How To Store Breast Milk

Expressing and conserving breast milk is sometimes necessary. To do it properly and maintain its properties, you should follow certain recommendations.
How To Store Breast Milk

Written by Edith Sánchez

Last update: 27 May, 2022

Just because mothers work or study doesn’t mean that they have to stop breastfeeding. In fact, if you know how to store breast milk properly, you’ll have more options when it comes to bottle feeding.
To understand this, let’s take a brief look at some of the issues.
The American Academy of Pediatrics states that breast milk is the only truly adequate food during the first 6 months of a child’s life, and it has been proven to provide multiple benefits for the health of the baby.
For this reason, experts consider that it’s convenient for the baby to be breastfed until 12 months of age, and even longer if the mother or child wishes.
As the mother has to continue with her daily routine throughout breastfeeding, doctors recommend that she learns how to store breast milk properly to make it easier for her to combine feeding her baby with her daily life.

General recommendations when it comes to storing breast milk

Breast milk.

Milk extracted from the mother’s breast and properly preserved maintains most of its properties without any problem. By every measure it’s far better than any formula milk.
In any case, the most important thing, both when extracting and storing breast milk, is to maintain proper hygiene. For example, it’s essential to wash your hands well before expressing or handling the milk.
Also, ensure that you wash the containers well, with soap and hot water. It’s very important to label these containers with the date of extraction.
To ensure safety, make sure you follow all the extraction and storage instructions, such as those explained in work carried out by researchers from the Ricardo Palma University. The most convenient thing to do is deposit the milk in small containers, as this helps its conservation and avoids waste.

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Where to store breast milk and how long for

There are two types of containers to store breast milk properly. The first is a bottle, or a glass or plastic container, that has a tight seal. The second is a sterile bag, which must be airtight.
For both of these, you should store only the amount that the baby consumes in one meal. For example, if the baby is used to taking 4 ounces, it’s recommended not to deposit more than 4 ounces in each container. Again, always ensure there is a label with the date of extraction.
Storage time depends on the temperature at which you store it. According to advice from the Center for Disease Control and Prevention, breast milk stays in good condition for up to 4 hours if kept at room temperature. If stored in the fridge, it can last around 4 days.
Finally, if you want to store it for 12 months, put the bottle or bag in the freezer. However, so that it doesn’t lose any quality and in order to keep its properties you should consume it within 6 months.

Methods of preserving breast milk

Storing breast milk.

If you’re going to use breast milk soon after extraction, there’s no need to refrigerate it. Instead, keep it in a clean container that protects it. If you want to store it for days or weeks later, it’s necessary to store it in the fridge.
To preserve breast milk properly, the following advice must be taken into account:
  • Keep breast milk cold before refrigerating it.
  • If you’re going to use it in the coming days, it’s best to store it at the back of the refrigerator.
  • If you’re going to use it in a matter of weeks, it’s best to freeze breast milk. You should do this as soon as possible.
  • Don’t fill containers more than three-quarters full, as breast milk expands when frozen.
  • The containers should preferably be located at the back of the freezer, as the temperature is more consistent there.

Other facts to take into account

Stored breast milk tends to separate into layers. Before giving it to the baby, you should shake the bottle gently. If you overdo it, some properties of the food may be altered.
Thawed milk stays good for two hours at room temperature, or 24 hours in the fridge. After thawing, it cannot be refrozen. The best way to defrost it is to put it inside the bottle and place it in a container with warm water.
Furthermore, never thaw it in the microwave or in boiling water. All of this is explained by this publication of the Spanish Association for the Promotion and Support of Breastfeeding.

It’s very common for milk to change its color and smell a little during refrigeration or freezing. If all the instructions for storing breast milk have been followed, there’s no need to worry. If the smell is very intense, it’s probably not suitable for consumption, so it’s best to get rid of it.


All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.



This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.