Storing and Preparing Breast Milk Safely

How you store and prepare expressed breast milk affects how safe and nutritious it stays. CDC's guidance, adapted from the Academy of Breastfeeding Medicine's protocol for full-term infants, covers storage times, thawing, warming and cleaning.

CDC and USDA human milk storage guidelines, also printable as a fridge magnet (CDC).

Before you express or handle milk

• Wash your hands well with soap and water, or use an alcohol-based hand sanitizer with at least 60% alcohol if soap and water aren't available.
• Milk can be expressed by hand or with a manual or electric pump. Check that the pump kit and tubing are clean, and replace moldy tubing immediately.
• On a shared pump, wipe the dials, power switch and countertop with a disinfectant wipe.

Storage times for freshly expressed milk

Freezing keeps food safe almost indefinitely, but following these times protects the milk's quality.

Containers and storage tips

• Use breast milk storage bags or clean, food-grade glass or plastic containers with tight lids — never disposable bottle liners or plastic bags not meant for breast milk.
• Label each container with the date it was expressed, and with your child's name if it goes to a child care provider (ask about their other requirements).
• Store milk toward the back, not in the door of the fridge or freezer, where temperatures swing as the door opens.
• If you won't use fresh milk within 4 days, freeze it right away.
• Freeze small amounts — 2 to 4 ounces, or one feeding's worth — and leave about an inch at the top, because milk expands as it freezes.
• When traveling, milk can be kept in an insulated cooler with frozen ice packs for up to 24 hours; then use it, refrigerate it or freeze it.

Thawing safely

• First in, first out: thaw the oldest milk first, since quality declines over time.
• Thaw it in the refrigerator overnight, in warm or lukewarm water, or under lukewarm running water.
• Never thaw or heat breast milk in a microwave, which can destroy nutrients and create hot spots that burn a baby's mouth.
• Milk thawed in the fridge should be used within 24 hours, counting from when it is fully thawed.
• Once milk reaches room temperature or is warmed, use it within 2 hours.
• Never refreeze thawed breast milk.

Feeding

Breast milk doesn't need warming — it can be served cold or at room temperature. To warm it:

• keep the container sealed and set it in a bowl of warm water, or hold it under warm (not hot) running water for a few minutes;
• test a few drops on your wrist before feeding;
• never heat it on the stove or in the microwave;
• swirl it to mix in fat that may have separated.

If your baby doesn't finish a bottle, use the leftover milk within 2 hours, then throw it away.

Cleaning equipment

Carefully clean, sanitize and store pump parts, bottles and other feeding items to keep the milk from being contaminated. CDC has detailed guidance on cleaning infant feeding items and on breast pump hygiene.

Sources

• Centers for Disease Control and Prevention: "Breast Milk Storage and Preparation," adapted from the Academy of Breastfeeding Medicine's Clinical Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants (revised 2017); a work of the United States government in the public domain.