Chapter 16.04: Finally – nitrate, nitrite, nitric oxide as valuable molecules and the triumph of nature over foolish strawman positions

Introduction to Bacon & the Art of Living

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


Finally

October 1960

Bacon & the Art of Living

When I say that it was my study of bacon that taught me the essence of the art of living, the reality is that in the first place it taught me to accept who I am in life. As important as my hopes and aspirations are, I am not my ideals and dreams. I am not the most current fad of the ever-changing mental world we live in. I am in the first place the physical being who lives in a physical world, connected to the bountiful earth that brought me forth. Despite the fact that I am in my mental world the centre of the universe, I am not! Life is not the life I live in my brain minus the physical world. It is all one thing and my mental world is only my perception of the real world I live in. In reality, I am nature!

I am Nature

My brain is a very complex physical event and my consciousness, as I define it with my human mind is here today and gone tomorrow. My thoughts, my thinking, is predicated upon my memory and indoctrination (learned information and past experiences). What is fundamental and what bacon taught me is that my connection with the earth itself is not primarily through my brain. The billions upon billions of atoms that form the molecules and the amino acids and bacteria and proteins and synapsis and organs that make up my body by its most basic essence is my connection to nature. My essential nature is my oneness with the universe and the universe is nature. Bacon curing is not a study of any food in that it mimics natural physiological processes essential for life. Nitrogen plays an essential role in it irrespective of the current thinking on the benefits or dangers of its consumption.

My initial resistance against eating bacon was initially not restricted to the question of nitrites. I had to work out for myself if I am comfortable eating other animals. Like the question about nitrogen, the fact that I eat other animals is a fact of my existence as a human being whether it is fashionable to do so or not. We only perceive this as a moral dilemma because we have departed our natural environment and so we think that in the plant kingdom the same predatory behaviour does not exist. If we see all living organisms as essentially the same, we will understand that to arbitrarily choose to eat one group and not another is non-sensical.

The Zambian Revelation

During my second trip to Zambia, I’ve spent days in the forests in the north of the country close to the Kongolese border with a remarkable man, Richard Horton. He looks at the trees and plants and knows every one of them by name. Which one is related to which. The basic characteristic of each individual fruit and flower. The locals call him “Capenta Mabullo,” meaning “The Man who Counts Leaves.” It was through the eyes of Richard and walking the forests of Zambia that I discovered that in the plant kingdom we find the same struggle for life and death as we find in the animal kingdom and the same predatory behaviour of many plant species. Walking with him through the woods becomes the same experience as seeing a lion hunt in the Kruger National Park or crocodiles hunting wildebeest in the great migrations on the Serengeti plains of Kenia.

It is here that I learned that to think that plants are different from mammals or other animals is a view based on our removal from the forests of our youth. Humanity lost its perspective on our essential nature. In the first place, the plants and trees of the forest are just as much alive with struggles and pleasures as the world of animals and insects. Both are living. Both have intellect – yes, not as we would define it in our human-centric worldviews of intellect. Choosing one over the other – to assign intellect and emotions as we understand it arbitrarily to the one group and not the other is supreme foolishness. In the Zambian forests, I have seen plants behaving like animals. They strive and compete; they weep and reach out in joy.

Evaluating the effect of the human intellect on the natural world, I am at a loss to see the benefit of our version of intellect and I fear that if we don’t come to our senses, our time as a species is short and nature will remove the element poised to destroy its world from the universe. Then, again, saying that we evolved intellect for a particular reason beyond simply survival is an assumption I can not make. That our intellect is not superior to that of plants and animals and insects and microbes is clear when we evaluate the effect our intelligence have on the natural world. The most we can say, it seems to me, is that our intellect is different in degree and an effective means to dominate. It manifests in a different way but I fail to see its superiority in quality or the result of its “differentness.” So, at least, it seems to me. Superseding everything is nature and it is nature that dictates that we eat in order to live and as a food source, nature feeds itself from all it brings forth, including humans as part of the world of animals.

I Consume and Will be Consumed – the Same Eternal Sycle for All

Before I could engage the issue of nitrites in meat I had to come to grips with the fact that no matter what I assign to animals and plants – the fact is that I consume both natural “forms” just as I will be consumed by them one day is the natural cycle of everything. The micro-world and insects will feast on my body one day long with plants. The possibility still exists that my initial end may be brought about by an animal if I continue to venture into forests. This does not make the animals or trees or microorganisms or insects immoral. It is life. Nature does not care about my view of morality. Nor yours!

When I transfer my view of emotion, righteousness or morality to non-human living beings (plants, animals, insects, microorganisms), it is supreme foolishness. These are mental constructs that operate solely in the mind-space of humans and within the ambit of human culture. It is natural in the sense that it is from nature (being our natural brains), but what we think and dream up is not a result of nature and is not inherently “natural.” It does not represent nature automatically.

One of the best recent developments in our mental world is the fact that we start to value the animals and plants who share the world with us. Abusing and mistreating them becomes cruel and unnatural. Inflicting suffering on nature for the sake of our own comfort is the most unnatural thing we can do and recognising this is a sign of a maturing understanding. Mistreating our food source becomes physical harm we do to them and mental harm we do to ourselves! However, to assign more to them than what nature intends is unnatural. I consume living beings that I share this world with. It took me years to understand this and it came to me through the understanding of the curing of bacon. I struggled with the fact that I am making my living through the death of other animals. The first lesson I had to learn was that it is unnatural to try and be more natural than nature itself.

The Basic Problem – Our Evolving Culture

As human populations increased and our culture developed we changed our natural habitat. We urbanised and had to design our own food sources. Humans incorporated the preparation of food into our culture and changed it for the sake of distributing it to the cities and towns we started living in. Food, in its most natural form, is best suited for our bodies as this is how we initially evolved. In so doing we did not always understand the implications of what we were doing. One of the most important lessons we had to learn, not just related to additives but also food sources themselves, like red meat, was the issue of “how much.” Including many additives at the wrong inclusion ratio becomes unhealthy and even poisonous. Red meat, for example, must be consumed in moderation. Too much will have serious health consequences. Not just ingredients and types of foods must be carefully considered, but also methods of preparations. Science is invaluable in a continual investigation into these matters so that we can improve our health.

A curious position emerged in particular related to the use of nitrites in foods. Despite the fact that nitrogen is an inherent constituent of animal and plant proteins and despite the essential role it plays in human physiology, there exist among parts of our population a perception that nitrite is one of the key villains in modern food. This group of our population further see the presence of nitrite restricted to cured meat and bacon in particular.

The advice from the WHO that intake of cured meat must be limited as is the case with red meat, alcohol, fatty food, refined carbohydrates and sugars, in particular, is something that every food scientist will agree with. In general, humans per capita consume more food than ever with the accompanying diseases of obesity and the impact on our general health. For some reason, the perception still exists that bacon or possibly cured meat should be singled out. Some go as far as to equate the consumption of these products with cigarette smoking.

Understanding why this is the case and dealing with this issue brought me to the greatest realisation about life namely the value of using nature itself as our guiding principle in the design of our food and our lives. Right at the outset then I can reveal that the greatest lesson I learned from bacon over many years is that if we want to be safe, we must strive to use the ratios and proportions of various compounds naturally found in the human body and in plants. This extends much further than only food. Over the years I have taken these lessons and applied them to every area of my life including things like exercise, water intake and stress. I learned to limit my mental activity during the day by quieting my mind whenever the flurry of mental activities goes out of hand. The blueprint of nature became the essence of my goals.

How I discovered that nitrate and nitrite have key physiological functions in the body and that it is by no means a villain to be avoided at all times in foods came to me through the contemplation of and search for the original location on earth where nitrate curing of meat most probably developed into an art form. I will deal with nitrosamines and the fact that most nitrosamines are cancer-causing in animals, but before I do so, let me start by giving you the chronology of my own discovery that nitrate, nitrite and nitric oxide are three absolutely essential molecules for our existence on earth.

How I discovered the Value of Nitrate, Nitrite and Nitric Oxide to Human Health

It was my search for the original location where meat curing was turned into an art form that made me look at the use of salt in meat preservation which predates the use of nitrogen salts. The general consideration of salt led me to mummification which took me natural deposits of nitrate in the Atacama Desert in South America and the Turfan Depression in the West of China. In searching for supporting evidence of the general development of technology related to nitrates, I happened upon a very clear and effective remedy from this region which used nitrate, a cure so revolutionary that it was only finally understood by science in the 1980s which unlocked the reality of the absolutely key role of nitrate, nitrite and nitric oxide in human physiology. So, in re-capping the progression of my search for the location of the birthplace of nitrate curing of meat, I am actually telling the story of my discovery of the value of nitrite, nitrate and nitric oxide to human existence and health.

