Breastfeeding A to Z

Storage of Breastmilk

These guidelines are for home use (not for hospital or donor situations) for a healthy, full-term baby.  If you have a premature or ill baby or if you are not expressing milk for your own use; check with your healthcare provider or milk bank about other guidelines for pumping and storing breastmilk that you might need to follow.

General Guidelines for Storing Breastmilk (1)

  1. Always use a clean container.  Standard glass or plastic baby bottles (bisphenol A [BPA] free preferred) or disposable bottle liners can be used.
  2. Label container with date (day, month and year may be helpful) and time and name if needed for daycare.  You’ll want to use the milk in the order it was expressed.
  3. Make sure to leave a space at the top of the container of about 1/2 inch (1-2 centimeters).  Milk expands when it is frozen.
  4. You can add breastmilk together to make enough for one feeding in the same container.  Chill freshly expressed milk for a least 30 minutes in refrigerator before adding to already refrigerated or frozen breastmilk.
  5. Freeze your milk in 1-3 ounce (30-90 milliliters) so you can easily meet your baby’s changing appetite without wasting much milk, or until you know what your baby consistently takes at a feeding.  Breastmilk has been referred to as “liquid gold”.
  6. Storing breastmilk can be done in any container that you would use in your refrigerator or freezer, but it is helpful to put expressed breastmilk in bottles or container it will be sued in so you aren’t losing any breastmilk when you are transferring it to the container you are feeding baby from.
  7. Thaw frozen breastmilk in its container under lukewarm running water or let it stand briefly in warm water, shaking to thaw.  Gently shake the container of thawed breastmilk to mix the fat layer that separated out.  Avoid using the microwave or hot water to defrost breastmilk.  Both can create hotspots in the milk that could burn your baby’s mouth.
  8. Use thawed milk within 24 hours.  If your baby does not consume all the breastmilk you have given them at a feeding, you should not save it to be used at another time.
  9. If your baby has taken some breastmilk, but not finished the bottle, often people ask if they can save what is left.  The science of food safety has shown, food between 40 -140 degrees F (5-60 degrees C) (3)  is more likely to grow bacteria and the warmer the environment the faster it multiplies (even though breastmilk has been shown to resist bacteria growth more than other foods, once you chill it, freeze it or heat it, it changes some of those components)  So remember, if it has been between 40-140 degrees F ( 5-60 degrees C)  for 2 hours it needs to be tossed out.  Putting it back in the fridge and hoping to use it again is a problem because baby’s saliva breaks down the breastmilk that is left in the bottle.  If you have given the bottle of breastmilk and it has NOT been consumed within 2 hours, of starting the bottle, throw it away.  No need for a sick kid.


  1. Wambach, K, Riordan, J, Breastfeeding and Human Lactation, 5th edition, Burlington, MA, Jones & Bartlett Learning, 2016, p 647.  Note: publishing date does say 2016.