for a fact that the Cossacks produced cured caviar. The Romans used a sauce called garum on their food. Garum was made among other with brine (salt solution). (Laszlo, P, 1998: 5, 7, 11)
Marcus Porcius Cato (234 BCE – 149 BCE) or Cato the Elder was a Roman statesman, who devoted himself to agriculture when he was not engaged in military service. (Wikipedia, Cato_the_Elder) He recorded careful instructions in dry curing of hams. (Hui, YH, et al, 2001: 505)
Curing took meat which we culled from nature and brought it into culture. (Laszlo, P, 1998: 14) It turned the art of preserving into an expression of community and “togetherness” by transforming “preservation of food” into culinary delights of great enjoyment.
As our way of life evolved, we domesticated our food sources. We started with the fig, probably many years before we did the same to grain. Archaeologists found domesticated figs dating back to 9400 BCE. Sheep were domesticated around 8000BCE, cattle and pigs around 7000 BCE. (Bitterman, M, 2010: 17)
In the time period 15 000 to 5000 BCE, we developed a need for salt for ourselves and our domesticated livestock. The livestock had to supplement their diet with salt and we needed it for curing and preserving foods, tanning hides, producing dyes and other chemicals and for medicine. “We evolved with a physiological requirement for salt; our culture was born from it. Access to salt became essential to survive. Salt localized groups of people.” (Bitterman, M, 2010: 17)
The Danes are great traders and Copenhagen is a key centre for trading Saltpeter.
There is evidence that by 1,200 BCE, another great traders civilization of ages past, the Phoenicians, were trading salted fish in the Eastern Mediterranean region. (Binkerd, E. F.; Kolari, O. E. 1975: 655–661) Saltworks were one of the main features of their settlements in Labanon, Tuniaia, Egypt, Turkey, Cyprus, Crete and Sicily.
By 900 BCE, salt was being produced in ‘salt gardens’ in Greece and dry salt curing and smoking of meat were practiced and documented. (Binkerd, E. F.; Kolari, O. E. 1975: 655–661)
Ancient records of 200 BCE tell us that the Romans learned how to cure meat from the Greeks and further developed methods to “pickle” various kinds of meats in a brine marinade. Salting had the effect of reddening the meat and the report of this observation became the first recorded record of the colour effect of saltpeter. (Binkerd, E. F.; Kolari, O. E. 1975: 655–661)
Phoenician ships spread the technology of salt making across the Atlantic, to Spain and as far north as England. India, China, Japan and Africa developed their own salt industries.
Hardly a region on earth or a civilisation could be found who did not produce salt. Salt was taxed, traded, used as currency and consumed on a global scale. (Bitterman, M, 2010: 17 – 25)
The domestication of our food sources, the need for preservation and the technology to produce salt developed hand in hand as features of the spread of culture and civilisation with humans.
What was the mechanism that made salt such an effective preservative?
In order to understand the mechanism of salts preservative power, we must first understand salts composition.
Before the 1700’s, scientist could not distinguish between the different alkali metals. Sodium and potassium were often confused. Potassium was produced artificially by slowly pouring water over wood ashes and then drying the crystal deposits. Some of these metals were also found naturally on the edges of dried lake beds and mines and sometimes at the surface of the ground.
Henri-Louis Duhamel (1700 – 1782) realised that certain metals had similar characteristics. He studied samples of salts found in nature and produced by people artificially. This included the study of saltpetre (potassium nitrite), table salt, Glauber’s salt, sea salt and borax. (Krebs, RE, 2006: 51) He discovered sodium carbonate and hydrochloric acid, a solution with a salty taste, in 1736. (Brian Clegg, rsc, chemistryworld)
Humphry Davy, an English Chemist, was the uniquely talented young man who changed history when he isolated sodium and potassium in 1807.
He had the first direct electric current generator at his disposal, the electric battery that Alessandro Volta had invented in Paris in 1800. Davy ran an electric current through caustic soda (sodium hydroxide) and was able to isolate sodium from it. He did the same for potassium, isolating it from potash.
Chlorine was already being produced through electrolysis by the decomposition of sea salt by the electric current. Caustic Soda and chlorine had many applications by the end of the 1700’s.
