Preparing Stored Breastmilk for Feedings

Always be sure to wash your hands before preparing a feeding,
and have a clean, sterile bottle and nipple ready for use.
Be sure to prepare the oldest, fresh milk available to ensure
that older expressed milk is not wasted.


Thaw frozen milk ahead of time. If the baby prefers a warm bottle, warm it immediately before feeding. To warm the bottle safely, hold it under warm, not hot running water. If milk layers have separated, gently swirl the bottle in a circular motion to mix the layers together before feeding it to the infant.

Thawing frozen milk

Breastmilk does not take very long to thaw or warm up. Milk can easily be thawed or heated up by holding the bottle under warm running water. Frozen milk may also be thawed overnight in the refrigerator. It can also be warmed or thawed by placing the container of milk in a bowl of warm water. Bottle warmers also provide a gradual warming option for breastmilk.

Do not attempt to thaw milk at room temperature, on the stove or in the microwave. It is far too easy to over heat milk on the stove. Microwaves do not heated uniformly therefore you cannot control the temperature and your baby may be burned by the milk. Overheating can destroy some of the milk’s nutrients.

Thawed milk may be left at room temperature for 4 hours or refrigerated for up to 24 hours. Once milk has been thawed, it should never be refrozen.

Reusing Milk From a Partially Eaten Bottle

If your child eats only half of the prepared bottle during a feeding, the milk should be discarded after half an hour. The reason the milk must be discarded is that during a feeding the baby’s saliva enters the bottle, which allows saliva enzymes to enter the milk and creates bacteria. If your baby does not finish a bottle often you should consider storing your milk is smaller amounts to avoid wasting milk regularly.

Milk that has been heated, but not eaten can safely be reheated once. Since the immunologic value of breastmilk decreases each time it is heated you should avoid reheating milk repeatedly to ensure that your child receives the best nutrition possible.

For more information on the proper storage of breastmilk read our article Breastmilk Storage Guidelines. The La Leche League Internationalwebsite also offers helpful information on the storage and feeding of breastmilk.

Return to: Breastmilk Storage Tips & Tricks

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