The Story at a Glance

My quest started with a consideration of salt which is older than humanity itself. My interest is in its use as a meat preservative. When did this start and how and what are its functional benefits? Most of this has been dealt with in Chapter 12.10: Meat Curing – A Review, but I left an important link out in that discussion namely a realisation that studying mummies and mummification technology through the ages may be a very productive way of searching for the oldest known meat preservation technology and the use of salts at a time before writing was invented. I applied this thinking and did a survey of the oldest mummies on earth which yielded the most startling two results.

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A semi-natural mummy in Chile’s Atacama Desert

The oldest mummies on earth, dating from around 7000 BCE are the Chinchorro mummies from the one place on earth that is at the same time the dryest and is replete with the highest concentration of natural sodium nitrate, the Atacama Desert from Chile and Peru!  What makes this startling is that sodium nitrate has been the curing agent of choice for meat until it was replaced after World War 1 by sodium nitrite. I always thought that the use of sodium nitrate in meat curing became popular due to the cured colour it imparts to meat and that its preserving ability was a secondary application. I also thought that its widespread use was a very recent development that reached a height in Europe at the end of the 1800s.  Following my logic about mummification technology, I was certainly not expecting a date of 7000 BCE for a probable use of sodium nitrate in meat curing.

I turned my attention to Asia from where, in an iconic review article from Binkerd and Kolari (1975), they claim that the use of nitrates in the curing of meat was first used as meat preservative “in the saline deserts of Hither Asia and in coastal areas.” They say that “desert salts contained nitrates and borax as impurities” and the discovery was accidental when they actually thought they use ordinary sea or bay salt (sodium chloride).  I wanted to examine the veracity of their claims.

What I discovered was the most startling possibility, that curing technology was developed into an art form between a particular location in China and another one in Austria. Even more than that, following the mummy trail, I managed to identify one particular geographic location which is a prime candidate for the exact location where the technology of curing was discovered, developed and spread across the rest of Asia and into Europe.  This is an amazing possibility and the fact presented by themselves are startling!

The oldest mummies in China are found in the Taklimakan Desert, in the Tarim Basin. Right here, in the region where the mummies are found, in the Turpan-Hami Basin, massive nitrate ore fields, close in proximity to the Tarim Basin exists.  Nitrate deposits, so massive that it is estimated to be at least 2.5 billion tonnes and comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile.

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A Tarim mummy

At the graves near Loulan, one of the bodies were subjected to radiocarbon dating which indicated that she died about 1200 BCE.  In the oldest cemetery so far discovered, the Small River Cemetery, mummies were discovered which carbon tests, done at Beijing University, show to be 3980 years old. This takes the known date for meat preservation, by our logic of linking it with mummification, to almost 4000 years ago in China.

The two areas in the Atacama Desert and the Taklimakan Desert in China share a striking similarity in weather. They are both some of the aridest regions on earth.  A second factor that plaid a role in the natural mummification is rapid freezing due to extreme cold conditions in the winter and then, of course, the very high sodium chloride content of the soil.

I honed in on this region in China for its geographical importance as being on the important Silk Road connecting Asia with the Middle East and Europe. I asked if there is any evidence of the development of sophisticated thinking pertaining to the use of sodium nitrate salt from this particular region.  My reasoning is that if meat curing as an art developed here, that would have been a springboard for the development of related applications.

The results of my enquiry have been nothing less than startling and leave me with little doubt that I have identified one of the exact locations on earth from where the art of curing meat developed and was spread into Europe and back into Asia.  Not that they were the only ones who would have discovered this. I am convinced the ancients in the Atacama Desert would have easily made the same link with meat preservation but it was here, in China’s Western front, on the Silk Road, where a level of sophistication in thought related to the application of sodium nitrate developed that is unrivalled, as far as I am aware off, by any other location on earth.

The first factor in favour of the Tarim Bason for the birthplace of curing technology that was spread into Europe is then the enormous natural deposits of sodium nitrate. Secondly, you have the mummies which are something that observant ancients would have noticed almost immediately. It won’t take you 4000 years to realise that something extraordinary is happening with the corpses. The third fact relates to the level of sophistication in the application of sodium nitrate.

The clue of such sophistication of thought comes to us in the discovery of an ancient medical prescription dating from some time between CE 456 and 536, during the life of the famous Daoist alchemist and physician Toa Hongjing in a cave close to the city of Dunhuang, right in our area of interest.

The text describes the treatment of a condition identified as a case of severe angina, i.e. restricted blood flow due to the narrowing of the cardiac arteries.  The treatment was to place saltpetre (potassium nitrate) under the tongue.

The basic curing pathway that alleviates the condition by the ancient prescription is a reduction of the nitrate through bacteria under the tongue to nitrite and in the tissue, transported there by the blood, the nitrite is converted to nitric oxide.  The role of nitric oxide as a vasodilator was, amazingly, only discovered in 1987 simultaneously by a group of researchers at the Wellcome Research Laboratories in Beckenham led by Professor Salvador Moncada and by a group in the USA led by Professor Louis Ignarro. So momentous was this discovery that the 1998 Nobel Prize in Physiology and Medicine was awarded for the work.  Once nitric oxide was identified as playing a role in physiological processes, it was found to be involved in many processes from inflammation to crying. So, here we have a text, detailing a medical prescription in the 5th and 6th decade of the Christan Era, from China, that has only been fully understood by modern science in 1987!  This by itself is an astounding fact!

It gets even more startling. It turns out that this exact reaction sequence of nitrate ion that is reduced to nitrite through bacterial reduction and changed to nitric oxide, along with the influence of acidity and various reductants on the speed of the process is something that is well known in meat science. Humphrey Davy, in 1812 (cited by Hermann, 1865) was the first one to note the action of nitric oxide upon haemoglobin. On 7 May 1868, Dr Arthur Gamgee from the University of Edinburgh, brother of the famous veterinarian, Professor John Gamgee (who contributed to the attempt to find ways to preserve whole carcasses during a voyage between Australia and Britain), published a groundbreaking article entitled, “On the action of nitrites on the blood.” He observed the colour change brought about by nitrite.  He wrote, “The addition of … nitrites to blood … causes the red colour to return…” Over the next 30 years, it would be discovered that it is indeed nitrites responsible for curing and not the nitrates added as saltpetre.  It was Polenski who first speculated that saltpetre is reduced to nitrite in the curing of meat in 1891 and 1901 Haldane showed that nitrite is further reduced to nitric oxide (NO).  (Fathers of Modern Meat Curing)

Meat curing has been known to follow this exact pathway since 1901. The tantalising possibility, now presents itself that the preserving nature of the salt was recognised from things like the natural mummification in this exact region in China. The salt was applied to meat in which it had an amazing preserving impact as well as, what must have been, a mysterious reddening effect. To the ancients, it probably looked as if the meat was coming to life again. The Chinese alchemists in all likelihood gravitated to this as a possible key component of the elusive elixir of immortality. Finding such an elixir was the goal of Chinese alchemy. They probably applied its preserving power to all kinds of ailments and in a process of trial and error, a treatment for angina must have been especially effective.

Such experimentation takes many centuries and if this was a known cure and part of a medical prescription by CE 400 or CE 500, it means that curing of meat must have been very advanced in terms of it being practised in this region by this time.  From here, in terms of its key position on the Silk Road, the curing technology would have spread across Asia and into Europe.

Mummification – Key to Preservation Technology

The use of salt in embalming is an obvious application of the preserving power of salt to meat. It also seems reasonable to speculate that salt for preserving meat for domestic consumption came first and the application of the technology to mummification was probably a later development. One obvious reason for this is that meat preservation for consumption would have been a daily requirement. An immediate need, for a large group of people. So, many people, over a long time would have been engaged in experiments with various salts and ingredients to determine by a simple process of observation which salts ingredients and combination of factors preserved meat best. Burying the dead and mummification, on the other hand, was a far more infrequent event, with very few people working on solving the problem resulting in a much slower development trajectory. It is far more probable that techniques for meat preservation in general use would have been applied to the preservation of human bodies after death and in the art of mummification.

If one assumes this logic, it becomes an important tool to establish a date by which food preservation with salt was done by a society. The use of salt in embalming leaves us with clear records with precise dates and exactly what was used in meat preservation. If one assumes that meat preservation for general consumption would have predated the use for embalming, we can fix precise dates by what time a society used which salts to preserve meat.

