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.

---

narrative – the history of bacon

---

The Salt of Meat

December 1892

Dear Children,

Salt is the most important ingredient used in bacon. Michael from Calne taught me a lot about it and while Minette and I are on our voyage back to England, it affords me a great opportunity to review it.

He knows a lot about salt. He has visited many of the great salt mines, from Poland to America, and from Austria to the Arabian Peninsula. Your grandfather has been to salt works in German West Africa to our North-East. Of course, you heard him tell the many stories of his travels with Livingston. On those adventures, they often tracked through salt pans. In my own travels across southern Africa, I have encountered salt mines, salt traders, and salt pans.

Historical Note: This is the only letter I wrote from England to my children about salt. The previous two I wrote many years later, namely Chapter 13.11: The Salt of the Earth and Chapter 13.12: The Salt of the Land and the Sea. I wrote a third, Chapter 13.13.2 Salt: The Austrian Priority, which is historically one of the most important ones as it ties many strands together that unfolded to me over almost two decades of research.

Salt had two key functions in antiquity. One was the taste! Exquisite salts were created by artisan salt makers whose trade has been handed down over thousands of years. Each region produces salts as unique to that region as the different wines from Spain or Italy. This is, to me, the supreme function of salt since it is what we love! The other great value is as a preservative of meat.

The Salt in Meat

Before we look at the salt that we put in meat, it is important to know that meat contains salt naturally. It is biologically essential! Historically, meat, blood, and milk were primary sources of salt which is richer in content compared to many plant-based foods. This natural abundance meant that nomadic tribes relying on their livestock or hunters consuming meat regularly had less need for external salt sources. My experience in southern Africa taught me that with an adequate intake of meat, no added salt is required in a diet. In contrast, those engaged in agriculture or with limited access to meat found themselves in need of additional salt to supplement their diet.

The critical role of sodium in human health cannot be overstated. It plays a vital role in setting membrane potentials in cells that are crucial for nerve and muscle function, and it is involved in various metabolic processes. Adequate sodium intake is essential for growth, with deficiencies leading to significant health issues. Studies, such as the one by Morris and colleagues, highlight the severe consequences of sodium deficiency. For instance, rats on low-sodium diets showed reduced growth in bone and muscle mass, requiring a specific daily sodium intake to maintain normal development. Furthermore, sodium restriction has been linked to adverse outcomes such as increased stillbirth rates, reduced brain size, and compromised brain development in animal studies. Sodium’s importance extends to glucose metabolism and the maintenance of blood viscosity, emphasizing its role in fluid balance within the body. Proper kidney function, essential for cardiovascular health, also depends on sodium to regulate body fluid homeostasis. Thus, Morris et al. (2008) aptly conclude that both survival and normal mammalian development hinge on sufficient intake and retention of sodium, underscoring its indispensable role in our diet and health.

A condition called hyponatremia emerges when the concentration of sodium in the blood falls below the necessary level, a scenario often resulting from excessive water intake without adequate sodium consumption or from an outright deficiency in sodium intake. The word, “hyponatremia” is derived from a combination of Greek and Latin roots. “Hypo-” is a Greek prefix meaning “under” or “below.” “Natrium” is the Latin word for sodium, which is also represented by the symbol “Na” in the periodic table and “-emia” is a suffix of Greek origin meaning “blood.” “Hyponatremia” literally translates to “under (low) sodium in the blood,” describing a condition where there is an abnormally low concentration of sodium in the bloodstream.

This imbalance disrupts the osmotic balance across cell membranes, leading to a range of symptoms. Individuals experiencing hyponatremia may suffer from nausea, vomiting, and headaches, which are early signs of the body’s struggle to maintain its essential sodium-water equilibrium. As the condition progresses, more severe symptoms can manifest, including confusion, a marked decrease in energy, fatigue, and mood disturbances such as restlessness and irritability. Additionally, the muscular system is directly impacted, leading to weakness, spasms, or cramps, as sodium plays a critical role in muscle contraction and nerve function. These symptoms collectively signal the body’s distress in managing its intracellular and extracellular fluid levels, highlighting the crucial role of sodium in maintaining homeostatic balance and proper physiological function.

