It is not recommended to eat the milk powder at most one month after unpacking to avoid the loss of nutrients and gastrointestinal discomfort. Milk powder is rich in nutrients, so it is easy to be contaminated by a variety of microorganisms and breeding, which can make the milk powder deterioration. Due to contact with oxygen in the environment after opening the milk powder, the nutrients in it can be rapidly lost, resulting in a decrease in nutritional value. In addition, the open milk powder is affected by the moisture in the external environment, it is easy to absorb moisture and caking, will also make the loss of nutrients. Especially the child’s formula milk, may lead to a variety of nutrients intake is insufficient, thus affecting the child’s growth and development, malnutrition disease and so on.