Collecting & Storing Breastmilk

November 29, 2011

Storing breastmilk 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 breastmilk 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.

Breastmilk Storage Guidelines:

  • Room Temperature: 4 to 6 hours
  • Cooler with 3 Ice Packs: 24 hours
  • Medela Cooler Bag with Ice Pack: 12 hours
  • Refrigerator: 3 to 8 days
  • Deep Upright Freezer: 6 to 12 months
  • Freezer Compartment of Refrigerator (separate doors): 3 to 6 months
  • Freezer Compartment of Refrigerator (one door): 2 weeks
  • Thawed Breastmilk: 24 hours (Do not refreeze)

Safe Handling Instructions for Collecting and Storing Breastmilk:

  • Store breastmilk in clean, BPA-free containers intended for breastmilk 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 breastmilk 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 breastmilk. 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 breastmilk 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 breastmilk.  To avoid this from occurring, scald the breastmilk (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 breastmilk.  It causes hot spots that can burn your little one’s mouth.  Microwaving can also change the composition of breastmilk.
  • 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 breastmilk guidelines for premature babies.

Looking for a breastmilk storage guidelines quick reference? You can download the chart below by clicking here.












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

79 thoughts on “Collecting & Storing Breastmilk

  1. Can I store my breastmilk in the fridge for 3-4 days after it’s been sitting in room temperature for almost 3 hours?

    • Hi Christina – Yes, you can store your milk in your refrigerator for 3 to 8 days and room temperature for 4 to 6 hours. Hope you’re having a great day!

  2. I pumped at worked around 4pm yesterday and placed my freshly pumped milk in an insulated cooler bag with a frozen hard plastic ice pack (the one specifically curved to fit bottles against). I got home late and forgot to put my milk in the fridge. I realized around 5pm today. The ice pack was no longer frozen but the milk still felt cool. A clean thermometer said the milk was 70 degreea. Any chance it can be salvaged?

  3. How can I store breastmilk in the cooler bag. Do I need to freeze the blue ice pack with gel inside? how long do I freeze. I have a flight and don’t know how.

    • Hi – You can keep your breastmilk in a cooler with ice packs for up to 24 hours. The ice packs should be frozen when you store your milk. Safe travels!

  4. Is there a way to store breast milk for longer than 12 hrs using the Medela cooler set? I don’t believe the space is sufficient to allow for additional ice packs.

    • Hi Shikha,

      Thanks for reaching out with this question. Unless additional ice packs can be used, we don’t recommend storing breast milk for longer than 12 hours using the Medela cooler set. If you have any additional questions, please get in touch with our Customer Service team at 1-877-633-3522. Thank you!

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