how long is breast milk good for

Freshly expressed breast milk is the best option for your baby, so if you're pumping and leaving bottles for your little one, you might want to work out a system that allows you to give your baby milk that hasn't been frozen if possible. An interesting fact about breastmilk is that if left at room temperature for 8 hours, it actually has more immune factors then refrigerated milk! So if you leave a bottle out, don't fret. It can safely be left on the counter for up to 10 hours.

When preparing to store your breastmilk, either in the fridge or freezer, be sure to date the container. Also be sure to use the right kind of container, you would not want your milk to spill or the container to come open or break.

Milk left over in a bottle can be saved until the next feeding, but after that it should be thrown out. Most Moms find that putting 2 to 4 ounces in each container is best. Breastfed babies take less milk than formula fed infants, and you don't want any of your "liquid gold" going to waste!

Storage Guidelines for breast milk
kept at 15 C (59-60 F) - 24 hours
kept at 19-22 C (66-72 F) - 10 hours
kept at 25 C (79 F) - 4-6 hours
refrigerated 0-4 C (32-39 F) - 8 days

Frozen milk
freezer compartment located inside a refrigerator - 2 weeks
separate door refrigerator/freezer - 3 or 4 months (temperature varies because the door opens frequently)
separate deep freeze at constant -19 C (0 F) - 6 months or longer

When you are ready to use your frozen breast milk, heat it under warm water. Do not microwave it. Microwaving removes some of the beneficial components of breast milk and creates "hot spots" in the milk that can burn your baby. Be sure to check the temperature to make sure it is not too hot.

Also, breast milk naturally separates since it is not homogenized. The creamy, fattier milk rises to the top. You can stir or swirl the milk to mix if you want, but there is no need to do so. And don't shake the milk too violently as this can denature the proteins. (Here is a reference to support this.)

As a side note, fresh breast milk (straight from the source!) is good for the length of your baby's nursing experience, whether that's 8 weeks or 3 years. A Mom's breasts don't expire, and breast milk is wonderful for the health of babies and even toddlers.