Examples of Hyponatremia from Primitive Societies

David Livingston describes that he often saw conditions in the early 1800s on his travels in Africa, where poor people were forced to live on a vegetarian diet alone and as a result of this developed indigestion. He was describing people suffering from hyponatremia. His observations were made in the context of the Bakwains, part of the Bechuana people, who reportedly allowed the rich and poor to eat from the meat hunted. This is interesting because he also states that the poor had little, if any, access to meat. He mentions that the local doctors knew what the cause of the indignation was and that it was related to a lack of salt intake. (Hyde, A., et al.; 1876: 150)

It is fascinating that Livingston describes that on two occasions later in his life, he was himself deprived of salt for months and yet, he did not have any cravings for it (Hyde, A., et al.; 1876: 150). Interestingly enough, he reported cravings for meat and milk which he knew had enough salt to cure the onset of symptoms associated with a low-salt diet.

Sodium Content in Animal Parts (Approximate Values per 100g)

In old Africa, the entire animal was consumed. I heard from traditional butchers across Africa that various cuts of meat are good for people suffering from various ailments. Muscle meat typically has between 50 and 75 mg of sodium which is equivalent to about 0.05% to 0.075%. It is slightly below the liver with a sodium content of between 70-80 mg per 100g. The heart and brain also have higher sodium content than muscle, with the heart around 100 mg and the brain potentially higher, though specific values can vary. The next highest is the blood with sodium content in animal blood that can vary between 100 and 150 mg of sodium per 100g. The kidney is the highest containing around 150 to 200 mg of sodium per 100g. Interestingly, the sodium content in the skin can vary widely depending on the animal and preparation method. However, it’s generally not a significant source of dietary sodium unless treated with salt during processing or cooking which was not a practice in southern Africa.

Active Lifestyles and Sodium Intake

Active lifestyles, particularly those involving high levels of physical labour or extensive walking and running, increase sodium loss through sweat. In hot climates, this effect is even more pronounced. Therefore, individuals with active lifestyles, including primitive societies in Africa, would require higher sodium intake to compensate for these losses, maintain fluid balance, and prevent conditions like hyponatremia.

The increased need for sodium was met through the consumption of meat. The adequacy of sodium in meat is highlighted by the fact that salt was not used as a condiment in Southern Africa before the Europeans arrived. So much so that the native Africans referred to the Europeans as people who eat salted meat. Among the Khoi people of Southern Africa, I could find the use of salt only when preserving locusts and as part of burial ceremonies. Despite salt water and salt pans being spread across the region, salt was not used in meat dishes by either the Khoi, the San Bushman or the other native African tribes in the region.

Do we Naturally Crave Salt if our Sodium Levels are too Low?

An interesting question came up by considering the experience of Livingston who reported that he did not crave salt when he was deprived of it. Do we feel “sodium deprived” and intuitively seek out salt? We have four or possibly five taste sensors in our mouths. Of the five, one is wholly dedicated to tasting the sodium ion, the charged atom responsible for the love of salt. Vegetarian/ herbivore and omnivore animals are similarly equipped. Interestingly enough, in a study on rats, it was shown that some of them naturally recognize salt deficiency as the cause of their hyponatremia. Others had to be taught through experience. Studies have shown and described how long-term changes in the brain as a result of hyponatremia may be behind an increased appetite for salt in animals. There is in other words, a biological reason for animals to be “directed” to salt. (De Luca, 2014) They either crave salt when in a sodium-deficient condition naturally and in some cases, it is clear that they developed the craving.

If we naturally craved salt, it would explain our love for salt and the fact that it is so dominant in our diets. People would have naturally sought out salt deposits to amend their diets. The fact, however, is that the salt appetite of humans does not fit the biological model. There are great similarities between humans and other animals in how we handle sodium, but also very important differences. The sodium ion is essential for both humans and animals and we both have special sensors dedicated to its detection. Humans and animals share the same physiological systems that regulate it in the body, both ingest far too much of it and both show that a lack of sodium immediately following birth enhances the love of it. 

Unlike animals, people do not enjoy pure salt. Humans don’t like it in water while it has been shown that some rats prefer it. Importantly, humans do not respond to sodium deficiency by craving for it and it never becomes a learned craving after an incident of hyponatremia. (De Luca, 2014)

Animals who have been deprived of salt increase their salt intake robustly. Studies in rats showed that if they have been deprived of it once, they permanently increase consumption of it but not so in humans. The dedicated sodium receptors in humans do not direct us to it when there is a deficiency in our bodies. There are records of humans dying from hyponatremia with salt around them. There have been many studies in humans to try and prove the opposite, but in every case, results are inconclusive at best. The evidence is clear that, unlike animals, humans will seek sodium to satisfy our pallets but not to save our lives. (De Luca, 2014)

In humans, there is no satisfactory current explanation for the prominence of our sodium taste receptors or “for the powerful influence it exerts on our predilection for salt as the prime condiment and food additive that gives taste and tang to our food and is of no nutritional necessity.” (De Luca, 2014) The question comes up, why not?  There must obviously have been a time in our pre-history when we did not need this or when having it, was a disadvantage.

