By Eben van Tonder, 25 March 25

Introduction: Getting to Know Amines

Amines are more familiar than they sound. Though the name may seem technical or obscure, these nitrogen-containing compounds are all around us, and even within us. Amines are structurally related to ammonia (NH₃), one of the most basic and recognisable nitrogen compounds. In fact, amines are derived from ammonia by replacing one or more of its hydrogen atoms with organic groups. Because of this, amines are considered foundational in the structure of amino acids, the building blocks of proteins (McGee, 2004).

When we talk about proteins, we’re talking about chains of amino acids. Each amino acid contains at least one amine group. Through cooking, fermentation, or decomposition, proteins break down into smaller molecules, and one of the key by-products of this breakdown is free amines. These include:

• Primary amines: one organic group attached to the nitrogen (R-NH₂)
• Secondary amines: two organic groups (R₂NH)
• Tertiary amines: three organic groups (R₃N)

Amines can have distinctive smells and flavours. Some contribute to the savoury, umami profile we associate with aged cheese or fermented fish. Others, particularly those formed during putrefaction, produce offensive, fishy, or stale odours. So while amines are essential to life and taste, too much, or the wrong kind, can signal decomposition, spoilage, or even health risks.

This investigation continues from our recent article on pomo (boiled and roasted cowhide), where we examined how traditional West African food preparation practices, especially boiling, drying, and roasting, likely served to remove ammonia and volatile amines from hides that had undergone early stages of putrefaction (van Tonder, 2024). These empirical methods, honed over generations, made pomo safe and enjoyable to eat long before modern biochemistry explained what was happening.

What Are Amines and Why Should We Care?

Amines form naturally during the breakdown of proteins. This happens in food ageing, fermentation, spoilage, and digestion. Some amines are even added deliberately to enhance flavour, as in soy sauce or fermented fish paste.

However, excessive accumulation of amines, particularly in spoiled meat or poorly handled products, can be a red flag. Some common amines in food include:

• Histamine: linked to scombroid food poisoning
• Putrescine and cadaverine: associated with the smell of rot
• Tyramine: found in aged cheese and linked to blood pressure spikes
• Dimethylamine and diethylamine: common secondary amines found in decomposing tissues (EFSA, 2011)

Secondary and tertiary amines are of special concern when it comes to food safety, not necessarily because they are directly toxic, but because of what they can become.

From Amines to Nitrosamines: A Dangerous Transformation

When secondary amines (R₂NH) encounter nitrites, common in cured meats like bacon or sausages, they can undergo a chemical reaction called nitrosation, especially under acidic conditions such as those in the human stomach.

This produces N-nitrosamines, a class of compounds widely recognised as carcinogenic. For example:

• Dimethylamine plus nitrite produces N-nitrosodimethylamine (NDMA) (IARC, 2010)

The name itself is revealing:

• N: Refers to the nitrogen in the amine that the nitroso group attaches to
• Nitroso: The –NO group
• Amine: The base molecule (primary, secondary, or tertiary amine)

This nomenclature comes from IUPAC rules and is used specifically when the substituent is attached to a heteroatom, such as nitrogen. That is why we see compounds named N-nitrosodimethylamine, rather than simply dimethylnitrosamine, to clarify the position of substitution.

In some rare or more complex molecules, you might also encounter other prefixes that indicate the site of nitrosation:

• O-nitrosation: where the nitroso group is added to an oxygen atom
• C-nitrosation: a less common form where the nitroso group is added to a carbon atom
• S-nitrosation: when the nitroso group is attached to a sulfur atom

However, for food safety and meat curing contexts, it is overwhelmingly N-nitrosamines that are of concern, as nitrosation typically occurs on secondary amines at the nitrogen atom.

These reactions were once common in mass-produced cured meats, which contained both amines and nitrites in abundance. Today, regulations limit the amount of nitrites allowed, and many curing methods use nitrate from vegetables combined with starter cultures to control the conversion rate (Honikel, 2008).

Taste and Smell of Amines

Amines can carry taste and smell. While low levels may enhance savoury notes, higher concentrations, particularly of secondary amines, often bring unpleasant or even off-putting characteristics—fishy, stale, or sharp. The Yoruba term “oorun eṣu” (smell of the devil), used in pomo markets, vividly captures this sensory revulsion.

In pomo preparation, as explored in our Hallstatt-inspired analysis of West African biochemical practice, boiling removes soluble amines, sun-drying allows evaporation of volatile ones, and roasting thermally degrades what remains. These combined steps transform an otherwise unpalatable hide into a beloved food, precisely because the amines have been stripped or reduced (van Tonder, 2024).

