Breast Milk Storage: 9 Wrong Ways Can be Dangerous for Your Baby


“The breast is the best.” Experts always tell new moms that feeding directly from the breast is the way to go. As your baby grows, her nutritional needs change. Your body picks up on these changing needs and adjusts the contents of your milk to give her just what she needs.

When you pump and store milk, a lot can go wrong. And your body won’t be able to pick up on those changes in your baby’s system.

Related: 5 Methods of How to Dry Up Breast Milk Fast

             What Every Mum Should Know about Breastfeeding

9 Wrong Ways to Store Breast Milk

There’s a right away and a wrong way to store breast milk. Improper storage can spoil your milk and make it downright dangerous for your baby to drink.

If you plan to pump and store your breast milk, avoid doing the following.

Using Contaminated Containers

Breast milk can be safely stored in:Wrong Ways to Store Breast Milk

  • BPA-free plastic bottles
  • Glass
  • Specially-designed breast milk bags (freezer-safe)

It’s not enough to have the proper storage container. You need to make sure the container is free of contaminants – inside and out.

If left dirty or wet, containers can easily become a breeding ground for bacteria.

Always wash containers with warm, soapy water after every use, and make sure that you dry the container each time.

Store freshly cleaned and dried bottles in a safe place. It may be convenient to store bottles near the sink after they’re cleaned and dried, but dirty dishes and people washing their hands can contaminate the bottles.

Freezing for Long Periods of Time

Having a freezer full of breast milk may sound like a convenient and simple way to meet your baby’s nutritional needs, but freezing milk for long periods of time is a bad idea.

The milk you produce is constantly changing and adapting to your baby’s needs. The milk you pump today will be very different from the milk you pump next week.

Technically, breast milk stays good in the freezer (at 0 degrees Fahrenheit) for four months. Yes, the milk will not spoil if it’s stored properly in the freezer, but it may not give your baby all of the nutrients she needs.

She may want more milk right after feeding, or she may start losing weight.

Freezing in Ice Cube Trays

It sounds like a good idea. These bite-sized cubes allow you to thaw just the right amount of milk, and they’re great for soothing sore gums. But freezing your breast milk in ice cube trays is a big no-no.

Ice cube trays are open at the top, which leaves the milk exposed to potentialWrong Ways to Store Breast Milk contaminants. If there’s any bacteria floating in the air inside of the freezer or any liquids are dripping near the tray, the milk may become contaminated.

Here’s the good news: Manufacturers now make special ice cube trays for breast milk. These trays have locking lids to prevent bacteria from getting inside.

Overfilling or Puncturing Freezer Bags

Freezer bags are a convenient way to store breast milk, but you need to be cautious when filling them. Milk expands when frozen. Overfilling can cause the bags to explode or break.

Storing bags near sharp edges also increases the risk of them puncturing. If you keep the bags on top of frozen meat, for example, bones from the meat can put a hole in the bag.

When breast milk bags are punctured or torn, it exposes the milk to germs.

If you plan to freeze your breast milk, do not use freezer bags designed for home use. Breast milk bags are BPA-free, a chemical that’s harmful to your baby’s health.

Storing Near Raw Foods

It’s easy to pump milk, and place it in the refrigerator for later. But if you’re storing the milk near raw foods, you may be unknowingly exposing it to germs and bacteria.

Storing milk near raw meats is particularly dangerous. The meat may touch the exterior false Ways to Store Breast Milkof the container, leaving bacteria behind. Raw meats sitting above the milk may also leak blood into the container.

Your hands may also pass bacteria to the bottle if you have to move things around to get to the containers.

Take the time to rearrange your refrigerator, and designate an area to milk storage.

Storing in the Refrigerator Too Long

Freshly pumped breast milk will only stay good in the refrigerator for so long.

  • 24 hours if thawed in the refrigerator after being frozen
  • 8 days if stored in the fridge right after pumping

If left in the refrigerator for too long, breast milk will spoil and be unsafe to feed your baby.

Leaving Bottles Out at Room Temperature

Moms have busy lives. It’s easy to forget about that bottle of milk you pumped earlier in the afternoon. Is it still safe for your baby to drink?

Breast milk goes bad very quickly when left out at room temperature. if you have a habit of storing your breast milk out on the kitchen counter, know that this is not the ideal way to store your milk.

At room temperature, breast milk stays good for:

  • 6-10 hours if the room is between 66 F and 72 F
  • 4 hours if the room is between 73 F and 79 F

Some experts disagree with these figures and believe that breast milk should not be left out at room temperature for any length of time.

If you pump more milk than you think you need, store it in the refrigerator right away to be on the safe side.

Adding Freshly Pumped Milk to Old Milk

Let’s say you fed your baby earlier in the day and she didn’t finish the bottle. To conserve your “liquid gold” milk, you pump more and add it to the bottle. Is it safe for your baby to drink?

Maybe not.

Experts advise against adding fresh milk to old milk. That includes:bad ways of Storing Breast Milk

  • Milk that’s been stored in the refrigerator
  • Milk that’s been thawed in the refrigerator
  • Milk that’s been sitting on the counter

If there’s milk leftover after a feeding session, toss it to be on the safe side. A half-empty bottle is an open invitation to bacteria.

Improperly Thawing the Milk

Even if you freeze your breast milk properly, improper thawing can make the milk unsafe to drink.

If you’re thinking of reaching for the microwave, don’t. The microwave should NEVER be used to thaw breast milk.

The microwave will heat the milk unevenly, leaving hotspots that could be dangerous. Microwaves also kill the living immune cells in the milk.

If the microwave isn’t a good idea, what about heating milk in a pan? Another big no-no.

The best way to heat refrigerated or frozen breast milk is to run it under warm water or to place it in a container with warm water. The goal is to heat the milk gradually to avoid breaking the plastic or glass.

The Dangers of Improperly Stored Breast Milk

What happens if you feed your baby milk that hasn’t been properly stored? The effects could be devastating.


When breast milk is stored in the freezer for too long, it may not provide your baby with the right nutrients.

This may not be too serious if the baby is fed the milk for just a few feeding sessions.Dangers of Improperly Stored Breast Milk But over the long-term, your baby may become malnourished.

Malnourishment is serious, and can cause:

  • Kwashiorkor: A protein deficiency that’s common in malnourished children. Symptoms include brittle hair, copper sheen, water retention, rashes and distended belly caused by bloating.
  • Stunting: A long-term effect. Malnourishment can stunt your child’s growth.
  • Marasmus: A severe protein deficiency. Symptoms include severe weight loss, hair loss, and thin, papery skin.
  • Vitamin and mineral deficiency: Malnutrition leads to deficiencies in essential vitamins and minerals.


Infection is another serious risk of feeding your baby improperly stored breast milk. Milk that has spoiled can cause an upset stomach.

Milk that has been contaminated by bacteria can cause more serious side effects,bad sides of Improperly Stored Breast Milk including infection. Unfortunately, it’s often hard to determine if milk has been contaminated by bacteria. For this reason, it’s so important to take steps to store your breast milk properly.

In July 2017, a preterm infant developed meningitis and wound up with destroyed brain tissue after being fed milk from a contaminated breast pump. The baby will now experience severe developmental delays.


It’s worth the time and effort to make sure that you’re storing your breast milk safely and properly. If you can, avoid storing it period and feed straight from the breast to avoid these potential complications.


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