MDM – Not all are created equal!

MDM – Not all are created equal!
By Eben van Tonder
16 April 2018

Frankfurters

Introduction

Last Saturday I turned 50.  I did three things that I insanely enjoy.  One was to spend time with a meat and business legend.  Over the years I have researched and got to know many such men.  Those who are still alive, I got to know personally.  Those who passed away, I studied their lives.  Jacobus Combrink who created arguably the most successful butchery in South Africa in the 1800s;  David de Villiers Graaff, his protege and the man who took Combrink & Co. and turned it into the Imperial Cold Storage and Supply Company Ltd. (ICS) which in turn merged into the food conglomerate Tiger Brands with the Combrink & Co part of the operation being assimilated into the Enterprise/ Renown merger;  JW Moore who set up the Eskort curing operation under his Farmers Cooperative Bacon Curing Company in Estcourt, Natal.  Further afield there is the three Harris’s.  Nick Harris, whom I have the privilege to know, was key in the creation of the New Zealand curing operation, Hellers.  Together with his brother, Bryan, they currently own an abattoir, deboning and processing plant in Cheviot where they grow up and where Nick owns large farmland.  From the previous century, the brothers George and Thomas Harris from Calne in Wiltshire who created C & T Harris, arguably the most successful bacon operation in British history.  From Australia, Wright Harris and his Castlemaine Bacon Company who fought in the second Anglo-Boer war in South Africa.  Interestingly enough, none of the Harris’s from New Zealand, Australia or England are related.  From the USA there is the legendary Philip Armour and his Armour Packing Plant in Chicago who was, according to my research, closely linked with the direct addition of nitrites in curing brines. His company is one of the reasons why anti-trust laws exist in the USA.  For my 50th birthday, I was on the farm of Etienne Lotter.

Etienne stands shoulder to shoulder with any one of these formidable men. It fascinates me that all these men share an unwavering focus, the ability to make quick and good decisions, resolve of steel, passion, commitment, and an obsession to invest in people.  A story is told of Phil Armour that he showed his packing plant to visitors one Sunday.  Ford got his idea about assembly lines from Phil and it was indeed something to behold.  A newspaper reporter tells the story that they were walking back from the factory and could see the church where many of the men who worked for him attended adult education after church.  He reportedly pointed to his packing plant and said, “there we make bacon” and then to the church and said, “and there we make men!” He liberally invested in people and he himself claimed that he never fired someone.  That is not to say that it was easy to work for him as is or was true of all these men.

The second thing I did which I insanely love was to hike up the Magaliesburg on Etienne’s farm, Eswitch Stud Farm.  There was no clear footpath up and it made for an adventure through the thick grass, trees, and ferns.

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The 3rd thing was talking meat curing with Etienne the entire Saturday and Sunday morning!  The experience was volcanic with its seismic aftershocks still reverberating through my psyche!  I’ve been in the meat industry no for 14 years.  Till my day with Etienne, I thought of MDM (Mechanically Deboned Meat) as something like flour or sugar, a commodity of uniform characteristics and quality.  Was I wrong!  It turns out that as is the case with all ingredient, functionality follows processing techniques.  Inspired by Etienne’s passion for MDM, I started to investigate  What a world started opening up!  I share some of my initial discoveries.

Definition

“Mechanically deboned meat (MDM), mechanically recovered meat (MRM) or mechanically separated meat (MSM) are synonyms used to mark the material, obtained by application of mechanical force (pressure and/ or shear) to animal bones (sheep, goat, pork, beef) or poultry carcasses (chicken, duck, turkey) from which the bulk of meat has been manually removed” (Hui, 2012)

There are a number of different methods to achieve this, but most of them result in cell breakage, protein denaturation, generally an increase in lipids and haeme groups and poorer mechanical properties.  (Hui, 2012)

MDM is mainly used in producing emulsion-type products such as Vienna’s, Russians, and Polony (in South Africa).  “Meat recovered from bones or carcass parts by mechanical procedures is generally considered to be of poor nutritional and microbiological quality”  (Hui, 2012)  In many parts of the world, strict legislation governs the use of these products.  When compared to the rest of the world, South Africa lags behind in this regard.  There are certain producers who choose to only use muscle meat in the production of its emulsion sausages, loaves, and hams, and the consumer is entirely left to study ingredients declarations to determine if MDM is present or not.  There are also a number of different qualities of MDM and it is by no means correct to claim that all MDM are of poor microbiological quality and share the same low nutritional characteristics.  The different production methods of MDM can broadly be separated into hard and soft MDM.