The Structure of Salt

Let us step back and look at the structure of salt to help us make sense of all this. Salt is a crystal that contains many elements, but as a matter of practicality and due to the widespread application of sodium chloride in industry, ended up being produced around the world with only these two elements. Both atoms consist of a nucleus with a positive electric charge – an island floating in a sea of electrons which are negatively charged particles. If one brings together one atom of each of these elements, the chlorine atom steals an electron from the sodium atom: the first becomes a negatively charged chlorine atom and the second is transferred into a positively charged sodium atom.

Solid sodium chloride is a crystal of extremely regular structure. The pattern of sodium +/ chlorine – repeats indefinitely in three-dimensional space. Just as a side note, this is also the explanation for the name since a negative chlorine is called a chloride. (Laszlo, 2001)

Salt in Water

Salinity refers to water that contains various concentration levels of salt. The magic of salt happens when it comes into contact with water. When one adds a spoonful of salt to a glass of water, the salt “melts” into the water. When we evaporate the water, the salt forms a crystal.

The sodium chloride (NaCl) comes into contact with a water molecule and the water molecule bestows on the positively charged sodium ion and the negatively charged chloride ion water-sodium and water-chlorine forces of attraction that are at least as strong as the sodium-chlorine force of attraction. This is indeed the case and so, the sodium and chloride ions are pulled apart in water. It “melts away.” (Laszlo, 2001)

The Salt we add to Meat

The interaction between salt (sodium chloride, NaCl) and water is a fundamental aspect of chemistry that has profound implications in biology, physiology, and food science. This relationship is crucial for understanding how NaCl, while potentially harmful in high concentrations, is physiologically essential in appropriate amounts, similar to the roles of nitric oxide (NO), nitrite (NO2-), and nitrate (NO3-). In the context of meat processing and preservation, NaCl is not merely a seasoning; it plays a pivotal role in enhancing meat’s quality, safety, and flavour profile through its interaction with meat proteins and water.

-> Water-Salt-Protein Interactions in Meat

The relationship between meat proteins and salt is a product of millions of years of evolutionary adaptation, where proteins have become ideally suited to interact with salt. This deep-rooted compatibility underlines the critical importance of salt in meat processing. Here’s how meat has evolved to function optimally with salt, the essential qualities of salt that perform vital functions in meat, and the basis of salt’s value in meat processing:

— Evolutionary Adaptation

1. Hydration and Water Retention: Throughout evolution, the structure of meat proteins has adapted to allow for efficient hydration and water retention in the presence of salt. This adaptation is crucial for the survival of organisms in varying environmental salt concentrations, ensuring that their muscles (meat) retain enough water to maintain function and structure.
2. Ionic Strength Sensitivity: Meat proteins have evolved to be sensitive to changes in ionic strength, a quality that salt directly influences. This sensitivity allows proteins like myosin and actin to maintain their structural integrity and functionality under different ionic conditions, essential for muscle contraction and, by extension, mobility and survival.
3. Preservation Against Microbes: The natural antimicrobial properties of salt have played a role in the evolution of meat’s biochemical makeup, enabling tissues to be less prone to spoilage and infection. This trait has been invaluable for the preservation of meat both in nature and in human food processing.

The last point needs further clarification. The antimicrobial properties of salt in living tissues, including those of animals, arise primarily from its ability to affect the osmotic conditions surrounding cells, including microbial cells. While the direct application of salt as an antimicrobial agent is more commonly associated with food preservation, its role in the living body is less obvious, involving the regulation of osmotic balance and immune system function. Let’s spend a minute to develop the concepts.

— Osmotic Balance and Antimicrobial Action

1. Osmotic Pressure: In the context of a living organism, cells maintain an osmotic balance with their surroundings to function properly. Salt (sodium chloride) plays a crucial role in maintaining this balance. High concentrations of salt outside microbial cells cause water to move out of the microbes through osmosis, leading to dehydration and potential death of the cells. While this principle is exploited in food preservation by adding high levels of salt to create an inhospitable environment for microbes, the body regulates salt concentrations in tissues to support cellular health and prevent microbial growth.
2. Ionic Environment: The presence of sodium and chloride ions is essential for various physiological processes, including nerve impulse transmission and muscle contraction. These ions also contribute to creating an ionic environment that can influence microbial survival. For example, certain levels of sodium ions can inhibit the growth of specific pathogens by interfering with their cellular processes.