Fats were processed with caustic soda to produce soap. Fabrics were being bleached with chlorine, a process discovered by Berthollet. (Laszlo, P, 1998: 50)
In 1807, Humphry Davy found that the “muriate of soda” produced by burning sodium in a vessel full of chlorine was chemically identical to salt. (Brian Clegg, rsc, chemistryworld)
Humphry wrote in 1840, “Sodium has a much stronger attraction for chlorine than oxygen; and soda or hydrate of soda is decomposed by chlorine, oxygen being expelled from the first, and oxygen and water from the second.”
“Potassium has a stronger attraction for chlorine than sodium has; and one mode of procuring sodium easily, is by heating together to redness common salt and potassium. The compound of sodium and chloride has been called muriate of soda, in the French nomenclature; for it was falsely supposed to be composed of muriatic acid and soda; and it is a curious circumstance that the progress of discovery should have shewn that it is a less compounded body than hydrate of soda, which 6 years ago was considered as a simple substance, and one of its elements. According to the nomenclature which I have ventured to propose, the chemical name for common salt will be sodane.”
“Common salt consists of one proportion of sodium, 88, and two of chlorine 134; and the number representing it is 222” (Davy, H. 1840: 247)
The importance of this is that the knowledge that the salt used for preserving food is mainly sodium chloride, existed from the early 1800’s.
It was now possible to analyse the nature of sodium chloride and the other kind of salts that exist. The nature of the composition of salt that has been dissolved in water and the interaction between salt and meat and between salt and microorganisms such as bacteria that are present in meat.
It is possible to look at everything that make up sea salt and salt from inland springs and dry salt beds and we can begin to understand and appreciate the effect of salting meat and how it happens that it preserves the meat.
It was found that salt had other metals and compounds of a diverse, but consistent nature. These other elements present in salt that we find naturally on earth, do they impact on the curing process at all? And if so, how? (4)
As I have learned, answering these questions would be very important in order to improve the consistency and the quality of the bacon we cure.
It has been a very busy week-end. Martin took me around the old city. I am excited to learn more about Livingston from his dad since I have heard that Livingston has seen many of the great salt beds and natural salt springs in Africa. So much work has been done by scientists in Europe and America, in India and China. Has there been any discovery in Africa that can help enhance our understanding of the effect of salt on curing in order to improve our processes and procedures and ultimately our products?
I am excited for the new week. Martin agreed to take me along when he is meeting with ship owners who buy their bacon. I hope to learn much from him. He has been trading with many of the Europeans who have moved into the north and central parts of Africa.
I continue to miss you guys. Keep my letters. Read them often. Work hard in school. Help Ava around the house.
(1) We have seen how pervasive the occurrence of nitrate is on earth. One expect to find it in every natural salt spring, salt marsh, dry salt lake and in sea water. “Some curing” will take place with almost any natural salt. However, it has been shown that bacon that was produced with either no nitrites or nitrite levels of 15 ppm, “off-flavours were high and increase rapidly. A significant reduction in off-flavours in pork during storage was observed when nitrites were added > 50 ppm.” (Rahman, SM, 2007: 307)
Salt springs, analysed in South Africa contained as little as < 1 mg/ L of Nitrate (H)
This does not correlate with the statement by Smith and the American Encyclopedia about the fact that normal salt was equally successful in curing meat.
Adding salt enhance the flavour, but it also accelerate lipid oxidation, even at low levels of addition. Lipid oxidation leads to off flavour development in meat that does not contain any nitrites. Even a 0.5% addition of sodium chloride significantly increase lipid oxidation when added to restructured pork chops and pork sausage patties following freezer storage. (Pearson, AM, et al, 1997: 269)
(2) ‘The binomial name Homo neanderthalensis – extending the name “Neanderthal man” from the individual type specimen to the entire species – was first proposed by the Anglo-Irish geologist William King in 1864 and this had priority over the proposal put forward in 1866 by Ernst Haeckel, Homo stupidus. The practice of referring to “the Neanderthals” and “a Neanderthal” emerged in the popular literature of the 1920.” (Wikipedia. Neanderthal)
(3). Meat curing can be defined as the addition of salt to meat for the purpose of preservation. (Hui, YH, et al, 2001: 505)
(4) It turns out that “food-grade salt of the highest purity should be used in meat curing practices. Impurities such as metals (copper, iron, and chromium) found in natural salt beds, salt produced from salt springs or sea salt accelerate the development of lipid oxidation and concomitant rancidity in cured meats. Although salt may be of very high purity, it nonetheless contributes to meat lipid oxidation. Nitrite and phosphates, help retard this effect.” (Hui, YH, Wai-Kit Nip, Rogers, R. 2001: 492)
Davy, H. 1840. The Collected Works of Sir Humphry Davy …: Elements of chemical philosophy. Smith, Elder & Co.