Hard MDM

Hard MDM is made from pork or beef where it will be hard to clear the bones from all the small meat bits.  When the valuable pieces of chicken and turkey (wings, breasts, and legs) are removed, hard MDM is made from the carcass that is left.  In this method, the bones or carcass is placed in some kind of a pressure chamber with small holes in it and the bones or carcasses where are subjected to high pressure which removes the skin, meat bits, connective tissue, etc. still stock to the bones.  These pass through the small holes of the barrel sieve (around 0.5 – 0.8mm in diameter).  The basic principle remains the same across many different machines namely that high pressure is used to clean the bones.  (Feiner, 2006)

Hard MDM should not contain bone bits larger than the hole size of the sieve, but in reality, on account of the enormous pressure used to remove the fragments from the bones, they often do.  The consequences of the presence of bone pieces in the MDM elevates the calcium and phosphorus content in hards MDM quite high.  These, in turn, interferes with the functionality of phosphates in emulsion sausages.  (Feiner, 2006)

The micro status of hard MDM is of great importance.  The reason for the high micro in this MDM is the large surface area of the meat.  The levels should not be higher than normal minced meat.  As always, processing conditions play the key role here and low micro levels are never guaranteed. (Feiner, 2006)

Another problematic feature of hard MDM is the presence of bone marrow, particularly in chicken MDM.  This speeds up the oxidation of fat since bone marrow contains a fair amount of metals such as iron, magnesium, and copper “which acts in a pro-oxidative manner.” (Feiner, 2006)

The fat content of hard MDM is inconsistent.  Protein, fat and bacterial levels should be part of MDM specifications.  The shelf life of pork and chicken MDM is much shorter than beef MDM in both chilled and frozen state.  The reason is the fatty acids in pork and chicken have high levels of unsaturated fatty acids in the fat fractions when compared with beef.  “Rancidity develops quickly within such material.”  (Feiner, 2006)

MDM has a  pasty texture. Due to the meat recovery method, there is a high proportion of “pulverised muscle fiber residue.”  There is also a large proportion of “partly destructured muscle fibers.”  We call such change in muscle fiber ‘‘destructuration” (Sifre and others 2009)”  (Feiner, 2006)

Soft MDM

Soft MDM, on the other hand, is produced from meat trimmings, high in connective tissues.  The process avoids the enormous pressure of the hard MDM methods by the action of a roller on the meat.  In this system, the material is put through a machine that separates the meat from connective tissues, cartridge, etc. based on the different hardness of these components.  The process is much more productive in terms of time and input required when compared to the hard MDM methods.  In many instances, a “Baader” machine is used or something similar. (Feiner, 2006)

A very typical production method is as follows.

  1.  Grind minced meat through 13 – 20mm mincer plate;
  2.  Feed through Baader machine
  3. The Baader machine has small holes in a rotating drum and the meat passes under the drum so that the drum presses ON the meat.  The soft lean meat, due to its texture, passes through the holes in the rotating drum and is collected there and fed out on the side of the machine;
  4. The harder connective tissue, bone fragments, etc. are ejected at the front of the machine, having been unable to be pass to the inside of the drum where only soft lean meat is collected. (Feiner, 2006)

Both the collected connective tissues, sinews, etc and the soft MDM from inside the drum has enormous functional applications and products are made from both.

Comparing hard MDM and soft MDM, the following functional differences emerge:

Soft MDM Hard MDM
Protein Content:  15% – 17% Protein Content:  12% to 15%
Of this, 70% to 80% is equal to protein found in muscle meat. Of this, 60% to 70% is equal to the protein found in muscle meat.
Consequently: Consequently:
– Much improved WBC (Water Binding Capacity); – Reduced ability to immobilise water
– Much improved ability to emulsify fat – Reduced ability to immobilise emulsify fat
70% to 80% WBC and emulsifying characteristics of lean muscle meat
All protein in soft MDM still functional Reason is: denaturing of proteins and cell breakage during processing.
Fine and mushy consistency
Consequently:
– Do not support firmness in final product
pH: between 6.2 and 6.4
Consequently:
– poor colour developmenty
– MDM only products exhibit a darker colour.

Legislation

Examples of legislation in place in many parts of the world related to MDM are the following:

Bones to be used in the production of Hard MDM must be stored at between 0 and 2 deg C no longer than 24 hours or be frozen for a maximum of 8 days before it is processed.  If it is frozen, this must take place immediately after production.  The chilled bones must be utilized within 24 hours.

