How to Store & Warm Breast Milk and Preserve Nutrients

Photo credit: Leo Carvajal

How you store and warm excess breast milk is important as temperature can greatly affect the composition and nutrients.

The most important thing to keep in mind when storing breast milk is avoiding cross contamination with other foods. All containers for collection and storage of breast milk should be kept clean and sterile. 

It is acceptable to store breast milk for up to 4 days in the refrigerator (preferably the back of the refrigerator to prevent intermittent warming from the door opening). If you are going to freeze breast milk try to freeze the fresh or refrigerated breast milk within 24 hours as the beneficial enzymes begin to change at approximately 25 hours. This doesn’t have to be a determining factor in the how quickly you freeze your refrigerated milk, but it’s worth consideration to store as soon as possible. If not used within 96 hours (4 days), fresh breast milk should be transferred to the freezer in a clean, freezer-safe container and dated.1

While it is acceptable to store breast milk in a freezer with an attached refrigerator (0°F or −18°C) for up to 6 months and in a deep freezer (−4°F or −20°C) for up to 9-12 months, the sooner you use it the better. Frozen breast milk lasts safely in the freezer for one month while preserving most of the nutrients, but after 3 months in the freezer, there is a noteworthy decline in concentrations of fats, calories and other macronutrients.2

Additionally, nutrition in breastmilk varies in response to a baby’s immediate needs – another phenomenon of nature! For example, if a baby is sick, the mother makes breastmilk containing numerous immune-boosting elements and probiotic bacteria.3 In short, fresh breastmilk is the most beneficial, but when storage is necessary, use the most recent breastmilk first vs. older milk stored in the freezer. If you experience a surplus, consider donating excess milk.

In summary:

  • Store breast milk in breast milk storage bags or clean food grade glass or plastic containers. 
  • Breast milk may be stored up to 4 days in the refrigerator
  • Freeze fresh breast milk within 24 hours to 96 hours (sooner is better)
  • You can freeze breast milk for up to 6 months in a freezer or 12 months in a deep freezer
  • Thaw overnight in the fridge, not on the counter
Correction to: ABM Clinical Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants, Revised 2017, by Eglash A, Simon L, and The Academy of Breastfeeding Medicine Breastfeed Med 2017;12(7):390-395. DOI: 10.1089/dna.2017.29047.aje. (2018). Breastfeeding medicine : the official journal of the Academy of Breastfeeding Medicine13(6), 459. https://doi.org/10.1089/bfm.2017.29047.aje.correx

How to Properly Thaw Frozen Breast Milk

To thaw frozen breast milk, plan ahead and defrost overnight in the refrigerator, and never on the counter. And because heating to excessive temperatures can greatly alter the nutrient quality, refrain from defrosting breast milk in the microwave or on the stove. Once breast milk is completely thawed, you have 24 hours to use it. And remember: breast milk does not have to be heated at all! Many babies will happily drink room temperature—or even cold—breast milk. 

Can You Cook with Breast Milk?

We know adding fresh breast milk to your baby’s food is beneficial. But what about cooking with breast milk? Does heat destroy the exquisite properties that Mother Nature intends for us to deliver to our babies?

Upon a close look, heat does change the structure, quality, and nutrient density of breast milk. But before we write off cooking with breast milk, let’s look more closely. Scientific research provides insight, but often doesn’t always apply in the real world. 

Some studies have suggested that when breast milk is heated to just 100.4°F (38°C)—slightly above body temperature—its proteins begin to break down. This means that even when we heat stored breast milk it can lose important immunologically “active” and digestive components that benefit babies. For example, enzyme activity (amylase, which breaks down carbohydrates and lipase, which breaks down fats) begins to decrease at 104 degrees F (40 C). These enzymes are important because they help infants with immature digestion to break down nutrients the milk itself, so that nutrients can be absorbed and utilized for growth.

So do you lose nutrients in the cooking process? Yes. That said, breast milk still offers amazing nutritional value, so if you have excess milk, you should absolutely feel good about incorporating it into other foods. Just know it would be better just to add some fresh breast milk stirred into food after it has been cooked. Read on for our suggestions for using excess milk!

Tips for Using Breast Milk in Solid Food

If you are able to produce excess breast milk there are a number of ways it can be incorporated into your baby’s food. We know, however, that heating breast milk can alter the nutritional profile. When possible, look for ways to incorporate fresh breast milk into your baby’s foods. Additional ideas:

Fresh breast milk (still quite nutrient-dense):

  • Stir into cooked, cooled quinoa, oatmeal or other cereals
  • Add to other smashed foods, such as with steamed root vegetables 
  • Use as a base (or partial base) in overnight oats or chia pudding
  • Use a few teaspoons to thin out nut and seed butters 
  • Add a small amount to cooked leafy greens, to mellow the taste 
  • Note: Food prepared with fresh breast milk can be refrigerated or frozen for later feedings

Thawed breast milk (fewer nutrients):

  • Whip a few tablespoons into scrambled eggs
  • Add a few tablespoons to pancakes in lieu of other milk
  • Remember: never refreeze thawed breast milk or foods with thawed breast milk

Frozen breast milk (especially older milk that you don’t want to waste):

  • Add to smoothies in place of milk, or in addition to nut milk/water (recipe below)
  • Add breast milk ice cubes to soup or stews to balance flavors and cool the bowl of soup enough for your baby or toddler to eat

Breast Milk Hibiscus Smoothie (12 mos+)

  • 1 small can of full fat coconut milk (BPA-free can)
  • ¼ cup breast milk (either frozen in cubes, thawed or fresh)
  • 8 oz hibiscus tea, room temp or refrigerated
  • 2 bananas
  • Juice and zest from 1 lime
  • Fresh mint (optional)

Blend ingredients and serve.

Reviewed by:

Jamie Truppi, MSN, CNS for Solid Starts

Rachel Ruiz, MD for Solid Starts

Source: Bransburg-Zabary, S., Virozub, A., & Mimouni, F. B. (2015). Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming MethodsPloS one10(6), e0128806 

  1. Human Milk Storage Information for Home Use for Full-Term Infants, Revised 2017, by Eglash A, Simon L, and The Academy of Breastfeeding Medicine Breastfeed Med 2017;12(7):390-395. DOI: 10.1089/dna.2017.29047.aje. (2018). Breastfeeding medicine : the official journal of the Academy of Breastfeeding Medicine13(6), 459. https://doi.org/10.1089/bfm.2017.29047.aje.correx
  2. García-Lara, N. R., Escuder-Vieco, D., García-Algar, O., De la Cruz, J., Lora, D., & Pallás-Alonso, C. (2012). Effect of freezing time on macronutrients and energy content of breastmilk. Breastfeeding medicine : the official journal of the Academy of Breastfeeding Medicine7(4), 295–301. https://doi.org/10.1089/bfm.2011.0079
  3. Eglash A, Simon L; Academy of Breastfeeding Medicine. ABM Clinical Protocol #8: Human Milk Storage Information for Home Use for Full-Term Infants, Revised 2017. Breastfeed Med. 2017 Sep;12(7):390-395. doi: 10.1089/bfm.2017.29047.aje. Epub 2017 Jun 29. Erratum in: Breastfeed Med. 2018 Jul/Aug;13(6):459. PMID: 29624432.
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