Gouverneur Emerson . 1858. The American Farmer’s Encyclopedia. A O Moore.
Hui, YH, Wai-Kit Nip, Rogers, R. 2001. Meat Science and Applications. Marcel Dekker, Inc.
Krebs, RE. 2006. The History and Use of Earths Chemical Elements. Greenwood Press.
Laszlo, P. 1998. Salt, Grain of Life. Columbia University Press.
Pearson, AM, et al. 1997. Healthy Production and Processing of Meat, Poultry and Fish Products, Volume 11. Chapman & Hall
Rahman, SM. 2007. Handbook of Food Preservation. Second edition. CRC Press.
“Bacon, that magical delicacy! Cured pork meat, mostly smoked, with a reddish, pinkish colour and a distinct taste.” I have always loved it.
The Dutch East Indian Company (VOC) established a trading station at the Cape of Good Hope to supply water, fresh vegetables and meat to passing ships on their long voyage between the East and Europe (Heinrich 2010: 10). Since this time bacon has been a prized commodity at the tip of the great African continent (Heinrich 2010: 32).
When the VOC’s Jan van Riebeek established the trading posit in 1652, pork meat was in short supply on account of the pigs that came with Van Riebeek found it hard to adapt. They died within months of landing and piglets did not live longer than a few days. (Heinrich 2010: 31, 32)
Imported bacon has since those days been better than local, heavily salted pork. As the local bacon from Van Riebeek’s day (Heinrich 2010: 32), the Combrinck bacon had to be soaked in water for 16 days before it could be eaten.
My dad was a local magistrate. Together we would undertake a weekly trip to the Combrinck & Co butchery in Woodstock to buy bacon. According to him Combrinck was taught how to make bacon by Othmar Scheitlin who started the butchery. He knew and liked Scheitlin a great deal.
Scheitlin was born in Switzerland. When he turned 18, he left home. He traveled through France, Holland, England and Germany, got a job as a cabin-boy and worked his way to the Cape of Good Hope. Here he set up the pork butchers shop in Woodstock where Jacobus Combrinck was a foreman and later took the business over when Sceitlin returned to Switzerland with his family (Linder 1997: 270; Simons 2000: 7).
My dad would make the hour long journey from our home to Papendorp, as Woodstock was known in those days, once a week to buy quality pork and this would always include bacon! He would tell me that the only thing Scheitlin and Combrinck could not do well was curing bacon!
The good bacon was made in Holland, Germany, Poland, Denmark and England with sweet Wiltshire Cure and imported by Scheitlin. I remember my dad buying it. Every time he took his money out, he would tell Jacobus Combrinck or whoever manned the cash register in a “lecture like voice”, “Quality, quality, I don’t mind paying for quality, young man!”
I was 6 years old when Combrinck & Co moved to an area in Cape Town called the Shamble. To shop number 4. The move happened in the 1870’s.
The quality of the bacon did not improve and the stench of the Shamble where the cities animals were slaughtered, would make me intensely dislike the weekly trips with my dad.
They would slaughter the animals and bury the offal on the beach so that the tide would carry it away. At night, one could hear what sounded like hundreds of homeless dogs fighting over scraps of food on the beach. By day there was the unbearable stench and the flies. Millions of flies. (Simons 2000: 13, 14).
My great grandfather on my fathers side fled to Holland from Denmark after the civil war between the Protestants and the Catholic’s. In Holland he was trained as a miller and limiting opportunities in Holland motivated a petition to the VOC to be sent to the new colony as a baker. On my mom’s side, my great grandfather came to the Cape as a soldier of fortune, trained in Waldeck, Germany, hired out to the VOC by the prince of Waldeck and sent to the Cape to protect it from the locals and enemy nations.