I found support for this reasoning from Valerie Wohl. She writes, “While we do not know exactly how embalming began, it is likely that methods common at the time for preserving meat, fowl or fish probably suggested a clue for early techniques. One might bleed a fish, for example, then preserve it by salting, smoking, sun drying or otherwise heating it to prevent decomposition and store it for a later time. By the time of the very earliest documentation of the process of embalming (in about 500 BCE), it had become a sophisticated technique that had been evolved over hundreds of years.” (Wohl, V.)

The Chinchorro Mummies of the Atacame Desert

This line of reasoning yielded the most surprising results imaginable. Not in my wildest imagination did I think that the oldest mummies and their preservation would be linked, not with sodium chloride, but with what has been the curing salt of choice up until at least 1905, namely sodium nitrate. I have always thought, based on research on the subject, that sodium nitrate was used for preserving meat from the 1600s and reached its height in Europe in the 1700s and 1800s before it was replaced with sodium nitrite from around 1905 and in particular after World War 1. I thought it was used in isolated places around the world where various cultures re-discovered the reddening effect it had on meat, independently and over a long time and that this slowly filtered through to Europe where it gained popularity over time until it became a general practice.  Never did I expect sodium nitrite to have been used for meat preservation since between 5000 and 7000 years BCE and not due to its reddening effect, but for its preserving properties. Let’s look at this case.

It turns out that the oldest mummies on earth are the Chinchorro mummies from the Atacama Desert in Chile and Peru, dating from as early as 7000 BCE. (Guillén, S. E.; 2005) Gypsum, a sulphate mineral, was later used with clay (3000 – 1300 BCE), but mud and clay played an important role from as early as 5000 BCE.

The fascinating link is between this region and sodium nitrate. Nowhere on earth are such large natural deposits of this salt found. The soil here is rich in sodium nitrate salt which is known as Chilean Saltpeter to distinguish it from potassium nitrate or regular saltpetre. A war was fought over these deposits and securing it was a major consideration of Germany going into World War 1. The second important factor is that the Atacama desert is the dryest place on earth. The soil is so rich in saltpetre and it is so dry that mummification occurred naturally, leaving mummies that exist since 7020 BCE.

Two of the most important ingredients in meat preservation namely heat/ drying and saltpetre were present in the mummifications rituals of the Chicharro people of the Atacama Desert since as early as at least 5000 BCE. I do not think that it is too far a stretch to assume that these people knew about the meat preserving ability by drying in combination with their special salts (sodium nitrate).  Even though it is complete conjecture, I am comfortable to say that preserving meat through sodium nitrate salt and drying was probably known since at least 5000 BCE in Chile and parts of Peru. It is then not a stretch to say that this was likely to be known in the other two main regions in the world where saltpetre is found naturally namely in China and India. This is, of course, a fascinating possibility since this particular salt became the curing agent of choice in the 1700s which gave rise to the food category of cured meats and directly resulted in our use of sodium nitrite in meat curing today. This date of between 5000 and 7000 BCE is completely in line with a date proposed by Binkerd and Kolari.

Despite this tantalising possibility, the actual sodium nitrate concentrations at the burial sites in the Atacama Desert has never been studied. The degree of mummification varies tremendously (Aufderheide, A. C.; 2003: 141) which will indicate that various factors have been present in varying degrees.

The Tarim Mummies of China

A date of between 5000 and 7000 BCE is completely in line with a date proposed by Binkerd and Kolari. According to their iconic 1975 review article about the history and use of nitrates and nitrites in the curing of meat, “it appears that meat preservation was first practised in the saline deserts of Hither Asia and in coastal areas. Desert salts contained nitrates and borax as impurities. However, the reddening effect of nitrates was not mentioned until late Roman times.” (Binkerd, E. F. and Kolari O. E.; 1975: 655)  A probable time for this discovery is however not given.

I first thought that what they were talking about was salt preservation generally, but the more I look at events in the Atacama desert, the more I wondered if the particular preserving power of sodium and potassium nitrate was not known from the earliest times and the discovery, focusing on its preserving power and not on its reddening effect on cured meat.

A further elaboration of what Binkerd and Kolari may have been talking about comes to us from a 1977 newspaper article. According to it, the suspicion is that prehistoric nomadic hunters in Western Asia began carrying salt, containing nitrate with them to preserve the hunting catch. (The Indianapolis Star;  1977) The focus was indeed on nitrate and its preserving ability and not just on salt generally. I learned that nitrate deposits occur and precipitate as an efflorescent crust in amongst other the Egyptian and Namibian deserts, the Abu Dhabi sabkhas, and deserts of the Mojave, Death Valley and of course, the Atacama Desert and the Gobi Desert.  (Warren, J. K.;  2016: 1278)

It is, however, the largest desert in China, the Taklimakan Desert of Western China that offers the biggest surprise when I find the oldest examples of natural mummification in China, right in this desert region, replete with natural nitrate deposits. The conditions are almost identical to those of the Atacama desert.

Like the Atacama desert, the Taklimakan Desert is at the same time one of the aridest regions on earth and massive nitrate ore fields exist in the Turpan-Hami Basin, close in proximity to the Tarim Basin, in the Xinjiang province, where the oldest mummies in China was found. The nitrate deposits are so substantial, that an estimated 2.5 billion tons exist, comparable in scale to the Atacama Desert super-scale nitrate deposit in Chile. (Qin, Y., et al; 2012) The mummification happened, as was the case with the mummies of the Atacama Desert between 5000 BCE and 7020 BCE,  spontaneously.

The initial discovery was made in 1939 by the Swedish archaeologist Bergman Folke. A set of tombs were discovered in the Chinese province of Xinjiang, known as the Xiaohe Tombs. For 60 years the tombs were forgotten until in 2000 a researcher, head of the Xinjiang Cultural Relics and Archaeology Institute, found the tombs again. It wasn’t until 2005 that the excavations were complete. (www.ancient-origins.net)

The size of the area is unprecedented. So far there have been 330 tombs found in multiple different layers. The tombs include adults and children as well as 15 intact mummies. About half of the tombs were looted by grave robbers. It is the first time anywhere on Earth that so many mummies have been found.  (www.ancient-origins.net)

“Several bodies have been excavated from graves near Loulan, a site that once bordered a still shrinking lake fed by the Kongi River. Among these is the body of a young female with remarkably well-preserved facial features, whose radiocarbon date indicates that she died she died about 1200 BCE.” Subsequently, more than 500 tombs have been studied.  Dr Wang Bing Hua, director of the Ürümxi’s Archeological Research Institute, attributes the spontaneous mummification to three factors:  arid climate, salty soil and shallow, winter burial. Average salt content of the desert soil near Turpan is about 10g/ L but in the very surface layer, it can be five times greater. At Hami the soil contains layers of gypsum and at Cherchen actual salt blocks are obvious within the soil, especially near the surface.  Most burials are only about a meter below the surface.  (Aufderheide, A. C.; 2003: 268, 269) In the oldest cemetery so far discovered, the Small River Cemetery, mummies were discovered which carbon tests, done at Beijing University, show to be 3,980 years old. This takes the known date for meat preservation, by our logic of linking it with mummification, to almost 4000 years ago in China. The nitrate in Xinjiang Lop Nur exists in two forms: natural sodium nitrate mine and natural potassium nitrate. (en.cnki.com.cn)

The Turpan Basin is a “fault-bounded trough located around and south of the city-oasis of Turpan, in the Xinjiang Autonomous Region in far western China, about 150 kilometres (93 mi) south-east of the regional capital Ürümqi.” “The surrounding mountain ranges are the central Tian Shan in the west, the Bogda Shan in the north-west, the Haerlike Shan in the north-west, and the Jueluotage Shan in the south. Beyond the surrounding mountain ranges lie the Junggar Basin in the north and the Tarim Basin in the south.” (www.revolvy.com)

“Some geographers also use the term Turpan-Hami Basin, which is understood as including the Turpan Depression along with the Hami Depression (located to the east of the Turpan Depression, and to the southwest of the city of Hami) and the Liaodong Uplift separating the two depressions.” (www.revolvy.com)

One of these mummies may hold a further clue to their preservation. She became famous for her “excellent preservation and beauty and it is known as the Beauty of Xiaohe. It is a white person with round eyes, perfect eyelashes, and long hair and has features that are more similar to a European person than a Chinese person.” (www.ancient-origins.net)

