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Breast Pump Basics: Storing Pumped Milk

So now you have all this freshly pumped milk. What do you do with it?

Begin by safely decanting it. With clean hands, transfer the breast milk to a clean screw-cap bottle or heavy-duty, sterile bag that will fit into a nursing bottle. Avoid regular plastic storage bags, which can leak. Special breast milk storage and freezer bags are convenient and widely available. Then label the milk with the date, so you can use the oldest supply first.

Pumped breast milk stays fresh longer than mixed formula, but it still can spoil and must be stored properly.

The CDC provides these guidelines for storing breast milk:

  • At room temperature (up to 77 degrees F or 25 degrees C), freshly pumped milk can be kept and used safely within 6 to 8 hours.
  • In an insulated cooler bag, such as the kind provided with many pumps, milk can be kept for 24 hours.
  • In the refrigerator, pumped milk can be stored for up to 5 days. Breast milk should be kept in the main part of the refrigerator.
  • In a freezer compartment that's in a refrigerator, you can store pumped milk for up to 2 weeks.
  • In a freezer compartment that has separate doors from those of the refrigerator, frozen pumped milk can be safely thawed and used for up to 6 months.
  • In a "deep freeze" -- such as a chest-style freezer -- the milk can be kept for 6 to 12 months.

It's always best to store pumped milk toward the back of the refrigerator or freezer, where it's coldest. Milk will stay fresher longer in a freezer or fridge that isn't opened often. (A spare refrigerator or freezer in the basement that's used for bulk items and not opened as often is a good place to store breast milk.)  Don't mix fresh breast milk with frozen breast milk or save leftover milk in a used bottle for another feeding.

Frozen milk can be thawed in the refrigerator. You can quickly thaw frozen milk by swirling the container in a bowl of lukewarm (not hot) water. Don't thaw it in the microwave -- that can break down some of its valuable nutrients and cause hot spots that could hurt your baby.