In this article we covered the basics of pumping breastmilk. Once you’ve pumped it, though, you need to store it and serve it to your baby at a later time. Here’s how to do that, safely.

Highlights:  Here’s a quick guide for safely storing and serving pumped breastmilk: Storing Breastmilk:  Store it in new breastmilk storage bags or clean, food-safe containers that are BPA-free.  Store breastmilk at room temperatures (77° F or less) for up to 4 hours, in a refrigerator for up to 4 days, or in a freezer for up to 12 months. Remember to label each container with the date the milk was expressed.  Warming and Thawing Breastmilk:  It’s fine to feed your baby room-temperature or even cold breastmilk.  You can thaw frozen breastmilk by placing it in the fridge, allowing it to thaw for 24 hours, and then using it within 24 hours. Or, you can run it under warm water or place it in a bowl of warm water until it’s thawed, then use it within 2 hours.  Never thaw frozen breastmilk in the microwave because overheating it can kill nutrients and high temperatures can burn your baby.  Leftover Breastmilk  You can put leftover milk in the fridge for up to 2 hours.  Keep in mind that it’s not safe to refreeze milk.

What do I store breastmilk in?

For storing breastmilk, use new breastmilk storage bags or clean, food-safe containers with a tight-fitting lid (many breast pumps come with storage containers and/or bags). If you’re using plastic containers, be sure they’re BPA-free.

How do I store breastmilk, and how for how long?

While breastmilk storage guidelines vary slightly amongst experts, the U.S. Center for Disease Control and Prevention says you can keep breastmilk:

• At room temperature (77° F or less) for up to 4 hours. Keep it away from heat sources like stoves or sunlight.
• In an insulated cooler bag with frozen ice packs for up to 24 hours. After that, use it or put it in the refrigerator or freezer right away.
• In the refrigerator for up to 4 days. For fridge (and freezer) storage, keep breastmilk closer to the back where the temperature is more stable.
• In the freezer for up to 12 months (6 months is best). If using breastmilk storage bags, leave about an inch of space at the top of the bag to allow the liquid to expand as it freezes. To save space, you can freeze breastmilk storage bags flat and pile them on top of each other. To avoid wasting milk, freeze in small amounts (2-4 ounces).

Be sure to label each container with the date the milk was expressed (and your baby’s name if it’s going to a childcare center), and use the oldest milk first.

How do I warm or thaw breastmilk?

It’s fine to feed your baby room-temperature (or even cold) breastmilk. If you want to warm it up, hold the sealed container under warm running water or place it in a bowl of warm water. Test the temperature on your wrist before feeding it to your baby.

You can thaw a container of frozen breastmilk a few different ways:

• Place it in the fridge (it takes about 24 hours to thaw). Once it’s thawed, use it within 24 hours. Keep in mind that it’s not safe to re-freeze milk.
• Run it under warm water until it’s thawed.
• Place it in a bowl of warm water until it’s thawed.

Breastmilk should never be warmed or thawed in a microwave because it can easily overheat (which kills nutrients) or heat unevenly (which could burn your baby).

Any time you warm or thaw breastmilk, use it within 2 hours.

Can I keep breastmilk that’s left over from a feeding?

If your baby doesn’t finish a bottle of breastmilk, you can put the leftovers in the fridge and use them within 2 hours. Keep in mind that breastmilk shouldn’t be warmed more than once, because it could promote bacteria growth.

Once you get into a pumping groove, you’ll quickly get into to a storing groove, too!