Can I boil breast milk?

In this brief article, we will provide you with the answer to the question: “Can I boil breast milk?”, discuss how to store and how to warm breast milk.

Can I boil breast milk?

No, breast milk should not be boiled or microwaved, as this type of heating can destroy its protective factors.

How to warm breast milk?

The ideal is to warm the breast milk in a bain-marie, to approximately 37°C. This retains the milk’s protecting components, which cannot be ensured by heating in the microwave or in direct contact with fire. Follow the steps outlined below:

Pour a drop of milk on the inside of your wrist to test the temperature.

Breast milk should always be thawed gradually. It is preferable to place it in the refrigerator or under running water. You can save milk from losing key nutrients by gently defrosting it.

Use thawed breast milk within 24 hours of thawing. 

Never, ever freeze again. Discard any residual amounts and do not re-use them.

Breast milk that has been preserved tends to split into layers, with the fat (cream) on top. Before feeding your baby, gently shake the bottle to combine the layers. Some of the nutritious and protective components of milk might be damaged by vigorous shaking.

It is natural for germs to transfer from your baby’s lips to the milk when he or she drinks breast milk from a cup or a bottle. As a result, it is preferable to discard any remaining half-drunk milk one to two hours after your initial feeding session. To prevent wasting milk, keep it in little quantities and only use what is needed. 

How to store breast milk?

Freshly expressed breast milk is preferable to refrigerate, and refrigerated is preferable to frozen. 

Fresh breast milk has the best bacteria-fighting qualities, as well as a greater antioxidant, vitamin, and fat content than refrigerated or frozen milk.

If you extract breast milk in a sanitary and safe manner, you can keep it at room temperature, in the refrigerator, or in the freezer, depending on when you want to use it.

There are three methods for sterilizing containers:

  • Using sterilizers: there are a variety of devices available, including those that can be microwaved.
  • The most popular way of sterilizing any pot is to boil the containers. Simply bring pots and lids to a boil for at least 15 minutes. Then hang them upside down to dry on clean rags.
  • In the oven: This method of sterilizing is only effective for glass jars. Place the pots face up on a metal baking sheet and bake for 10 minutes at 108 °C. In the meantime, the lids must be boiled. Then, just place the lids and pots on a clean towel to dry and cool naturally.

If you refrigerate or freeze breast milk, always mark the bottles or bags with the volume and date of expression so you can track and manage your saved milk.

Recommendations for storing expressed milk properly in the refrigerator

After expressing your breast milk, place it in the refrigerator as soon as possible.

Clean breast milk bottles or BPA-free storage bottles should be used to store your breast milk. BPA is a chemical that has been widely used in plastic containers and liners but is being phased out owing to concerns about its long-term consequences.

Small amounts of expressed milk can be added to the same chilled container, as long as the milk has been cooled in the refrigerator first. Do not mix body temperature milk with chilled milk.

Breast milk should be kept in the coldest portion of the fridge, which is towards the rear, on the shelf above the vegetable compartment. 

Breast milk storage in the freezer

After extracting your breast milk, freeze it as soon as possible.

You can add expressed milk to already frozen breast milk as long as the milk has been chilled in the fridge first. Frozen milk should not be mixed with body temperature milk.

Store your milk in tiny volumes for easier defrosting and reduced waste (less than 60 ml). After they have thawed, you may add them.

Check to see whether your breast milk storage containers can be frozen. Some items (for example, glass jars) can break at extremely low temperatures. 

You may find that your refrigerated or thawed breast milk smells different at times. This is due to lipase, an enzyme that breaks down lipids and releases fatty acids, preventing dangerous germs from developing.

Some women claim that their stored breast milk smells soapy or rotten. However, if you have followed all of the rules in this article on safe storage, you should be able to utilize it without issue. 


In this brief article, we provided you with the answer to the question: “Can I boil breast milk?”, discussed how to store and how to warm breast milk.


Medela. “Como conservar, congelar e descongelar leite materno.” Accessed January 21, 2022.

Danone Nutricia. “Como tirar, conservar e aquecer o leite do peito,” November 8, 2019.–conservar-e-aquecer-o-leite-do-peito.

Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.