Freezer temperature is generally around minus 18 ℃, in such an environment, typically will be inhibited or killed bacteria, so it is stored inside the food product has a better preservation effect. Although freezing can preserve food for a longer period of time, the microorganisms in the food do not die. Once the temperature rises, they will continue to grow and reproduce. Therefore, the food stored in the refrigerator must be re-cooked before eating, otherwise it will also cause intestinal infections and even food poisoning.