Is it Ok to Store, Freeze, and Defrost Breast Milk in Plastic?

Why some plastic options are okay and what the alternatives are if you're not into plastic.

First of all, hats off to you for bringing forth and sustaining a life with your body! We salute you!

And, if you've managed to figure out your breast pump, a pumping schedule, and bottle feeding, then you deserve all the props in the world. Now, you have nutritious breast milk for your little one while you sleep, go to work, or go out on the town (gasp!). If you are curious about how to safely store, freeze, and defrost your liquid gold, we've got you covered.

For other questions about pumping and all other things breastfeeding related, KellyMom is a highly recommended online resource.

Refrigerating Milk

If you are just storing the milk for a short period of time before your baby gulps it down, no need to freeze it. Store it in extra glass or stainless steel bottles until your baby drinks it, which also helps to cut down on dishes. Even bottles that say BPA free can have hormone-altering chemicals that can get into your breastmilk, so check out our roundup of glass and stainless steel bottles. And since substances that are fatty (hello milk!) or acidic can leach more of these plastic additive chemicals into the food/liquid, it's a good idea to avoid storing your milk in plastic bottles. Additionally, heat and UV damages plastic (like when you sterilize or wash the bottle) which makes it even more likely that the bottle is leaching chemicals into the milk.

Freezing Milk

If you are building up a stash for when you head back to work or when you'll be away from your little one, then you'll need to freeze your milk.

One of the easiest ways to freeze breast milk is in a plastic breast milk storage bag. A lot of moms freeze these bags laying flat, which allows them to be compactly stored. These storage bags are thicker than normal food storage bags and usually have really good seals on them to prevent spillage. They are generally made of food grade LDPE (low density polyethylene), which falls under the #4 recyclable category. LDPE plastics are also commonly found in bags for dry cleaning, frozen foods, bread, and the linings of hot beverage cups. The good news is that LDPE plastic does not contain additives like BPA or similar chemicals and is generally considered a safer material (1). Make sure to buy high quality breast milk storage bags, because cheap versions may be mixed with other types of plastics. The bad news? There's not really any right now, but some people are still concerned because it's plastic.

If you're looking for a plastic free option for freezing and storing breast milk, some moms have had good luck with 4 oz mason jars or other small baby food containers that are made of glass. There are a couple on our recommended baby food and storage roundup. Just make sure to leave enough room at the top of the container for the milk to expand a bit as it freezes.

Another option is to freeze breast milk in silicone freezer trays and then when the milk is frozen solid, to pop the frozen milk out and store them in the freezer in either freezer ziplock bags, silicone bags, or large glass jars. This requires an extra step, but can be a handy way to only defrost the exact amount of breastmilk you want at any given time. Our baby food and storage roundup also includes a silicone freezer tray if you want to go this route.


One of the easiest ways to defrost milk is by putting it in the fridge overnight. This works no matter how you've frozen your milk. If you are looking to more quickly defrost milk, or you are a busy mom and having to remember to do something the night before is a non-starter, then it depends on how the milk is frozen. If you stored it in a breast milk storage bag, we recommend quickly running it under lukewarm water (not hot!), dumping it into a glass or stainless steel container or bottle when it's still in icy chunks, and then defrosting and heating up the milk in a bottle warmer or under hot water. That way you can minimize any risk that heating up the plastic bag will release chemicals. For those using glass containers, we recommend a warm bath to defrost. Just keep in mind that it will take a bit longer for the middle to fully defrost. Lastly, if you've got your milk in frozen cubes, take the cubes out and put them in a glass or stainless steel bottle and then defrost in a warm bath. If the bottle you use to feed your child is plastic (no judgement if you just can't make stainless steel or glass work!), heating up the milk in a different glass or stainless steel container and then pouring it into the plastic bottle is a simple way to limit exposures to chemicals that could potentially leach from the bottle.



Why Creating Your Own Compost Might Be Easier Than You Think

We've got step-by-step instructions, tips and tricks to get you the best looking soil around (seriously!)