According to Elizabeth Wayland Barber, her “beautiful eyelashes finally proves an earlier hypothesis, deduced from little detail at Zaghunluq, that those bodies that mummified had to have died in early winter, flash freezing and gradually freeze-drying over the next few months whereas other bodies decomposed.” She was dismayed at people’s acceptance or refutation of his arguments without dealing with the arguments posed.  In the Beauty of Xiaohe she, at last, had hard evidence. “Eyeballs, being wet, cause rapid decomposition of both themselves and the eyelash-holding eyelids when warm; but by the same token, being wet, cause rapid decomposition of both themselves and the eyelash holding eyelids when warm, but by the same token, being wet, both they and the thin overlaying eyelids will freeze rapidly when being very cold, thus securing the eyelashes in place.  Unlike putrefaction, the gentle process of freeze-drying will not dislodge eyelids.” (Mair, V. H., Hickman, J.;  2014:  35)

It has been known from the earliest times that meat curing could be done only in the winter in the absence of refrigeration. If not, the putrefying and decomposing forces would overtake the preserving action of saltpetre and decomposition would be unstoppable. It is the combination of cold and dry conditions along with the use of sodium nitrate to preserve and ordinary salt (sodium chloride) to aid in drying out the meat, that forms a link between the earliest forms of mummification and modern meat-curing techniques. It seems unreasonable to think that the result of these forces, in combination, would have gone unnoticed. I further suspect that the power of these forces would have been practised in relation to fish, fowls, game and domesticated animals for centuries before they found inclusion in the earliest mummification practices.

The Silk Road

The location of the Turpan-Hami and Tarim Basins are very important. Crossing the Taklimakan Desert is possible at the foot of the mountains surrounding the Turpan-Hami Basin or along its streams such as the Tarim, “that spring from the mountains to enter the desert from its periphery but soon vanish into the sand. As ancient caravans from Eastern China approached Dunhuang at the edge of this segment of what eventually came to be part of the Silk Road to the Mediterranean, the near absence of water in the desert’s centre forced them to make a choice. The southern option skirts the desert along its southern edge at the foot of the steep Kunlun slopes descending from Tibet’s high plateau. Alternatively, the northern route passes through Hami and those communities living along the Kongi and Tarim rivers that lead to Loulan and Lop Nor.  It is along these routes that mummies from the Tarim Basin have been found.”  (Aufderheide, A. C.; 2003: 268, 269)

The caravans on the Silk Road approached Dunhuang, crossing vast sodium and potassium nitrate deposits. If the knowledge of its power was developed in this region and exported to Europe, I am sure that there should be remnants of this ancient knowledge in this city.

“One of the people who has extensively studied the Caucasian mummies of China, Professor Victor Mair of Pennsylvania University, said that he believes that early Europeans long ago spread out in different directions. He believes that some of these peoples travelled west to become the Celts in Britain and Ireland, others went north to become the Germanic tribes, and still, others journeyed east to find their way to Xinjiang. These ancient European settlers are believed to represent some of the earliest human inhabitants of the Tarim Basin, and Mair has stated that from around 1800BCE the earliest mummies to be found here are exclusively Caucasoid or Europoid rather than Chinese in origin.”

The origins of the mummies have been studied extensively using DNA technology.  Writing in the journals BMC Genetics and BMC Biology, Chunxiang Li, an ancient DNA specialist at Jilin University, and colleagues report on their analysis of human remains from the Xiaohe tomb complex also on the eastern edge of the basin.

They conclude that by reconstructing a possible route by which the Tarim Basin was populated, Li and colleagues conclude that “people bearing the south/west Asian components could have first married into pastoralist populations and reached North Xinjiang through the Kazakh steppe following the movement of pastoralist populations, then spread from North Xinjiang southward into the Tarim Basin across the Tianshan Mountains, and intermarried with the earlier inhabitants of the region, giving rise to the later, admixed Xiaohe community.” (Killgrove, K, 2015)

“The populations from the Russian steppe seem to have contributed more genetically to this population than did the populations from the oases of Bactria. “The groups reaching the Tarim Basin through the oasis route,” the researchers note, “may have interacted culturally with earlier populations from the steppe, with limited gene flow, resulting in a small genetic signal of the oasis agriculturalists in the Xiaohe community.””  (Killgrove, K, 2015)

A New York Times article on the origin of these people presents the picture clearly. It reads that “all the men who were analyzed had a Y chromosome that is now mostly found in Eastern Europe, Central Asia and Siberia, but rarely in China. The mitochondrial DNA, which passes down the female line, consisted of a lineage from Siberia and two that are common in Europe. Since both the Y chromosome and the mitochondrial DNA lineages are ancient, Dr Zhou and his team conclude the European and Siberian populations probably intermarried before entering the Tarim Basin some 4,000 years ago.” (Wade, N; 210)

It is however not the origin of these people who interest me as much as their destination and the destination of the traders who passed through this region. The Silk Road that ran through this region reached into the heart of the Middle East and Europe to the West and into the rest of China and India to the East. There is an interesting possibility that comes up and that is if it is possible that the Europeans brought the technology with them. Of course, this is a possibility but then there is the matter of the unique level of sophisticated insight into saltpetre from this exact region. Such a level of understanding of saltpetre did not exist in Europe for many centuries. It seems more likely that the transfer of technology went from Tarim, East, into Europe, rather than the other way round. The next section explains what I mean by this.

Dunhaung

The question is if there is any evidence that anything was done with the nitrate deposits and the clear evidence of its preserving power in the mummification. If this was the region where curing of meat was progressed into the art that we know it as today, is there any evidence of this? Any ancient document or reference, not just from China generally, but linked to this region. These were the actual questions I asked myself as I was searching. This is not a device I employ after the fact for the sake of creating drama.

I knew my general geographic area of focus was the one I show below featuring the Tarim Basin.

IMG_0132[1].PNG

I started plotting the important points.

IMG_0134[1].JPG

Looking at the images above, the saltpetre deposits are the largest at Yuli, marked as NO3-. Loulan is the city where many of the mummies have been found. Dunhuang is a major city before the trip past or across the desert was undertaken on the Silk Road past the Tarim Basin.

I did a search for any reference to saltpetre from the city of Dunhuang which would have been a key trading city in the area and important in terms of its location on the Silk Road. Not in my wildest imagination did I expect to uncover what I found!

It is here, in the Mogao Caves, where a remarkable find was made by the Daoist monk, Wang Yuanlu on 25 June 1900. The mix of religious and secular documents date from the 5th to the early 11th centuries.  One text is of particular interest to us, the Dunhuang Medical Text. “The text has been carefully studied by China’s leading experts in traditional Chinese medical literature and ancient manuscripts. The text is attributed to the famous Daoist alchemist and physician Toa Hongjing (CE 456 – 536).” (Cullen, C, Lo, V.;  2005) There is evidence that it relies on earlier traditions from the Han and Sui Dynasties. “The original was decorated with images of the Three Daoist Lords and the Twelve Constellations, indicating links with Doist traditions.  In Translation, it reads as follows:

Dunhuang Medical Manuscripts 1
Dunhuang Medical Manuscripts 2

(Cullen, C, Lo, V.;  2005)

Until the 1500s this is the only script of its kind that we know off. “The symptoms described by the patient, as described in the Dunhuang manuscript, suggests an advanced case of cardiovascular distress. The colour of the fingernails (cyanosis) indicates ischaemia (lack of oxygen in the tissue) due to restricted blood flow.  Cold hands and feet are additional symptoms of this condition. Also, acute pain suggests that the patient may be suffering from severe angina, i.e. restricted blood flow due to the narrowing of the cardiac arteries.”  (Cullen, C, Lo, V.;  2005)

“Modern treatment for angina is glyceryl trinitrate or isosorbide dinitrate. So, at first glance, there seems to be a similarity in treatment. All three remedies contain the all important nitrate. Salpeter is, however, an inorganic compound that exists as a positively charges potassium cation (K+) and a negatively charged nitrate anion (NO3-). Concerning organic nitrate, such as glyceryl trinitrate, there is a covalent bond or a molecular bond between the nitrate moieties (NO3) where they share electron pairs which form the bond with the rest of the molecule (CH2). Where glyceryl trinitrate relaxes the muscle lining of the artery to relax, enlarging the vessel and so allowing more blood flow, saltpetre by itself will have no effect on the treatment of angina. (Cullen, C, Lo, V.;  2005)

