Refrigeration is the most important factor when it comes to the storage of milk products. Whether you are storing breast milk, prepared formula milk or cow's milk, it is crucial that you adhere to the recommended guidelines for refrigeration and freezing times to maintain the quality of the milk and prevent excessive bacteria growth. Parents should be familiar with the guidelines for storing and freezing breast milk, formula milk and cow's milk.
According to breast-pump manufacturer Medela, freshly expressed breast milk can be stored at room temperature for four to six hours at 66 to 78 degrees Fahrenheit. Breast milk can be kept in a cooler, together with three frozen ice packs, for up to 24 hours at 59 F. In a refrigerator, breast milk will last for three to eight days at 39 degrees Fahrenheit or lower.
BabyCentre, the award-winning pregnancy and parenting website, warns against storing formula you have mixed from powder in the fridge for any length of time, because milk powder is not sterile and this increases the risk of bacteria building up. Ready-made cartons of formula milk can be stored in the refrigerator, once opened, for up to 24 hours. The carton should be placed in the main section of the fridge, as this is the coldest part.
Manufacturers recommend storing pasteurised cow's milk in the refrigerator, using it within five days of being opened and consuming it by the use by date. According to Clemson Cooperative Extension, however, if milk is properly stored it can be stored in the refrigerator for up to two weeks. The colder the temperature cow's milk is stored at, the longer it lasts.
Breast milk can be stored in a freezer for six to 12 months at a temperature of zero to 4 degrees F. It is not advisable to freeze formula milk, as this can affect the quality and texture of the milk. Cow's milk can be frozen on the day it is purchased, and should be used within one month. It should be defrosted thoroughly in the fridge for a minimum of eight hours and used within three days. Skimmed and semi-skimmed milk should be frozen in small quantities -- around 1 quart -- because it takes a long time to defrost. After it has thawed, shake it well to blend it.