Collecting & Storing Breast Milk

November 29, 2011

Storing breast milk is a great option no matter if you’re returning to work, exclusively pumping, or just looking to give other family members an opportunity to feed your little one. The benefits of breastfeeding are extensive, however it’s important that nursing mothers understand breast milk storage guidelines and safe handling instructions before they get started. So, use the information below as reference when giving your baby the best nutrition possible.

Breast Milk Storage Guidelines:

  • Room Temperature: up to 4 hours
  • Refrigerator: up to 3 days
  • Freezer: up to 6 months
  • Breast Milk Thawed in the Refrigerator:
    • At room temperature up to 2 hours
    • In the refrigerator up to 24 hours
    • Do not refreeze!

Safe Handling Instructions for Collecting and Storing Breast Milk:

  • Store breast milk in clean, BPA-free containers intended for breast milk storage.
  • It is normal for stored milk separates into layers with the cream at the top.  Gently swirl warmed bottles to mix the milk layers. Don’t shake.
  • You can continue to add small amounts of cooled breast milk to the same refrigerated container throughout the day.  Avoid adding warm milk to already cooled milk.
  • Pumped milk may be added to frozen milk provided it is first chilled and the quantity is less than what is frozen.
  • Store your milk in collection bottles or in disposable bags specifically designed for breast milk. Avoid using plastic bottle inserts.
  • Freeze milk in 2 to 5 ounce portions.  Small amounts will thaw more quickly.  You will also waste less milk this way and avoid over-feeding.  Liquids expand when frozen so be sure to leave some extra room at the top of the container so the bottle or bag won’t burst.
  • Seal containers tightly.  Write the date on a piece of tape on the bag or bottle.  You can also use Medela’s Labeling Lids for convenient organization.
  • Sometimes defrosted breast milk can have a soapy taste or odor.  This is due to a normally occurring enzyme, lipase, which helps to digest the fat content of the breast milk.  To avoid this from occurring, scald the breast milk (do not bring to a boil) on a stove until tiny bubbles appear along the sides of the pan; do this before it is frozen.  The scalding process will neutralize the enzyme preventing the soapy taste or smell.
  • Never microwave breast milk.  It causes hot spots that can burn your little one’s mouth.  Microwaving can also change the composition of breast milk.
  • Thaw milk overnight in the refrigerator, or hold the bottle under warm running water to quickly thaw.  You can also place the sealed container in a bowl of warm water for 20 minutes to bring it to body temperature.

Note: These guidelines may differ if your baby was born premature. Check with your healthcare provider for specific breast milk guidelines for premature babies.

Do you have any tips for breast milk collection and storage? Share them in the comments below.

118 thoughts on “Collecting & Storing Breast Milk

  1. How come the medela ice pack produce slimy substance instead of watery when it starts to defrost? I just notice it everytime I use it with the medela bag.

    • Hi Macel,

      We’re sorry to hear that and would like to put you in touch with our Customer Service team so we can help. Please call 1-877-633-3522. Thank you!

    • Hi Katie — If you plan to use your milk within 8 days, you can store it in the refrigerator. Otherwise, store it in the coldest part of the freezer, where it can remain for up to four months.

  2. If i need to go out and want to take some milk from my storage (freezer) in the cooler bag (one ice pack) how long can last the milk

    • Hi, Hana. That’s not something we can predict with certainty due to many factors that could affect the milk temperature inside of the cooler pack. Definitely follow the guide above and don’t keep breast milk at room temperature longer than four hours. If you’re concerned about your milk, we recommend checking with a local Lactation Consultant to answer your questions.

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