This is however not the full story. The remarkable feature of the Dunhuang text is that the combination of the use of saltpetre, not on its own, but when applied according to the dictates of the text, becomes a remedy for exactly the condition described. “The thing about glyceryl trinitrate is that this too, in itself, is not a vasodilator (relaxing of the arterial lining). It is transformed, probably in the arterial wall, into a chemical species which is the vasodilator. Under very special circumstances, exactly as detailed in the Dunhuang text, the nitrate ion from saltpetre also converts to exactly the same species which is the vasodilator. Despite the fact that glyceryl trinitrate has been in use for over a hundred years, the identity of this species has only been discovered in 1987.” (Cullen, C, Lo, V.;  2005)

“Lining almost all blood vessels on the inside is a layer of cells known as the endothelium. A very important function of the endothelium was first reported in 1890 by Furchgott and Zawadzki. The presence of acetylcholine (a small biologically active molecule) in the bloodstream affects vasodilation and it was generally assumed that acetylcholine acted directly upon vascular muscle. However, this was found not to be the case. Furchgott and Zawadzki showed convincingly that acetylcholine acted, not upon the muscle of the artery, but upon the endothelium and the endothelium produces a “second messenger” which then acts upon the muscles to effect relaxation. This second messenger was christened “the endothelium-derived relaxing factor” (EDRF).” (Cullen, C, Lo, V.;  2005)

During the 1980s, an intense effort was effected to identify the EDRF. It was initially assumed that it would turn out to be a complex molecule like a hormone. This speculation enhanced the surprise when the chemical nature of the molecule was finally determined. It turned out to be a small diatomic molecule called Nitric Oxide (NO).  “That it had a physiological role, in a process as important as vasodilation, came as a complete surprise.” (Cullen, C, Lo, V.;  2005)

“The discovery was made simultaneously by a group at the Wellcome Research Laboratories in Beckenham led by Professor Salvador Moncada and by a group in the USA led by Professor Louis Ignarro. The 1998 Nobel Prize in Physiology and Medicine was awarded for this discovery. Once nitric oxide had been detected in one physiological process it was found to have roles in many others, from inflammation to crying. That it should have remained undetected during a hundred years of intense scrutiny of human physiology is astonishing. Glyceryl trinitrate is a vasodilator because it is transformed by an enzymatic process (possibly by the enzyme xanthine oxidoreductase) into nitric oxide.” (Cullen, C, Lo, V.;  2005)

Let us now return to the Dunhuang text. Is there any way that the inorganic nitrate could be transformed into nitric oxide?  “In a healthy body it is very unlikely, that nitrate which is present in the blood plasma, is converted to nitric oxide. However, there is a species, nitrite (NO2-), very closely related to nitrate (NO3-), for which conversion into nitric oxide is quite possible. Do humans ever convert nitrate into nitrite? Such a conversion can occur in the mouth and it is this aspect of the Dunhuang prescription that is so interesting. The saliva contains many bacteria, some of which contain the enzyme nitrate reductase, which converts nitrate into nitrite.” (Cullen, C, Lo, V.;  2005)

“Experiments on rats have shown that reduction of nitrate to nitrite is confined to a specialised area on the posterior surface of the tongue. If the same applies to humans, the Dunhuang procedure, which specifies that the saltpetre should be placed under the tongue will maximise the conversion of nitrate into nitrite. The retention of saliva as described would also enhance nitrite production.  Unlike nitrate, nitrite is physiologically active.  t is an antiseptic and a vasodilator, although not a powerful one. It has been suggested that animals, particularly cats, lick wounds because of the antiseptic effect of nitrite in the saliva. Although not a powerful vasodilator, there is now direct evidence that rat hearts, when subjected to global ischaemia, generate nitric oxide and that a significant proportion comes from nitrite present in the tissue. Ischaemic tissue is very acidic and the acid affects the conversion of nitrite to NO via the following equilibria:”

reaction of NO2 to NO.png

(Cullen, C, Lo, V.;  2005)

“Calculations, assuming only a modest level of nitrite in ischaemic tissue, show that enough nitric oxide from the above equilibria to activate guanylate cyclase, the enzyme responsible for the initiation of the cascade of reactions which lead, eventually, to vasodilation. So, if nitrite enters the plasma, as a result of administration of sublingual saltpetre, it could generate nitric oxide in ischaemic tissue. Because of the abundance of blood vessels under the tongue sublingual administration of a drug is a good way of getting a drug into the bloodstream and bypassing the stomach. Also, the tongue, in traditional Chinese medical theory, is linked to the function of the heart.” (Cullen, C, Lo, V.;  2005)

“The interaction of saliva and nitrate to generate nitrite before conversion to nitric oxide in ischaemic tissue gives considerable credence to the Dunhuang procedure as a treatment for cardiovascular distress.” (Cullen, C, Lo, V.;  2005)

Here, in the Tarim Basin, we have three things present. One of the world’s largest natural saltpetre deposits. Natural mummification dating back to just over 3000 years ago. From these, the preserving power of these soils would have been evident to all since the mummies existed then already. The longevity of the corpses would have been evident to the ancients. We have a record of very sophisticated use of saltpetre from very early in the Christian Era from this exact region. In fact, some of the most sophisticated use of the salt on record and the exact mechanics is even today mirrored in the act of curing itself which has been until the early 1900’s when the direct addition of sodium nitrite replaced saltpetre as curing agent of choice.

Until that happened, curing was done by the addition of saltpetre which was reduced, through bacterial action to nitrite which diffused into the muscle for the purpose of preservation. The similarity in the curing action and the mechanism relied on, in the utilisation of saltpetre in the Dunhuang Medical Manuscripts is startling, to say the least. Of course, I am not suggesting that the full or even a partial understanding of the mechanism was known to the ancients, but the application did suggest a much more detailed understanding of saltpetre and its efficacy on meat muscles which could easily have originated from the experience with curing! Seeing the preserving power of the salt and the reddening effect of the meat could have led them to an application of the salt for heart conditions even though the reduction steps may not have been fully understood.

This is without a doubt the best possible location from anywhere in the world where the curing of meat could have originated in an art form which would have been preserved and transmitted to successive generations through societies which later became known as guilds. The picture is not of wondering hunters who stumbled upon the salt and early farmers using it for preserving meat – or at least, it could have started like this. But if it happened in this exact region, it soon found itself in the most advanced society on earth of its time with the most sophisticated thinking about chemistry. The Chinese alchemists in all likelihood gravitated to this as a possible key component of the elusive elixir of immortality. Finding such an elixir was the goal of Chinese alchemy.  They probably applied its preserving power to all kinds of ailments and in a process of trial and error, a treatment for angina must have been especially effective.

Here, at a key location on the silk road, the knowledge of curing and the power of saltpetre could easily have been spread through India and China to the East and right into the heart of Europe to the West.

This is a remarkable find!

The possibility that the art of meat curing was developed in Turpan and spread around the world is most promising. Despite this not being my main point under discussion here, it is important to note that Europe may also have influenced the community around Turpan. Influences certainly did not only go one way.

A fascinating link has been discovered between the mummies in Turfan and the Austrian city of Salzburg. Victor Mair, a professor of Chinese in the Department of Asian and Middle Eastern Studies at the University of Pennsylvania was committed to trace the ancestry of the mummies. “In Xinjiang, a Chinese colleague had slipped him a . . . gift: a swatch of blue, brown, and white cloth taken from a twelfth-century-bc mummy. The fabric looked like a piece of Celtic plaid. Mair passed it over to Irene Good, a textile expert at the University of Pennsylvania Museum. Good examined it under an electron microscope. The style of weave, known as a “two over two” diagonal twill, bore little resemblance to anything woven by Asian weavers of the day. (Indeed, it would be almost another two millennia before women in central China turned out twill cloth on their looms.) But the weave exactly matched cloth found with the bodies of thirteenth-century-BCE salt miners in Austria. Like the DNA samples, the mysterious plaid pointed straight towards a European homeland.” (Tocharians: The Whites of Ancient China)

This startled me. The thread that ties it all together is salt and meat curing. Is it possible that a mummy found in the region which I believe may have been pivotal in spreading nitrate curing of meat across the world may have some direct or indirect link with the Austrian salt mines? It unlocks the possibility that work done on the use of nitrate salts was influenced by work done in Austria.

In my mind, the fact that nitrate and nitrite did not only have negative effects on human health was discovered by contemplating the possible location where the art of meat curing with nitrate originated. Today students learn this from textbooks but I somehow like the journey of discovery that I took much more.

