Breastfeeding your baby: Safe Storage of Breast Milk for Full-term Babies December 14, 2012 10:07

If you have to be separated from your baby for an unplanned event or because you are returning to work or school, you can express and store your breast milk.  By following these simple guidelines, you can safely provide your baby with high-quality nutrition and protection from illnesses. 

Some nutrients and health properties of human milk change with storage, but properly stored breast milk is still better than formula for your baby’s nutritional needs and protection from illness.

How do you safely prepare to store your breast milk?


Wash your hands with soap and warm water or use an alcohol-based hand sanitizer. Hands that are clean during pumping or expressing will decrease bacteria growth during storage and keep protein levels in the breast milk high.

If you are using a breast pump to express your milk, make sure all pump parts are clean and sterilized. Wash all parts in warm, soapy water and rinse well. Sterilize parts before first use and then once a day using any one of the following methods:

»» Use the top shelf of dishwasher, (if recommended by pumpmanufacturer)


»» Boil in water on high heat on the stove for 10 minutes »» Use a sterilizing machine in the microwave

»» Use a specially-designed sterilizing bag that goes in the microwave »» Use a counter-top sterilizer


Use glass bottles or BPA-free plastic bottles made from polypropylene. BPA-free, polypropylene plastic bags designed for human milk storage can also be used. They should be sturdy, sealed well, and stored in an area where there is no risk of damage to the bag. Steel bottles and plastic bottles made from polyethylene are not recommended since both can cause a decrease in the quality of stored milk. 

You do not need to sterilize bottles for your breast milk. Wash them in hot, soapy water and rinse, or wash them in the dishwasher.

How do you safely store your breast milk?


After you have manually expressed or pumped your breast milk, label the container with the date so you can use the oldest milk first. If you are planning to freeze the milk, leave space at the top of the container to allow room for the breast milk to expand during freezing.

The chart below is a guide for how long breast milk can be safely stored.



Reference: Proper Handling and Storage of Human Milk @

You can add small amounts of cooled breast milk to the same refrigerated container throughout the day, but avoid adding warm milk to already cooled milk.

How do you safely thaw breast milk?


You can thaw your breast milk in the refrigerator overnight, under warm running water, or in a pan or bowl of warm water.

Defrosting frozen milk in the microwave is unsafe because the milk heats unevenly and can cause “hot spots.” In addition, microwaving breast milk decreases its anti-infective quality.

Expressed milk separates into layers. This is normal. Simply swirl the warmed milk to remix it. Do not shake breast milk. This may damage the proteins.

Breast milk that has been frozen and thawed for 24 hours in the refrigerator, should not be left out at room temperature for more than a few hours.

If your baby does not finish the entire bottle of expressed milk, discard the leftover milk after 1-2 hours.



Academy of Breastfeeding Medicine Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants. (Original Protocol March 2004; Revision #1 March 2010) handling_breastmilk.htm




The Nursing Mother’s Companion 6th ed. byKathleen Huggins (2010)


The Ultimate Breastfeeding Book of Answers Revised and Updated: The most comprehensive problem-solving guide to breastfeeding by JackNewman MD and Theresa Pittman (2006)


The information presented here is not intended to diagnose health problems or to take the place of professional medical care.