Because repeated heating of food will not only destroy the original nutrients, but also increase substances such as nitrite and nitrate. If you eat too much, you will be at risk of cancer.

At the same time, the boiled soup generally contains less salt, and at a suitable temperature, microorganisms are easy to reproduce and metabolize, producing lactic acid. The sour soup we are talking about is the result of microbial proliferation and metabolism.

Health experts believe that it is best to drink less or not to drink such soup. First, the hot weather may make the soup taste bad, which is easy to cause intestinal diseases. Secondly, many soups, especially those like tremella soup or fish soup, will react chemically in the pot, thus producing harmful substances. Therefore, experts suggest drinking overnight soup as little as possible.

Extended data:

If you really want to drink overnight soup, you can take the following measures.

The best way to preserve soup is not to put seasoning such as salt at the bottom. After the soup is cooked, scoop out what you want to drink that day with a clean spoon, and it is best to keep it in the refrigerator with a clay pot. Because the leftover soup is stored in aluminum pot and stainless steel pot for a long time, it is prone to chemical reaction, so it should be kept in glass or ceramic utensils.