Many breastfeeding moms pump their breast milk to give to their baby when they are away. Here’s how to safely store, defrost, and warm your breast milk.
You can freeze and/or refrigerate your pumped (or expressed) breast milk. Store it in clean bottles with screw caps, hard plastic cups that have tight caps, or nursing bags (pre-sterilized bags meant for breast milk). When freezing, it’s best to store breast milk in 2- to 4-ounce (59.1 to 118.2 milliliters) portions rather than larger portions so none goes to waste.
It's helpful to label each container with the date when the milk was pumped (and your baby's name if the milk is going to childcare providers).
For healthy full-term infants:
You may find that different resources have different recommendations on how long you can store breast milk at room temperature, in the refrigerator, and in the freezer. Talk to your doctor if you have any concerns or questions.
You can thaw frozen milk in a couple of ways:
Never microwave breast milk. It can create "hot spots" in your breast milk, which can burn your baby’s mouth. The heat can also destroy important nutrients and proteins like antibodies, which help protect your baby from illness.
Once thawed, use the milk within 24 hours. Do not refreeze it. When your baby starts to drink from the bottle, use it within 2 hours.
Breast milk that's been frozen or refrigerated may look a little different from fresh breast milk, but that’s OK. It's normal for early breast milk to look kind of orange and the mature milk to look slightly blue, yellow, or brown when refrigerated or frozen. And it may separate into a creamy looking layer and a lighter, more milk-like layer. If this happens, just swirl it gently to mix it up again.
Thawed milk may smell or taste soapy due to the breakdown of fats in the milk. The milk is still safe to drink, and most babies won't have a problem with it. If your baby doesn't like it, the milk can be heated to scalding (bubbles around the edges) right after it is pumped or expressed and then quickly cooled and frozen. This switches off the enzyme that breaks down the milk fats.
Before their first use, wash and then sterilize the nipples, bottles, and washable breast pump supplies (for example, the breast shields and any other part that touches your breasts or your milk) by boiling them for 5 to 10 minutes. Check the manufacturer's directions for how long to boil the parts.
You also can sterilize the parts with a countertop or microwaveable sterilizer, but boiling works just as well and costs nothing. After that, wash the bottles, nipples, and pump supplies in hot, soapy water (or run them through the dishwasher) after every use.
Reviewed by: Kristen Littleton, IBCLC, Jamila H. Richardson, BSN, RN, IBCLC
Date Reviewed: Jan 1, 2021