In our breastfeeding class, we were taught the rule of 5. 5 hours out at room temp, 5 days in the fridge, and 5 months in the freezer. Hope this helps:-)
In addition to the above I was told if I was going to freeze surplus milk do it within 24 hours of pumping it. Certainly in my case if I left it longer than that before freezing my baby wouldn't like to drink it after it was defrosted. If I knew it would get used I would store it in the fridge for a few days.
The La Leche League website usually has the current recomendatins for handling and storing breast milk on their website.
I'm no expert but I have been BF for the past 10 months. There is so much information out there about rules and guidelines. Here is what I have done and continue to do.
I'm an on demand BF mother. I do work part time so I pump 1x when I am at work and generally I pump 1x in the middle of the night.
I will leave milk at room temperature for up to 3-4 hours if I must and immediately refrigerate. I generally will keep milk in refridgerator for up to 3-4 days before freezing.
Once in the freezer I purge it after 6 months if not used.
Milk does lose some of its nutritional value (but still better than formula) once it is frozen, so don't freeze unless you need to stockpile to go back to work, etc. It is better to feed your baby the expressed milk before freezing it.
I do know for sure that once you defrost the milk it must be used w/in 24 hours of defrosting.
Hope this helps.
Thanks you all for your reply. there is so much info out there that it could get confusing.