— Immune System Function

Salt does not act as an antimicrobial agent in living tissues in the same way it does in food preservation. However, the body’s regulatory mechanisms for salt concentration play a supportive role in immune function:

1. Inflammatory Response: Recent research suggests that dietary salt can influence the immune response. For instance, high salt concentrations have been shown to enhance the antibacterial activity of certain immune cells, such as macrophages. However, the relationship between salt intake and immune function is complex, and excessive salt can also have adverse health effects.
2. Wound Healing: The skin’s natural barrier function is partly maintained by salt balance, and the wound healing process involves a carefully regulated ionic environment. Salt concentrations in sweat and other body fluids can help create a hostile environment for pathogens at the site of wounds, supporting the body’s natural defence mechanisms.

— Essential Qualities of Salt in Meat

This “partnership” between salt and protein is the basis of the supreme value of salt in meat processing. We evolved with salt and the human body tightly intertwined! The exact forces that make salt biologically essential are what we exploit in meat processing.

1. Water Binding and Solubilization: Salt enhances the water-holding capacity of meat by solubilizing muscle proteins, leading to a firmer, juicier product. This is due to salt disrupting the protein structure, exposing hydrophilic sites that bind water more effectively.
2. Texture Formation: The ability of salt to extract proteins (notably myofibrillar proteins) and facilitate their interaction is foundational in forming the desired texture in processed meats, such as sausages and emulsions. This extraction process is a direct application of salt’s interaction with meat proteins, allowing for the creation of cohesive, stable products.
3. Flavour Enhancement: Salt’s interaction with meat proteins not only affects texture and moisture retention but also enhances flavour. This is partly due to salt’s ability to increase the solubility of flavour compounds in meat, making them more perceptible to taste.
4. Microbial Growth Inhibition: Salt reduces the water activity in meat, inhibiting the growth of spoilage and pathogenic microbes. This antimicrobial action is crucial for extending the shelf life of meat products and ensuring food safety.

— The Power of Solubalisation

To “solubilize proteins” means to make proteins soluble in a solvent in which they are not normally soluble, such as water. This process involves the interaction between the solvent (e.g., water) and the protein molecules, leading to the dispersion of protein molecules throughout the solvent. When put in the context of “dissolve,” solubilizing proteins can be thought of as the process by which protein molecules become thoroughly dispersed or dissolved in a solvent, becoming a homogeneous solution.

-> Protein Solubilization Mechanism

Meat proteins, particularly myofibrillar proteins like myosin and actin, are initially organized in a complex, highly ordered structure within muscle fibres. Salt ions disrupt the electrostatic and hydrogen bonding that holds these proteins together in their native state. Sodium (Na+) ions shield the negative charges on the protein molecules, while chloride (Cl-) ions interact with positive charges. This disruption reduces the interaction between protein molecules, making them more soluble in water.

By disrupting protein-protein interactions, salt exposure causes proteins to unfold partially or change their conformation. This unfolding exposes hydrophilic (water-attracting) amino acid residues that were previously buried inside the protein structure. These exposed sites can then bind water more effectively, increasing the protein’s hydration and solubility.

The solubilized proteins can form complexes with salt ions and water molecules. This complex is more soluble in the meat’s aqueous environment, allowing the proteins to move more freely and interact with each other in new ways. This is particularly important in processed meat products, where protein solubility is crucial for texture and binding properties.

-> Implications of Protein Solubilization

What solubilization does not mean is as important as what is meant by it. It does not mean that proteins are dissolved into a solution in the way salt or sugar dissolves in water. Instead, proteins become more dispersed in the water present in meat, enhancing their ability to interact with each other and with water. This increased solubility is crucial for processes like the extraction of proteins to the meat surface in emulsified products, where they act as binding agents to hold fat and water, forming a stable matrix.

When we say that solubilization implies a partial change in the protein’s three-dimensional structure, also remember that the protein’s primary amino acid sequence remains unchanged. The protein only “unfolds” to some extent. This unfolding is reversible under certain conditions but is essential for the functional properties of meat proteins in processed foods.

