After breast milk is expressed, it is recommended to let it cool down and then freeze it, usually for about half an hour. In general, if you have more breastmilk to express, you can keep it in a milk storage tool if there is any left over to satisfy your baby’s needs. If you need to freeze the milk, it is recommended that you wait until it cools down before putting it in the emergency room of the refrigerator. If you put it in the refrigerator when the temperature is too high, it may affect the quality of breast milk and also the function of the refrigerator. However, in case of time constraint, you can also put it into the freezer directly. In addition, if you need to store the breast milk, it should be sealed immediately to avoid exposure to airborne microorganisms that may affect the quality. Usually, breast milk can be stored frozen for about 1 week and it is recommended to consume it as soon as possible to avoid safety risks. In addition, when storing breast milk, attention should be paid to ensure the cleanliness and hygiene of the breasts. Milking machines and milk storage supplies should be properly cleaned and disinfected to avoid infection of the milk.