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How Long Does Breast Milk Stay Good For?

Hi, Friends! I’m Amanda DeWeese, International Board Certified Lactation Consultant (IBCLC) with Lactation Link and breastfeeding mama with four sons.

Have you ever heard anyone call breastmilk “liquid gold”?

Breast Milk has some truly A M A Z I N G properties! In fact, the Academy of Breastfeeding Medicine (ABM) tells us that, “Human milk is a fresh, living food with many antioxidant, antibacterial, prebiotic, probiotic, and immune-boosting properties in addition to nutrients.”

These properties help make it very robust, especially in terms of storage and freshness. However, there are some universal guidelines that are recommended by the ABM for safely handling breast milk.

Today, we’re going to explore the answers to some of our most frequently asked questions about: How long does breast milk stay good for?

How long does breast milk stay good?

Whether you are planning ahead for a fun night out or are getting ready to head back to work, knowing how to safely handle and store breast milk is crucial! 

How long can breast milk stay good on the counter?

According to the ABM, freshly expressed breast milk can be safely left at room temperature/on the counter (10–29°C, 50–85°F) for at least four hours.

Research has shown a range of times that could be acceptable, varying based on cleanliness of the expressed milk and ambient temperature, with an upper range of 6-8 hours being acceptable if the expressed breast milk is very clean and there is a cooler ambient temperature.

How long can you store breast milk in the fridge?

Conservatively, breastmilk kept in a refrigerator at around 4°C, 39.2°F has been evaluated for safety around 2-3 days. If the breast milk has been expressed with little contamination, studies have shown that it is still safe to use after as many as 4-8 days in the refrigerator, according to the ABM.

How long can breast milk stay good in a cooler with ice packs?

For a small cooler with ice packs (around 15°C, 59°F), research has shown that breast milk shows minimal bacterial growth at 24 hours. Thus, the ABM suggests breastmilk can be safely stored on ice packs for up to 24 hours.

This method of storing milk would be best for temporary situations, when there are no other convenient options, such as while traveling or working. Here I am, on-the-go, breast pump in hand!

How long can you store breast milk in the freezer?

Breastmilk has been shown to be safe (in regards to bacterial contamination) for at least three months in the freezer at temperatures of -4°C to -20°C, 24.8°F to -4°F. Studies have found that some vitamins and minerals can begin to decrease in frozen milk as early as after 90 days, while other nutrients have been determined to be stable for as long as 6 months.

Thus, the ABM suggests that the optimal time for storing breast milk in the freezer is 6 months, but 12 months would also be in the acceptable range.

What if baby doesn’t finish a bottle? Can I offer it at the next feeding?

If breastmilk that has previously been frozen has been thawed and offered to baby, it can be offered to baby at the next feeding within 1-2 hours. However, once baby begins to drink expressed breast milk, bacteria from her mouth could contaminate the milk.

To date, there has been insufficient research examining the exact amount of time that breastmilk can be left at room temperature after being partially fed, and there are many factors that could affect this period of time.

Thus, the ABM proposes that 1-2 hours after baby has finished eating would be a reasonable period of time before needing to discard unused milk. In order to avoid wasting this liquid gold, it may be helpful to store milk in smaller portions; even though many storage bottles and bags have a 6-oz capacity, many babies may only take between 2-4 oz per feeding.

Can I refreeze previously thawed breast milk?

Breastmilk that was previously frozen and thawed should not be refrozen. There is insufficient research regarding the bacterial growth and antibacterial activity on thawed and refrozen breast milk.

What about if I combine milk pumped at different times?

Breastmilk that is expressed at different times can safely be stored together. If you would like to combine freshly expressed milk with milk that has already been in the refrigerator, it is best to wait until the fresh milk cools down to the temperature of the older milk before adding it to the refrigerated milk. This prevents the cooler milk from getting warm. Always use the date/time of the older milk when labeling.

More Tips!

In general, how you store or use expressed breast milk can vary depending on how the milk is expressed, the temperature, and where you are storing it.

Keep in mind that breastmilk is highly robust, and there has been limited research regarding bacterial growth and contamination of expressed human milk. When in doubt, you may feel comfortable using the most conservative guidelines, especially if your baby has special medical considerations.

Click here for a printable chart with Human Milk Storage Guidelines from the Centers for Disease Control and Prevention (CDC) showing conservative guidelines or here to read the full ABM Clinical Protocol for Human Milk Storage Information for Home Use for Full-Term Infants.

Want more easily accessible information about how to store and use expressed breastmilk? Check out Lactation Link’s online Pumping & Storing Breastmilk course! Need more individualized support or demonstrations for you and your little one?

We can walk through it together! E-consultations provide the expertise of a lactation specialist without having to take one step away from the couch, while in-person visits provide the convenience of learning how to handle expressed breast milk in your own home with your own tools. 

If you’ve enjoyed reading this post, follow me on Facebook and Instagram for more great tips, photos, and videos! Let’s be breast friends!

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