How Many Times Can You Reheat Breastmilk: The Safety Protocols

Unused breastmilk can be reheated only once to protect its quality and ensure the retention of its nutrients. Unlike cow’s milk, storing human breastmilk is quite complex because of its sensitive nature. Breastmilk contains all the good bacteria and nutrition that is tailored for your child’s age and needs. Reheating can destroy the beneficial microorganisms, which cancel out the benefits that your child can receive. Also, it spoils out easily when left at room temperature or even in your refrigerator. Thus, reheating it many times may pose harmful health risks to your child.

The CDC provides the guidelines for proper storage and safe preparation of expressed milk for every child.

Basically, you can reheat unused or partially consumed breastmilk once before discarding it. But for partially consumed milk, you can do so only within four hours to avoid bacterial contamination that can harm your baby.

How to store breastmilk

Pumping and storing breastmilk is one of the reliable ways for moms whose work or lifestyle cannot afford them the convenience of breastfeeding.

Keeping a stockpile of breastmilk is necessary, especially when moms have to be away from their babies for a time. Proper storage and preparation of expressed milk are important to ensure its safety and best quality.

Here are the rules for proper storage according to the CDC:

  • Store freshly expressed breastmilk in the heart of your freezer. You can keep it under favorable conditions for 6 to 12 months.
  • Store fresh breastmilk in the refrigerator for up to 4 days.
  • Breastmilk at room temperature (77°F at most) is good for only 4 hours.
  • When traveling, pack them in an insulated cooler with frozen ice packs. You can use it or store it in the freezer immediately once you arrive at your destination.

In storing breastmilk, remember to use only clean, food-grade containers with tight-fitting lids or seals.

You should also label it with the date it is expressed and always use the oldest date – so first in, first out.

Thawing and preparation

Proper thawing of breastmilk will help it retain all its nutrients and prevents it from spoiling too easily.

You can feed your baby breastmilk at room temperature or serve it cold once it has thawed. But you may also serve it warm by submerging the bottle in a bowl of warm water.

You can defrost breastmilk properly by taking it out of the freezer and leaving it in the refrigerator overnight. You can use it within 24 hours, counting from the time it has completely thawed.

Once it has thawed out, do not put it back in the freezer.

Reheating breastmilk

You can reheat breastmilk – I say it again – only once to ensure its safety.

If your baby has not finished his milk, put it into the refrigerator. You may reheat and use the remaining milk only within four hours. After that, you can reheat by dipping the container in a bowl or pan of hot water. Or, you may also use a bottle warmer for convenience.

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Do not reheat breastmilk on the microwave or direct heat, and definitely do not boil it.

Boiling will not only destroy healthy components, but you also risk scalding your baby’s mouth.

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To avoid wasting breastmilk, you may keep expressed milk in small packs. Store them in two, three, or four-ounce breastmilk containers that you think your baby can consume at a time.


Can I thaw breastmilk at room temperature?

Breastmilk will thaw faster at room temperature, but we do not recommend the practice.

It’s the perfect temperature that will invite a host of bacteria to flourish. But when the situation calls that you thaw it at room temp, make sure to let the baby consume it within 2 hours.

Do I need to heat breastmilk before using it?

It is at your baby’s discretion. Some babies prefer the warm bottle, while others may enjoy it cold. Feeding him with cold milk is preferable, though, as it will not risk destroying the nutrients and components in breastmilk.

Can I refrigerate breastmilk after heating it?

Yes, you can store it in the fridge only for four hours. But do not refreeze it or leave it at room temperature.  


Reheating breastmilk is generally allowed, provided you follow certain conditions that ensure its safety and quality.

Most of the time, storing frozen breastmilk is a necessity, especially when mom needs to be away for a while. But you should make sure that you educate the caregiver on the proper preparation and dispensing.

It will all redound for your baby’s health and safety.

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Ann Marie is a licensed nurse in the Philippines. She experienced handling and assisting deliveries of newborns into the world. She also trained in labor rooms and pediatric wards while in nursing school - helping soon-to-be mothers and little kids in the process. Though not a mother by nature but a mother by heart, Ann Marie loves to take care of her younger cousins as well as nephews and nieces during her free time.

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