storage of breast milk

Storage of Breast Milk

Breast milk can be stored in clean glass or hard BPA-free plastic bottles with tight-fitting lids. You can also use milk storage bags, which are made for freezing human milk. Do not use disposable bottle liners or other plastic bags to store breast milk.

After Each Pumping

  • Label the date on the storage container. Include your child's name if you are giving the milk to a childcare provider.

  • Gently swirl the container to mix the cream part of the breast milk that may rise to the top back into the rest of the milk. Shaking the milk is not recommended. This can cause a breakdown of some of the milk's valuable components.

  • Refrigerate or chill milk right after it is expressed. You can put it in the refrigerator, place it in a cooler or insulated cooler pack, or freeze it in small (2 to 4 ounce) batches for later feedings.

Tips for Freezing Milk

  • Wait to tighten bottle caps or lids until the milk is completely frozen.

  • Try to leave an inch or so from the milk to the top of the container because it will expand when freezing.

  • Store milk in the back of the freezer -not in the freezer door.

Tips for Thawing and Warming Up Milk

  • Clearly label milk containers with the date it was expressed. Use the oldest stored milk first.

  • Breast milk does not necessarily need to be warmed. Some moms prefer to take the chill off and serve at room temperature. Some moms serve it cold.

  • Thaw frozen milk in the refrigerator overnight, by holding the bottle or frozen bag of milk under warm running water, or setting it in a container of warm water.

  • Never put a bottle or bag of breast milk in the microwave. Microwaving creates hot spots that could burn your baby and damage the components of the milk.

  • Swirl the milk and test the temperature by dropping some on your wrist. It should be comfortably warm.

  • If thawed breast milk is not refrigerated and at room temperature (from 60°F to 85°F), it’s best to use it within 1 to 2 hours. Three to four hours is okay.

  • Use refrigerated (39°F or colder) thawed breast milk within 24 hours.
    Do not re-freeze thawed breast milk.

  • You can keep germs from getting into the milk by washing your pumping equipment with soap and water and letting it air dry.

Guide to Storing Fresh Breast Milk for Use with Healthy Full-Term Infants

Countertop, table

  • Temperature

    • Room temp (60°F-85°F)
  • How Long

    • Up to 6-8 hours is okay for very clean expressed milk.
  • Things to Know

    • Containers should be covered and kept as cool as possible; covering the container with a clean cool towel may keep milk cooler.
    • Throw out any leftover milk within 1 to 2 hours after the baby is finished feeding.

Small cooler with an ice pack

  • Temperature

    • 59°F
  • How Long

    • 24 hours
  • Things to Know

    • Keep ice packs in contact with milk containers at all times; limit opening cooler bag.


  • Temperature

    • 39°F or colder
  • How Long

    • Up to 5-7 days is okay for very clean expressed milk.
  • Things to Know

    • Store milk in the back of the main body of the refrigerator.


  • Temperature

    • 24°F or colder
  • How Long

    • Up to 6 months is best.

    • Up to 12 months is okay if milk is stored at 0°F or colder.
  • Things to Know

    • Store milk toward the back of the freezer where temperature is most constant.
    • Milk stored at 0°F or colder is safe for longer durations, but the quality of the milk might not be as high.

Updated January 13, 2022

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