Crucially for our purposes, the solubilization and partial unfolding of proteins improve their functional properties, such as water-holding capacity, emulsifying ability, and gel formation.

Salt as a Preservative

Let’s look at salt as a preservative. Salt can not possibly be responsible for killing microorganisms. At least not in the concentrations we use. There must be some interaction between the salt and the microorganisms and it can’t always be negative for the bacteria. If this were the case, how would the bacteria responsible for changing the nitrate into nitrite from Dr. Polenski’s experiments survive and how would the microorganisms in the ocean deal with different levels of salinity?

The sodium and chlorine ions are separated in the water and have vastly different functions in meat. The first way that salt preserves is however a general one which is the result of the presence of salt on the outside of the cut of meat. It dispenses its first curing action by removing water from inside the pork muscle. Microorganisms want to live in a wet environment. The drier it is, the less active it will be. (Dworkin, M et al, 2006: 146) It is important how much water is available. Most bacteria need water activity at the same level as seawater at 25 degrees C to flourish. (1) (Dworkin, 2006)

Water Stress

Water stress, as it is called, is one of the key functions of salt in processing bacon. It becomes very complex, very fast when one relates this to wet cures. However, when we consider dry cure, it is obvious. Salt curing goes in the first place, hand in hand with partial drying techniques, aimed at preserving protein in a more lasting way. (Laszlo,1998) Salt “extracts” moisture from the meat by the water migrating out of the muscle towards the salt in an attempt to “balance” the salt levels on the outside of the meat with the inside. Salt at the same time “migrates” into the muscle.

Once inside the muscle, the salt now poses a threat to bacteria found inside the meat through the process of osmosis. Osmosis is the passage of solvent through a semipermeable membrane in response to different concentrations of solute on the two sides of the membrane. The description comes from the notion that salt or sugar attracts water when it touches the meat.

In 1748 J. A. Nollet used an animal bladder to separate chambers containing water and wine. He noted that the volume in the wine chamber increased and when the chamber was closed, a pressure developed. He named the phenomenon osmosis from the Greek word meaning thrust or impulse. (Sperelakis,1995)

Salt and Bacteria

Most bacteria will not grow at 3% concentration levels of sodium chloride (NaCl). It is important to remember that there are several important exceptions to this rule. Some bacteria and archaea (single-cell organisms) called halophiles (from the Greek word salt-loving) require NaCl to grow. Moderate halophiles, such as marine bacteria, may show optimum growth at 3% NaCl. They require at least 1.5%. Some bacteria have been found growing in 25% NaCl concentrations. However, most bacteria stop growing at 3% NaCl. This, besides the lack of available water, is the only other way that salt performs its magic as a preservative for meat.

High salt concentration disrupts the membrane and denatures many proteins. (Srivastava, 2003) Generally speaking, salt has the same effect on microorganisms in the meat as it has on the meat itself. Since the sodium chloride (NaCl) concentration outside the microorganism is higher than inside, water flows out of the organism in order to try and restore equilibrium. The effect will be a slowdown in growth and activity.

The Lewis and Clark Expedition

Lastly, I want to give you a flavour of some of the ways that salt has been used in the recent past to preserve meat. Let’s consider wet vs dry curing. Wet curing has been used as a technique for curing pork for hundreds of years. There is a notable description of this process that Jeppe showed me from a historical American document.

In May 1804, an expedition departed from near St Louis on the Mississippi River, planning to make their way westward, through the continental divide to the Pacific coast. The expedition was known as the Lewis and Clark Expedition or the Corps of Discovery. It was the first American expedition to cross what is now the western portion of the United States.

The expedition was commissioned by President Thomas Jefferson shortly after the Louisiana Purchase in 1803. It consisted of a select group of U.S. Army volunteers under the command of Captain Meriwether Lewis and his close friend Second Lieutenant William Clark.

The journey lasted from May 1804 to September 1806. The primary objective was to explore and map the newly acquired territory, find a practical route across the Western half of the continent, and establish an American presence in this territory before Britain and other European powers tried to claim it.

The campaign’s secondary objectives were scientific and economic: to study the area’s plants, animal life, and geography, and to establish trade with local Indian tribes. With maps, sketches and journals in hand, the expedition returned to St. Louis to report their findings to Jefferson.

On 3 April 1804, Clark described how pork was being packed and cured in barrels. He wrote on 17 April that they “completed packing 50 kegs of pork and rolled and filled them with brine”. It is clear that they were not using a dry salt preparation but rather a water-diluted salt mixture and perhaps adding sugar or adding flavourings that would make it taste better than and not as harsh as straight salting.

