One of the topics that new parents are curious about is the storage time of breast milk. If you are breastfeeding directly, the storage time for breast milk at room temperature, refrigeration, and freezing is not very important. You can feed the baby directly from the mother's breast.

However, there are several situations in which direct feeding isn’t possible. In these cases, frozen breast milk can be used to feed the baby after collecting the breast milk in a bottle using a breast pump (ex. Hospitalization, work, etc.).

So, how long is breast milk safe to store? Let’s find out the storage time of breast milk according to the room temperature, refrigeration, and freezing conditions!

Storing Expressed Breast Milk at Room Temperature: Up to 3 Hours

If freshly expressed breast milk is kept at room temperature (near 25 degrees Celsius), it can last up to 3 hours (for full-term infants). However, premature infants should be fed or refrigerated within 1 hour. Breast milk that has already been refrigerated or frozen thawed should be fed to your baby within 1 to 2 hours at room temperature.

Tip. What if you use an icebox (15 degrees Celsius) with ice packs to store breast milk?

In the icebox, frozen breast milk can be stored for up to 24 hours (for full-term infants). Because premature babies are weakly protected bacteria and their intestines are immature, it is not recommended to feed them breast milk that has been stored for longer than 1 to 2 hours in places other than refrigerators or freezers.

Refrigerated Expressed Breast Milk: Up to 3 Days

If you store freshly expressed breast milk in the refrigerator (4 degrees Celsius), it can last up to 72 hours (3 days). This time is based on where the milk is stored inside the refrigerator. If you store it near the refrigerator door, the temperature changes every time you open or close the door, so breast milk can easily spoil.

Frozen milk can be stored in the refrigerator for up to 24 hours. In terms of preserving the immunological components in breast milk, refrigeration is better than freezing.

When storing breast milk, if you want to store it for more than 3 days, put it straight in the freezer. If you move breast milk that has been stored in the refrigerator to the freezer after a while, the quality of breast milk may deteriorate.

Freezing Expressed Breast Milk: Up to 3 Months

Breast milk can be stored for up to 3 months in a -18°C freezer and up to 6 months in a -40°C freezer (for full-term infants). It is important to keep your breast milk deep inside the freezer. If you store breast milk near the door of the freezer, the temperature may change, and the milk may spoil.

Thawed breast milk after freezing should never be re-frozen. If you have leftovers from frozen breastfeeding, you should discard them and not feed them to your baby. Breast milk expands when it freezes, so containers or bags should not be overfilled. Fill them only about 3/4 of the way and seal them.

It is recommended to select a container that does not release environmental hormones. You should keep the milk sterile and store it in a breast milk storage bag. When thawing frozen breast milk, it is good to either move it to the refrigerator the day before feeding and thaw it naturally or boil it in 55-degree warm water.

Microwaving it is not recommended as it destroys nutrients.

The storage period of breast milk is different for full-term babies and premature babies.

What if the baby was born prematurely and is receiving medical attention? Or even if the child is full term, what if they are currently sick and in the hospital? More stringent breastfeeding storage guidelines are needed.

For premature infants, breast milk can be stored at room temperature (25°C) for up to 1 hour, refrigerated for up to 48 hours, and frozen at -40°C for up to 3 months. We recommend that you feed your baby with expressed breast milk as soon as possible.

# Parenting advice from Director Hyang-Hwa Kwon

With breast milk shelf life, the theory and reality may vary.

The guideline that 'frozen breast milk can be used up to 6 months' is typical, but in my experience, 1 month was the safest. Realistically, when storing breast milk, bacteria can enter, and it is difficult to maintain the perfect temperature of -18 degrees Celsius.

Contrary to in theory, breast milk cannot constantly be stored in perfect conditions. Therefore, if you want to follow the safest storage period of breast milk, we recommend storing for 1-2 hours at room temperature, up to 3 days in the refrigerator, and up to 1 month in the freezer.

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Author: Kwon Hyang-hwa

- Newborn Childcare Coach
- IBCLC International Breastfeeding Specialist
- Worked as the director of a postpartum care center for 10 years.