What is storing breast milk?

Collecting breast milk is a way of giving your baby breast milk in a bottle. If you collect milk, you can store it so you don't have to use it right away.

Why store your breast milk?

Storing breast milk lets you feed your baby later or allows someone else to do it. This is useful if you're going back to work or will be gone at feeding time. It's also a way to give your baby breast milk if he or she can't breastfeed.

How can you store it safely?

• Be sure to wash your hands before you pump or handle milk that will be stored.
• Wash the storage containers in hot, soapy water or in the dishwasher.

  They should be clean and dry. They don't need to be sterile.

• Use plastic bottle liners, small freezer bags, or glass bottles for storage.

  If using freezer bags, hold them upright in cups. Be sure the bags are sturdy and are stored in a place where they won't get punctured or damaged.

• If you plan to freeze the milk, allow a little space at the top of the bag or bottle.

  The milk will expand when it freezes.

• Write the date the milk was pumped on the outside of the bag or bottle.

  The date will help you know which milk to use first and when to get rid of milk you didn't use.

• You can combine the milk from both breasts expressed during the same session in one container.

  It's best to use a container that holds only enough milk for one feeding. Then you'll be less likely to have to throw away unused milk.

• Store milk at the back of the refrigerator or freezer compartment.

  This will give the best temperature control.

• Thaw the breast milk carefully.

  Run warm water over the storage container until the milk becomes slushy. You can also thaw breast milk overnight in the refrigerator. Then warm the breast milk by setting it in lukewarm water for 20 minutes. The water should be no warmer than 40 °C (104 °F).

• After you thaw the milk, swirl the container gently.

  Frozen breast milk will separate because the fat floats to the top. This separation is normal. It doesn't mean that the milk has spoiled or can't be used. Swirling helps the fat mix evenly.

• Don't refreeze thawed milk.
• Don't use thawed (and then refrigerated) breast milk after 24 hours.
• Don't use a microwave oven for warming milk.

  Microwaves heat unevenly, creating hot spots that can burn your baby's mouth and throat.

There is very little research about how safe it is to refrigerate and reuse breast milk left over from a previous feeding. But many experts say it's best to throw away any breast milk left in the bottle after a feeding.

How long can you store it?

Breast milk can be stored in the following ways:

• Kept at room temperature [16 °C (60 °F) to 29 °C (85 °F)] for 3 to 4 hours. If the milk was collected under clean conditions, such as by using properly washed hands and properly cleaned pump parts and containers, milk may be kept at room temperature for 6 to 8 hours.
• Kept fresh in a cooler with an ice pack [15 °C (59 °F)] for 24 hours.
• Stored fresh in the refrigerator [4 °C (39 °F)] for up to 4 days. If the milk was collected under clean conditions, it may be stored for 5 to 8 days.
• Kept in a freezer [-18 °C (0 °F)] for up to 6 months.