They would have used good kegs as leaking kegs were often responsible for meat spoiling. It went well and a month after Clark’s pork went into the barrels, Major Rumsey inspected it and condemned only approximately 10% of the meat. A curing method for pork that was documented in 1776 shows that wet curing must have been practised for many years before Clark’s description in 1804.

“After the meat has cooled, it is cut into 5 lb. pieces which are then rubbed well with fine salt. The pieces are then placed between boards a weight brought to bear upon the upper board so as to squeeze out the blood. Afterwards, the pieces are shaken to remove the surplus salt, [and] packed rather tightly in a barrel, which when full is closed. A hole is then drilled into the upper end and brine is allowed to fill the barrel at the top, the brine is made of 4 lb. of salt, 2 lb. of brown sugar, and 4 gallons of water with a touch of saltpetre. When no more brine can enter, the hole is closed. The method of preserving meat not only assures that it keeps longer but also gives it a rather good taste.”  (Holland, 2003)

The account of Clark is intriguing and was the motivation for Michael and my water and salt experiments. If he left the pork for two weeks in the brine, he must have noticed that he took out heavier pieces of meat than he put in when the wet cure method was used. The meat “soaked up” the water. Wet curing was in wide use by the mid-1800s. John Yeats wrote in 1871 about salt and sugar curing of pork, “There are two methods of salting; in one the meat is packed in dry salt, in the other, it is immersed in brine.”

Not just curing by wet cure in barrels, wet cure was applied to meat through a variety of injection methods. Yeats writes in 1871 that a certain “Professor Morgan, in Dublin, has recently proposed a method of preservation by injecting into the animal as soon as killed a fluid preparation, consisting, to every hundredweight of meat, of one gallon of brine, half a pound of saltpetre, two pounds of sugar, half an ounce of monophosphoric acid, and a small quantity of spice.” (Yeats, J, 1871: 225) The plan was widely tested at several factories in South America and by the Admiralty, who had reported that they had good results from the technique. (Yeats, 1871)

Edward Smith described another method of injection of brine that he witnessed in his book, Foods in 1873. He accounts for the events of a certain “Mr Morgan [who] devised an ingenious process by which the preserving material, composed of water, saltpetre, and salt, with or without flavouring matter, was distributed throughout the animal, and the tissue permeated and charged. His method was exemplified by him at a meeting of the Society of Arts, on April 13, 1854, when I [Edward] presided.” (Smith, 1873)

He then describes how an animal is killed in the usual way, the chest is opened and a metal pipe is connected to the arterial system. Brine was pumped through gravity feed throughout the animal. Approximately 6 gallons were flushed through the system. Pressure was created to ensure that it was flushed into the small capillaries.  Smith reported overall good results from the process with a few exceptions. The brine mix that Mr Morgan suggested was 1 gallon of brine, ¼ to ½ lb. of sugar, ½ oz. of monophosphoric acid, a little spice and sauce to each cwt of meat. (Smith, 1873) An interesting note that we must return to later was the common use of monophosphoric acid, probably as an added preservative.

When the muscle is left in the brine, the brine seeps into the meat. By the mid-1800s, the use of wet cute has evolved to include some form of injection. A process that would have further added the likelihood of water to have been retained in the muscle tissue.

Johann Fey has been working on a device in the early 1890s that created compressed air below meat in a curing solution to facilitate a more equal absorption of the brine in the meat. (3) (Patents. US474446)

The Salt Experiments

To see if we can figure out all the functions of salt in bacon, Michael and I did an experiment on the salt back at the Harris test kitchen. We selected three pork sides, all killed on the same day and from the same pork breed. All were the same size and prepared in the Wiltshire cut. In experiment 1 we diluted salt in the usual amount of water and injected meat with a mixture of salt. We omitted sugar and saltpetre. We rested it and cured it as per the usual method of a wet brine. We then dried and smoked it in a drying oven for 6 hours.

For experiment 2, we repeated the experiment without any salt. Instead of salt, we added the normal amount of water as was used in the salt brine that we injected in experiment 1. We also performed a 3rd experiment as our control where we used a regular amount of salt, water, and saltpetre. Still, we omitted sugar from the mix to allow us to focus on the effect of the salt. After every experiment, the meat was smoked and dried at the same time and the same temperature. The starting weights were carefully noted before any injection was done, after injection but before smoking and drying and after smoking and drying. We were interested to see what the effect of salt is on the weight of the bacon after smoking and drying.

