It is said that "saving is a traditional virtue of the Chinese nation", but in the face of the leftovers at home, many people have made difficulties in their hearts: it is a pity to dump them; Eat hot the next day. The words "excessive nitrite", "carcinogenesis" and "poisoning" make people worried Can I eat the overnight food? Which dishes should be poured out without hesitation and which can be saved for the next meal? How should we deal with overnight food scientifically? Today, Xiaobian will answer the questions one by one~ one Overnight dishes contain nitrite Toxic and carcinogenic? First of all, let's be clear: the so-called "overnight food" does not simply mean the food left over from the day and put on the next day. Scientifically speaking, dishes that have been stored for more than 8-10 hours belong to overnight dishes. The longer the food is stored, the more nitrite content will increase. Many people are always worried about nitrite poisoning and even cancer. Is that really the case? ? Nitrite itself is not carcinogenic In fact, nitrite itself is not carcinogenic. It widely exists in the natural environment, especially in food. For example, the average content of nitrite in vegetables is about 4mg/kg, meat is about 3mg/kg, and eggs are about 5mg/kg. The vegetables and fruits will continuously produce nitrite after being picked and harvested. In addition, nitrite is also a food preservative that can be used legally. As long as it is within the scope of national food safety standards, there is no health risk. For example, nitrite may be added to the cured foods such as ham and bacon that we often eat in our life. ? Nitrite is toxic under certain conditions However, people always say that overnight dishes are toxic and carcinogenic, which is not entirely groundless: On the one hand, if excessive nitrite is ingested in a short time, it will cause acute poisoning, affect the operation of red blood cells, and make the blood unable to transport oxygen. Mild symptoms such as dizziness and weakness, chest tightness and shortness of breath, nausea and vomiting, abdominal pain and diarrhea, and blue lips and fingertips may occur; In severe cases, it may lead to lack of oxygen in the brain, or even death. On the other hand, when nitrite enters the acidic environment of the stomach, it will react with the protein it eats to produce nitrosamines that are truly carcinogenic. Long term consumption in large quantities may lead to cell mutation, and even induce gastric cancer, esophageal cancer, liver cancer, colon cancer and other cancers. ? Did nitrite in overnight dishes exceed the standard? According to relevant domestic research reports, the minimum toxic dose of nitrite for adults is about 300mg-500mg, and ingestion of 1-3g can lead to death. What is this concept? Generally, overnight vegetables (excluding pickled vegetables and processed meat) stored in the refrigerator for 24 hours will not contain more than 10mg/kg nitrite. Therefore, the nitrite content in overnight dishes is far from the toxic dose. It is not a problem to eat a little occasionally. There is no need to "talk about the color change of overnight dishes", focusing on the frequency and amount of food. two These four overnight dishes are too dangerous If you can't finish eating, you'd better pour it out! So, can we eat the overnight food safely and boldly? no way! This is because during the storage and secondary heating of overnight meals, some nutrients will not only be destroyed and lost, but also easy to breed bacteria, which will easily cause gastrointestinal discomfort and even food poisoning after eating. In particular, the following four kinds of overnight dishes do great hidden harm to the body. If you can't finish eating them, you'd better throw them away: ? Overnight vegetables There are many advantages to eating vegetables regularly. According to the dietary guidelines for Chinese residents, adults should eat 300~500 grams of vegetables every day. But there is an old saying that goes well: "it is better to leave meat than vegetables." If the vegetables are stored for too long or improperly after cooking, a large amount of nitrite will be produced under the decomposition of nitrifying bacteria, so that the content in the leftovers is likely to reach the severe limit. Zhejiang Ningbo food inspection institute once conducted an experiment and found that green leafy vegetables such as celery and water spinach were fried and stored at 25 ℃ at normal temperature. After 24 hours, the nitrite content reached an astonishing 100mg/kg. It is strongly recommended not to eat green leafy vegetables overnight. ? Overnight seafood For seafood products such as shrimp and crab, it is difficult to completely eliminate all kinds of bacteria that may exist in seafood by using general cooking and eating methods. If they are not cooked while fresh and eaten in time, corruption may occur from inside to outside! If you don't eat on the same day and then eat overnight, it may cause bacteria to multiply and produce bacterial toxins, resulting in damage to liver and kidney functions. ? Overnight Tremella mushroom Many people put a pot of tremella soup in the refrigerator and eat it several times. But such a practice is actually very dangerous! Generally speaking, the nitrite content of dried tremella and mushrooms, whether cultivated indoors or collected in the field, is lower than that of vegetables. However, if it is soaked at room temperature for a long time, or it is stored after cooking for a long time, it will not only increase the production of nitrosamines after eating, but also easily breed bacteria. If it is stored improperly, it may produce Flavobacterium toxin, and after eating, it will cause abdominal pain, diarrhea and other symptoms. [tips]: it's OK to keep tremella soup sealed and refrigerated in the refrigerator for 1-2 days; But after 3 days, it is better not to drink; If there is no cold storage for the remaining Tremella in the bowl, it is best not to eat it the next day. ? Overnight "soft eggs" Many people prefer to eat half cooked "soft eggs" rather than boiled eggs. However, the half cooked eggs are not thoroughly sterilized, and may contain a variety of pathogenic bacteria such as Salmonella; It is easier to breed bacteria after long-term storage, and it will harm the intestines after eating. [tips]: if the eggs are cooked for the first time and stored under low temperature and sealed conditions, it is generally not a problem to eat them overnight. three Scientific storage of leftovers Eat more at ease In general, it is better to eat and cook as much as possible. If there is too much to eat, the rest can be handled according to the following four points: ? Prefer meat dishes to vegetarian dishes When you are destined to have leftovers in a meal, you should give priority to eating all the vegetables. If you can't eat all the meat and meat dishes, you can save them for the next meal. For details, please refer to the following save time ranking: Green leafy vegetables: stored for 0 days (cold dishes should be eaten as soon as possible); Staple food: keep for 1 to 2 days; Livestock, poultry, meat and meat dishes: the storage time shall not exceed 3 days. ? Don't wait until it's completely cold The longer the leftovers are stored at room temperature, the greater the risk of bacterial breeding; Moreover, some of the toxins produced by the bacteria may not be able to be killed by normal home cooking. Therefore, when the dishes are cold enough to keep them warm, you can put them in the refrigerator in fresh-keeping boxes. Don't put them in the refrigerator until they are completely cold. ? The location of leftovers in the refrigerator is also crucial ① The upper layer of the cold storage area: you can put leftover meals and other cooked foods; ② In the middle of the cold storage area: suitable for fruits and vegetables; ③ The lowest layer of constant temperature cold storage area: eggs, dairy products, bean products and meat to be eaten on that day can be placed. In this way, the raw food and cooked food are separated, which can prevent some parasites and bacteria carried in the raw food from falling onto the cooked food such as leftovers, and reduce the risk of cross infection. ? Heat thoroughly before eating Leftovers must be thoroughly heated before eating, especially meat. Thorough heating means that the whole dish is heated to 100 ℃ and kept boiling for more than 3 minutes. In order to avoid uneven heating, you can use chopsticks, forks and other tools to look at the inside of the food and make sure that it is thoroughly hot before coming out of the pot. (outlook new era)