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Breast-Feeding: Storage and Handling of Breast Milk

There may be times when you need to be away from your baby and cannot nurse. You may need to return to work before your baby has stopped nursing. Your spouse or other family member may want to feed the baby. Or, your baby may not be able to breast-feed for a while because of a medical problem. When your baby cannot be breast-fed, you can hand express or pump your breast milk and then store it safely for later use.


  • Always wash your hands and make sure that your breasts are clean before you hand-express or pump your breasts.
  • After each use of a breast pump, wash all of the parts that come into contact with your milk. Use hot soapy water or a dishwasher.

Collecting milk

  • Pour the milk expressed during one pumping session into a clean plastic or glass container. Don’t use thin plastic bottle bags. They tear too easily. And don’t use plastic bottles that contain bisphenol A (BPA).
  • Tightly cap bottles. Do not store bottles with nipples attached.
  • You can buy special breast milk storage bags.
  • Label each container with your baby's name and the date and time the milk was expressed. This is very helpful if your baby is in daycare.

Storing breast milk

You can keep fresh breast milk at room temperature (up to 85°F, or 29°C) for 6 to 8 hours. Cover the container and keep it as cool as possible.

You can store milk:

  • In an insulated cooler bag with ice packs for 12 to 24 hours
  • In the refrigerator (34 to 39°F, or 1 to 4°C) for 72 hours after pumping and 24 hours after thawing. Store it in the back of the main body of the refrigerator
  • In a freezer at:
    • 20 to 28°F (minus 7 to minus 2°C) for up to 2 weeks
    • 5 to 15°F (minus 15 to minus 9°C) for 3 to 6 months
    • 0°F (minus 18°C, or lower) for 6 to 12 months

Do not store breast milk in the door of your freezer, where the temperature may change frequently.

Thawing milk

You can thaw milk slowly or quickly:

  • Leave frozen milk in the refrigerator to thaw slowly. It may take several hours to thaw 3 or more oz (100 or more mL).
  • To quickly thaw milk, run warm water over the container or put the container in a bowl of warm water, making sure that the top of the container stays above the water at all times. Do not thaw frozen milk by letting it sit at room temperature.

After the milk thaws, swirl the container to mix the cream back in. Do not leave defrosted milk at room temperature for more than 1 or 2 hours, and do not refreeze it.

Warming milk before feeding

You need only to take the chill off cold milk before feeding your baby. You do not need to heat it. You may warm a bottle of chilled milk by:

  • Running warm water over it.
  • Putting it in a bowl of warm water. Keep the top of the milk container above the water at all times.
  • Putting it in a purchased bottle warmer. Be careful not to overheat the milk.

Do not use a microwave or stove to thaw or warm expressed milk. Milk can overheat very easily in a microwave. Babies have been burned by milk that was too hot. Also, many of the nutrients of breast milk can be destroyed by overheating.

Other safety tips

  • If you have milk left in the bottle after a feeding, throw it out.
  • Do not feed your baby milk that looks stringy or smells bad.
  • For healthy babies who are not in the hospital, it’s safe to layer milk collected at different times on the same day in the same bottle. Chill freshly expressed milk in the refrigerator for an hour before adding it to previously frozen milk. Do not add warm breast milk to frozen milk because it will partially thaw the frozen milk.
Developed by RelayHealth.
Pediatric Advisor 2015.2 published by RelayHealth.
Last modified: 2014-02-07
Last reviewed: 2013-12-18
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Copyright ©1986-2015 McKesson Corporation and/or one of its subsidiaries. All rights reserved.
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