Expressing and storing Breastmilk

Breastmilk Storage Guidelines

Where Temperature Ideal Time Acceptable Time
At Room Temperature 66 to 78°F (19 to 26°C) Within 4 hours Up to 6 hours
In a Refrigerator <39°F (<4°C) Within 3 days Up to 8 days
In a Freezer -0.4 to -4°F (-18 to -20°C) Within 6 months Up to 12 months

What Type of Container to Use

Refrigerated or frozen breastmilk may be stored in:

  • Hard-sided plastic or glass containers with well-fitting tops.
  • Freezer milk bags that are designed for storing breastmilk, like

Other storages tips:

  • Containers should not be filled to the top — leave an inch of space to allow the breastmilk to expand as it freezes.
  • Disposable bottle liners are not recommended, due to greater risk of contamination.
  • Bags are less durable and tend to leak, and some types of plastic may destroy nutrients in breastmilk.
  • Mark the date on the storage container. Include your baby’s name on the label if your baby is in a day care setting.
  • Keep frozen or refrigerated breastmilk in the middle or back of the freezer or refrigerator away from the sides or the door where the temperature can fluctuate.

How to Warm the Breastmilk

  • Thaw and/or heat under warm, running water.
  • Do not bring temperature of breastmilk to boiling point.
  • Gently swirl breastmilk before testing the temperature. Swirling will also redistribute the cream into the breastmilk. (It is normal for stored breastmilk to separate into a cream and breastmilk layer.) Do not shake vigorously as it could damage some of the live components of breastmilk.
  • Do not use a microwave oven to heat breastmilk.

Thawed Breastmilk

  • Previously frozen breastmilk that has been thawed can be kept in the refrigerator for up to 24 hours.
  • It should not be refrozen.