Fresh milk can be put at room temperature for a few hours, the specific time is related to the temperature, the higher the temperature can be put the shorter the time. Fresh milk 2 ~ 6 ℃ refrigerated shelf life is generally about 2 to 8 days, specifically with the manufacturer process, the packaging will be printed on the shelf life. Milk is not stored properly or left for too long, and drinking it after heating it can also cause diarrhea. Protein and lactose in milk is the nutrients for bacterial growth, the milk sold through regular channels will be sterilized before leaving the factory. Fresh milk that is pasteurized milk, sterilization temperature is lower than room temperature milk, better taste better flavor, nutritional retention is more complete, but the protein and calcium content is not much difference. Any variety of milk should be drunk as soon as possible after opening, undrinkable cover and refrigerated storage, it is recommended to drink within 24h.