You made it! Now that you're here, don't run yet! Gone are the days when composting meant throwing a heap of your leftovers in the dirt and banking on magic to make some soil (not that you still can't). BUT, we've got everything you need to know to jump on the composting train, reduce your carbon footprint and start saving money on fertilizer without all the headache and mess.

Keep Reading Show Less
Want more news like this?
Sign up to receive our email newsletter and never miss an update!
By submitting above, you agree to our privacy policy.

9 Veggies You Can Grow Indoors

Gourmet dinners with fresh veggies and no more plastic herb packets are in your future

What's better than having an indoor plant baby? How about one that gives you food? Even if you don't have a backyard, you can grow some vegetables and herbs on a windowsill inside. We found 9 veggies and herbs that are easy to grow inside and are useful to have on hand.

Keep Reading Show Less

Why You Should Care About Soil Contamination If You're Starting a Garden in Your Backyard

Here's the dirt-y details you're going to want to know and what to do about it

Dreary winter blues might have you dreaming of blue skies, warm weather and some home grown vegetables. But before you go jetting off to your nearest Home Depot or nursery, you might want to take a second and get to know your soil. We're serious! No, not the hello, my name is ____, more like the hey, what's in my soil? Not all soils are created equally and trust us when we say that you'll definitely want to make sure the soil you're using for growing food to eat is top notch!

Keep Reading Show Less

What All Those Certifications on Mattresses Actually Mean

Label Education: Decoding what GOTS, GOLS, Greenguard, Organic, and more mean

Choosing the right mattress is so important for sound sleep and health, yet with so many options the shopping can be confusing and stressful! Obviously you want to take comfort and pricing into consideration, but there are some chemical ingredients you might want to consider too. Standard synthetic foam mattresses can contain various harmful chemicals we don't want to be sleeping on. And these chemicals can evaporate into the air, or collect in house dust, which is yucky and no good for your family's health.

The great news is that there are a bunch of healthier alternatives, and these labels below can help you find them. We also have a roundup of 12 non-toxic mattress brands if you just want a quick guide to organic mattresses and natural mattresses you can buy.

Keep Reading Show Less

12 Non-Toxic Mattresses

options for every budget that are free of any harsh chemicals and petroleum-based foam, including organic mattresses

Step 1: Start researching organic mattresses or natural mattresses. Step 2: Get confused! Step 3: Look at our roundup where we did all the research on safe, well reviewed, comfy mattresses for you. Step 4: Order a healthy, non-toxic, organic mattress Step 5: Sleep more peacefully. We found options for every budget, so what are you waiting for?

All of the mattress brands we found use natural materials like 100% natural latex, organic cotton, and wool, and do not use petroleum-based foams or no chemical flame retardants. For our budget picks ($), a base model queen retailed for less than $1000. For the quality picks ($), a queen ran between $1000 and $2000. And the splurge picks ($) retailed for above $2000. Some brands use inner coils and some are made of just latex layers. We hope this list of natural mattress brands is a good starting place for a better night's sleep.

Keep Reading Show Less

Are your noisy neighbors and traffic noises from outside making you mad? Quite possibly! All the noise you experience throughout the day might be taking a toll on your health. Besides just being supremely annoying, studies show that noise pollution - yep that's really what it's called - is intricately linked to many mental and physical health problems.

Not only does the constant annoyance of irritating noises make people more anxious, but noise makes working more difficult. The noise itself disrupts memory, affects your ability to focus, and decreases performance (1). And if the noise is disrupting your sleep, then that might mean even more bad news!

Keep Reading Show Less

We all have our favorite lipstick. The one that we wear practically every day, is acceptable for work and going out, and that you are always sure to buy extras of, just in case the store runs out. Maybe yours is bright red, a nude pink, or maybe you like to go all out and wear a different shade every week. Regardless of how you get your perfect pout, it might be time to put on your detective hat and take a deeper dive into what makes your lips shine.

Keep Reading Show Less
Want more news like this?
Sign up to receive our email newsletter and never miss an update!
By submitting above, you agree to our privacy policy.