1. Meat food is frozen in the refrigerator to prevent bacteria from multiplying, so that the food will not go bad. However, food will be oxidized after long-term storage, and freezing can't prevent food from protein oxidation. Therefore, food stored for a long time will cause certain harm to people's health after eating.

2. Frozen food prevents bacteria from multiplying, but it doesn't mean that there are no bacteria in food at all. Bacteria only grow slowly at a very low temperature and will slowly penetrate into food. Therefore, frozen food should not be stored for a long time, but should be eaten as soon as possible.

3. According to experts and authoritative sources, the shelf life of frozen food will be different according to different types of frozen food and frozen temperature. If there is less than one month, the longest storage time cannot exceed half a year. Foods that have passed the storage period can no longer be eaten.

4, frozen food should not be thawed repeatedly, because food will breed bacteria and pollution in the process of repeated thawing and freezing. Not only does it accelerate the deterioration of food, but it also tastes bad. After eating it again, it will produce some toxins that are harmful to people's health.

Second, the selection skills

1. Pay attention to the brand and shelf life. Generally speaking, big brands are more guaranteed in terms of quality. When purchasing, read the packaging bag clearly, and there must be no less information such as product name, manufacturer address, production date and shelf life. Although the shelf life of quick-frozen foods is long, those close to the production date should be selected when selecting.

2. "Look at words and observe colors" to pick bulk frozen foods. All kinds of bulk frozen foods in supermarkets are always very popular, and these bulk fast foods that are "picked and picked" need more attention. If the frozen food is partially white, it is mostly because the refrigeration temperature changes too much and the water is lost and becomes dry, so don't buy it. Products that have no thawing phenomenon and no adhesion between individuals should be selected. Dumpling skin: The really good dumpling skin has no additives. We can see from the color that if the skin color of a good dumpling is white, then the flour he uses definitely contains an additive-whitening agent. The noodles of good dumplings are not absolutely white. Stuffing: The more "pill" is, the more attractive it is, the more suspicious it is. It is possible to add a group agent, thickener, edible essence and so on. So buy dumplings, the best, not the cheapest.