Because the biggest feature of probiotics is living bacteria. Probiotics should maintain a certain order of magnitude during the shelf life in order to play their due role as living bacteria. Therefore, from the effect of drinking, if probiotics want to reach the stomach and produce benign effects, they must first survive in the sales process. Therefore, general supermarkets put yogurt at 0-4℃, and many small shops put probiotic yogurt at room temperature, so the survival of probiotics is limited. Generally, the shelf life of probiotic yogurt is 15-20 days, so consumers should choose the latest probiotic yogurt. Yogurt can not be cooked and heated, nor can it be heated by microwave oven, otherwise it will agglomerate, and the lactic acid bacteria inside will be killed and lose its original health care function. Therefore, yogurt can only be a cold drink or heated with warm water.