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How can I Store Breast Milk!

Updated: Apr 18, 2022

Breast milk storage can be confusing. Follow these practical tips on choosing containers, freezing breast milk, thawing breast milk and more.

Whether you have a larger supply of breast milk and want to put some aside for later use, or if you need to go back to work while still breastfeeding and need to delegate some of the feeding duties to your partner or a babysitter, you might need to collect breast milk for storage.

Types of Breast Milk Storage Containers Portioning the Breast Milk for Storage Hygiene Guidelines for Pumping Breast Milk

Types of Breast Milk Storage Containers

The following are options for storing breast milk, and the recommended containers to use:

  • It’s best to collect freshly pumped or expressed breast milk in clean glass or plastic screw cap bottles or hard plastic storage cups with tight-fitting lids.

  • Avoid any plastic containers that have the recycling number 7, as this means the container may have been made with BPA-containing plastic.

  • You can also use special breast milk storage bags that are pre-sterilized for storing breast milk.

  • Don’t store breast milk in disposable bottle liners or regular plastic storage bags that weren’t designed for breast milk storage.

Some baby bottles are designed so you can store breast milk in them straight after pumping. Read up on baby bottles for more info on them.

Portioning the Breast Milk for Storage

Store the breast milk in two- to four-ounce portions, which is about the right amount for one feeding (read more on breastfeeding), in order to avoid waste.

Mark whichever storage container you’ve chosen with the date of pumping, and with your baby's name if the milk will be consumed at day care. Always use the oldest stored breast milk first, as long as it’s still within its use-by limit.

If you’re going to place the container in the freezer for storage, make sure to leave an inch of air space at the top since the liquid will expand when frozen.

Hygiene Guidelines for Pumping Breast Milk

There are some steps you can take to prevent transmitting bacteria to the breast milk and to your baby.

Before using your breast pump for the first time, make sure to sterilize all its parts, including the nipples, bottles, and any parts that come into contact with your breasts or the milk.

Sterilize by boiling the parts for 5 to 10 minutes. Check the manufacturer’s directions for sterilizing and follow the recommended boiling time in case it’s a little different.

Each time you use the pump, make sure to wash your hands thoroughly.

After every time you use the pump, make sure to wash the parts in hot, soapy water, or in the dishwasher, if the parts are dishwasher safe.

Freshly expressed or pumped breast milk can be stored in the following ways:

How to Defrost Frozen Breast Milk

Follow these tips for thawing breast milk stored in the freezer:

  • Thaw frozen milk by holding the container under cool running water. As it begins to thaw, switch to warm running water.

  • Or allow the frozen breast milk to thaw in the fridge — it might take about 24 hours.

  • Once the milk has thawed, give it to your baby within 24 hours.

  • Never thaw frozen milk at room temperature.

  • Do not refreeze thawed breast milk.

Can You Reheat Chilled Breast Milk?

Yes. Breast milk that’s been stored in the refrigerator, whether it’s been previously frozen or not, can be reheated if you would like to give your baby warm milk. But know that breast milk does not need to be given to your baby warm. It’s OK to feed your baby breast milk that’s chilled or at room temperature.

If you wish to reheat breast milk after storage in the fridge, follow these steps:

  • Place the bottle of breast milk in warm water. Use a pan or bowl of warm water to reheat your baby’s bottle, or use a bottle warmer.

  • Do not heat bottles on the stovetop or in the microwave. High temperatures can kill breast milk’s disease-fighting antibodies and can also create hot spots that could burn your baby’s mouth.