Any kind of food has a shelf life and a safe eating period. After the shelf life, the food may have gone bad, and if it is eaten again, it will endanger people's health.
2. Substances harmful to human health in expired food:
Salmonella: Salmonella is often associated with meat, eggs and milk. The symptoms of poisoning are mainly acute gastroenteritis. Early symptoms include nausea, headache, general weakness and chills. The main symptoms are vomiting, diarrhea, abdominal pain, yellow-green watery stool, sometimes accompanied by pus and mucus. Generally, the temperature of fever is 38 degrees Celsius to 40 degrees Celsius. In severe cases, symptoms such as chills, convulsions, convulsions and coma occur. The course of the disease lasts for three to seven days, and the prognosis is generally good, but the elderly, children and the infirm can die if they are not treated in time.
Escherichia coli: Escherichia coli often appears in animal-derived foods, such as beef, chicken, milk and dairy products, which can cause peritonitis, cholecystitis and appendicitis. Infants, the elderly, the infirm, patients with chronic wasting diseases and extensive burns, Escherichia coli can invade the blood stream and cause sepsis, and some serotypes of Escherichia coli can also cause human diarrhea.
Aflatoxin: Aflatoxin mainly exists in various nuts, especially peanuts and walnuts. Aflatoxin is positively correlated with hepatocellular carcinogenesis. Long-term consumption of food containing low concentration of aflatoxin is considered to be the main cause of liver cancer, gastric cancer, intestinal cancer and other diseases. Aflatoxin Bl is a highly toxic poison, which mainly causes human poisoning, such as liver injury, hepatitis cirrhosis, liver necrosis and so on. Clinical manifestations include stomach discomfort, loss of appetite, nausea and vomiting, abdominal distension and tenderness in the liver area. In severe cases, edema, coma and even convulsion may occur.
Nitrosamine: Nitrite enters the human body with grains, vegetables, fish and egg milk every day. Nitrite easily combines with amine to form nitrosamine. Nitrosamines are strong carcinogens, which can cause tumors in offspring through placenta and milk. At the same time, nitrosamines have teratogenic and mutagenic effects. Population epidemiological investigation shows that some human cancers, such as gastric cancer, esophageal cancer, liver cancer, colon cancer and bladder cancer, may be related to nitrosamines.
3. Brief introduction of shelf life:
The shelf life of a product refers to the best edible period of the product. The shelf life of the product is provided by the manufacturer and marked on the product for limited use. During the warranty period, the manufacturer of products is responsible for the quality of products meeting relevant standards or explicitly guaranteed quality conditions, and the seller can sell these products with confidence, and the consumer can use them with confidence.
Shelf life is not the only criterion to identify whether food and other products have deteriorated. The reason for deterioration may be the premature deterioration of substances with changes in storage methods and environment. Therefore, food should be eaten as soon as possible before the expiration of the shelf life.
The shelf life of opened food will be shortened, so use it as soon as possible to avoid the deterioration of product quality.
4. The validity period of food is a relative period, and there is generally room for it. Storage and custody are very important. If it doesn't go bad when you eat it, it means it doesn't go bad. Eat a little, you don't have to be afraid at all, what's more, our bodies still have some resistance.