Besides these, fat percentages, minimum requirements on nutritional value, and percentage connective tissue are set in many countries.

Functional Characteristics

Despite the fact that many different MDM producers achieve these values, there exists an enormous range of varying functional characteristics of MDM, produced by different manufacturers, on account of different process and machines employed in its production.

Lets first evaluate meat that was recovered through deboning with meat processed with an MDM machine. Froning (1970) for example compared hard deboned white and dark chicken meat with chicken backs and necks and turkey frames processed with a Paoli machine and chicken backs processed with a Beehive deboner for emulsification properties. (McMillan, 1980)

He found that MDM was most stable in a bowl cutter to temperatures of 7.2 to 12.8 deg C. Above 12.8 deg C, the tensile strengths of finished emulsions decreased and the amounts of fat and gel-water released during processing increased. By comparison, the hand boned broiler meat was stable at all chopping temperatures.  (McMillan, 1980)

He further found that MDM had less protein matrix available for emulsion than hand-deboned meat, “due to greater collagen dispersion and possible loss of protein solubility caused by deboner protein denaturation.”  (McMillan, 1980)

The tests may have been conducted in the 1970s and 1980s, but the principals are equally valid.  Froning  et al. (1971) used 15% turkey MDM in red meat frankfurters to study its stability and acceptability. The MDM was produced with a Paoli deboning machine and the results indicated a higher capacity to emulsify oil per 2.5g sample than pork trimmings, but a reduced capacity than boneless cow meat.  (McMillan, 1980)

Turkey MDM  had a reduced WHC compared to red meat sources.  Gel-water loss was greater in frankfurters made with 15 percent turkey MDM.  Their research alluded me to another very important consideration in the functionality of MDM.  In SA, all MDM is sold frozen, but in other countries, MDM is customarily produced, sold and used unfrozen.  Froning  et al. found that frankfurters which fresh MDTM had less cook
than franks containing MDTM which was stored frozen for seven days prior to use.  (McMillan, 1980)

In terms of taste, no major differences were found between control frankfurters, frankfurters containing previously frozen turkey MDM and fresh MDM in terms of taste and colour.  The superiority of pure meat over MDM was confirmed by Schnell et al (1973).  They compared poultry MDM with hand boned carcass meat.  The texture frankfurters produced with hand-deboned meat was firmer than those produced with MDM. (McMillan, 1980)

Another interesting study, confirm the differences between different MDM producers was done by Baker et al. (1974).  They compared poultry MDM from three machines to measure the effect of chopping time on taste panel evaluation and frankfurter stability. “Chopping time had little effect on results of these tests, but source of the MDPM caused differences in frankfurter yield, stability during cooking, emulsion viscosity, and taste panel scores of texture and juiciness. More dense poultry MDM and smaller, more evenly distributed fat globules contributed to the stability of frankfurters with two of the poultry MDM sources as compared to the third MDPM source (Angel et al., 1974).  (McMillan, 1980)

Some researchers have reported that they were able to “manage” negative characteristics in certain MDM typed through various techniques such as controlling and altering the pH, but if this can be duplicated in a factory environment if questionable.

Foodnavigator reported in 2018 on a project in the EU seeking to test MDM in terms of the structural integrity as a key indicator for its quality. The software reportedly use image processing algorithms to quantify degrees of degradation in meat. The aim is to test cheap imports into the EU which claims comparability with high quality EU MDM.

In the EU, certain producers such as Polskamp Meat Industrie in Holland is able to produce MDM of exact specifications. Processors can choose fat content of ±11%, ±12%, ±14% and ±16% and protein content of between ±15% to ±18% The colour of their chicken MDM is consistent being the typical colour of fresh chicken meat of pink-red. This sets them apart from many producers who is unable to certify such exact parameters, again confirming our thesis that not all MDM are created equal!

Polskamp is a good example of using technology to overcome the inherent problems in hard MDM. They pioneered low pressure technology to remove meat from bones, thereby avoiding the negative aspects associated with high pressure meat separation.

