Generally speaking, after the milk powder is opened, it can not be stored in a relatively low temperature, dry and clean environment for more than 1 month at the longest. Milk powder is rich in proteins, lactose, vitamins and minerals, after opening the milk powder direct contact with the air, especially suitable for bacterial growth and reproduction. The trace elements, such as iron, are also prone to oxidation in the air, causing gastrointestinal discomfort. The water-soluble vitamins in milk powder are also prone to moisture caking and deterioration, resulting in the loss of nutrients. Life, milk powder should pay attention to light preservation, not too high or too low temperature, the storage environment should be relatively dry, to prevent caking, breeding bacteria. Once opened, it is recommended that it be consumed within 1 month, and it is not recommended that it be consumed for more than 1 month, so as not to adversely affect the child.