Storing Breast Milk

Safely prepare and store breast milk. Use clean containers. Breast milk can be stored in glass or hard BPA-free plastic bottles with tight fitting lids and milk storage bags, which are sterile and made for freezing human milk. Do not use disposable bottle liners to store breast milk.

After pumping:

It is best to refrigerate or chill milk right after it is expressed. Label the date on the storage container and always use the oldest dated milk first.

Stored breast milk tends to separate in its container into two parts, what looks like cream rising to the top and then lighter colored milk. Human milk can look clear, bluish, yellowish, or brownish. Gently swirl the container to mix the cream back into the rest of the milk. Shaking the milk is not recommended as it can cause a breakdown of some of the milk's valuable components.

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When freezing milk:

Wait to tighten bottle caps or lids until the milk is completely frozen. Try to leave an inch or so from the milk to the top of the container because it will expand when freezing.

Freeze the milk in small amounts, such as 2 to 4 ounce servings, to reduce waste if the baby does not finish all of it.

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Thawing and warming up milk:

Breast milk does not necessarily need to be warmed. Some moms prefer to take the chill off and serve at room temperature. Some moms serve it cold.

If you want to warm the milk, never put a bottle or bag of breast milk in the microwave. Microwaving creates hot spots that could burn your baby and damage the components of the milk.

Hold the bottle or frozen bag of milk under cool and then warm water for a few minutes until it thaws, then warm to a comfortable temperature. You also can allow frozen milk to thaw to room temperature on a counter or other clean surface.

Or, heat a pan of water on the stove, remove from the heat and place the container into the warm water.

Swirl the milk and test the temperature by dropping some on your wrist. It should be comfortably warm.

Cool fresh milk in the refrigerator before adding it to milk that has been frozen.

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Guide to Storing Fresh Breast Milk

for use with healthy full term infants

Place Temperature How Long Things to Know
Countertop, table Room temp (up to 77 degrees F)
Colostrum can be stored at room temp for up to 12 hours.
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 degrees F 24 hours Keep ice packs in contact with milk containers at all times; limit opening cooler bag.
Refrigerator 39 degrees F 5-8 days Store milk in the back of the main body of the refrigerator.
Freezer compartment of a refrigerator 5 degrees F 2 weeks Store milk toward the back of the freezer where temperature is most constant.? Milk stored for longer durations in these ranges is safe, but the quality of the milk might not be as high.
Freezer compartment of refrigerator with separate doors 0 degrees F 3-6 months Same as above
Chest or upright deep freezer -4 degrees F 6-12 months Same as above
Thawed, Room Temp (66 degrees F to 72 degrees F) 1 hour Do not refreeze.
Thawed, refrigerator (32 to 39 degrees F) 24 hours Do not refreeze.

Source: LaLeche League International and Academy of Breastfeeding Medicine

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