I receive so many inquiries about the proper storage of human milk that I thought I would just add the most updated version of the information given by the CDC – Center for Disease Control and Prevention and the AAP – American Academy of Pediatrics

Proper Handling and Storage of Human Milk

By following safe preparation and storage techniques, nursing mothers and caretakers of breastfed infants and children can maintain the high quality of expressed breast milk and the health of the baby.

Safely Preparing And Storing Expressed Breast Milk

•Be sure to wash your hands before expressing or handling breast milk.

•When collecting milk, be sure to store it in clean containers, such as screw cap bottles, hard plastic cups with tight caps, or heavy-duty bags that fit directly into nursery bottles. Avoid using ordinary plastic storage bags or formula bottle bags, as these could easily leak or spill.

•If delivering breast milk to a child care provider, clearly label the container with the child’s name and date.

•Clearly label the milk with the date it was expressed to facilitate using the oldest milk first.

•Do not add fresh milk to already frozen milk within a storage container. It is best not to mix the two.

•Do not save milk from a used bottle for use at another feeding.

Safely Thawing Breast Milk

•As time permits, thaw frozen breast milk by transferring it to the refrigerator for thawing or by swirling it in a bowl of warm water.

•Avoid using a microwave oven to thaw or heat bottles of breast milk

◦Microwave ovens do not heat liquids evenly. Uneven heating could easily scald a baby or damage the milk

◦Bottles may explode if left in the microwave too long.

◦Excess heat can destroy the nutrient quality of the expressed milk.

•Do not re-freeze breast milk once it has been thawed.

Source: American Academy of Pediatrics.

Storage Duration of Fresh Human Milk for Use with Healthy Full Term Infants

Location Temperature Duration Comments

Countertop, table Room temperature (up to 77°F or 25°C) 6–8 hours Containers should be covered and kept as cool as possible; covering the container with a cool towel may keep milk cooler.

Insulated cooler bag 5-39°F or -15-4°C 24 hours Keep ice packs in contact with milk containers at all times, limit opening cooler bag.

Refrigerator 39°F or 4°C 5 days Store milk in the back of the main body of the refrigerator.

Freezer Store milk toward the back of the freezer, where temperature is most constant.
Milk stored for longer durations in the ranges listed is safe, but some of the lipids in the milk undergo degradation resulting in lower quality.

Freezer compartment of a refrigerator 5°F or -15°C 2 weeks
Freezer compartment of refrigerator with separate doors 0°F or -18°C 3–6 months
Chest or upright deep freezer -4°F or -20°C 6–12 months