Storing and Warming Breast Milk

Working Mothers

When breastfeeding is not always possible many women choose the option to express breast milk. Some women work or study outside of the home and are not able to directly breastfeed their babies all the time. Expressing breast milk in these situations allows mom to provide healthy breast milk to baby when she is away. Milk can be expressed by pumping or through hand expression. Once expressed, breast milk can be stored in a refrigerator or frozen for later use. It is important to know how to store and warm breast milk safely.

Storing Breast Milk

Learning how to properly store breast milk makes it possible to feed babies breast milk even when Mom is not home. This is important because breast milk is healthier for babies than formula. Breast milk is the Gold Standard in infant nutrition. It is also good to remember that fresh breast milk is the best choice, because when it is stored it can lose some of the nutrients. Refrigerated breast milk loses fewer nutrients than frozen milk. However, even nutrient loss in frozen breast milk is not very much. Stored breast milk is still healthier than formula.

To store breast milk, put it in a clean storage container. If you will be potentially freezing the milk, make sure the container is freezer safe. Some possibilities may include glass or hard plastic containers with tight fitting lids, or plastic bags made for storing human milk. It is a good idea to put just enough milk in each container for one feeding. Usually 2-4 ounces is a good amount. This will help reduce waste because any milk left in a bottle after feeding should be thrown away.

Make sure you mark on the container with a permanent marker the date that the milk was expressed. Then you will know when it needs to be used or thrown out. Use the oldest milk first and the newest milk last. Make sure to use the milk within a safe time period. The chart below gives guidelines for how long breast milk can be stored. Milk that is kept longer than the suggested amounts of time should be thrown away.

Deep Freeze
Room Temp
Fresh Milk
6 months
3 months
8 days
10 hrs.
Thawed Milk
Do not refreeze
Do not refreeze
24 hrs
2 hrs

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Warming Breast Milk

Warming breast milk is not necessary, although some children might like it better. It is just fine to feed babies milk straight from the fridge, as long as they accept it. Because milk straight from the breast is warm, babies may prefer their milk warmed. Use one of the safe methods listed below to warm the milk. After warming it make sure to check the temperature before giving it to baby. This can easily be done by dripping a little of the warmed milk on the inside of the wrist. It should no longer feel cold, but does not need to feel warm. If the milk is about room temperature or the same temperature as the skin it should be fine.

Safe ways to thaw frozen breast milk:

  • Place it in the refrigerator for up to 24 hours.
  • Place it under warm running water.
  • Place it in a container of warm water until it thaws.

NOTE: Never refreeze thawed breast milk. It may be unsafe and make children sick.

Safe ways to warm breast milk:

  • Place it under warm running water.
  • Place it in a container of warm water.

Do not use a microwave to warm or thaw breast milk. This can be dangerous because microwaves often heat foods unevenly. This makes some parts of the milk very hot and other parts may be warm or still cold. This could make the milk feel fine to an adult when they test it, but there still might be hot spots that can burn baby’s tongue when he drinks it.

NOTE: Do not store or reheat unused breast milk at another time. When baby has drunk all that he wants throw the rest out.

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North County WIC Clinic

599 South 500 East
American Fork, UT 84003

801-851-7329 (fax)

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151 South University Ave Ste 2100
Provo, UT 84601

801-851-7303 (fax)

Orem WIC Clinic

816 N 980 W
Orem, UT 84057

801-851-7346 (fax)

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910 E 100 N, #125
Payson, UT 84651

801-465-0911 (fax)