Dangers of Pickled Foods A major feature of Ningbo cuisine is pickled foods, such as pickles, salted fish, ham, sausages and other foods, which contain nitrates and nitrites. Nitrates can be reduced to nitrates. Nitrates. In the pickling process of Ningbo vegetables, nitrates or nitrites are often used. If the dosage is improper, there is a risk of forming nitrosamines. At the same time, there are also certain amounts of nitrates and nitrites in people's saliva. Fresh vegetables contain a certain amount of non-toxic nitrate, which will be reduced to toxic nitrite during the salting process. Under normal circumstances, nitrite begins to increase significantly 4 hours after salting, reaches a peak in 14-20 days, and then gradually decreases. Therefore, either eat pickles that have been pickled within 4 hours, or eat pickles that have been pickled for more than 30 days. Nitrite can cause hypoxia symptoms such as bruising, and can also combine with secondary amines in food to form carcinogenic nitrosamines. After being eaten into the stomach, nitrite reacts with secondary amines, a product of protein breakdown, under the action of gastric acid to form nitrosamines. There is also a type of bacteria in the stomach called nitrate-reducing bacteria, which can also combine nitrites with amines to form nitrosamines. These bacteria thrive when there is a lack of stomach acid. Therefore, regardless of the amount of gastric acid, it is beneficial to the production of nitrosamines. Nitrosamines have strong ulcerogenic effects and mainly cause esophageal cancer, gastric cancer, liver cancer and colorectal cancer. Ammonium nitrite is a well-recognized strong carcinogen. Nitrosamines are a class of organic compounds. Simply put, nitrosamines are compounds composed of nitrate and amines. There are many types of nitrosamines. Some people have conducted animal tests on more than 100 nitrosamines, and found that more than 80 of them are carcinogenic. Experiments have shown that as long as amines and nitrites are taken in at the same time, nitrosamines can be synthesized in the human body. Nitrosamines may induce tumors in important organs of the human body, such as the liver, stomach, intestines, kidneys, etc. Ammonium nitrites can be synthesized in the human body. The nitrites and nitrates that each person consumes every day react with secondary amines in the stomach or intestines of the human body to easily generate amine nitrites, thereby increasing its danger to the human body. . Therefore, to avoid the synthesis of nitrite amines, we must start by cutting off its precursor substance nitrite. The dose of nitrite that causes acute poisoning in humans is 0.003~0.005 grams, and the safe value per person per day is 0.003~0.005 grams. If the safe value is exceeded, nitrite amines may cause harm in the human body, induce liver cancer, and cause tumors in the esophagus, stomach, small intestine, lungs, bladder and other systems. Attachment: Theoretical demonstration of the harm of nitrite. Nitrite interacts with lactic acid in muscles to produce free nitrite. Nitrous acid is extremely unstable, so it decomposes to produce NO, which combines with myoglobin to form nitrosomyoglobin, which is heat-stable. Toxicity: Oral LC50 for novices 220 mg/kg ADI: tentatively 0~0.2 mg/kg (total nitrite is calculated as sodium nitrite). It is one of the most toxic substances in food additives, with a maximum dose of 0.3 grams. Ingesting a large amount of nitrite can cause methemoglobin to turn into methemoglobin and lose its oxygen-carrying function, causing enterogenic cyanosis. However, this disease will not occur under normal dosage conditions. Nitrite can also form nitrosamines with secondary amines (secondary amines), which is a carcinogen. Therefore, its limit must be strictly controlled.