The family on my mom’s side were at this time living in the Orange Free State and the Zuid-Afrikaansche Republiek, the ZAR.
The scene was set for the adventure of a lifetime.
Oscar Klynveld was farming with milies, cattle and pigs. His farm was in the old Boer republic of the ZAR, in the Potchefstroom district.
I knew him from visiting friends in the Fredefort district, close to Parys. We became friends when I helped him one year to get his chickens to the different kooperasie stores in the district in time for Christmas when his ossewa fell into a ditch during a terrible storm. We distributed his chickens and bread flower and became friends for life.
I have always been irritated by the thought that the bacon produced in the Cape was of such inferior quality. Bacon was still being imported from the Britain and Europe to the Cape and sold to the locals and passing ships who were prepared to pay high prices for it.
War and roomers of war were again in the air by the late 1800’s. I was 26. The Anglo Boer War of 1881 made me realise that Britain wanted to control the trade route to India at all costs. They also wanted to control the recently discovered Diamonds from Kimberly and the gold from the Transvaal. They would never relinquish them!
Unlike most of my countrymen, I did not see any possibility for victory against the might of the British Empire. Instead, the thought started to develop that we must think past the war and strengthen ourselves economically. No matter who’s flag was flying in the Cape! “God only help those who help themselves!” was another one of my dad’s many sayings.
This was the point that Oscar and myself have been discussing at his farm when I told him about the bacon and he told me about his pigs. How one sow produced many piglets compared to cows and sheep who had few babies in a year. A picture started to form in our minds.
We made the decision that we would make and sell quality bacon. Nothing else would do. Sold across our land and to passing ships, the best bacon on earth!
When it seemed imminent that war would break out sooner rather than later, we started to market our plan to carefully selected friends and family. We needed support for the venture.
A meeting was held in Oscar’s voorkamer on the farm(1). It was a bitterly cold night. A hand full of burgers came. Oscar’s wife, Trudie, expecting their 3rd daughter was there. My Ava was there. James and Willem, Oscars two brothers came and Anton his father-in-law.
Oscar’s dad was a minister in the Dutch Reformed Church. He opened the meeting with scripture reading and prayer and said a few words.
We decided that since my kids were in primary school already in Cape Town, and Oscar’s kids were much smaller, that I have to go. Travel to Europe and Britain and learn the art of curing bacon! Oscar would stay behind, muster the support and prepare for our factory in Cape Town.
We decided not to go to England straight away. On the one hand there was the fear that war could break out any day and this would jeopardize our quest. On the other hand, since my ancestors came to the Cape of Good Hope from Denmark and since an old spice trader advised us to visit Copenhagen first, the decision was made to start there.
The next thing I knew, cold Free State wind was in my face and I raced back to the Cape through Bloemfontein. I spend a last week-end with my Ava and the kids.
We hiked up our beloved Table Mountain. It was the mountain that brought us together. As kids we would spend hours and days exploring its majestic cliffs. As teenagers we both acted as guides, taking European and American visitors to the top.
We climbed one of our favourite routes. At the top we sat for a long time, looking down on a growing city. A small mountain stream ran all the way from a crack in the mountain where a gorge has been formed by geological activity that non of us understood, through the city basin, past the VOC castle and into the sea. I wished the moment would last forever!
Before I knew it I was off to a waiting steam ship in the Cape Town harbour and the adventure of a lifetime!
What follows is the collection of letters I sent to friends and family from Europe and later, from the Cape Colony.
We set out to discover the art of curing bacon. In the process we all changed. During the quest, we not only had to learn the art of curing meat, we came face to face with ourselves and who we are. Our deepest fears and hopes. We learned about love, family, great friendship, trust, comradery, courage and following an unlikely dream.
These letters tell both the story of bacon and the art of living.
Heinrich, Adam R. 2010. A zooarcheaelogical investigation into the meat industry established at the Cape of Good Hope by the Dutch East Indian Company in the seventeenth and eighteenth centuries, The State University of New Jersey.
