Breast milk should be placed in a special breast milk storage bag, or BPA-free plastic or glass container or bottle that has been cleaned with hot, soapy water, then rinsed and dried. Write the date on the container and leave a little space to allow for expansion. Breast milk can be kept at the back of the freezer for three months (or six months in a chest freezer).
Breast milk separates, especially after freezing. To get it homogenized again, wait until the milk is room temperature and roll the bag or bottle between your hands for 30 seconds.
Have more bottle-feeding questions? Download our chart here and put it on the fridge—it has the answer to all your questions.