Storing Breastmilk
It is essential to properly store your expressed (pumped) milk to maximize its nutritional, immunological and antioxidant qualities. Human milk has antibacterial properties that help it stay fresh. When stored properly, human milk can maintain many of its nutritional qualities.
Prior to expressing and storing milk you should:
Wash your hands
Use containers that have been washed in hot, soapy water, rinsed and air dried
These storage tips are for HEALTHY newborns. If your baby is hospitalized you should receive special instructions for storing your milk from your baby’s healthcare team.
General storage tips:
All milk should be dated before storing. Use the first in, first out rule and use the oldest milk first.
Storing milk in 2-4 ounce (60 to 120 ml) amounts may reduce waste.
Refrigerated milk has less fat loss and more anti-bacterial and protective properties than frozen milk.
When combining milk expressed from different pumping sessions, ensure fresh milk is chilled in the refrigerator before adding it to previously expressed milk.
STORAGE CONTAINERS
Bottles
glass or hard-sided plastic containers with well-fitting tops
avoid containers made with the chemical bisphenol A (BPA), identified with a number 3 or 7 in the recycling symbol. A safe alternative is polypropylene, which is soft, semi-cloudy, and has the number 5 recycling symbol and/or the letters PP. You can avoid the risks of plastic completely by using glass.
containers which have been washed in hot, soapy, water, rinsed well, and allowed to air-dry before use or washed and dried in a dishwasher
containers should not be filled to the top – leave an inch of space to allow the milk to expand as it freezes
Bags
freezer milk bags that are designed for storing human milk
squeeze out the air at the top before sealing, and allow about an inch for the milk to expand when frozen.
stand/lay the bags in another container at the back of the refrigerator shelf or in the back of freezer where the temperature will remain the most consistently cold.
Disposable bottle liners or plastic bags are not recommended. With these, the risk of contamination is greater. Bags are less durable and tend to leak, and some types of plastic may destroy nutrients in milk.
REHEATING BREAST MILK
Thawing From Frozen
If possible, thaw in the refrigerator overnight
Run warm water over the sealed frozen container of milk
Place frozen container in cup of warm water
*Avoid boiling and microwaving
Warming Refrigerated Milk
While many infants may be content drinking room temperature milk, some may have a preference for warmer milk. It is recommended to warm milk slowly in lukewarm water to protect fat content and nutrients.
COMMON QUESTIONS
Why is my milk separating?
Human milk naturally separates into a milk layer and a cream top when it is stored. This is normal. It is safe to shake or swirl the milk to combine the cream prior to feeding.
Is it safe to refreeze my milk after thawing?
Previously frozen milk that has been thawed can be kept in the refrigerator for up to 24 hours. There is currently limited research that supports the safety of refreezing breastmilk as this may introduce further breakdown of nutrients and increases the risk of bacterial growth. At this time, the accepted practice is not to refreeze thawed milk.
Can I reuse previously fed milk if my baby does not finish?
If baby does not finish the bottle during a feed, the recommendation is milk may be reused within 1-2 hours and after this time frame should be discarded to avoid transfer of bacteria from baby’s mouth to bottle. Many moms find storing milk in smaller quantities can help reduce waste if baby does not finish the bottle.
