Disposable, Leakproof Milk Bags with Milk Protection from Medela. Recyclable & BPA Free. Store, transport and warm breast milk in these convenient, ready-to-use breast milk storage bags. Constructed from a durable, double layer material and built-in double zipper seal to keep your breast milk safely stored in the fridge or freezer. For added convenience, the bags are self-standing and come with a large write-on area so you can track the date and other important information.