I feel like every time this question is asked, there are a million different answers!For the sake of this article, I will be citing the information available from the CDC. You are always encouraged to discuss things with your IBCLC or doctor. You should always store breast milk in breast milk storage bags or clean, food-grade containers made of glass or plastic that have a tight-fitting lid. You should never store breast milk in plastic bags that have not been specifically designed for breast milk. Here are the CDC recommendations for storage. When storing in the fridge, keep at the back of the fridge. In the freezer, it's best to avoid freezing in the door.