Breastmilk storage - What you need to know.
Pumping and expressing breastmilk is hard work. The last thing you want is to forget how long it's been sitting out and unnecessarily dump it. And btw, you don't have to dump it! Get creative, find alternative uses like a milk bath or breastmilk lotion.
Breastmilk Storage Recommendations
There are slightly different recommendations from the CDC, the WHO and the ABM. Below is a reference for milk storage. Print it, pin it up, keep it for quick reference.
Freshly pumped milk can stay at room temperature for 4-5 hours. In *ideal* conditions the ABM reports this can be 7-8 hours. This means that middle of the night pump won't go bad if you forget to put it in the fridge.
Breastmilk can be refrigerated for 4-5 days. This is great for those who pump infrequently or only catch the letdown and combine breastmilk to use or freeze for a full feeding.
What's important to understand is that breastmilk doesn't ''go bad'' after it reaches the 4 hour, 4 day or 6 month marks. These time frames are just reference points that have been studied and shown to be ''optimal.'' The milk does not necessarily spoil, but its composition changes. It begins to lose its nutritional properties. Carbohydrates, fats, proteins, vitamins and mineral concentrations can decrease.
Combining milk
The general recommendation when it comes to combining milk is to make sure they are the same temperature. Recently, the AAP (American Academy of Pediatrics) had silently updated their guidlines that included mixing freshly expressed milk with refrigerated milk. This was awesome news, as many mamas naturally do this, especially exclusively pumping moms. But just as quickly and quietly as they published those updates...they took them down, without word or explanation. So this is where your personal preference comes in, if you feel comfortable mixing different temperatures, great. If not the CDC and ABM do recommend combining milk that is the same temperature, meaning chilling the milk first.
Combining breastmilk from different pumping sessions and then separating into portions to freeze, actually is beneficial too. Milk composition changes throughout the day, more watery in the morning and fattier at night.
Freezing and Thawing Breast Milk
When freezing breastmilk, consider your storage space and containers. More popular are plastic freezer bags that fit individual portions. To save space, make sure to remove all the air in the bag, and lay it flat to freeze.
Alternatively, silicone freezing trays and silicone reusable bags are becoming more popular. Depending on the item it can freeze in half ounce or full ounce serving sizes.
However you choose to freeze breastmilk, when it comes to thawing, there are some finite rules. Never MICROWAVE breastmilk. It destroys the immune cells, changes the composition, and unevenly heats the fat globules.
Once breastmilk is completely thawed, it cannot be refrozen. If thawed in the fridge it should be used within 24 hours.
The caveat is, if breastmilk still has ice crystals, many will recommend it may be refrozen. However, the research and evidence on refreezing breastmilk is limited, so there is no official guidance. Refreezing partially frozen breastmilk is still a personal preference.