Breast milk storage guidelines: fridge, freezer and cooler
Breast milk storage guidelines from the CDC in one calm place: how long milk keeps in the fridge, freezer and cooler, how to thaw and warm it, and when to let it go.
The Stenviax team6 min read
Every ounce you express is a little gift of time and love. Storing it well means none of it goes to waste.
These breast milk storage guidelines gather the CDC's figures in one place, along with the small habits that make them easy to follow on a tired day. Where health bodies give slightly different figures, the numbers here are the CDC's.
How long does breast milk last?
Here is how long freshly expressed breast milk keeps, according to the CDC:
| Where you store it | How long it keeps |
|---|---|
| Room temperature, 77 °F or colder | Up to 4 hours |
| Refrigerator | Up to 4 days |
| Freezer | About 6 months is best; up to 12 months is acceptable |
| Insulated cooler with frozen ice packs, when traveling | Up to 24 hours |
Store milk toward the back of the fridge or freezer, not in the door. The CDC explains that further inside, the milk is protected from the temperature changes each time the door opens.
What are the breast milk storage guidelines for freezing?
Freezing well is mostly about portions and labels. The CDC's advice:
- Freeze small amounts. Store 2 to 4 ounces, or the amount offered at one feeding, so nothing is wasted.
- Leave room at the top. Leave about one inch of space, because breast milk expands as it freezes.
- Label every container. Write the date the milk was expressed. The AAP adds your child's name if the milk is going to a child care provider.
- Cool before combining. The CDC says it is best to cool freshly expressed milk before combining it with older, previously cooled or frozen milk.
For containers, the CDC suggests milk storage bags or clean, food-grade containers with tight-fitting lids, made of glass or BPA-free plastic.
Warm stored milk to a setting you choose, in about 70 seconds.
Stenviax Portable Bottle Warmer Pro, Silk Beige, $69.90
How do you thaw frozen breast milk safely?
Always thaw the oldest milk first, the CDC says. You can thaw it in the refrigerator overnight, in warm or lukewarm water, or under lukewarm running water.
If you thaw milk in the refrigerator, use it within 24 hours. The CDC is specific about when that clock starts: count the 24 hours from when the milk is completely thawed, not from when you took it out of the freezer.
How do you warm stored breast milk?
Gently, and never in a microwave. The CDC warns that microwaving can destroy nutrients in breast milk and create hot spots that can burn a baby's mouth. Its own method is to set the sealed container in a bowl of warm water, or hold it under warm, not hot, running water for a few minutes.
A warmer with fixed settings gives you the same known result every time. On the Stenviax Bottle Warmer Pro, you pour the milk into the chamber and choose 92, 95 or 98 °F, and the manual sets 98 °F as the highest to use for breast milk.
Measured from refrigerator temperature at a full charge, 4 oz reaches 98 °F in about 70 seconds. The warmer beeps twice when it is ready, and you pour the milk into your baby's bottle.
Shake stored milk before you warm it, since its nutrients settle. Once it is warmed, the CDC says to use it within 2 hours. There is more on temperatures in our story on warming breast milk in a portable warmer.
What do you do with leftover breast milk?
If your baby did not finish the bottle, the CDC says to use the leftover milk within 2 hours. After 2 hours, it should be thrown away.
The easiest way to waste less is to warm what your baby usually takes. If another caregiver is handling a feed, clear labels help them follow the same rules; we cover the handover in sharing night feeds with your partner.
Clean feeding items well, too. The CDC says to clean baby bottles after every feeding, and to sanitize them daily if your baby is under 2 months old, was born prematurely or has a weakened immune system. Let everything air-dry, and skip the dish towel, which can transfer germs.
For the warmer, the manual says to rinse the chamber and lid with clean or mildly soapy water as soon as you have poured.
Frequently asked questions
- How long can breast milk stay in the fridge?
- Up to 4 days, according to the CDC. Keep it toward the back of the refrigerator rather than in the door, where the temperature changes each time the door opens.
- How long does breast milk last in the freezer?
- The CDC says about 6 months is best and up to 12 months is acceptable. Freeze it in 2 to 4 ounce portions, labeled with the date it was expressed, and thaw the oldest first.
- Can you refreeze breast milk after it has thawed?
- No. The CDC says never refreeze breast milk after it has thawed. Milk thawed in the refrigerator should be used within 24 hours of being completely thawed.
- Can you save leftover breast milk for the next feed?
- Only within 2 hours. The CDC says leftover breast milk can be used within 2 hours after your baby finishes feeding, and should be thrown away after that.
- Can I warm breast milk in the microwave?
- No. The CDC says never thaw or heat breast milk in a microwave, because it can destroy nutrients and create hot spots that can burn a baby's mouth.
Sources
- CDC: Breast milk storage and preparation (opens in a new tab)cdc.gov
- CDC: Breast milk storage questions and answers (opens in a new tab)cdc.gov
- CDC: Travel recommendations for nursing mothers (opens in a new tab)cdc.gov
- AAP (HealthyChildren.org): Storing and preparing expressed breast milk (opens in a new tab)healthychildren.org
- CDC: How to clean, sanitize, and store infant feeding items (opens in a new tab)cdc.gov
Made for the nights ahead
The Stenviax Portable Bottle Warmer Pro warms 4 oz of breast milk to 98 °F in about 70 seconds, with no cord and no trip to the kitchen. A thoughtful gift for a new mom, too.
Measured from refrigerator temperature at a full charge.
Silk Beige finish
