Supporting Breastfeeding

La Leche League Canada

Storing and Using Breastmilk

on January 27, 2014

How long can I store my breastmilk in a refrigerator/freezer?

Preferably, human milk should be refrigerated or chilled right after it is expressed. Acceptable guidelines for storing human milk are as follows:

At room temperature (19-26°C, 66-78°F,) for 4 hours (ideal), up to 8 hours (acceptable)
In refrigerator (4°C, 39°F) for 72 hours (ideal); up to 8 days (acceptable)
In freezer compartment of refrigerator with a separate door (-18°C, 0°F) for 3-6 months.
In deep freezer (-20°C, -4°F) for 6 months (ideal); up to 12 months (acceptable)

What is the best way to thaw my milk?

You can thaw your frozen breastmilk by holding it under cool running water. Gradually increase the water temperature to heat it to a comfortable feeding temperature. This is a temperature that feels warm, not hot, on your wrist. Periodically mix the milk in the bag or bottle by swirling gently, as it defrosts. Milk can also be thawed in a refrigerator overnight. Do not thaw or heat your milk in a microwave or directly on the stove.

How soon do I need to use thawed milk?

Thawed milk should be kept refrigerated and used within 24 hours. If it hasn’t been used by that time, it should be discarded or refrozen. However, repeated freezing and thawing will affect milk quality.

Dad care

If my baby doesn’t drink all the breastmilk in a bottle, can I give him the rest at the next feeding?

Unfortunately, there is no clear answer to this question as there is no research about whether it is safe or not. Until recently, the standard answer was to discard any breastmilk left in the bottle after a feed. However, recently it has been suggested that it might be okay to store breastmilk in the fridge for a short time. The current thinking is that bacteria growth is possible, but not likely, because fresh breastmilk has anti-bacterial properties, and a breastfed baby has a strong immune system to deal with any bacteria that do grow. If the breastmilk has been frozen and thawed some of these properties are lost. The final choice is yours; let common sense be your guide. If the baby’s next feeding of pumped breastmilk ends up being 7 or more hours later (because he slept through the night, for example) or the breastmilk was stored in the fridge for several days before being fed to the baby, you may choose to err on the side of caution. To avoid wasting precious breastmilk, mothers usually prepare bottles with a small amount, 1 to 2 oz (30 to 60 ml), to start a feeding. More breastmilk can be added to the bottle if needed.

Can I store my expressed breastmilk in the common fridge at work?

Yes. Expressed human milk can be kept in a common refrigerator at the workplace or at a daycare centre. Check that the refrigerator temperature is 4C (39F) or less. Both the US Centers for Disease Control and the US Occupational Safety and Health Administration agree that human milk is not among the body fluids that require special handling or storage in a separate refrigerator.

3 generations sm

Lipase and frozen breastmilk:

Some mothers who are pumping and storing breastmilk for later use find that their milk develops a soapy smell. This may be noticeable after a short time in the freezer or after longer periods of freezing. The likely cause is high levels of lipase, the enzyme that breaks down fat. The breakdown of the fat in breastmilk by lipase is normal but not noticeable when the baby is feeding directly at the breast.

Breastmilk that smells a bit soapy after freezing is considered safe for the baby and most babies will accept it. If the baby refuses the milk the change in smell/taste can be prevented by scalding the milk shortly after it is pumped. Scalding deactivates the lipase. Milk frozen after being scalded will not develop a soapy smell from the action of lipase.

Stored milk that smells or tastes sour or rancid is more likely to be caused by chemical oxidization or bacterial contamination. Chemical oxidization could be caused by high iron or copper levels in the mother’s local drinking water or by high intake of polyunsaturated fats (fish and flax oils).

Detailed information about breastmilk storage and scalding breastmilk can be found on the La Leche League International website  *

Where can I print out all this information about storing human milk?

This information is covered in The Womanly Art of Breastfeeding “Storing Milk for Your Healthy Full Term Baby” and the LLLC Information Sheet Storing Human Milk, which can be requested from your local Leader.


By Nicola Aquino, LLLC Professional Liaison Department


If you need more information or have a breastfeeding problem or concern, you are strongly encouraged to talk directly to a La Leche League Leader.  In Canada, Leaders can be located by clicking  or  Internationally  


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