Linder, Adolphe. 1997. The Swiss at the Cape of Good Hope. Creda Press (Pty) Ltd
Simons, Phillida Brooke. 2000. Ice Cold In Africa. Fernwood Press
(1) Woodys prepared for their own factory in 2011. It was the culmination of a process that started on a flight between Johannesburg and Cape Town in January 2011 where Oscar and Eben decided to re-think the entire Woodys strategy and gear themselves for a much bigger company. Oscar and Eben has been joined by Willem on the Woodys Executive by this time. The first step of the plan was a transition from contract packers to an own factory.
You should be by my side and experience it yourself. They harness the wind to generate electricity for their cities. The technological advancement and the speed with which they adapt to new inventions are remarkable (Pedersen 2010: 3)
I miss you terribly! During the voyage my mind effortlessly wondered to you, my love! The uncertainty became like the changing waves with the only certainty in my thoughts being you.
I did much thinking on the voyage. I have been less certain about our quest than in the weeks before I left Cape Town. I wondered if we are completely crazy!
I would pace the deck and tell myself that the plan is simple and good. We want to cure bacon.
I have been questioning everything and reflected on the road and influences that got us to this point.
David Graaff had a huge impact on me. He may be short but has a “big” personality. (Simons 2000: 143) I was 6 when I met him at their butchers shop at the Shamble (4). and he must have been 16. I went with my dad for his weekly meat purchase as I continued to do every week after that.
I liked Dave immediately, as much as my dad liked his uncle, Jacobus Combrinck, his boss at that point. It was Combrinck who taught David how to be a butcher (Simons 2000: 8 – 41) (2) and the fact that they could never get bacon curing right is our future.
It was you and me who took him on a hike up Table Mountain when my dad suggested it. Since that first hike up Platteklig Gorge, we must have been up with him more times than with anybody else.
It dawned on me during the voyage why he did it so often. We were kids, looking for pocket money. Taking foreigners and wealthy locals up on a mountain where there are no established footpaths, were fun to us. We did what we love and got money for it.
For David it must have been a way to escape the squalor of the Shamble. The stench and disorderliness. Its difficult to imagine how things can get so out of hand and how the city’s slaughter area can become such a disgrace. They are making a small fortune at their number 4 shop, but the conditions are hideous.
The sensation as you make your way up the mountain is something that is hard to explain to people who have not done it. It is as if you ascend to another plain. The air becomes fresh and sweet. Even gale force winds that sometimes blow invigorates the body and mind. The dramatic movement of the coulds. The exquisite plant life. The intoxication beautiful shape of the rocks. As you climb, you get distance between you and the world you live in and it is as if you soar above all difficulty and stress of every day life. You forget about everything except the splendour of the surroundings you find yourself in. If it was true for us as kids, growing up in Cape Town, how much more must this have been for David Graaff!
I realised that everybody needs a Table Mountain to escape to. Who would have guessed the close friendships that developed.
Remember our hikes up Kasteelpoort to the Valley of the Red Gods. David always went on about how he would build a reservoir for drinking water to Cape Town at the top of Kasteelpoort (Slingsby) one day. Now that he is running for major, I wonder if he will build it. (Simons 2000: 25, 26). (3) I really wish him the best! He is a remarkable man and when he takes the business over from Combrinck, as was the plan right from the beginning, he will own a very successful enterprise!
Jacobus Combrinck and my dad introduced us to David Graaff. His uncle introduced him to being a good butcher. We introduced him to Table Mountain. I hope we will now show him that its possible to make good bacon in Cape Town.
The disappointment of Oscar and my first attempt to make bacon still haunts me. The pig we slaughtered on his farm was healthy. We cured it with the curing salt we bought in Johannesburg, the meat turned reddish/ pinkish, as it should. We smoked it. When we ate the meat two weeks later, it was off. Why? I know I have asked this question all the way from Potchefstroom, back to Cape Town on the train.
Uncertainty entered my mind. Why not just leave curing bacon to the people from Calne in the UK with their extra smoked Wiltshire Cure? I am sure this is where David and Cornelius buy the bacon they import. Was my mom not right when she told us that Oscar and me are trying to be too clever again.
I was glad when we arrived in Copenhagen. New places take my mind off nagging doubt.
Denmark is much better than I expected. The people are as friendly as the people at home. I thought they would be off-ish, but they are not.
