I store my breast milk in milk storage bag and freeze it for 2 months, my baby still like it very much and finish it all. I first defrost it in the 2-8oC compartment 24 hours before actual feeding time and warm it up when feeding. My baby is very healthy, no sickness at all until now.
If you don't want to store it for too long, you can rotate the stock but please don't waste these precious milk.