Breast milk storage: times, thawing & labels

Freshly expressed milk

These CDC home-storage guidelines are for healthy, full-term infants. Follow your care team’s instructions for premature or medically vulnerable babies.

CDC storage limits.

Thaw milk for the next feed

Use the oldest stored milk first. Smaller frozen portions let you thaw what you expect to use instead of a whole large container.

Planning ahead

Thaw the container in the refrigerator overnight. Record when it is completely thawed for the 24-hour refrigerated limit.

Need it sooner

Thaw in warm or lukewarm water, or under lukewarm running water. Once warmed or brought to room temperature, follow the two-hour limit below; quicker thawing does not create extra storage time.

Already thawed and cold

Warming is optional: breast milk can be served cold. If you warm it, keep the container sealed in warm water, test a few drops on your wrist, and swirl to mix separated fat.

Do not microwave or heat milk directly on the stove. Use the state-specific limits and note relevant times on the caregiver label. CDC thawing and preparation guidance.

Thawed milk and unfinished bottles

Thawed in the refrigerator

Use within 24 hours of complete thawing. The clock starts when the milk is fully thawed, not when it leaves the freezer.

Warmed or brought to room temperature

Use within 2 hours. Warming does not provide another 24-hour storage period.

Milk left after a feed

Use within 2 hours after the baby finishes feeding, then discard. This does not extend an earlier storage limit.

Do not refreeze fully thawed milk or use a microwave to thaw or warm it.

If the power goes out or frozen milk starts to thaw

Keep refrigerator and freezer doors closed as much as possible. Check the milk's condition and known history; power returning does not start a new storage clock.

Ice crystals remain

CDC considers this milk still frozen and says it can be refrozen. Keep its original date; refreezing does not make it newly expressed milk.

Fully thawed, but kept cold

Refrigerate and use within 24 hours of complete thawing. Do not refreeze. An earlier warming or feeding limit still applies.

Warm, or history unclear

Known warming follows the two-hour limit above. Unknown time or temperature cannot be given a fresh deadline; if safe storage is in doubt, discard the milk.

Record when you checked it, whether ice crystals remained, and the complete-thaw time if known on the handover record. These observations do not establish that a bottle is safe. CDC emergency storage guidance.

Make labels easy to read

Use milk-storage bags or clean food-grade containers with tight lids. Label the expression date, store milk inside the refrigerator rather than in its door, and use older milk first. An insulated cooler with frozen ice packs can hold milk for up to 24 hours.

Use a consistent date format and include the details your childcare provider requires.

Leave about an inch of expansion space when freezing. Freeze promptly if you will not use fresh milk within four days. CDC freezing guidance.

Combining milk: keep the older date

Cool freshly expressed milk before combining it with older stored milk. For cooled milk from different days, base storage time on when the older milk was first stored; newer milk does not reset that date. CDC combining guidance.

Check both labels first. If the older milk’s storage history is unknown, do not assign it a fresh deadline.

A handover label for the next caregiver

Copy the relevant fields onto a label and mark unused ones “not applicable.” Ask childcare what else it requires.

CDC recommends the expression date and child’s name; the extra clock fields are our planning aid. Labels do not extend storage limits or resolve unknown temperatures.

Keep a reference with your supplies

Keep the CDC storage reference with your supplies for preparation details and printable resources.

If storage duration or temperature is unknown, check current guidance and ask your child’s care team. Do not extend a limit by guesswork.