Andreas met me at the harbour. He is a very intelligent guy. Friendly and he did not mind that I know nothing about curing bacon. When I put my bags down in my room, he immediately called me into the kitchen. He poured us two glasses of home brewed beer. He sat down and before I even had a sip of the beer, he bluntly asked me: “So, you want to do what with the pork meat?” This was the last time I doubted our quest. Since then everything has changed.
I am eternally thankful to the old Danish spice trader in Johannesburg who gave Oscar and me his name and said that if we want to learn how the English cure bacon, that I must visit his friend in Copenhagen.
Andreas is a young man and I am very much impressed with him. After we had his home made beer, Andreas showed me a textbook from the time when he did his apprenticeship at the pork abattoir in Copenhagen. Edward Smith from Great Britain wrote it in 1873 (Smith, Edwards. 1873). Three years after David joined Combrinck’s butchery. (2) He showed me the book but since it was Sunday we did not talk about bacon any more.
Instead he took me on a tour of the city. It is smaller than I expected. Everybody knows everybody. The way they organise their meat districts are impressive. Sheep, cattle, pork and chicken are all handled in separate areas. The Shamble (4) in Cape Town is a disgrace. I am very happy that David is talking as much about cleaning this up as he is about electricity and water supply to the city. I hope he becomes major! (3, 4) My ancestors have much to teach us about decent living. Life is worth living well! This includes taking care where we live. Life must reflect what nature teach us. It must be simple, clean and orderly.
For starters, they dont let chaos and filth prevail. They get architects to demarcate and design buildings for specific purposes. He took me to the Meat District of Kødbyen. Special pens have been build to hold the animals. Not like it Cape Town where the frightened animals often break out of poorly constructed camps and rampage through the streets (Simons 2000: 11).
The next day was Monday and work started. We got up early and I went with Andreas to work. This has been the routine every day. In the afternoon we have the last meal at around 9:00 p.m. After supper, Andrea’s dad read for us (Borgen, Wilhelmine and David: 50). He reads from different books the kind of thing that men should know while his wife and Andreas’s sisters do their sowing and needle work. I feel it is to “humor me” that they are reading from Foods by Edward Smith, but I dont mind. It leads to the most fascinating discussions.
I dont want to boar you with the details of what I am learning. I know you are very interested, but I dont want my letters to you to become lectures. I miss you too much and besides, I dont want to write Oscar about nice buildings and the how clean everything is. This is the kind of thing you and I have complained much about in Cape Town and I think you find it interesting.
I will write in great detail to Oscar and this kids about what I am learning. You can read the letters to the kids and when I am home, I will tell you the rest. What we are learning is both an art and a science. Curing pork, like breeding good pigs, is an art. The farmer is not a farmer. He is an artist, nurturing his pigs for months in exactly the right way to produce good, healthy, firm meat. Delivering it to the market with pride. Interestingly enough, not to the meat district. Pork and chicken are slaughtered and sold at the old and new market areas. (Gammeltorv, Nytorv, Wikipedia)
Likewise, the deboner is an artisan. He knows exactly how to remove the meat from the bones so that the meat are presented in a way close to how it will be sold. This is what David has been doing since he started with at Combrinck & Co. I now wish that I also started to work with him when I was 11.
There is the curer. He enters the curing room early and only leaves for lunch and when the days work is done. He specialises in salts and making sure the meat doesn’t spoil. This is after all the point behind curing. Changing fresh pork to cured pork that families can eat it for weeks instead of having to consume it all after slaughter as is the case with lamb, beef and chicken.
There is another artisan. The spice specialist. The world of aromas and flavours. He change the taste by giving the meat different tones. Subtle tastes that excite the senses.
These artisans work together to produce extraordinary results. Each different step in the process being handled by a tradesman. What David Graaff and Jacobus Combrinck do with the meat in Cape Town is crude salting. Anybody can do this. What I am seeing here is Denmark is an art! The results are the same as the bacon Combrinck & Co imports from Great Britain.
I am completely overwhelmed by the practical training. Besides all of this, there is the readings every night about the science behind each process. An application of the scientific method to the butchery trade. Discovering the science behind each process is like a fever that took hold of Europe.The realisation that cause and effect govern. The mechanical reasons behind everything.
