How to Store Breast Milk

At room temperature:

• Stores safely at room temperature (66-72° F, 19-22° C) for up to 10 hours

In the fridge:

• Stores safely in the refrigerator (32-39° F, 0-4° C) for up to 8 days
• Store in the back of the refrigerator, not in the door

In the freezer:

• Stores safely in a freezer compartment inside a refrigerator (variable temperature due to the door opening frequently) for up to 2 weeks
• In a freezer compartment with a separate door (variable temperature due to the door opening frequently) for up to 3 to 4 months
• In a separate deep freezer (0° F, -19° C) for up to 6 months or longer

*Talk to your provider about more conservative storage guidelines if your baby is premature, immune compromised, or seriously ill. 

 
Warming Tips:

• Thaw and/or heat under running water
• DO NOT bring temperature of milk to a boiling point
• Gently swirl milk before testing temperature. Swirling will also redistribute the cream into the milk. It is normal for stored milk to separate into a milk and cream layer.
• DO NOT use a microwave to heat human milk. Microwaving kills many of the living immune cells that fight disease. Microwaving any beverage can also create hot spots that can burn your baby's mouth

Thawing previously frozen milk

If milk has been frozen and thawed, it can be refrigerated for up to 24 hours for later use. It should not be refrozen.

Source: http://www.workandpump.com/storage.htm