Villifying Nitrite: A Drama for Fools

After telling the story of my own discovery that nitrate, nitrite and nitric oxide is far from evil molecules, tantamount to poison being added to meat, I return to the primary subject at hand. Is bacon safe to consume? Is the use of nitrate and nitrite in meat curing irresponsible? What about the claims that it causes cancer?

There is no greater illustration of willing enslavement to an incomplete understanding of nature than the drama related to the use of nitrites in meat processing. Humans happened upon a natural phenomenon that special salts containing nitrate change the colour of meat and has the power to preserve it. Since the start of the use of nitrites in meat curing, it was viewed with great suspicion due to its inherent toxicity. Much of Bacon & the Art of Living is dedicated to chronicling the unfolding of the great saga of nitrate and nitrite and the discovery of its essential nature and role in meat curing. There is no need to repeat any of what has been written by me earlier in this work except to point the reader specifically to the following chapters. The first two deal with the initial objection against the use of nitrite in food as a poison. This dilemma was resolved through science and legislation.

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

Chapter 12.04: The Direct Addition of Nitrites to Curing Brines – The Spoils of War

The use of a substance that is, in high concentrations, poisonous is, after all, nothing new to humans. Alcohol is one of the best examples. Aspirin is another example where, in high dosages, it is dangerous despite its positive benefits at low dosages. Ultra-high dosages of ascorbic acid are equally likely to have adverse effects, cause diarrhoea and nausea. Vinegar is another good example which in moderation is beneficial but consuming too much over a long period of time will have serious detrimental health implications. There are hundreds of other examples we can give. I heard of a well-known speaker in the Uk who addressed a group of meat processing professionals and started his talk by accusing them of poisoning the public through the use of nitrites. Statements like this show a serious lack of understanding not just nitrites but almost every other food ingredient customarily used in food production.

A far more serious issue was discovered in the late 60s and early 70s related to the formation of n-nitrosamines. Nitrosamines are cancer-causing. We have already dealt with the matter in great detail in Chapter 12.06: Regulations of Nitrate and Nitrite post-1920’s: the problem of residual nitrite where we outlined the scientific, industry and government response to the issue.

A friend of mine who is a 3rd generation German Master Butcher tells the story of his grandfather who used to buy nitrites from the pharmacy in the early days and made the most beautiful rich pink bacon. There were no limits on ingoing nitrites in those days and the role of ascorbate was poorly understood and sadly he passed away from colon cancer. This anecdotal account has been subsequently confirmed by countless studies and indeed it is true that at the wrong concentrations, without the use of ascorbate or erythorbate, the high nitrite levels used in curing meat is tantamount to poisoning the consumers. The chapter which I just mentioned deals with the international response to the subject and the combined legislative framework for the use of nitrites in food. The minuscule amounts of nitrites used in bacon curing today along with the use of ascorbate render bacon a safe product to consume in moderation. Of course, the caveat should always be remembered that this should be done in moderation as is the case with any other processed food, red meat, beer, cheese, milk, alcohol, dried milk powder, etc.

What has been said before should settle the issue, but over the years a number of other factors occurred to me which must be added to the discussion to un-vilify nitrite.

Nitrosamines – A Much Broader Issue than Bacon

At the outset, I want to apologise to the reader because the issue becomes wonderfully complex almost right from the start. You don’t have to remember all the terms used and all the intricate connections. I chose an article as the basis for our discussion which broadly introduces you to enough of the important factors so that you will be able to see that the issue with bacon is the same issue with beer, cheese, fish, red meat and many other foods. You will see that it even extends to packaging and food preparation. So, don’t be intimidated by the technical discussion which follows.

I firmly believe that despite the fact that a mammoth amount of work has been done on bacon and cured meat since the 1970s; despite the fact that I am absolutely convinced that based on the preponderance of the latest scientific data on nitrite in meat showing that it is a completely safe food to consume, the responsible producer will continue to work on doing even better by limiting residual nitrite in its products after it has been prepared by the consumer even further so that the consumer will be satisfied that concerns, valid and non-valid are being taken seriously by the producer.

Having said all this, let’s now delve into the issue.

a. What is N-nitrosamines?

Nitroso compounds refer to non-organic compounds containing the NO group. This immediately will get the readers attention because we know that it is NO (nitric oxide) which is responsible for the pinkish/ reddish colour in cured meat. The NO group in nitroso compounds for example directly binds to the metal via the N atom, giving a metal–NO moiety. A nonmetal example is the common reagent nitrosyl chloride (Cl−N=O).

If you combine nitroso with amines, you get nitrosamines or as they are more formally called, N-Nitrosamines. So, the next question is: what is an amine. Amines are compounds and functional groups with a nitrogen atom and a lone pair. Amines are formally derivatives of ammonia (NH3). Nitrosamines then is a group of organic compounds with the chemical structure R2N−N=O, where R is usually an alkyl group. An alkyl group, very simply stated, refers to hydrogen and carbon atoms arranged in a tree structure in which all the carbon-carbon bonds are single. The nitroso group (NO+) binds to a deprotonated amine. The reader with no background in organic chemistry will be able to spot the nitrogen in the three structures below.

The important point for our discussion is that most nitrosamines are carcinogenic in animals.

b. How are they formed in Food?

Look at the three structures of amines represented above. Nitrosamines are formed by the reaction of secondary or tertiary amines with a nitrosating agent, such as nitrite from which nitric oxide and an R-NO group formes. When water is eliminated from a compound, we say that an anhydrate is formed. This describes the formation of NO (nitric oxide) from NO2 (nitrite). So, in food, NO is formed from nitrite in an acidic, aqueous solution. The nitrosating agent is usually then a nitrous anhydride, formed from nitrite in an acidic, aqueous solution. This is, for example, the condition found in our stomachs or in the mouth and if we ingest nitrites, we run the risk of nitrosamine formation after we swallowed the food.

Another culprit for nitrosamine formation is the frying of bacon. Nitrite in combination with fats (lipids) seems to be the nitrosating agent during the frying of bacon. “The formation is related to the relatively high internal temperature of bacon during frying and the relatively low moisture content of bacon as compared to other cured meat products. When bacon is cooked by other methods, particularly in a microwave oven, considerably lower amounts of nitrosamines are found.” (Scanlan, 2003) 

c. Bacon is not the only Product of Concern

From the point just made about the frying temperature of bacon in an environment where there are lipids and low internal water content which leads to nitrosamine formation, it should be a clue to the fact that processing techniques are also responsible for its formation. This was indeed shown and since the late 70s and 80s, it has been known that processing techniques, as well as packaging procedures, are responsible for introducing these carcinogens into food. Hotchkiss (1984) writes that these processing and packaging “procedures include drying foods in direct flame heated air, migration from food contact surfaces and direct addition as contaminants. In addition, other reports of N-nitrosamines in foods have less well defined routes of contamination.”

Hotchkiss (1984) cautions that despite the presence of nitrosamines in food, it is actually “occupational exposures” which may be responsible for “the highest individual exposures (Fine and Rounbeh1er, 1981).” Still, “the largest numbers of people have been exposed to exogenously formed N-nitroso compounds through the diet.”

There are three abbreviations I want to introduce at this point namely NA (N-nitrosamines), NVNA (non-volatile NA) and VNA (volatile nitrosamines where “volatile” refers to those compounds amenable to gas chromatography without derivatization). VNA includes for example “N-nitrosodimethylamine (NDMA), N-nitrosopyrrolidine (NPYR), N-nitrosopiperidine (NPIP) and N-nitrosodiethylamine (NDEA), which occurs generally at low levels <5 µg kg−1 but levels up to 20 µg kg−1 has been reported (Hill et al, 1988, Massey et al, 1991). NDEA has been evaluated as the most potent carcinogen among the known meat related VNAs (Peto et al., 1984).” (Herrmann, 2015) NVNA include “the N-nitrosamino acids, e.g. N-nitrosohydroxyproline (NHPRO), N-nitrosoproline (NPRO), N-nitrososarcosine (NSAR), N-nitroso-thiazolidine-4-carboxylic acid (NTCA), N-nitroso-2-methyl-thiazolidine-4-carboxylic acid (NMTCA), generally occur at significantly higher levels than the VNAs, i.e. up to several thousand microgram per kilo (Herrmann et al, 2014a, Massey et al, 1991, Tricker, Kubacki, 1992).” (Herrmann, 2015)

Hotchkiss (1984) continues that “several groups have demonstrated that a number of foods can contain trace quantities of VNA. To date nearly all types of foods have been analyzed for VNA and, hence, some important generalizations can be made. Most importantly is that the use of nitrite as a curing agent is not solely responsible
for the VNA content of foods. Several foods to which nitrite has not been intentionally added have now been shown to contain trace levels of VNAs. Equally significant is that the N-nitrosamine content of foods has decreased as a result of research in this area. He classified the routes and mechanisms by which foods can become contaminated. “The routes of contamination can be divided into 5 groups: Additives; drying processes; migration from contact surfaces; addition of performed NA; and those for which the route is not clearly defined.