The Crispy Bacon Paradox

Roasting removes amines from meat. The question is then if crispy bacon, having been roasted or fried at high temperatures, should be healthier due to the reduction of secondary amines. This makes biochemical sense on one level, but we need to walk through the whole picture because as with most things in meat science, it is about trade-offs.

Roasting and Frying Can Destroy Amines

High-heat cooking methods like roasting, grilling, or pan-frying can:

• Drive off volatile amines, including some secondary amines
• Prevent the formation of certain amine-based odours and unpleasant flavours
• Reduce the likelihood of ingesting amines that could later nitrosate into harmful nitrosamines in the stomach (Sindelar & Milkowski, 2012)

In this sense, well-cooked bacon may carry less amine load than raw or boiled bacon.

But New Compounds Are Formed

This is where it becomes more complex.

Much of the amines are driven off when the food is cooked, especially under conditions involving high, dry heat. However, some amines may remain, creating the potential for N-nitrosamines to form if nitrite is also present. According to Sindelar and Milkowski (2012), the risk of N-nitrosamine formation within the human stomach is significantly reduced when cured meat products are manufactured and cooked using current best practices. They emphasise that nitrosation, the chemical reaction leading to nitrosamine formation, requires specific conditions: the presence of secondary amines, nitrite, and an acidic environment. When meat is grilled or roasted to proper culinary standards, thoroughly cooked but not charred, the volatile secondary amines are often driven off by heat, and residual nitrite levels are already minimal due to regulated usage and interaction with added ascorbate or erythorbate during processing. Sindelar and Milkowski argue that “under realistic gastric conditions and modern food manufacturing practices, the formation of nitrosamines in vivo is biologically limited,” especially when cooking avoids excessive charring and nitrite levels are properly controlled. Therefore, for a well-grilled piece of bacon or ham, the likelihood of in-stomach nitrosamine formation is not only low but biologically constrained by multiple layers of prevention.

So, the formation of N-nitrosamines in the stomach is unlikely if the food is properly grilled or cooked, but what about its formation before it gets to the stomach? Nitrosamines, especially N-nitrosodimethylamine (NDMA), can still form during high-heat cooking, particularly when nitrites are present as in cured bacon. This formation happens in the food itself. Ironically, roasting or frying can create exactly the compounds you are trying to destroy if nitrites react with residual amines at high temperatures.

In addition, heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogens formed when meat is cooked at very high temperatures, especially over an open flame or during charring (Skog et al., 1998). The crispier the bacon, the more likely HCAs and PAHs are present, though levels vary depending on cooking method and time.

Finding the Ideal Zone

From a meat science and health perspective, it is about finding balance. You want enough heat to destroy or drive off unwanted amines and pathogens, but not so much that you induce carcinogenic pathways.

Ironically, lightly crisped bacon—cooked thoroughly but not burned or blackened—might hit that sweet spot.

Potential Formation of Nitrosamines and HCAs: The Role of Curing Practices

The risk of nitrosamine formation depends not just on how meat is cooked, but on how it is cured. Around the world, the use of sodium nitrite in meat curing is tightly regulated. One of the most important protective measures is the mandatory inclusion of ascorbate or erythorbate (forms of vitamin C), which inhibit the nitrosation reaction by blocking the conversion of nitrite into reactive nitrosating species. This addition alone dramatically reduces the formation of nitrosamines during cooking (Sebranek & Bacus, 2007).

Moreover, the level of ingoing nitrite is carefully controlled by law. In most countries, it is not permitted to use sodium nitrate (NO₃⁻) together with nitrite in fast-curing environments such as ham and bacon plants. This restriction exists because nitrate acts as a long-term reservoir of nitrite via microbial reduction, potentially creating sustained nitrosating conditions. By outlawing this combination, regulatory bodies minimise the risk of prolonged nitrosamine formation (EFSA Panel on Food Additives, 2017).

With these controls in place—limited nitrite levels, no nitrate in rapid cures, and obligatory inclusion of ascorbate or erythorbate—the formation of nitrosamines in properly cured and cooked bacon is likely reduced to negligible levels. According to the European Food Safety Authority (EFSA, 2017), when sodium nitrite is used within regulated limits and in combination with antioxidants such as ascorbate or erythorbate, the formation of N-nitrosamines is minimised. The World Health Organization (WHO, 2010) also recognises that adherence to good manufacturing practices significantly reduces the potential for nitrosamine formation. These findings support the conclusion that the risk is minimal when modern curing protocols are followed.

