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Storage of Breastmilk

By Melissa Kotlen Nagin, About.com

Updated April 21, 2009

About.com Health's Disease and Condition content is reviewed by the Medical Review Board

Breast milk is often referred to as "liquid gold," and storing it safely is key. There is a lot of conflicting research about the advantages and disadvantages of storage containers made from particular materials. When storing breast milk at home after pumping, it's generally recommended that you pour the milk into a clean BPA-free plastic storage container or polyethylene bottle liner, or simply keep it in the pump bottle. Label the container with the date that the milk was pumped. (If you're in the hospital, a specimen bottle, polypropylene centrifuge tube, or a Volu-Feed are fine, but remember to label the containers with your name, as well as the date and time the milk was expressed).

The general guideline for breast milk storage for a full-term baby is easy to remember: Just think "the number 6." (For premature or ill babies, guidelines are different.)

Pumped breast milk may be kept:

  • at room temperature for 6 hours
  • in the refrigerator for 6 days
  • in a standard freezer for 6 months
    (Set yours to a level that makes your ice cream rock-hard. Most freezers reach this temperature, but if you are concerned at all, you should buy an inexpensive freezer thermometer to set your mind at ease.)

In addition, milk can be stored:

  • in a cooler with ice packs for 24 hours
  • thawed in the refrigerator for 24 hours
  • in a deep freezer for 1 year
Keep in mind that refrigerated or defrosted milk will naturally separate so that the fattier milk is on the top of the bottle. This is normal, and gently swirling the bottle will help mix the milk up.

Choosing and Using Storage Containers

There are many different types of containers used for storing milk. They are made of everything from glass to plastic to stainless steel.

When selecting, think about how long you plan to store your milk. Some milk storage bags, for example, are particularly designed for freezing. If disposable bottle liners are used for freezing breast milk, they may require additional protection to stop leaking and contamination. If you'd like to freeze milk in harder containers, glass gives the most protection because it is the least absorbent. You will also want to leave some room when freezing your milk, as the milk expands when it is frozen. You should use a solid, one-piece cap for the best seal and hold off on tightening it until after the milk has been frozen.

Here are some tried-and-true choices:

If you plan to go back to work while you're breastfeeding, a small refrigerator may be very useful to have in your office. I like the Unisar Mini Fridge. This way, you can keep your expressed milk in your own private cooler, rather than the cluttered company fridge.

VIDEO: Pumping Breast Milk - How to Pump, Store, and Reheat Breast Milk

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