How to Store Your Breast Milk Safely

How long is safe in the fridge, freezer – and more
preparing frozen breast milk for baby

The old adage says there’s no use crying over spilled milk. But, when it’s your milk for your little one, it’s sad to see any go to waste. With proper planning, you can prevent wasting any breast milk you’ve pumped to nourish your baby or toddler. 

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How long will it keep in the fridge or freezer? What containers should I store it in? What’s the best way to thaw it? Here, lactation consultant Kimberly Falatic, BSN, RNC-NIC, IBCLC, has all of your questions covered.

Breast milk storage basics

Don’t waste a drop of your precious “liquid gold.” Use this cheat sheet to ensure your breast milk is fresh — with optimal nutrients and immune-system boosters. “These guidelines are for healthy, full-term infants,” Falatic clarifies.

You can safely store your breastmilk in the freezer or refrigerator, Falatic says. Just follow these guidelines.


  • Up to three to four months inside a standard refrigerator freezer. 
  • Up to six to 12 months in a separate deep freezer. 
  • Label milk with the date it was expressed and the child’s name if delivering to childcare.
  • Freeze milk in small amounts of 2 to 4 ounces to avoid wasting any.
  • Store milk in the back of the freezer or refrigerator, not the door.
  • When freezing, leave an inch of space at the top of the container for milk to expand as it freezes.
  • Milk can be stored in an insulated cooler bag with frozen ice packs for up to 24 hours when you are traveling.
  • If you don’t plan to use freshly expressed milk within 4 days, freeze it right away.
  • Freshly-expressed milk can be stored at room temperature for four hours.


  • Use oldest milk first.
  • After bringing milk to room temperature, use milk within two hours.
  • If milk has been frozen and completely thawed, refrigerate and use within 48 hours. “Never refreeze once thawed milk,” Falatic says. “To be safe, discard any previously-frozen milk that’s been heated and served to your baby after one to two hours.” 


  • Milk can be given to your baby cold, room temperature or warm.
  • Do not heat milk directly on the stove or in the microwave.
  • To heat, place milk in a sealed container into a bowl of warm water or hold under warm running tap water.
  • After heating, swirl the milk to mix the fat which may have separated.
  • Put a few drops of milk on your wrist to test the temperature after warming. It should feel warm, not hot.
  • If your baby didn’t finish the bottle, use leftover milk within two hours.

Frequently asked questions

Here, Falatic answers some of the most common questions she receives about storing and using your breast milk freezer stash.

Q: How should I thaw and heat breast milk? 

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A: Thaw or heat frozen containers of breast milk under running water or soak in a bowl of warm water for several minutes. Then, swirl the separated cream and milk layers back together. You can also use a bottle warmer if you have one. 

The stove and microwave are no-no’s. If needed, warm water in a pan on the stove and remove. Then, place your breast milk container in the warmed water. High heat or boiling may destroy vital nutrients. 

Q: What kind of containers can I use to store my breast milk? 

A: Glass is the first choice for breast milk storage. It preserves the components of milk the best. Glass breaks, however, so some daycare centers won’t allow it. 

Hard-sided plastic containers are the second choice alternative for breast milk storage. Look for PBA-free and opaque options (evidence suggests dye may leach into your milk). 

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Breast milk freezer bags are best for storage in the freezer. While freezer bags are convenient and space-saving, they can leak. To avoid damage, place your bags in firm, plastic containers so you can grab the oldest bags first. 

Q: What milk should I use first? 

A: Always label your bags with a permanent, smudge-proof marker with the date expressed and amount of milk before storing. Use the oldest milk first to keep supplies fresh. Label any milk taken to daycare with your baby’s name to avoid mix-ups. 

Breast milk has many nutrients tailored to your baby’s growing needs. With a little planning, you can continue providing for your baby throughout their infancy. 

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