The results were fascinating!  The effect of salt on bacteria, at least in the concentrations we use is very limited. However, we found that there is a considerable difference between bacon where salt was added or not in terms of its weight after smoking and drying. The sides where salt was added are materially heavier than where only water was injected. We could see first-hand the effects of salt “holding” the water inside the meat.

When Minette and I get back to the Harris operation, I am planning to repeat the test but focus my attention on sugar. I also intend to use beet sugar in one trail and Calne sugar in another.

Water Holding Capacity, Improved Curing and Taste

The issue of water holding capacity of curing brines slowly but surely started to come to the fore from the mid-1800s even though it has certainly been a consideration in the meat industry for many years despite the lack of documentary evidence. From Michael and my experiments, one thing was clear salt increases the water-holding capacity of meat. One of the professors from Bristol who consults for John Harris elucidated the mechanism behind our observation.

Remember that we have said that salt exists in water as sodium (Na+) and chloride (Cl-) ions. We will see how the different ions have different functions in curing, starting with the aid of the water-holding capacity of the meat. “It is the ions that are responsible for this preserving action. An ionic strength of 0.5 or more will cause myofibrils (4) to swell and disintegrate, depolymerizing myosin filaments (threads), and solubilising the myofibrillar protein.”

A salt concentration of 2% or more in most meat formulations will achieve the necessary ionic strength. However, even at lower concentrations such as 0.5 – 1.0% as used for many moisture-enhanced fresh meats, the Cl-ion from salt will interact with meat proteins to increase the negative electrical charge on the proteins and increase the water-binding properties of the meat mixture.

This is an essential role of the chloride ions in meat systems because the interaction with meat protein that swells the protein structure is responsible for allowing the proteins to hold more of the weakly bound water within and between their structure. The increased retention of water by the protein structure in the presence of chloride ions has a major impact on cooking yields, juiciness, tenderness, and mouthfeel when the product is consumed.” (Tarte, 2009)

“The chloride ion is much more important than the sodium iron for achieving increased water binding by meat proteins.” (Tarte, 2009)  This is important because it means that for water binding, one could use other salts such as potassium chloride.

The next direct benefit of salt to the curing process is in the area of colour development. “This is because the chloride ion from salt (Cl-) has been reported to accelerate cured colour formation in cured meat by increasing the rate of nitric oxide formation from nitrite.” (Tarte, 2009)

It is the sodium ion that is responsible for the salty taste in salt. The sodium ion not only gives sodium chloride its salty taste, but it is also responsible for a heightened intensity of all other flavours.

It is important to note that other minerals and metals present in natural salt deposits alter the taste of salt slightly so that salt becomes the most important curing agent in pork. Woody’s team can produce bacon, as unique as the great African land where we will be making our bacon. In the bacon that we produce, we can capture the spirit of the Bushman and the winds that blow across the vast salt pans of Bechuanaland by the use of our native salt.

These inquiries have completely captured my imagination! In my wildest dreams, I would never have predicted that curing bacon is so beautifully complex with the most magnificent processes at work! I can not imagine being at any other place on earth than on a steamer with Minette, on our way back to Calne which has become the centre of my entire universe.

One of my highest privileges is introducing you to this amazing world through my letters! Send my regards to everyone!

Your Dad.

---

---

(c) eben van tonder

---

Stay in touch

Notes

(1) “It is now generally accepted that the water requirements of micro-organisms should be described in terms of the water activity (Aw) in the environment. The parameter is defined by the ratio of the water vapour pressure of the food substrate to the vapour pressure of pure water at the same temperature: Aw = P/Po

Where P is the vapour pressure of the solution and Po is the vapour pressure of the solvent (usually water).

The concept is related to relative humidity in the following way: RH = 100 x Aw

Pure water has an Aw of 1.00;
A 22% NaCl solution (w/v) has an aw of 0.86;
A saturated NaCl has an Aw of  0.75
(Jay, JM, et al. 2005: 45)

Microbial growth in the range of water activity between 0.998 and 0.6 (Dworkin, M et al, 2006: 146)

What is the effect of other ingredients on Aw? So many great discoveries still ahead!

(2) In 1895, Emile van Emergem, professor of bacteriology at the University of Ghent, in Belgium, identified the microorganism causing sausage poisoning as Clostridium botulinum.