Additives

This is the class where cured meats fall in. We are already familiar with the story as we discussed it in Chapter 12.06: Regulations of Nitrate and Nitrite post-1920’s: the problem of residual nitrite. Let’s recap what we said by quoting Hotchkiss (1984). “The suspicion that the use of nitrite in foods might result in the formation of NA stems from an incident in which animals fed nitrite preserved fish meal developed liver necrosis. The causal agent was determined to be NDMA and it was shown that the compound resulted from the nitrosation of the amines in the fish by nitrous
acid formed from nitrite (Ender et a1., 1964). Nitrite is an economically and technically important food additive in the curing process in order to fix color, develop flavor and inhibit toxigenesis by C1. botulinum.” (Hotchkiss, 1984)

“Since the late 1960s, a substantial research effort has resulted in a body of information concerning the occurrence and formation of VNA in cured meats. This has resulted in the knowledge that the addition of nitrite to meat is not, in most cases, sufficient to routinely cause the formation of VNA. In order for cured meats to consistently contain more than 1 μg /kg VNA6 the product must be subjected to temperatures greater than 100 C in a low moisture environment. The only cured product which meets these criteria is bacon. Other cured products only sporadically contain VNA in excess of 0.1 μg /kg (Gray and Randall, 1979). In a recent large survey, only 6 of 152 cooked sausage products had a VNA content greater than 5 μg /kg and only 4 of 91 dry sausages had similar VNA contents. In the same study, however, 11 of 12 dry-cured fried bacons contained VNA, some as high as 280 μg/kg. The fact that fried cured bacon consistently contains detectable VNA has been observed by numerous workers (Scanlan, 1975).” (Hotchkiss, 1984)

“Efforts have been directed at determining the chemical mechanism and precursors to the major VNA, NPYR, found in fried bacon. While several potential precursors to NPYR have been identified, including collagen, ornithine, hydroxyproline, citrulline, putrasine and arginine, it is generally accepted that the major precursor is proline (Gray, 1976). While the free-radical mechanism proposed by Bharucha et a1. (1979) is often cited as the mechanism which best fits observations, the steps of the reaction have not been clearly elucidated. At least two possible routes exist; proline could be nitro sated to form NPRO which is subsequently decarboxylated during frying to NPYR, or proline is first decarboxy1ated to the amine pyrrolidine which is then subsequently nitrosated. Both decarboxylation and nitrosation, regardless of order, must occur during frying because uncooked bacon does not contain NPYR or sufficient preformed NPRO (Hansen et aI, 1977). Nakamura et al. (1976) have suggested that the mechanism is temperature dependent; at temperatures above o 175 C decarboxylation precedes nitrosation and at lower temperatures nitrosation precedes decarboxylation.” (Hotchkiss, 1984)

“In addition to NDMA and NPYR, Kimoto et a1. (1982) and Gray et a1. (1982) each have reported that fried bacon also contains NTHZ. This VNA was likely missed by many researchers due to its long retention time or its on-column decomposition. We have also confirmed this VNA in fried bacon and have further identified the compound in the fried-out fat from bacon. NDMA and NPYR are, under most frying conditions, found in higher concentration in the fried-out fat than in the edible portion. However, in our experiments NTHZ consistently occurs in higher concentrations in the edible portion regardless of the frying conditions. The mutagenicity of NTHZ has been demonstrated (Sekizawa and Shib, 1980) but the compound has not been tested in whole animals for carcinogenicity. The formation of precursors of NTHZ have also not been studied in fried bacon but thiazolidine has been identified as a browning product in a glucose-Cysteamine model system (Mihara and Shibamoto, 1980).” (Hotchkiss, 1984)

“Nitrate may be added to certain cheeses to retard the growth of microorganisms which might cause defects. Concern has been expressed that the nitrate might be reduced to nitrite by reductase containing microflora and that this nitrite could nitrosate amines endogenous to the product. The Danish government has published the results of a large survey of cheeses in which no correlation between the use of nitrate and concentration of VNA in the product could be made (Anon. 1980). Only very small amounts (less than 0.7 μg/kg) were found in any cheese. Sen et al. (1978), however, found 21 of 31 cheeses imported into Canada contained VNA up to 20 μg/kg. These apparent discrepancies with regard to the use of nitrate in cheese have not been resolved.” (Hotchkiss, 1984)

Drying

“In addition to the use of nitrite and nitrate as additives, a second general mechanism by which foods may become contaminated with NA is through the drying of foods in air which has been directly heated in an open flame. The highest levels of VNA resulting from this common method of food processing have been in the kilning of malted barley. Concentrations of NDMA -in the dried malt of over 100 μg/kg have been reported (Hotchkiss et al. 1980; Preussmann et al. 1981). A number of workers have shown that the NDMA in the malt survives the brewing process and can be detected in the resulting beer in concentrations expected from the dilution of the malt (Havery et al. 1981). This widespread contamination was shown to be the result of the formation of oxides of nitrogen in the air as it is heated in the flame. Oxides of nitrogen have been demonstrated to be effective nitrosating agents over a wide pH range (Challis and Kyrtopoulos, 1978).” (Hotchkiss, 1984)

“Scanlan and coworkers have extensively investigated the formation of NDMA in malt. They have demonstrated that the plant alkaloids hordenine and gramine are effective precursors of NDMA in model systems and that it is likely that NVNA may also be present in direct fired kiln dried malt (Mangino et a1. 1981).” (Hotchkiss, 1984)

“The first reports of NDMA in beer indicated average concentrations in the range of 2 to 6 μg/kg (Spiegelhalder et a1. 1981). While these levels seem, at first, low it is possible to consume 1 to 2 kg of beer at a single serving. This represents more NDMA exposure than from any other food source. Spiegelhalder et a1. (1980) have estimated that 64% of a West German’s dietary NDMA came from beer. There is recent evidence, however, that the VNA content of beer has decreased sharply (Mangino et a1. 1981). This decrease is due to the widespread use of sulfur dioxide or indirect heating of the drying gases in the malting industry. The application of sulfur dioxide during the early part of the kilning process may be either by direct injection of gaseous sulfur dioxide or by burning elemental sulfur in the drying air. The inhibition by sulfur dioxide is most likely due to the formation of bisulfite which may react with the nitro sating agent in a redox reaction.” (Hotchkiss, 1984)

“Other foods which are dried in direct flame heated air have also been shown to contain trace amounts of VNA, albeit at lower levels than malt. Most notable is the finding that nonfat dried milk may contain traces of NDMA. Several reports have shown NDMA levels of 0.1 to approximately 5 μg/kg (Libbey et al. 1980; Lakritz and Pensabene, 1981). In a recent nationwide survey of 57 nonfat dried milks conducted by the US Food and Drug Administration, an average NDMA level of 0.6 μg/kg was found with 48 samples being positive (Havery et al. 1981). Apparent NPYR and NPIP were also detected in sub μg/kg concentrations. Because nonfat dry milk is diluted lOx before consumption some have onsidered it not to be a significant problem while others have been concerned because of the widespread use of this product by the young.” (Hotchkiss, 1984)

“Other dried foods have been shown to sporadically contain detectable VNA. Sen and Seaman (1981) analyzed nonfat dry milk, dried soups, and instant coffee and found VNA in all dried milks, 3 of 20 dried soups and 5 of 10 instant coffees, most at levels of less than 1 μg/kg. Perhaps more importantly, 3 of 8 dried infant formulas contained detectable VNA. Fazio and Havery (1981) have observed VNA in soy isolates and concentrates and dried cheeses.” (Hotchkiss, 1984)

Migration

“In addition to formation from direct additives or from the direct flame drying process, recent evidence indicates VNA may enter foods through migration from food contact surfaces. In 1981 Spiegelhalder and Preussmann (1981) reported that a number of rubber products including nursing nipples contained substantial levels of VNA and that these compounds could migrate to water and milk. Later Havery and Fazio (1982) investigated one brand of nipple available in the US. They confirmed the presence of VNA in this product and demonstrated that when inverted nipples were sterilized in milk or formul, migration occurred.” (Hotchkiss, 1984)

