The shelf life of milk powder varies from manufacturer to manufacturer and from milk powder to milk powder, so be sure to read the instructions on the outer packaging. The shelf life of sealed nitrogen-filled cans of milk powder is two years, non-nitrogen-filled cans of milk powder for one year, bottles of milk powder for nine months, bags of milk powder for six months, and after opening the shelf life in the case of light, ventilation, dry in a month. The protein content of milk powder is relatively high and prone to bacterial growth. After opening, milk powder should not be stored in the refrigerator, as the temperature difference can lead to dampness, lumps or deterioration of milk powder, which must be placed in a cool, light-proof and dry place, and the packaging mouth needs to be sealed tightly after each consumption. If the milk powder is more than one month old, you should not give it to your child. You should buy the right amount according to the amount of milk your child needs to drink.