What to know about breast milk storage

Ruth Health

May 18, 2022

Breastfeeding Postpartum

Ruth Health

May 18, 2022

Fast facts:

Proper storage and preparation of breast milk is essential to your baby’s health.

Freshly expressed or pumped breast milk can be safely stored at room temperature for up to four hours, in the refrigerator for up to four days, or in the freezer for 6-12 months.

Store expressed milk in a glass container, breast milk storage bags, or a plastic container that does not contain BPA.
Thawed breast milk must be used within 24 hours.

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How do I store and use breast milk?
How long can breast milk be stored before going bad?
Why can't you refreeze breast milk?
Tips for freezing and refrigerating breast milk
We're here to support your breastfeeding journey

If you’ve chosen to breastfeed and are expressing or pumping breast milk, it’s important to know how to store it.

Proper storage and preparation of breast milk is essential to your baby’s health.

If you are experiencing challenges with your milk supply, a lactation consultant can observe you and your baby during a breastfeeding session and offer individualized solutions.

Ruth Health offers nearly 24/7 virtual lactation support from Certified Lactation Counselors (CLCs) to provide individualized care on your time.

Here’s an overview of breast milk storage, so that you can maintain the quality and nutritiousness of expressed breast milk.

How do I store and use breast milk?

Proper storage and preparation of breast milk starts before you express or handle your breast milk.

It’s critical to practice good hygiene throughout the expressing or pumping process. Wash your hands thoroughly with soap and water or an alcohol-based hand sanitizer.

If you are using a pump, make sure your tubing is clean and remove any moisture. Never pump with moldy tubing. If you are using a multi-user or hospital grade rental pump, wipe down the pump dials and power switch.

Expressed breast milk can be stored at room temperature or in the refrigerator or freezer using one of the following:

A glass container
A clear plastic container that does not contain BPA (short for an industrial chemical called bisphenol A)
Breast milk storage bags

Here are several tips to ensure proper storage and preparation of breast milk.

If storing your breast milk in a container, make sure the lid fits tight.
Label your breast milk with the date it was expressed.
Avoid storing your breast milk in the door of your refrigerator or freezer. This is to prevent any temperature changes that may happen when the door opens and closes.

How long can breast milk be stored before going bad?

A variety of factors affect how long it’s safe to store breast milk, including milk volume, room temperature at the time of milk expression, and temperature fluctuations in your refrigerator or freezer.

Follow the general guidelines below to ensure proper storage and preparation of breast milk.

Freshly expressed or pumped breast milk can be stored:

At room temperature (77°F or colder) for up to four hours
In the refrigerator (40°F) for up to four days
In the freezer (0°F or colder) for 6-12 months

If your baby doesn’t finish all of the expressed milk within one feeding, you can use your breast milk again within two hours without refrigeration.

While breast milk can be safely stored in a freezer for up to 12 months, it’s ideal to use frozen breast milk within six months for the best quality. To avoid temperature changes as the door opens and closes, put your milk toward the back of the freezer.

If you don’t anticipate using freshly expressed or pumped breast milk within four days, it’s best to freeze it immediately to preserve its quality.

Why can’t you refreeze breast milk?

Refreezing breast milk may introduce a risk of bacteria. It's best to use thawed breast milk within 1-2 hours at room temperature or within 24 hours of being stored in the refrigerator.

There are several ways to safely thaw frozen breast milk:

If you don’t plan to use your breast milk right away, leave it in the refrigerator, where it will take about 24 hours to thaw.
If you need to use your breast milk sooner, place it in a container or bowl of warm water.
If you need to use your breast milk immediately, put it under lukewarm running water.

Never heat breast milk in the microwave. This can overheat the milk, which can compromise its enzymes and immune properties and is not safe for your baby to consume.

Always use your oldest breast milk first, as the quality of your milk will gradually decrease over time.

Thawed breast milk must be used within 24 hours. The 24-hour window starts when your breast milk is completely thawed, not when it was first taken out of the freezer.

Tips for freezing and refrigerating breast milk

We probably don’t have to tell you that it’s not ideal to toss expressed breast milk, so store it in small amounts to avoid waste.
The average amount of milk consumed in a feeding is 2-4 ounces, but depending on your baby’s age and feeding habits you may want to store your breast milk in even smaller amounts (1-2 ounces).
Breast milk expands as it freezes, so leave about an inch of space at the top of your container or bag.
If you are traveling, it’s safe to store breast milk in an insulated cooler with frozen ice packs for up to 24 hours.

We’re here to support your breastfeeding journey

Support from a lactation consultant can be pivotal if you encounter any challenges on your breastfeeding journey. You can also use this support to prepare for breastfeeding even before your baby arrives.

Ruth Health offers nearly 24/7 virtual lactation support from Certified Lactation Counselors (CLCs) to provide individualized care on your time.

Learn how we can help with your breastfeeding journey.

And don't forget to join our community by signing up below!

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