There will likely come a time when you will need to express breastmilk, either by hand or with a pump, and that liquid gold should not go to waste! Proper breastmilk handling procedures are key to keeping the milk safe for consumption. The chart below by the CDC lists the recommend optimal storage time frames.
Milk should be stored in BPA-free containers, either bottles or breastmilk bags. They even make breastmilk ice cube trays that freeze the milk in thin tubes so you can pop them directly into a bottle. Don’t fill bags and bottles all the way because the milk will expand when it freezes. I learned this the hard way with my first son and I wondered why my milk was leaking everywhere when it thawed—the bag had split open in the freezing process!
The further away from the door (whether the fridge or freezer), the better, so aim to stick that milk way in the back of the refrigerator or at the bottom of a deep freezer.
Ideally, milk should be thawed overnight in the refrigerator. Once thawed, it needs to be used within the next day or two. Do not refreeze it! Speaking of which, what constitutes “frozen”? A contacted me the other day who had lost her electricity during a bad storm and did not regain it for almost 24 hours. Cue: panic mode. She was afraid she would have to use all of her stored milk within 48 hours or dump it. Some of the milk had started to thaw. The good news is, as long as there are still some ice crystals in the milk, it is still considered “frozen” and can be refrozen. Milk that is completely thawed but still cold can be used within 48 hours. Milk that has been thawed and is no longer cold should be discarded. Some new studies are coming out that are testing the nutrient-content and bacteria levels of milk that has been thawed and re-frozen, and it is looking promising to give moms a bit more leeway with milk storage, but this is still preliminary. More to come on that topic at a later date. In the meantime, err on the side of caution.
Handling and Warming
Breastmilk naturally separates and the fat/cream floats to the top. Gently swirl it to mix. (Don’t shake it or it will create air bubbles that can upset baby’s tummy). Milk can be warmed gently in a bottle warmer, or by placing in a bowl of warm water. Always test the temperature of the milk before giving it to the baby. Never warm milk in the microwave. If the baby does not finish the bottle during the feeding, you can offer it again within 2 hours, but it should be discarded after that.
Lastly, always date the milk you’ve expressed so you can keep track of how long it has been stored!