2, because the refrigerator stores food for a long time and is often cleaned, it will breed a lot of bacteria. Although the food in the refrigerator looks fresh, it has actually gone bad. Cooked meat should not be stored in the refrigerator for more than 4 days.

3. The commonly used refrigeration temperature for food preservation in refrigerator is 4℃ to 8℃. In this environment, the growth rate of most bacteria will slow down. But some bacteria are psychrophilic, such as Yersinia, Listeria, etc., which can grow and reproduce rapidly at this temperature. If you eat food infected with this kind of bacteria, it will cause intestinal diseases. The temperature in the freezer of the refrigerator is generally around-18℃. At this temperature, bacteria are generally inhibited or killed, so the food stored in it has better fresh-keeping effect. But freezing does not mean that it can be completely sterilized, and some bacteria with strong freezing resistance will survive. Therefore, from another perspective, if the refrigerator is not disinfected frequently, it will become a "hotbed" for some bacteria.

In addition, don't store too much food in the refrigerator, which will make the external temperature of food low and the internal temperature high, leading to deterioration.