Whether you’re going back to work, want your partner to help out with feedings, or are leaving your baby with your parents or in-laws, storing your breast milk comes in handy when you have to be away from your baby for a certain period of time. And since you’ve taken the time and effort to express and pump your precious milk, you wouldn’t want it be put to waste or thrown away because of improper handling and storage. So today we’re talking about some do’s and don’ts you have to keep in mind when storing your breast milk.
As with anything that comes with your baby, you have to make sure your hands are clean. When you express and pump, and even when you transfer your milk to containers or bags, using clean hands will help keep bacteria away. Even when you pump and express milk, make sure the pump and pumping parts you use have been thoroughly cleaned.
If you are thinking of storing your breast milk in plastic bags, your best bet for this would be bags that are specifically made to store breast milk. Using food storage bags, zip locks, or baby bottle liners aren’t designed to store breast milk and may tear, leak, and puncture easily. You can also opt to use clean, food-grade containers with tight fitting lids made out of glass or plastic. Just make sure to avoid bottles or plastic containers with the recycle symbol number 7, which means that the container may be made out of plastic containing BPA.
One common mistake moms make when freezing their breast milk is filling the container to the brim. But, breast milk expands when you freeze it, so it may either expand the container or break through it. Either way, you don’t want to end up with a bent container or contaminated milk, so leaving an inch or two of space from the top is a good idea. You might also want to wait to tighten the bottle caps or lids until the milk is completely frozen.
Since breast milk has a certain shelf life, that means that you have to keep track of when you’ve expressed your breast milk. Once you’ve put it in a container, mark it with the date that you expressed it on. It’s best to do this with waterproof labels or ink to keep accidental erasures to a minimum. Legible handwriting is also recommended, so you don’t have to waste time trying to decipher the date you put.
The last thing you want to do is waste breast milk, so one solution to this would be to store your breast milk in amounts that you’ll be sure your baby will be able to finish (usually 2-4 ounces). Remember that breast milk has a certain shelf life, depending on where you store it, so try to gauge how much your baby drinks in one feeding session, and use that as your baseline.
The temperature at the doors of refrigerators and freezers is more likely to change compared to the temperature in the middle of the fridge or freezer. And since breast milk is best stored in consistent temperatures, try to avoid storing them in the doors to avoid possible thawing or heating.
Another thing you can do to avoid temperature fluctuations is store your containers or storage bags on a flat surface one on top of the other. Putting them against other items inside your fridge or freezer can also lead to the milk getting squished, and the container possibly breaking.
This is a big no no! Once you’ve thawed and warmed breast milk, don’t try to refreeze any leftovers it again. So if you’ve still got some left, your best bet would be to throw it out. You can still refrigerate it for the next 24 hours, but that’s about the maximum shelf life of the milk. While the reasons for this vary, many experts don’t recommend refreezing thawed out breast milk.
Keep this golden rule in mind: First in, first out. (This is also why labeling your containers is so important–it helps you keep track of which one you should pull out and use first.) The reason for this is that the quality of breast milk decreases over time, and you wouldn’t want to leave it in for too long.
Research suggests that the longer you store your breast milk (whether in the fridge or the freezer), the greater the loss of vitamin C in the milk, especially if the milk has been frozen for more than five months. Also keep in mind that the milk you produce when your baby is a newborn won’t contain the same nutrients that he or she will need when he is a couple of months older.
Here’s another big no no! Microwaving can actually destroy or break down the nutrients in your breast milk, and can create hot spots, which can burn your baby’s mouth. You can try leaving a frozen container of breast milk in the fridge overnight, setting it in a container of warm water, or running it under lukewarm water instead.
It’s quite normal to see separated layers in frozen breast milk. This is just the separation of fats from the rest of the milk. Before feeding your baby, gently swirl the milk to mix in the fat. While it’s normal instinct to shake the container, some research shows that the force of shaking has the potential to destroy the protein structure in active substances such as breast milk.
To test whether the milk is warm enough to feed to your baby, use a small spoon, straw, or other utensil to transfer a few drops onto your wrist. (The milk should be warm, not hot!) It is not advised to touch the milk directly with your finger because of the possible transfer of germs and bacteria.
Let’s say your thawed out breast milk isn’t enough and you want to add freshly expressed milk to it–while this is okay, you should thoroughly cool your freshly expressed breast milk in the fridge or in a cooler with some ice before adding it to your previously frozen milk. The fresh, warm milk may partially rewarm the frozen milk, which may invite bacteria.
Once you’ve thawed or warmed breast milk that has already been stored, it should be consumed by your baby within the next two hours at best. While the quality of frozen breast milk is almost the same as freshly expressed milk, once it is thawed and the longer the exposure to warm temperature, the enzymatic processes could change the milk quality.
- Boyata, Kelly. “Breastmilk Storage & Handling.” Kelly Mom. Last updated March 15, 2018.
- CDC Staff. “Proper Storage and Preparation of Breast Milk.” Centers for Disease Control and Prevention. Last updated March 26, 2019.
- Eglash, Anne and Liliana Simon. “Human Milk Storage Information for Home Use for Full-Term Infants.” The Academy of Breastfeeding Medicine. Last updated June 29, 2017.
- Mayo Clinic Staff. “Breast Milk Storage: Do’s and Don’ts.” Mayo Clinic. Last updated April 6, 2018.
- Office of Women’s Health Staff. “Pumping and Storing Breastmilk.” Women’s Health. Last updated July 9, 2018.
- Virgallito, Mary. “Keep Breast Milk Safe: Tips for Handling, Storing, and Thawing.” Children’s Hospital Los Angeles. Date accessed April 2, 2019.