Storing Breast Milk and Milk Storage Tips

Handling and storing breast milk with care is very inmportant, because the same immune properties in your breast milk that protect your baby also help protect the milk from bacteria growth while it sits on the refrigerator shelf.

What kind of container should I use to store my breast milk? Storage options include hard containers, like bottles, made of plastic or glass, or soft containers, which are plastic bags.

The most important storage criteria usually involve:

• protecting your breast milk and all its valuable components; and
• your convenience and that of the baby's caregivers.

Unfortunately, there is not a lot of research about how storage containers affect human breast milk. One study showed that the leukocytes in breast milk (the live cells that transfer immunity from you to your baby) sticks to the side of glass containers, but subsequent research showed greater numbers of leukocytes in glass containers than in plastic, as the cells were released from the sides of the containers over time. Research has also shown a loss of antibodies and fat in milk that is stored in plastic bags, but this information applies only to disposable plastic nurser bags, the thin ones you can buy at most stores to use with baby bottles. If you do choose to store your milk in these, use two bags to protect against breakage and "freezer burn." Use twist ties to close the bags.

Glass/Plastic Bottles and Containers

The information currently available suggests that glass or hard-sided plastic milk bottles and containers (the kind of plastic that is clear, not cloudy) provide the best protection for nutrients and immunities. Hard containers should have secure, one-piece tops. If your baby is getting a lot of his nourishment directly at the breast, you don't need to be as concerned about nutrient loss through freezing and contact with storage containers as you do if your baby is getting only expressed milk and not nursing directly at the breast.

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Plastic Bags For Breast Milk Storage

Plastic bags esspecially designed for freezing pumped expressed breast milk are available from many companies that specialize in products for breastfeeding mothers and babies. These bags are sturdier than those used in baby bottles and have self-closures that are easier to seal and label. They do a better job of protecting milk components than nurser bags. Some types can be attached directly to your breast pump. Plastic bags take up less room in the freezer and are one-use disposable items, so there's no dishwashing involved. However, filling them and pouring milk out of them can be awkward.

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Additional Milk Storage Tips

1. Label each container with the date, so that you can use the oldest milk first and avoid needless waste.
2. Store your milk in small amounts, about two ounces in each container, at least at first. (If you're pumping milk for a premature baby, you may want to store it in even smaller amounts.) Breastfed babies take smaller amounts of milk at each feeding than do formula-fed infants, and smaller amounts are also quicker to thaw. Milk left in a bottle after a feeding can be saved until the next feeding, but after that it should be discarded, and you don't want to waste expressed milk. Eventually, you may decide to put more milk in each bottle, based on your caregiver's report on how much your baby takes at each feeding.
3. You can add more milk to already-frozen milk, but cool the added milk in the refrigerator first. There should be less added milk than already-frozen milk.
4. Always leave about an inch of space at the top of the container to allow for expansion. Just like water for ice cubes, human milk expands when you freeze it. Hard containers will pop open as the milk expands. Bags will break. Squeeze out the air at the top of the bag and fasten it an inch above the milk.
5. Bags containing human milk should be placed inside another container in the refrigerator or freezer. This makes for better protection and easier handling.
If you lay the bags down in a container in the freezer, you'll get flatter packages that will thaw more quickly. (But be sure they're sealed well, or you'll have a leaky mess.)
6. You might want to keep all your hard containers of milk together in the freezer or refrigerator inside a larger plastic box.