In summer, people especially enjoy going out for barbecues and beer, preferring to buy ready-made cooked meats rather than sweat over stewing or stir-frying them themselves. But are you truly aware of the risks involved?
When it comes to food safety awareness, people often panic over newly discovered risks while completely ignoring those they encounter daily.For instance, people fear leftover vegetables and tea from the night before, worried about a toxic substance called "nitrite." Yet they remain unaware that "nitrosamines" found in salted fish, cured meats, sausages, and dried shrimp are the true carcinogens—far more concerning than leftovers.
The four most common categories of carcinogens produced during food processing:
1. Polycyclic aromatic hydrocarbons (PAHs)
The most well-known is benzopyrene, generated when fats and oils are heated. It accumulates most during charcoal grilling and prolonged deep-frying.
2. Heterocyclic Amines (HCAs)
These carcinogens form when proteins are heated above 200°C (392°F). The warning against consuming charred fish or meat stems from these compounds.Refer to this literature on the link between heterocyclic amine exposure and various cancer risks. It highlights associations between heterocyclic amines and colorectal cancer, breast cancer, prostate cancer, and others, increasing the risk of these cancers. They exhibit strong mutagenicity and have demonstrated clear carcinogenicity in animal studies.
III. Acrylamide
A suspected carcinogen formed when starchy and protein-rich foods are heated above 120°C (248°F), with production increasing significantly at temperatures over 160°C (320°F). It is commonly found in fried, pan-fried, or baked staple foods and potato products.
IV. Nitrosamines
More accurately termed N-nitroso compounds, this category includes nitrosamides, nitrosoguanines, nitrosoureas, and others. It encompasses a broad class of toxic or carcinogenic substances, with nitrosamines being the most prevalent. Examples include dimethylnitrosamine,diethylnitrosamine, nitrosomorpholine, nitrosopyrrolidine, and others. These compounds are ubiquitous—found in cured meats, dried fish, aged beer, tobacco, cosmetics, pharmaceuticals, rubber products, and polluted air. Research indicates many possess teratogenic, mutagenic, and carcinogenic properties.
Readers may not yet be familiar with nitrosamines in food. This article aims to clarify their origins, formation processes, prevention methods, and ways to mitigate their toxicity.
Studies indicate that during the production of many commonly consumed fish and meat products—such as ham, salted fish, cured meats, and sausages—nitrosamines, a class of carcinogens, are present in the final products, whether made at home or in industrial settings. The materials that create these toxins are nitrites and amines produced by the breakdown of proteins.People often view cooked hams as everyday staples, sausages and cured meats as comforting treats, and dried fish, shrimp, and squid strips as nutritious and delicious snacks... Few associate them with carcinogens, yet they genuinely contain nitrosamine carcinogens.
Where do nitrites come from?
They have two common sources. The first is the nitrites (sodium nitrite, potassium nitrite) that are essential for making ham, sausages, and many other meat products.According to ancient Chinese texts like the Essential Techniques for the People's Welfare, the practice of adding nitrites to meat dates back centuries. Humans use nitrites for two main purposes: to give meat products their appealing pink color and to extend shelf life by preventing dangerous pathogens like Clostridium botulinum from producing toxins within the meat.
Since the 1980s, research has linked consumption of processed meats containing nitrosamines—such as sausages, ham, bacon, salami, red-colored braised meats, and cooked red meat pies—to increased risks of various cancers. These include colorectal cancer, pancreatic cancer, stomach cancer, and esophageal cancer.For instance, an 18-year follow-up study of 61,433 Swedish women revealed that those with the highest dietary nitrosamine intake—specifically from processed red meats like bacon, sausages, hot dogs, and Western-style ham—faced a doubled risk of stomach cancer compared to those with the lowest intake. This effect was not observed with unprocessed meats.
One might ask: If nitrite addition produces carcinogenic nitrosamines, why not eliminate it entirely? The reason is that botulinum toxin produced by Clostridium botulinum is tens of thousands of times more toxic than carcinogens like nitrosamines, having claimed countless lives throughout history. Thus, this practice employs a "minor toxin" to prevent a "major toxin."
Unfortunately, higher nitrite levels correlate with increased nitrosamine formation in meat products. Current meat product inspections typically test only nitrite residues, rarely measuring nitrosamine levels. This is because nitrosamine detection is complex, requiring expensive equipment and advanced technical expertise—resources often unavailable to grassroots testing personnel.
Research has found that adding vitamin C to cured meats can reduce the formation of nitrosamines.A closer look at the ingredient lists on meat product labels reveals that most sausages, hams, and similar items contain added vitamin C or "sodium isoascorbate." These substances accelerate the breakdown of nitrites into nitric oxide, which enhances the meat's coloration, resulting in a more appealing appearance. This process also reduces the residual nitrite levels in the meat.However, phosphates—commonly used as water-retaining agents in meat products—have the opposite effect, increasing nitrosamine formation. Adding various spices to sausages, cured meats, and grilled products does more than just enhance flavor; it also reduces carcinogen production.Previous studies have shown that spices reduce the formation of heterocyclic amines and polycyclic aromatic hydrocarbons in grilled meats. Research on sausages indicates that spices like cloves and star anise effectively inhibit nitrosamine formation, with essential oils being the active component. In experiments, this inhibition reached up to 80%.
Since nitrites are permitted food additives worldwide, manufacturers must include them in meat products to inhibit Clostridium botulinum and enhance appearance. Therefore, when purchasing, simply examine the ingredient list on the packaging for the term "sodium nitrite."If present, the product inevitably contains trace amounts of the carcinogen nitrosamine.
Pink processed meat products should never be consumed.
Some may ask: Does homemade braised beef also produce nitrosamines?The answer is: It depends on whether you add nitrites. Without artificial nitrite additives, natural meats contain almost no nitrosamines. For example, making brown braised beef, red-cooked beef, or stir-fried/grilled lamb at home poses no risk of nitrosamine formation.However, many home-cooked meats and sausages do contain added nitrites. Traditional dishes like Zhenjiang braised pork (nitrite-cured) and Pingyao beef require nitrite preservation.Properly cooked meat should appear grayish-white or brown. If it's uniformly pink throughout, nitrites have definitely been added. If red yeast rice pigment is used, only the surface turns red while the interior remains uncolored—as seen in char siu pork or fermented tofu, where red yeast creates surface coloring.
Some also ask: Can carcinogens break down when heated? Do they decompose in the stomach? The answer is that while nitrite residues decrease after heating, the formation of nitrosamine carcinogens actually increases under steaming or boiling conditions. Unlike bacteria, these compounds are not eliminated by heat.Studies simulating gastric conditions reveal that when nitrites encounter protein-rich foods like fish in the stomach, they form new nitrosamines. While existing nitrosamines decrease, they are not entirely eliminated. Notably, adding tea or citrus juice to gastric fluid effectively inhibits nitrosamine formation in the stomach (Krul, 2004).
In summary, pink processed meats are not entirely off-limits, but they should not be consumed frequently or in large quantities, as this increases cancer risk.
Many people enjoy bacon fried until crispy, sausages grilled until dripping with fat, and lamb skewers charred to a crisp.Unfortunately, meat products that are browned, charred, and dripping with fat during frying or grilling may produce more carcinogens. This is because overheating proteins generates heterocyclic amines, starch additives in sausages produce acrylamide, and dripping fat directly exposed to heat creates polycyclic aromatic hydrocarbons like benzopyrene.It's safe to say these foods are a gathering of several common household carcinogens.