How Long Does Breast Milk Last After Warming | How to Store Breast Milk

Breastfeeding is a great way to feed your baby, but it can be hard to tell how long breast milk lasts after warming.

You don’t want to give your baby expired breastmilk, but you also don’t want to throw out any perfectly good milk. 

This article will show you how long breast milk lasts after warming and some guidelines on storing it for later use. We’ll also share some tips that help keep breast milk fresh longer!

How Long Can You Leave Breast Milk Out After Warming it up?

The CDC recommends using warmed breast milk within two hours. Breast milk has antibacterial properties but some of those are lost when frozen. One study shows the only breast milk sample that grew bacteria in even a small amount was a previously frozen breast milk sample. Whereas the fresh breast milk had no bacterial growth.

Some breastfeeding moms have smelled or tasted the milk to see if it has spoiled but this would be at your own discretion.

The CDC recommends you don’t add freshly expressed milk from your breast to a bottle that’s been sitting out for more than 2 hours.

Instead, hold off on feeding until the baby is ready to eat again, which might mean you need another bottle (or two or three) before it’s time for the next breastfeeding session.

When My Baby Doesn’t Finish a Bottle. Can I Reuse the Bottle Later?

There are varying factors that play into this. This is because the bacteria from your baby’s mouth has been introduced into the bottle of breast milk.

Unlike formula which has no antibodies or antibacterial properties, breast milk will continue to fight off the bacteria that is in the bottle of breast milk.

Here are some things to consider before reusing it for later:

  • Is it freshly expressed milk?
  • Has it been stored in the refrigerator for days?
  • Has it been previously frozen?
  • How long has it been frozen for?
  • How clean were the pumping parts when you pumped?
  • Is your baby sick or has a compromised immune system?

Freshly expressed milk will have the most antibacterial properties and the longer it has been frozen and thawed, the more chances of bacterial growth. 

Can You Put Breast Milk Back in the Fridge After Warming?

You can put breast milk back in the fridge after warming. The CDC recommends using breast milk within 2 hours after warming whether it is stored at room temperature or in the fridge.

Can You Reheat a Bottle of Breast Milk?

Moms can put milk in the fridge for later. Sometimes they want to warm it up again. As of now, there are no warnings against this.

Can I Refreeze Frozen Breast Milk?

The CDC recommends never to refreeze leftover breast milk. If your breast milk hasn’t been fully thawed and still contains some ice crystals, then it is not considered to be fully thawed and can be placed back into the freezer.

Can I Let Breast Milk Come to Room Temperature from the Fridge?

Yes, you can but you will have to use the breast milk once it has hit room temperature.

Can I put breast milk in a closed bottle and leave it at room temp for hrs?

Experts say not to do this. The more time the milk is out, the higher chance there is of bacteria growth.

What is the Best Method to Store Breast Milk?

The best way to store breast milk is in a clean and tightly sealed container. Either stored in a sealed bottle or a breast milk storage bag.

How Long Can I Store Expressed Breast Milk?

The fridge must be maintained at a minimum of 39°F, and the maximum time for breast milk in a fridge under ideal circumstances is three days or five days.

Best Breast Milk Storage Tips

Here are some tips that might help keep your own breast milk fresh longer:

  1. Refrigerate freshly pumped breast milk as soon as possible (within an hour).
  2. You can also put the milk in a closed container and place it in an ice-water bath to keep it cool for several hours if you are unable to get it into the refrigerator within an hour of pumping it.
  3. Do not leave the milk out for longer than 4 hours at room temperature.
  4. You should never leave breast milk in a hot car to feed your baby later because the temperature is inconsistent.
  5. Use freshly pumped milk within 4 days if refrigerated and within 3-6 months if frozen.
  6. You can store it in the freezer for up to six months, and store it in the back of a freezer where it is the coldest.
  7. Use a first-in, first-out method – use up the oldest breast milk first to prevent spoilage. Try this log to help keep track!
  8. Do not refreeze breastmilk that has been previously frozen.

9.If you are pumping on the go, store it in an insulated cooler with ice packs to keep it cool.

How to Best Store Breast Milk in the Fridge

The best way to store your breast milk in the fridge is to store it in a clean bottle, food-grade storage container, or a milk storage bag at the back of the fridge. The back of the fridge has a more consistent temperature rather than the fridge door.

Be sure to label the date you pumped your milk onto the bottle or bag. Store in the fridge for up to 4 days.

How to Store Breast Milk in the Freezer

  • If you are planning to store it in the freezer, it’s a good idea to store it in the back of the freezer as soon as you are done expressing with your breast pump to preserve as many nutrients as possible.
  • Store your milk in a clean, airtight container such as a milk storage bag or a sealed bottle.
  • Be sure to label the date that you pumped your milk onto the bottle or bag. Breast milk can be stored in the freezer for 3 months and in a deep freezer for up to six months.
  • If you plan to store lots of your milk, it is best to use storage bags rather than bottles as they will take up more space than bags in your freezer.
  • You should never refreeze previously frozen breastmilk as it may result in some loss of nutrients that occur after thawing.
  • Be sure to leave room in the bottle or bag. Breast milk expands when it is frozen.
  • Store breast milk in small amounts to prevent any from being wasted.

How to Store Breast Milk at Room Temperature

  • If the room is 77 degrees Fahrenheit or cooler, it is safe to store freshly expressed milk on the counter for up to 4 hours.
  • Just be sure to store it in an air-tight and food-grade container
  • Make sure all the supplies have been properly clean and sanitized before use

Related Article: Best Breast Milk Storage Coolers

How to Best Thaw Breast Milk

Always clearly label and date your breast milk before storing it in your freezer. There are a few ways to thaw your breast milk. Just make sure to thaw the oldest breast milk first since the quality of the milk decreases over time.

Here are some ways to thaw and warm breast milk:

  • Leave your breast milk in a bowl in the fridge to slowly thaw and to catch any leaks if your bag happens to leak.
  • Run it under lukewarm water
  • Warm milk using bottle warmers
  • Set it in a bowl of warm water
  • Never use hot water as it can damage the nutrients in breast milk.

Never use the microwave oven to reheat your breast milk as it can cause hot spots in the milk and lose most of the nutrients.

Related Article: Best Bottles Warmers


You can store breast milk in many different ways, and the best way to store it depends on your needs. Knowing how long you should refrigerate or freeze your milk after pumping is important for avoiding spoilage and ensuring that your baby gets the freshest possible nourishment.  As well as how to thaw breastmilk, I have compiled all the tips for this. Follow these guidelines when storing breast milk so that you can enjoy a healthy relationship with breastfeeding!


About the author

Lacy Reason is a highly experienced and compassionate lactation counselor, who has dedicated her career to educating and supporting new mothers on their breastfeeding journey.

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