That is, about ten days. Sour milk (commonly known as yogurt) is an extremely important and common dairy products, it is cow's milk or recovered milk as the main raw material, with or without the addition of excipients, after pasteurization, access to lactobacillus strains, insulation and fermentation of products made of a kind of nutritional food for young and old alike. However, the bacteria it carries are still fermenting, so the shelf life is not long.