Here are a few facts on breast milk storage and preparation that every nursing mother needs to know. Times change and life gets busy so these tips are even meant for mothers who nurse but don't expect a future need to refrigerate or freeze their baby's liquid sustenance.
How long can you store breast milk?
Room Temperature - 1 to 3 hours, preferably no longer. It is always safer for your baby if you toss the breast milk out when it has been left out for more than an hour, especially, when the indoor and outdoor temperatures are warmer. For cooler temperatures it should be fine if it is left at room temperature for over 1 hour, but never use if it has been out longer than 3, and never go longer than 1 hour unless your baby is completely healthy. If you suspect you won't be needing to use newly expressed breast milk for a while try putting it in the refrigerator for storage until you need it.
Fridge - 2 to 3 days if properly labeled and stored in an area that does not experience any temperature fluctuations. Many like to store breast milk containers in the door of the refrigerator but I would not recommend this unless you intend to use it right away. Try storing it instead towards the back of the refrigerator.
Freezer – Typically you can use the freezer for breast milk storage up to 3 months if it is kept at 0* F. Store in the back of the freezer and not towards the front where it is exposed to warmer temperatures from the doors being opened.
What can you store breast milk in?
Place in air tight plastic containers such as baby bottles with solid tops. (Often when you purchase a new baby bottle it will come with a flat round disc that can be used inside the cap in place of the bottles nipple you can even pick up solid lids that are sold for storage and travel purposes, as well) Any sterile plastic container with an airtight lid will work, too or breast milk storage bags can also be purchased to store breast milk.
Keeping track of your stored breastmilk:
Make sure to label all of your breast milk containers, before storing, with the date and time (don't forget to add AM or PM) that it was expressed and put away. You can do this by adding a piece of scotch tape and writing on it or if you are using breast milk bags they should have an area designed and ready for labeling.
Thawing and warming cold or frozen breast milk:
NEVER heat your breast milk up in the microwave. This can cause hot spots that are not noticeable by the standard wrist temperature check, which can cause serious burns. It is also thought to take out some of the nutritional value known to be passed through a mother's milk.
You can put containers of frozen breast milk in the refrigerator 24 hours ahead of time to let it start to slowly de-thaw or you can place it in warm (not hot) water to help speed up the thawing process. If you partially fill up a deep pan or sink you can set the bottle in the warm water occasionally giving the bottle or container a twirl to help even out the thawing process.
Only thaw milk that has been kept in cold storage in warm water if you intend to use it within a short time because it can not safely be put back in the refrigerator or freezer after you have thawed it out.