What foods should not be stored in the refrigerator, and why?

After tomatoes are frozen at low temperature, the flesh of tomatoes is blistered, soft and rotten, or cracked, with black spots on the surface, immature and tasteless, and even rotten in severe cases.

Bananas will turn black and rot when stored below 12℃.

Fresh Litchi If Litchi is left at 0℃ for one day, the skin will turn black and the pulp will go bad.

After the chocolate is put into the refrigerator, once it is taken out, it will form a layer of frost on the surface at room temperature, which is easy to go moldy and deteriorate and lose its original flavor.

Ham If ham is kept in the refrigerator at low temperature, the water in it will freeze, the fat will precipitate, the ham meat will agglomerate or loosen, and the meat will become stale and perishable.

During the baking of bread, amylose in flour has aged, which is the reason why bread has elasticity and soft structure. With the singing of preventive practice, the linear chains of amylose in bread are slowly associated, and the soft bread is gradually hardened. This social phenomenon is called "aging". Aging speed is related to temperature. It hardens faster in a low greenhouse, and bread hardens faster in a refrigerator than at room temperature. So if it is stored for a short time, it should be kept at room temperature to prevent the bread from hardening.

Don't put Chinese medicine in the refrigerator. If the medicinal materials are put in the refrigerator and mixed with other foods for a long time, not only are all kinds of bacteria easy to invade the medicinal materials, but they are also easy to get wet and destroy the medicinal properties of the medicinal materials. Therefore, for some precious medicinal materials, such as ginseng, velvet antler, gastrodia elata, codonopsis pilosula and so on. If it needs to be preserved for a long time, you can put it in a clean glass bottle, then add a proper amount of glutinous rice fried to dark yellow with slow fire, and cover the bottle cap.

Don't put the leftover moon cakes in the refrigerator. Moon cakes are cakes made of flour, oil, sugar and nuts. Baked food should not be stored in the refrigerator. Although for some kinds of moon cakes, putting them in the refrigerator can prolong the shelf life, it will still affect the taste. This is because the starch in the raw materials of moon cakes will mature and soften after baking, but at low temperature, the mature starch will precipitate water and age (that is, "retrogradation"), making the moon cakes hard and the taste worse.

Mooncakes with less oil and water, such as Zilaihong and Zilaihai in old Beijing, are harder. If it is placed in a low-temperature and humid environment in the refrigerator, it will not only harden quickly, but also become moldy. But for Cantonese moon cakes, the oil content is high, the flour is low, and the taste change will be relatively small.

Fish in the refrigerator should not be stored for too long. The refrigeration temperature of household refrigerators is generally-15℃, and the best refrigerators can only reach -20℃. However, when the storage temperature of aquatic products, especially fish, is lower than -30℃, fish tissues will be dehydrated or undergo other changes. For example, crucian carp will be prone to rancidity, and its meat quality will change and it cannot be eaten. Therefore, fish stored in the refrigerator should not be kept for too long.

Frozen food should not be stored after thawing. Frozen foods bought from the market, such as meat, fish, chickens, ducks, eggs and quick-frozen vegetables, should be processed and eaten as soon as possible once thawed, and should not be stored. If stored for too long, meat, fish, chicken, duck, etc. It will be restored by the vitality of bacteria and enzymes, which will not only rapidly reproduce and decompose protein and cause deterioration, but also produce toxic histamine substances, which will cause food poisoning if people eat it; Frozen vegetables stored for a long time will not only change color, lose nutrition and decrease quality, but also rot easily and become inedible. Frozen meat, frozen fish, frozen chicken and frozen duck, their tissues and cells will be destroyed by the crystallization of water. Once thawed, a large amount of protein will ooze from the damaged tissues and cells and become food for bacteria to multiply. The experiment showed that the fresh mackerel frozen 1 day was stored at 30℃ for 6 hours, and its spoilage rate was faster 1 times than that of fresh fish. After thawing, the number of bacteria increased by about 2 times when the egg yolk was placed at 65438 08℃ for 2 hours, and increased by more than 50 times after 8 hours. Frozen fresh eggs were stored at 0 ~ 65438 05℃ for more than 65438 00 days. Due to the long-term change of cold and hot temperatures, not only the egg membrane becomes loose and the egg white becomes thin, but also the eggs become sticky, yellow, and even moldy and smelly, making them inedible. Frozen vegetables, especially in hot weather, are not suitable for storage, otherwise green leafy vegetables will turn yellow soon and vitamin C will be easily destroyed. When vegetables are stored at 20℃, the decomposition loss of vitamin C is twice that of vegetables stored at 6 ~ 8℃.