They claim that their 3 millimeter meat is “produced using special machines that can separate meat from the bone. Contrary to mechanically separated meat, 3 millimeter meat is produced using low-pressure technology that better preserves the structure of the chicken meat. 3 Millimeter meat is also characterised by its lower calcium content and lighter colour. Polskamp Meat Industrie offers its buyers several types of 3 millimeter meat, e.g. a white product and a rose-coloured product.” (polskamp.com)

Conclusion

These and more recent studies indicate the need for the processor to conduct a thorough evaluation of its MDM source.  At the end of the day, all these studies point to the fact that the different MDM’s on the market, produced by various manufacturers, using a range of different source material’s are not all created equal.

By choosing the right MDM source, it may be possible to omit binding and water absorption material such as the different soya products or starches.  The effect of freezing and freezing time on MDM is another key aspect to be evaluated and along with aspects such as fat %, connective tissue%, and water content must command our careful attention.

Finally, careful attention should be given to the different methods to extend the shelf life of MDM by reducing lipid peroxidation and of microbial growth.

Even if pure meat products is our objective, the lessons found in the production of MDM and the subtle techniques of optimizing yield, profitability while achieving exceptional product quality will benefit us tremendously if we master it!

Further Reading

The nutritional and physical characteristics of mechanically proc

Hui, Y. H. (Editor) 2012. Handbook of Meat and Meat Processing. CRC Press.

Hiking photos

It is not every day that one turns 50.  Here are the rest of the photos from my hike up the Magaliesberg on 13 April 2019.

Hiking Photos – 50th birthday

References:

Feiner, G.  2006.  Meat Products Handbook: Practical Science and Technology.  Woodhead Publishing.

Hui, Y. H. (Ed.) 2012.  Handbook of Meat and Meat Processing. Chapter: Mechanical Deboning.  CRC Press; Taylor & Francis Inc.

McMillan, K. W..  1980.  The nutritional and physical characteristics of mechanically processed beef and pork product.  Iowa State University.  Retrospective Theses and Dissertations. 7342. https://lib.dr.iastate.edu/rtd/7342

https://polskamp.com/product/3-millimeter-meat/

Photo Credit:

Continental Franks: https://www.amazingfoodmadeeasy.com/define/charcuterie/what-is/frankfurters

All other photos by Eben

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Soya: Review of some health concerns and applications in the meat industry

Introduction

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):

“Abortion, ague, alcoholism, anodyne, antidote for aconite or centipede or croton, antivinous, anus, apertif, ascites, ataxia, blindness, bone, bugbite, burn, carminative, chestcold, chill, circulation, cold, complexion, decongestant, diaphoretic, diuretic, dogbite, dysentery, dyspnea, eczema, edema, enuresis, feet, fever, halitosis, headache, hematuria, impotence, intoxication, kidney, labor, laxative, leprosy, malaria, marasmus, marrow, melancholy, metrorrhagia, nausea, nervine, ophthalmia, pile, pregnancy, preventive (abortion) puerperium, refrigerant, resolvent, rheumatism, scald, sedative, skin, smallpox, snakebite, sore, splenitis, splinter, stomach, tinea, venereal, vertigo, vision.”

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.

Trypsin Inhibitors

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

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:

Phytic Acid in food

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

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.

Lectin Effects

“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)

Further reading

A tremendous resource on research on soya is HISTORY OF SOYBEANS AND SOYFOODS IN THE MIDDLE EAST

Conclusion

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.

Reference

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.

Arnarson, A.  2018. Phytic Acid 101: Everything You Need to Know.

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.

Engelking, Larry R. (2015-01-01). Textbook of Veterinary Physiological Chemistry (Third Edition). Boston: Academic Press. pp. 39–44. ISBN 9780123919090.

Flavin DF. The effects of soybean trypsin inhibitors on the pancreas of animals and man: a review. Review article. Vet Hum Toxicol. 1982. 1982 Feb;24(1):25-8.

Groves, M..  2018.  Is Soy Good or Bad for Your Health?

Hassan, S. M..  2013.  Soybean, Nutrition, and Health.  Intech  http://dx.doi.org/10.5772/54545

Kühne, W. 1877. “Über das Trypsin (Enzym des Pankreas)”, Verhandlungen des naturhistorisch-medicinischen Vereins zu Heidelberg, new series, vol. 1, no. 3, pages 194-198

Messina, M.  2018.  Is Soybean Lectin an Issue?  The Soy Nutrition Institute
The latest findings in soy health research, https://thesoynutritioninstitute.com

Perkins, S.  2018. What Happens if You Eat Raw Soybeans?

