How to store breast milk for the baby and for donation

Breastfeeding is a natural process for the human species and for all other mammals, as this guarantees their survival. The mother’s milk is the best source of nutrients and the main food for the newborn child.

According to the Ministry of Health, breast milk is able to supply the child’s nutritional needs alone for at least the first six months of life.

Still in the second year of life, it remains an important source of nutrients, especially proteins , fats and vitamins .

Breast milk undergoes changes in its composition according to the baby’s needs, the time and the phase of the feeding. For this reason, it can be considered a living food.

Because of this, the extraction and storage of this milk must be done carefully, to maintain its nutritional properties and prevent it from spoiling.

The following recommendations can be considered for storing breast milk for their children and also for mothers who have surplus milk and want to donate to a human milk bank. Check out!


How to express breast milk?

Breast milk can be withdrawn manually or with a suction pump. Each extraction should take about 10 to 15 minutes and should be done every 2 or 3 hours during the day and at least once at night. It is not advisable to spend more than 8 hours without expressing milk.

Check out the recommendations of the Ministry of Health for breast milk extraction:

  1. Remove accessories such as rings, bracelets and watches;
  2. Wash your hands and forearms thoroughly with soap and water;
  3. Wash the breasts only with clean water;
  4. Dry your hands and breasts thoroughly with paper towels or a clean cloth;
  5. Pin your hair and put on a cap or scarf;
  6. With the bottle ready for storage, positioned close to the breast, sit comfortably and try to be relaxed;
  7. Then start the breast massage. Make circular movements with your fingertips across the areola and then across the breast;
  8. Place the thumb above the line where the areola ends and the index and middle fingers below it;
  9. Firm your fingers and push back towards the trunk;
  10. Press your thumb against the other fingers carefully, until the milk comes out and continue repeating this movement;
  11.  Disregard the first jets or drops;
  12. Then, open the bottle and place the lid on the table, with the inner side facing up;
  13. Remove the breast milk with your hands or with a manual or electric pump;
  14. After collecting, close the bottle tightly.

If the milk is not enough to fill the bottle, you can complete it in another collection (on the same day). The other day, start with a new bottle.

Always leave a space of two fingers between the mouth of the bottle and the milk.

Following these recommendations is very important to preserve the quality of the milk and avoid the risk of contamination.

How to store breast milk?

After expressing breast milk, it must be stored in a suitable container with identification, containing information such as the date and time of collection. If it is not consumed within the next 2 or 4 hours, it must be refrigerated or frozen.

It must be stored in sterile containers so as not to run the risk of contamination. Sterilization should be done in boiling water for 15 to 20 minutes.

After sterilization, the container should dry naturally, with the opening facing downwards and on top of a clean towel or dish towel.

What are the recommended containers for storing milk?

According to some studies, there is no consensus as to the most suitable container for storing breast milk.

The options can be glass or in a plastic container (polypropylene).

Milk can also be stored in the regular sterilized baby bottle, as long as it is well sealed and with a lid.
According to the Ministry of Health, glass containers with plastic lids, properly sterilized, can also be used (such as soluble coffee or mayonnaise).

There are also sterile plastic containers on the market to store milk in a practical way.

How long does breast milk last?

The durability of breast milk may vary depending on the storage location.

In addition to the appropriate sterile container, the storage location (refrigerator or freezer) and temperature (room or refrigerated) will establish the duration of the milk.

If stored correctly, breast milk does not lose its nutritional properties. The recommendations are:

At room temperature

Breast milk at room temperature, when properly stored, can last for up to 4 hours. This time is also valid during breastfeeding.

If the baby has started to take breast milk and has not taken it all, that same milk can still be consumed within 4 hours. After that time, the milk must be discarded.

It is worth remembering that in seasons or warmer regions, this time may be shorter.

The best thing is that the child consumes the milk immediately after being removed. This is because with time there is an increased risk of contamination by microorganisms present in the environment.


The Ministry of Health recommends that raw (unpasteurized) breast milk be kept in the refrigerator for up to 12 hours.

Remembering that it must be in a suitable and sterilized container and stored correctly in the refrigerator without temperature variation.


In the freezer, the indication of the Human Milk Bank is to store for a maximum of 15 days.

The freezer must not be of the type fitted inside the refrigerator. Ideally, breast milk should be stored in the freezer and never left at the door, because in that place there is a greater variation in temperature.

The indication is that the storage temperature in the freezer is around -10ºC.

How to defrost breast milk?

Do not let breast milk thaw at room temperature. The ideal is to leave it in the refrigerator to be defrosted and immediately after being heated.

It is not recommended to freeze breast milk after it has been defrosted. Use it immediately and discard what’s left.

How to heat?

The milk must be defrosted and heated in the bottle itself. It must be heated in a water bath and stirred before being offered to the child.

The Ministry of Health warns that it is not recommended to boil or heat the milk in the microwave, as this type of heating can destroy protective factors of breast milk.

Hot milk that has not been used should be discarded.

Breast milk conservation tips

When stored in a suitable container and stored correctly, the preservation of breast milk is effective and maintains its nutritional properties.

But for this, some tips for conservation are important:

  • Properly sanitize the storage container;
  • Avoid keeping the bottle open after cleaning. This prevents any type of dirt from falling and being contaminated;
  • Do not fill the bottle completely. The ideal is to leave at least two fingers left. This prevents the milk from coming into contact with the lid and can be spilled when opening the container;
  • Avoid storing it in the refrigerator or freezer door. This location has a wide variation in temperature, which can impair the duration of the milk;
  • Always remember to put the date of milk withdrawal in the jars. This prevents it from being consumed after the proper storage period.

Breast milk is the best food for the baby and is essential for it to develop in a healthy way. If extracted and stored correctly, it can be offered to the baby without losing its nutrients.

If you want to continue receiving pregnancy, breastfeeding and health tips from mom and baby, keep following Minute Healthy.