How to Store Breast Milk

Freezer or Fridge: A Basic Guide to Breast Milk

Yes, it is worth crying about spilled milk—at least, when it's your own milk that's been spilled. You've missed meetings, lost sleep and sacrificed cocktail hour to pump that breast milk, so having to throw it out because of improper storage is a huge loss. Nourishing your child with it makes all that sacrifice worthwhile, which is why storing your breast milk properly is so important. It will last just hours at room temperature or as long as a year in the freezer.

Packing Breast Milk

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Using clean, airtight containers to store breast milk protects it from contamination. As soon as you express it, pour the milk into a glass or hard plastic BPA-free bottle with a tight-fitting lid or into a plastic bag made especially for storing breast milk. Other types of plastic bags or containers aren't suitable for this purpose.

Aim to fill each container with a single serving of milk. That way, you can thaw and serve a single bottle at a time. Leave at least an inch of space at the top if you plan to freeze the milk because it will expand as it freezes. Write the pumping date and the quantity of milk on a label and attach the label to the container.

Wash your hands with soap and water before expressing milk. If you touch anything between pumping and packaging the milk, wash your hands again before transferring the milk to the containers.

In the Fridge

Breast milk can be stored safely in the refrigerator for up to five days, if the internal temperature is no greater than 39 degrees F. Place the containers near the back of the fridge to keep them as cold as possible. Avoid overcrowding that area of the refrigerator, so the cold air can circulate around the containers. Don't put breast milk on a shelf on the fridge door because it will be exposed to warm air every time the door is opened.

In the Freezer

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The colder the freezer and the less frequently it's opened, the longer breast milk will keep. Store it for up to six months in the freezer half of your refrigerator if it has a separate door from the fridge. If your freezer doesn't have its own door, such as a mini-fridge, store milk in it for no longer than two weeks.

A chest or upright freezer is the best option of all. Presumably, you don't open it regularly, so milk stays frozen consistently inside. Store it for up to 12 months in this type of freezer, again placed near the back or bottom of the freezer to keep it as cold as possible.

In a Cooler

Storing milk in a cooler is a convenient way to keep it cold when you're traveling or if you don't have access to a fridge at work. Keep the containers in an insulated cooler, surrounded on all sides by frozen ice packs, for up to 24 hours. Aim to open the cooler only after you're home and ready to transfer the milk to the fridge or freezer, so don't put other food and drinks in the cooler with the milk.

On the Counter

On a cool day, milk can stay safely on the counter for up to eight hours—but only if the room is no warmer than 77 degrees F. Don't store breast milk on a counter or table if the room is hotter than that. Cover milk containers with a towel to protect them from light and heat.

Reheating Breast Milk

Always grab the oldest milk from the freezer or fridge, assuming it's still within the window of time for safe storage. Thaw frozen milk by putting it in the refrigerator overnight. To thaw it quickly, place a container of milk in a bowl of warm water or hold it under a stream of warm water. Give the container a swirl every minute or so until it's completely liquid.

A picky baby may refuse milk unless it's warm. Heat up any stored breast milk by running it under warm water or by following the directions for your bottle warmer. Don't heat milk in the microwave or in hot water; it may scald your baby's mouth.

It's important to only thaw the amount of milk you need for the next day. Once it's thawed, use it with 24 hours or discard it. Seeing all that hard-earned liquid go down the drain is a bummer, so err on the side of thawing too little milk at a time. You can always heat up more milk quickly if you need to, but you can't safely refreeze milk once it's thawed.