How Ethyl Carbamate Ends Up in Our Everyday Meals and Why It Matters

Food safety is not just about avoiding raw meat or washing your hands. Both authorities and consumers have serious concerns about food safety. Pesticides, heavy metals, and microbiological pollutants receive a lot of attention and while we hear about them, there is another quiet poison in our meals, another toxicant created during food preparation that deserves attention but are frequently overlooked. One such substance is ethyl carbamate (EC), sometimes referred to as urethane, a naturally occurring carcinogen found in fermented foods. Ethyl carbamate is often operating in the shadows. This sneaky compound is not something you will find listed on food labels. Yet, it lurks in some of the foods and drinks many of us consume regularly.

So what is ethyl carbamate, how does it end up in our meals, and why should you care? Let us unpack the mystery behind this silent poison.

Ethyl carbamate (EC) is an organic compound with the chemical formula C₃H₇NO₂. This compound has caught the attention of scientists and food safety experts because it has been classified as a Group 2A carcinogen by the International Agency for Research on Cancer (IARC), which means it is carcinogenic to humans due to evidence of carcinogenicity in animal studies. In other words, there is enough evidence in animal studies to raise red flags for human health. While EC is not intentionally added to foods, it forms naturally during fermentation, storage, and heat processing of certain foods and alcoholic beverages.

How Does This Toxin Form in Our Food?

Ethyl carbamate is formed when ethanol (alcohol) reacts with substances like urea, citrulline, or cyanate which are precursors that are  naturally present in certain foods. These precursors are typically produced during fermentation by yeast and lactic acid bacteria. So, anytime a food is fermented, heated, or stored for a long period, especially if it contains alcohol, EC has a chance to form.

In alcoholic beverages like wine, beer, sake, and spirits, yeast activity during fermentation produces urea as a byproduct. This urea can later combine with ethanol to form EC, particularly during aging or storage.

Fermented foods like soy sauce, miso, kimchi, and fermented tofu can contain proteins and ethanol that react under the right conditions to form EC.

Even fruit-based spirits may produce EC through reactions involving cyanogenic glycosides from fruit pits.

Heat-processed foods like roasted coffee, baked bread, or smoked meats can also trigger chemical reactions that result in EC formation, especially when nitrogen-containing compounds are present.

In simple terms, if it is fermented, aged, stored for a long time, or exposed to heat, there is a chance that ethyl carbamate could be hiding inside.

Most Surprising Sources of EC

You might expect to find food contaminants in unknown products, but EC shows up in some surprisingly common foods. For example sake, brandy, and whiskey all contain EC and are all aged, fermented, and ethanol rich. Soy sauce and miso which are pantry staples, especially in Asian cuisine, also contain EC. Roasted coffee, your favorite morning brew might contain trace amounts of EC. Toasted bread with its popular golden crust comes with its own chemical story. Some cheeses and yogurts which are fermented dairy products can develop trace amounts of EC due to bacterial activity depending on processing. Fruit spirits and preserves, especially those using stone fruits like peaches or plums contain EC due to natural cyanide precursors in pits. The cyanide precursors in these pits can convert into EC during fermentation. : Fermentation processes in pickling of some vegetables can also create the perfect conditions for EC formation. The list goes on but it is not about scaring you away from your favorite foods but rather about having awareness and making smart choices when it comes to food and our safety.

Why Should You Be Concerned?

Let us be honest about the matter. Just hearing the word carcinogen is enough to spark concern in us but what makes ethyl carbamate particularly alarming is that it is naturally formed, unavoidable in small amounts, and not directly added to our foods. This makes it a bit of a ghost in the machine. Animal studies have shown clear evidence of EC's ability to cause tumors, especially in organs like the lungs, liver, and blood vessels. While human studies are still limited, the IARC classification is a precautionary measure based on animal data. EC is not highly toxic in small doses, but chronic, low-level exposure over time is what experts worry about most. Frequent consumption of EC-containing foods cumulative effect could increase long-term health risks. In other words, it is not about what one meal does. It is about the cumulative exposure of these tiny traces consumed over a lifetime. Regulatory agencies like the FDA and WHO have not established a "safe" level. Meaning there is no safe threshold emphasizing the need to avoid and minimize it as much as we can.

How to Reduce Exposure

If you probably are wondering if anything can be done to avoid and minimize exposure to EC, Yes, there is, and yes you can. While it may not be realistic to avoid EC entirely, you can take steps to limit your intake. These includes opting for fresh, unprocessed foods as much as possible. The fewer the fermentation and storage steps, the lower the risk of EC poisoning. When it becomes necessary to have fermented food products, we must keep them in cool, dark places to slow EC formation. Alcohol and alcoholic food products particularly aged and fermented drinks like whiskey, sake, and brandy must be consumed moderately. You should use soy-based condiments in moderation, especially fermented ones like soy sauce or miso. Limit excessively heating foods, especially when baking, toasting, or roasting. You should also choose younger wines and spirits when possible as they tend to have lower EC levels than aged products. We must also diversify our diet by rotating fermented and heat-processed foods with fresh alternatives. Only support companies and brands that obey regulation and are transparent. Look for producers who test and limit EC content in their products, especially in regions where food safety laws are stricter.

With these measures in place, you would not have to give up on your favorite foods. We should just be mindful. Food safety is generally about knowing hidden dangers like ethyl carbamate, not only about avoiding visible contaminants. Although research is still being conducted on the toxin, exposure can be reduced with awareness and wise decisions.

Although it may not be well-known, ethyl carbamate is a component of the modern food ecosystem and one of many naturally occurring compounds that serve as a reminder of the complexity of our food system. Making educated decisions is more important than panicking. We may push for safer food processing standards, demand clearer labels, and ask better questions as consumers. After all, food safety is not just about what is added but rather about what is created along the way. Therefore, we must keep in mind that even the smallest compounds might have fascinating backstories So, the next time you sip a glass of wine, drizzle soy sauce over your sushi, or enjoy a slice of toasted bread, remember this. 

References

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Food and Drug Administration (FDA). (2006). Guidance for Industry: Action Levels for Poisonous or Deleterious Substances in Human Food and Animal Feed. Silver Spring, MD: U.S. FDA.

World Health Organization (WHO). (2005). Ethyl Carbamate. WHO Food Additives Series, No. 55. Geneva, Switzerland: WHO.

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Nettleship, A., Henshaw, P. S., & Meyer, H. L. (1943). Induction of Pulmonary Tumors in Mice with Ethyl Carbamate (Urethane). Journal of the National Cancer Institute, 4(3), 309-319.

Park, K. K., et al. (2015). Occurrence and Reduction of Ethyl Carbamate in Fermented Foods. Comprehensive Reviews in Food Science and Food Safety, 14(5), 611-626. https://doi.org/10.1111/1541-4337.12148