Dr. Joe Sebranek of Iowa State University has stated, “When good manufacturing practices are followed, including the use of ascorbate and controlled nitrite levels, the risk of nitrosamine formation in modern cured meats is extremely low” (Sebranek, 2009). Similarly, Sindelar and Milkowski (2012) note that “scientific and regulatory advances have enabled the safe use of nitrite in meat products by minimising residual levels and controlling processing conditions.”

While not technically zero, the risk is so low that it is arguably comparable to, or even lower than, the risks posed by regular consumption of alcoholic beverages. Studies such as Bouvard et al. (2015) in The Lancet Oncology suggest that while processed meat carries a minor relative risk increase, it is modest compared to alcohol, tobacco, or obesity. As noted by van Tonder (2024) in EarthwormExpress, “Public fear surrounding nitrites often stems more from historical associations than current science. When modern regulations are observed, cured meats can be enjoyed safely as part of a balanced diet.”

One could argue, then, that the health risk of consuming a moderate amount of properly cured and cooked bacon—say, a few rashers for breakfast and a ham sandwich for lunch—is less significant than drinking a few glasses of wine or beer daily. While both behaviours should be considered within the context of an overall lifestyle, the scientific evidence does not support the idea that cured meats, especially those made under modern regulatory systems, pose a unique or exceptional risk.

So, by adhering to strict curing protocols that prevent nitrosamine formation and avoiding excessive surface charring during cooking, the generation of heterocyclic amines and polycyclic aromatic hydrocarbons is virtually eliminated, making properly cured and well-prepared meats among the safest options in high-temperature cooking.

Conclusion: Ancient Wisdom, Modern Insights

Whether we are preparing pomo in West Africa or crisping bacon in a modern kitchen, the biochemical dynamics are remarkably similar. Through boiling, drying, or roasting, traditional and modern societies alike have developed ways to manage the presence of amines, both for safety and flavour.

Understanding the chemistry behind these processes not only allows us to preserve ancestral knowledge, but also helps us refine modern techniques for curing, cooking, and enjoying meat in ways that are both delicious and health-conscious.

In short, what seems like simple cooking, boiling, drying, roast, may in fact be a complex act of biochemical engineering, rooted in tradition, and supported by science.

---

Parent Page: The Culinary Evolution of Pomo: Ancestral Processing of Animal Hides and the Management of Ammonia in West Africa

Series Home Page: The Hallstatt Curing Method

---

---

References

Bouvard, V., Loomis, D., Guyton, K. Z., et al. (2015). Carcinogenicity of consumption of red and processed meat. The Lancet Oncology, 16(16), 1599–1600.

EFSA Panel on Contaminants in the Food Chain (CONTAM) (2011). Scientific opinion on risk for public health related to the presence of N-nitrosamines in food. EFSA Journal, 9(12): 2407.

EFSA Panel on Food Additives and Nutrient Sources Added to Food (ANS) (2017). Re-evaluation of sodium nitrite (E 250) and potassium nitrite (E 249) as food additives. EFSA Journal, 15(6): 4786.

Honikel, K. O. (2008). The use and control of nitrate and nitrite for the processing of meat products. Meat Science, 78(1–2), 68–76.

IARC. (2010). Ingested Nitrate and Nitrite, and Cyanobacterial Peptide Toxins. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, No. 94.

McGee, H. (2004). On Food and Cooking: The Science and Lore of the Kitchen. Scribner.

Sebranek, J. G., & Bacus, J. N. (2007). Cured meat products without direct addition of nitrate or nitrite: What are the issues? Meat Science, 77(1), 136–147.

Sebranek, J. G. (2009). A safety assessment of sodium nitrite in the diet. Food Technology, 63(1), 34–40.

Sindelar, J. J., & Milkowski, A. L. (2012). Human safety controversies surrounding nitrate and nitrite in the diet. Nitric Oxide, 26(4), 259–266.

Skog, K., Johansson, M. A., & Jägerstad, M. (1998). Carcinogenic heterocyclic amines in model systems and cooked foods: a review on formation, occurrence and intake. Food and Chemical Toxicology, 36(9–10), 879–896.

van Tonder, E. (2024). The Culinary Evolution of Pomo: Ancestral Processing of Animal Hides and the Management of Ammonia in West Africa. EarthwormExpress.com.