Leftovers should be kept for 5-6 hours, and it is better not to eat overnight food.

According to scientific determination, some overnight vegetables, especially overnight green leafy vegetables, not only have low nutritional value, but also produce pathogenic nitrite. The amount of nitrite produced in stored vegetables increases with the increase of storage time and temperature, but if vegetables are stored in refrigerator (2-6 degrees Celsius), the increase of nitrite is less.

It's winter, and some families think that it's cold and leftovers don't need to be put in the refrigerator. This view is also wrong. Now, the widespread use of refrigerators in cities has reduced the nitrite content people consume from food, but it does not mean that putting vegetables in the refrigerator can be completely reassuring; After a long time, the nitrite content will still increase.

It is worth mentioning that different kinds of vegetables produce different amounts of nitrite under the same storage conditions. Usually, stem and leaf vegetables are the highest, melon vegetables are slightly lower, and roots and cauliflowers are in the middle. Therefore, if you buy different kinds of vegetables at the same time, you should eat stems and leaves first, such as Chinese cabbage and spinach. If you are going to cook more vegetables and eat them hot the next day, you should try to make fewer stem and leaf vegetables and choose melon vegetables.

After frying, there is oil and salt in the dish. After a night, the vitamins in the dish are oxidized, which greatly increases the content of nitrite and turns into nitrite after entering the stomach. Although nitrate is not a direct carcinogen, it is a big health hazard. After nitrite enters the stomach, it will produce a substance called NC (N-nitroso compound) under certain conditions, which is one of the risk factors of gastric cancer. Especially in hot weather, overnight meals are contaminated by bacteria, which will multiply and easily lead to gastroenteritis and food poisoning.

Many fried dishes can't be eaten and stored, especially some high-protein and high-fat leftovers, which are even more inedible. Harmful bacteria in the air will attach to the leftovers within 2 hours and start to reproduce. As we all know, most of protein and fat will produce harmful substances under the action of bacteria, such as hydrogen sulfide, amines, phenol, etc., which are harmful to human body.

It is an indisputable fact that eating leftovers for a long time is easy to cause cancer. Therefore, you can't eat overnight dishes. When cooking, the best way is to tailor your clothes, not to harm your health!