Since Friedrich Wöhler made urea in a laboratory in 1828, everything has changed. Let me explain to you why this was an important discovery. The owner of the butchery explained it to me yesterday. Urea is part of human urine. It is made by our bodies. For the first time, when Friedrich Wöhler made it himself, we realised that something that came from “life” could be produced in a laboratory. Synthesized. Copied exactly. (Urea, Wikipedia) Before Wöhler laboratory urea we thought that there is some kind of a vital life force creating these things. A divine energy.
The entire Europe is struct by some kind of Gold Fever. Not physical gold. The gold of discovering of minerals, elements and processes. Taking what was previously only possible for nature to produce and making it in a laboratory with chemicals, compounds, liquids and gasses. Understanding the “how” and the “why” (Vitalism, Wikipedia). Everybody dream about a great discovery that will bear his or her name and bring untold riches.
The peculiar reddish/ pinkish colour of cured pork. The fact that pork spoil so easily during the summer. Why smoking the meat makes it possible to send the bacon on long sea voyages to South Africa, Australia and the Americas. It is this scientific aspect that I enjoy most.
I love the apprenticeship part, but in the evenings I cant wait for us to read about the science. The chemical processes. It is like figuring out a gigantic jigsaw puzzle. During the day, the slaughter house, the deboning hall, curing room, the spice room – for me, they change into laboratories where we perform experiments. I cant wait to start writing home about the things that I learn.
Today was a cultural festival in Copenhagen. I missed you tremendously. It is strange that when I was at home, I wanted nothing more than to be here. Now that I am here, despite all that I learn, I would love nothing more than to be at home. Hold you tight at night and hiking our beloved mountains on the week-ends and after work. Smelling your coffee on the anthracite stove in the mornings. Taking our dogs for a hike. Helping the kids with their homework and visiting David and his brother. I miss you so much that tears come in my eyes when I see the sun setting over the sea and I think of you, my beloved!
Tell the kids that I love them! I will write them next. I promise. Please send word to Oscar that you heard from me. I cant wait to be back soon! David Graaff will know that we can make good bacon when I get back. I am convinced of this.
(1) Eben and Chris arrived in Copenhagen on Sunday, 9 October 2011. It was the first destination on an extensive European and UK trip to investigate bacon production methods, ingredients and equipment.
(2) Jacobus Combrinck took David Graaff, a small dutch speaking boy, from his home in Franschoek at age 11, to come and live with him in Cape Town and to join him in working in his pork butchery. Combrinck visited the Graaff family in 1870. He was a distant relative. He was looking for someone to whom he could teach his trade and was impressed by David. David’s own family fell on hard times and the arrangement was practical for everybody. (Simons 2000: 8, 9)
(3) David Graaff became major of Cape Town at age 31 on 12 August 1891. He was responsible for building a new drainage system for the city, the construction of a reservoir at the summit of Table Mountain, excavating a tunnel crying pipes to the city and the introduction of electricity to the city with the construction of the first power station in 1892. (Simons 2000: 25, 26)
(4) A quote from Ice Cold in Africa, p 12 about the Shamble: “Cape Town’s slaughterhouses took their name from the original Shambles at Smithfield Market which was situated outside London’s northwest walls. In the twelfth century, Smithfield had been the fashionable scene of jousts and tournaments but, over the centuries, it deteriorated into one of public executions and witch-burnings.
By mid-nineteenth century, the district had become a filthy and stinking slum, a sink of vice inhabited by criminals. It was only in 1868, after the opening of London’s new Central Market at Deptford, that the slaughterhouses moved to more salubrious premises which consisted of 162 shops under a vaulted ceiling covering over three acres.
It was to the refrigeration section, added in the 1880’s, that frozen meat from overseas countries, such as Australia and South Africa, was first consigned. In general disorder and unpleasantness, Cape Town’s Shambles must have resembled those at Smithfield. Writing in 1894, the journalist, Richard William Murray, gave a vivid description of them as he remembered them half a century earlier. ‘Slaughtering shambles were attached to the butchers’ sales stores,’ he wrote, ‘ and the drainage from the shambles – blood and offal – coursed along the margin of the Bay, and a good deal of it was left in a state of putrefaction, and on hot days the smell was nauseating to every living thing but blue-bottle flies who regaled themselves without stint and who buzzed away in delight as musically as the drone of the doodlesack.’ (Simons 2000: 12)