In 1897 there was a botulinum outbreak after a funeral dinner where smoked ham was served as the main course. Emile was called to find the cause.

For the bacon industry, this is an organism that should be tested every month by micro-swabbing. Salted, smoked and vacuum-packed products can contain the organism if it has been improperly prepared. Forms of the organism exist that can resist heat treatment. (Emmeluth, D , 2010: 19)

(3) John patented his device in 1892.

(4) “A myofibril (also known as a muscle fibril) is a basic rod-like unit of a muscle.[1] Muscles are composed of tubular cells called myocytes, also known as muscle fibres, and these cells, in turn, contain many chains of myofibrils. They are created during embryo development in a process known as myogenesis.

Myofibrils are composed of long proteins such as actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thin filaments and thick filaments, which repeat along the length of the myofibril in sections called sarcomeres. Muscles contract by sliding the thin (actin) and thick (myosin) filaments along each other.

Actinomyosin motors are important in muscle contraction (relying in this case on “classical myosins”) as well as other processes like retraction of membrane blebs, filiopod retraction, and uropodium advancement (relying in this case on “nonclassical myosins”).”

(Wikipedia. Myofibril)

References

To integrate the references used in our discussion on salt and rearrange the list in alphabetical order, including the newly added references, we will proceed as follows:

• Baron S, et al., eds. (1996). “Clostridia: Sporeforming Anaerobic Bacilli”. Baron’s Medical Microbiology (4th ed.). Univ. of Texas Medical Branch.
• BBC Staff (23 August 2011). “Impacts ‘more likely’ to have spread life from Earth”. BBC. Archived from the original on 24 August 2011. Retrieved 2011-08-24.
• Bitterman, M. 2010. Salted. Ten Speed Press.
• Bud, R. and Warner, DJ. 1998. Instruments of science. The Science Museum, London and the National Museum of American History.
• Dworkin, M et al. 2006. The Prokaryotes: Vol. 1: Symbiotic Associations, Biotechnology, Applied Microbiology. Springer Science and Media, Inc.
• Emmeluth, D . 2010. Botulism. Infobase Publishing.
• Holland, LZ. 2003. Feasting and Fasting with Lewis & Clark: A Food and Social History of the early 1800’s. Old Yellowstone Publishing, Inc.
• Jay, JM, et al. 2005. Modern Food Microbiology. Springer Science + Business Media, Inc.
• Laszlo, P. 1998. Salt, Grain of Life. Columbia University Press.
• Smith, Edwards. 1873. Foods. Henry S King and Co.
• Sperelakis, N. 1995. Cell Physiology: Source Book. Academic Press.
• Srivastava, S. 2003. Understanding Bacteria. Kluwer Academic Publishers.
• Stringer, R. and Johnston, P. 2001. Chlorine and the environment, An Overview of the Chlorine Industry. Kluwer Academic Publishers.
• Tarte, R, et al. 2009. Ingredients in Meat products. Springer Science + Business Media, LLC.
• Yeats, J. 1871. The technical history of commerce; or, Skilled labour applied to production. Cassell, Petter, and Galpin.
• http://www.google.com/patents/US474446
• http://www.britannica.com/EBchecked/topic/174678/Henri-Dutrochet

Pictures

Figure 1:  https://www.facebook.com/pages/Historic-Cape-Town-Pictures/172728429409395

Figure 2:  Lauren and salt by Eben  (2015)

Figure 3: Tristan and salt by Eben (2015)

Figure 4:  Holland, LZ, 2003:  9

Figure 5:  http://www.google.com/patents/US474446

Figure 6:  Salt at the cape of Good Hope by Eben (2015)

Figure 7:  http://en.wikipedia.org/wiki/Myofibril

Side note:

Two very interesting aspects of this post.

1.  The 1st picture was taken at the same place where the cover picture for this blog was taken.  The one in 2012 or 2013 and the other in 1949.  It was a complete coincidence that I included it.  I did not realize where it was taken.  I just liked the image when I found it and it related back to the Cape of Good Hope that in the story, I miss and where I currently live.

2.  Is Mr Morgan that Edward Smith talks about in 1854 the same person that Yeats describes in 1871 as Professor Morgan, from Dublin,  17 years later?  Probably.  I am not sure if the methods described are exactly the same. Chances are that Mr. Morgan became Dr and Professor Morgan and that he refined his techniques.

The method of injection through the arterial system is one that is still practiced at select butcheries in Germany in 2014.  There is even a butcher in Cape Town who still use this method.

//