Nitrite is one of the most common causes of food poisoning, which is also called enterogenous cyanosis, cyanosis, black mouth disease and so on. Generally, poisoning is caused by eating pickled meat products, pickles and spoiled vegetables with high nitrite content, or eating industrial sodium nitrite as salt by mistake, and a few are caused by drinking bitter well water and boiler water containing nitrate or nitrite. Nitrite can oxidize low-iron hemoglobin which normally carries oxygen in blood into methemoglobin, thus losing its oxygen-carrying ability and causing tissue hypoxia.
Nitrite is a highly toxic substance. Adults can be poisoned if they ingest 0.2-0.5g, and can die if they ingest 3g. Nitrite is also a carcinogen. According to the research, esophageal cancer is positively correlated with the amount of nitrite ingested by patients. The carcinogenic mechanism of nitrite is that nitrite reacts with secondary amines, tertiary amines and amides in food under the environment of gastric acid and so on to generate strong carcinogen nitrosamines. Nitrosamines can also enter the fetus through the placenta and have teratogenic effects on the fetus. 20 17127 October, in the reference of the preliminary arrangement of the list of carcinogens published by the World Health Organization, nitrate or nitrite ingested under the conditions leading to endogenous nitrosation was listed in the list of Class 2A carcinogens.
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Nitrite can be used as a color fixative for meat products, which reacts with myoglobin in meat products to produce rose-colored nitrosmyoglobin, thus improving the color of meat. It can also enhance the flavor of meat, act as a preservative, prevent the occurrence of Clostridium botulinum and prolong the shelf life of meat products. Although the national standard stipulates that it is legal to use a small amount of nitrite color fixative, for health reasons, we should try to avoid buying such meat products.