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

https://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/soy-isoflavones

Image Credit: https://semillasdealegria.com/products/soya?variant=29970856133

Bacon and the art of living 9: Ice Cold in Africa (1)

25 December 1891

Dear Children and my beloved Ava,

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.

Cape Town, 1877
Cape Town, 1877

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.

The Groote Kerk, 1841.  Center of religious life for David Graaff.  Also the church where Jacobus Combrinck was buried from in 1891.
The Groote Kerk, 1841. Center of religious life for David Graaff. Also the church where Jacobus Combrinck was buried from in 1891.

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.

Prague Ham
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.

Christmas love and greetings from Denmark!

Your Dad.

Bacon and the art of living Home Page

 

Notes

(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)

 

Phillida Brooke Simons
Phillida Brooke Simons

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.

The cooler on the farm Stillehoogte.  Taken some time before 1977
The cooler on the farm Stillehoogte. Taken some time before 1977

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)

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Tristan and Lauren with the Curry Cup, September 2014

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References

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.

Smith, Edwards. 1873. Foods. Henry S King and Co.

http://de.lutetia.fr/equipement.php?id=7

The Cape Town Guide 1897 Cover

http://madadpakjan-sunshine.blogspot.com/2012/05/traditional-denmark-food.html

http://mfo.me.uk/histories/harris.php

http://reference.sabinet.co.za/sa_epublication_article/cabo_2014_a5

http://en.wikipedia.org/wiki/Culture_of_Denmark

http://en.wikipedia.org/wiki/Fl%C3%A6skesteg

http://en.wikipedia.org/wiki/Currie_Cup#History

 

Pictures

Figure 1:  https://www.flickr.com/photos/8270787@N07/sets/

Figure 2: https://www.flickr.com/photos/8270787@N07/sets/

Figure 3:  http://www.gavrilovic.hr/en/product/prague-ham/68/

Figure 4:  http://www.namibiana.de/namibia-information/who-is-who/autoren/infos-zur-person/phillida-brooke-simons.html

Figure 5:  Photo supplied by Andre van Tonder.  I think my dad took the pic.

Figure 6 – 11: Eben van Tonder of the Curry Cup at the Springbok museum in Cape Town

Bacon and the art of living 5. The salt of the earth

October 1891

Dear Tristan and Lauren,

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.

Lithograph of Livingstone and his party going down the Zambesi rapids Credit: Wellcome Library, London
Lithograph of Livingstone and his party going down the Zambesi rapids
Credit: Wellcome Library, London

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.

Archaeologists in Bulgaria have discovered the oldest prehistoric town ever found in Europe, dating back to the fifth millennium BC.  The area is home to huge rock-salt deposits, some of the largest in southeast Europe and the only ones to be exploited as early as the sixth millennium BC.
Archaeologists in Bulgaria have discovered the oldest prehistoric town ever found in Europe, dating back to the fifth millennium BC. The area is home to huge rock-salt deposits, some of the largest in southeast Europe and the only ones to be exploited as early as the sixth millennium BC.

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.

The salt mines of Trapani and Pacco, flamingoes with an Arab windmill (WWF Italy Archivi, photo credit: Gerardo Cortellaro)
The salt mines of Trapani and Pacco, flamingoes with an Arab windmill (WWF Italy Archivi, photo credit: Gerardo Cortellaro)

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)

In 1802  Humphry Davy was appointed Professor of Chemistry at the Royal Institution and soon after Director of the Laboratory.
In 1802 Humphry Davy was appointed Professor of Chemistry at the Royal Institution and soon after Director of the Laboratory.

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.

Warm greetings, with love!

Your Dad.

Bacon and the art of living Home Page

Notes

(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)

 

References

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.

http://en.wikipedia.org/wiki/Neanderthal

http://en.wikipedia.org/wiki/Cato_the_Elder

http://www.rsc.org/chemistryworld/podcast/CIIEcompounds/transcripts/salt.asp

http://en.wikipedia.org/wiki/Neanderthal

 

Pictures

Figure 1:  http://www.livingstoneonline.ucl.ac.uk/biog/dl/bio.html

Figure 2:  http://www.france24.com/en/20121031-bulgaria-oldest-prehistoric-town-discovered-europe-provadia-solnitsata-ancient-salt-site-archaeology/

Figure 3:  http://www.culturaitalia.it/opencms/museid/article.jsp?language=en&article=/en/contenuti/percorsi/percorso197/capitolo_0004.html&tematica=&selected=

Figure 4:  http://www.engineerswalk.co.uk/hd_walk.html