Tips on Storing Breast Milk Safely

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Storing Breast Milk

The following information is meant for full-term, healthy babies. If your baby is premature or has a medical condition, consult your health care provider for further instructions.


Do not use disposable plastic nurser bags, the ones used with baby bottles. These bags are thin and because of this, fat and antibodies in the breast milk can be lost.

If you choose to use plastic bags, use ones that are specially designed for storing breast milk. They are stronger so they are better at protecting milk components. They also come with self-closures so they can be closed easily and securely.

Glass or hard-sided plastic (clear, not cloudy) containers are best in protecting breast milk. These containers can be washed in hot soapy water and be reused. After washing, air dry the containers by placing them on a towel. Containers can be washed in a dishwasher.

Storing Breast Milk

Write the date and time on each container before storing. Use the oldest milk first.

Add small amounts (about 2-4 ounces) to each container. Smaller amounts are quicker to thaw.

Do not fill the containers completely. Leave about an inch of space because breast milk will expand. With plastic bags, squeeze the air out of the top and close it one inch above the milk.

Plastic bags should be placed in another container like a bin.

Length of time:

  • room temperature (66-78° F): 4 (ideal) - 6 (acceptable) hours
  • refrigerator (32-39° F): up to 8 days
  • freezer (-0.4 to -4° F): 6 (ideal) - 12 (acceptable) months.

Previously thawed breast milk can be stored in the refrigerator for 24 hours. Do not refreeze.

You can add fresh milk to already frozen milk but cool it in the refrigerator first. Your container should contain more frozen milk than fresh milk.

Traveling with Breast Milk

When traveling with breast milk, it is best to put your containers in an insulated pack using frozen gel packs. Do not use ice if transporting frozen milk. Ice is warmer (freezes at 32° F) than frozen milk (freezes at 0° F) and this will cause the breast milk to thaw.

Click here for more information on storing breast milk and thawing/warming breast milk.


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