I have found a way to freeze breast milk that's simple and easy on the environment. Get rid of those one time use plastic bags and try the Slim Lines Milk Trays ^TM system for freezing breast milk. Each tray holds eight 1 oz. portions of expressed breast milk. Once the portion is frozen, you can transfer it to a freezer-safe reusable container. It makes more room in the freezer and the unique design allows for the "sticks" to fit any bottle neck size. Great product with so many more benefits that can be described here. See for yourself: www.slimlines.biz