In addition to the destruction of nutrition, overnight vegetables will also produce disease-causing nitrites. This is because the longer the storage time, the nitrite content in the vegetables will increase. Stir-fried vegetables, meat contains a lot of oil, salt, long time after the nitrite content will also increase. Nitrite is not directly carcinogenic, but there are some health risks to the body.

overnight dishes in the humid, mixed with a variety of food environment, it is easy to breed bacteria. Especially in the hot summer, the speed of bacterial reproduction accelerated, overnight dishes are easily contaminated by bacteria, people eat again, it is easy to cause gastrointestinal diseases, and even food poisoning.

For overnight dishes, many people feel that it must be "overnight", in fact, all kinds of food have its freshness, more than this period, it is not recommended to consume, and has nothing to do with overnight, the preservation of food conditions, preservation of time to determine the freshness of the food. For example, the morning fried greens eaten into the night, even if there is no overnight, it is not recommended to eat again.

For leafy greens, we may all know that put a long time inconvenient to eat, this is because leafy vegetables in the nitrate content is very high, especially spinach and celery, nitrate many times heated easily converted into nitrites harmful to the body. Leafy vegetables are mostly inexpensive, for those who can't finish eating and discard the general public will not be too painful, if those who need to prepare meals on the next day, it is recommended to choose the root, cauliflower, melon and fruit vegetables, which contain nitrites compared to leafy vegetables are lower.