“We have investigated the VNA content of 8 types of rubber nipples available in the US from several domestic and foreign manufacturers (Babish et al. 1982). One or more VNA were detected in all nipples tested and when each nipple was boiled for 3 minutes in 150 ml water or incubated 3 hours at 37oC, 6 to 44% migration occurred. Total VNA contents ranged from 42 to 617 μg/nipple (nipple weight is approximately 5 gm) and most nipples contained more than one VNA.” (Hotchkiss, 1984)

“Direct food contact paper and paperboard packaging may also be a source of VNA and nitrosatable amines in foods. Analyses of 34 food packages by GC-TEA revealed 9 to be contaminated with NMOR. Perhaps more importantly, all packaging materials examined had levels of the parent amine morpholine ranging from 98 to 842 μg/kg (Hotchkiss and Vecchio, 1982). Morpholine is easily nitrosated and there is evidence that it may be nitrosated in the stomach to produce the carcinogenic N-nitroso derivative (Mirvish, 1975). Two experiments indicated that both the NMOR and morpholine may migrate to dry foods. First, when a food package was found to contain NMOR and morpholine, the food closest in the package often also contained NMOR and morpho line (Hoffmann et ale 1982). Secondly, when paperboards which contained NMOR and morpho line were incubated at elevated temperatures in closed vessels with dry foods migration could be demonstrated. Further research is needed to determine the extent of the contamination and degree of migration under normal conditions.” (Hotchkiss, 1984)

Direct Addition

“When agricultural chemicals or food additives contain preformed VNA, it is conceivable that a portion of the VNA contaminate could be added to food. For example, meat curing premixes which contained salt, sugar, spices and nitrite and were designed to facilitate the mixing of curing brines were shown to contain relatively high levels of VNA including NPIP (Sen et ale 1974). This VNA resulted from the nitrosation of piperidine ring containing compounds in the spices. The NPIP was then added along with the cure solution to the meat and could be detected in the product.” (Hotchkiss, 1984)

“Certain agricultural chemicals were shown at one time, to contain mg/kg quantities of VNA (Ross et al. 1977). Although current levels have been greatly reduced (Oliver, 1981) it has been demonstrated under laboratory conditions that when these mixtures are applied to food crops, absorption of the VNA either directly through the plant or indirectly through the soil is possible (Khan, 1981). For example, Dean-Raymond and Alexander (1976) have shown that radio labeled NDMA incorporated into soil could be taken up by edible plants. A recent survey of dried waste sludge also indicates most sludges contain small amounts of VNA (Mumma et al. 1982). If sludge is incorporated into soil uptake may be possible. It should be noted that no confirmed report of VNA in foods as a result of the use of pesticides or sludge in actual field use has appeared. On the contrary, Ross et al. (1978) analyzed soil, run off water and edible plant tissue after the application of a commercial herbicide containing NDPA and failed to detect the VNA in any sample. As pointed out by Oliver, (1981) it is difficult to draw conclusions about the VNA contamination of foods based on laboratory experiments.” (Hotchkiss, 1984)

“Another potential source of direct addition of NA to food maybe through the use of processing water which has been deionized by anion exchangers. Kimoto et al. (1980) have shown that NDMA and NDEA at levels of less than 1 μg/kg can be detected in water which has been passed through an anion exchange column. This is a common treatment process in food plants.” (Hotchkiss, 1984)

Miscellaneous

“In addition to the above four mechanisms by which food may become contaminated with small amounts of VNA, other less well defined or uncorroborated contamination processes have been reported. For example, one group of Japanese workers have reported that broiling fish under a gas flame may result in substantial increases in the VNA content of the food (Matsui et al. 1980). The average NDMA content of 20 fish and seafood products increased 3 fold after broiling under a gas flame and one dried squid sample increased in NDMA from 84 to 313 μg /kg. When broiled under an electric element or covered with aluminium foil smaller increases in NDMA content were seen. Presumably, VNA is being formed by a mechanism similar to that occurring in dried foods such as malt and nonfat dried milk. Further work is needed to evaluate this source of dietary NA. Smoking fish has also been reported to result in the nitrosation of the amines associated with fish (Kann et aL 1980).” “Another potential source of direct addition of NA to food maybe through the use of processing water which has been deionized by anion exchangers. Kimoto et al. (1980) have shown that NDMA and NDEA at levels of less than: 1 μg/kg can be detected in water which has been passed through an anion exchange column. This is a common treatment process in food plants.” (Hotchkiss, 1984)

The Occurance and Benefit of Nitrate in Our Diet

So far we have looked at the occurrence of nitrite and the dangers associated with nitrosamines. I deal with it directly because it is the main charge levelled against the curing industry that poison is used to cure the meat. The second, and equally important consideration is the benefit of nitrate in our diets. The reader should be well familiar by now that nitrite is converted through bacteria from nitrate. Such bacteria occurs for example in our mouths and when we ingest nitrate much of these are converted into nitrite. So, in a way, when we talk about nitrate, we also talk about the occurrence of nitrate in our food.

Nitrate has been shown to be beneficial to our health and occurs naturally in, for example in beetroot. It has been credited with a speedy recovery after a strenuous workout, thus enhancing our exercise performance as well as lowering our blood pressure. Nitrates are the active ingredient in medicine for the treatment of angina where blood flow is restricted causing chest pains.

It is reported by the BBC that “only around 5% of nitrates in the average European diet come from cured meat, while more than 80% are from vegetables. Vegetables acquire nitrates and nitrites from the soil they grow in – nitrates are part of natural mineral deposits, while nitrites are formed by soil microorganisms that break down animal matter.” BBC

Uddin (2021) published an extremely helpful list of fruits and vegetables containing nitrate and the mg/kg which they typically contain all of which should be the end of the debate about nitrite in bacon.

Mean concentrations of nitrate in the tested fruits and vegetables.
From: Study of nitrate levels in fruits and vegetables to assess the potential health risks in Bangladesh

The Guiding Power of Nature

My life has been guided by invisible forces from my birth. I believe this force to be nature itself. The biggest thing I have learned is that what I believe is completely irrelevant. Nature does not care for my belief! It is not swayed by it! What IS will prevail, irrespective of my personal belief or even our universal belief as humans. Every step of life was crafted by nature itself in a way that I don’t understand.

I came to realise that my own intellect and our ability as humans to perceive life through the matrix of our minds is not the most important aspect of our lives. I examined the most important mental constructs very carefully and realised that they are all bankrupt. The first quest was to understand God.  I wrote a book about it, The Anatomy of a Sceptic.  This magical time in my life introduced me to the amazing world of the human mind and the gods we create! We first create them and then we worship them just as we do with all our mental constructs. We do the same with concepts such as democracy and the free market system and yes, even with the idea of science! We first created these mental concepts and then we worshipped them.

It was my quest to understand bacon that brought me back to nature and to understand that I exist as a living being, in the first place not in my mind, but in my body as every bodily need and desire and instinct and drive is connected in the first place to nature. I eat to live and I eat that which I share this earth with. My quest to understand the secrets of bacon taught me that life is infinitely interconnected and I am nature itself!

Bacon evolved over millennia in a way that my quest only briefly introduced. Living life excellently means that I re-connect with nature. This is the art of living! It is why so many people who looked deeply into this tell us that the problem is not that we think too little. The problem is often that we think too much and the art of reconnecting with life is to become quiet and to stop thinking! It is that simple.


(c) Eben van Tonder


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(c) eben van tonder

Bacon & the art of living” in book form
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References

Herrmann, S. S., Duedahl-Olesen, L., Christensen, T., Olesen, P.T., Granby, K.. 2015. Dietary exposure to volatile and non-volatile N-nitrosamines from processed meat products in Denmark. Food and Chemical Toxicology, Volume 80,
2015, Pages 137-143, ISSN 0278-6915, https://doi.org/10.1016/j.fct.2015.03.008. (https://www.sciencedirect.com/science/article/pii/S0278691515000873)

Hotchkiss, J. H.. 1984. Sources of N-Nitrosamines Contamination in Foods. Adv Exp Med Biol. 1984;177:287-98. doi: 10.1007/978-1-4684-4790-3_14.

Scanlan, R. A.. 2003. Nitrosamines. Encyclopedia of Food Sciences and Nutrition (Second Edition).

Uddin, R., Thakur, M.U., Uddin, M.Z. et al. Study of nitrate levels in fruits and vegetables to assess the potential health risks in BangladeshSci Rep 11, 4704 (2021). https://doi.org/10.1038/s41598-021-84032-z