Is it Safe to Reuse Milk Bags?

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For moms who choose them, using breast milk bags instead of bottles has many advantages. They come in various sizes, which is awesome since every pumping session doesn’t bring the same results. They also fit much more neatly into your refrigerator or freezer, making them perfect for larger families with less food storage space. Because of their convenience, new moms often ask, “Can you reuse milk bags?”

According to the CDC, they are a very convenient and safe way to store your breast milk after pumping. However, only certain types of bags are safe to reuse. Hence, it is essential to know which ones are made to be used again so that you don’t risk contaminating your baby’s milk. 

Let’s take a look at which breast milk storage bags are meant to be reused and which are not.

All Milk Storage Bags are Not Created Equal

bags of breast milk

In the past, all breast milk bags were made of disinfected plastic and were only intended to be used once. That is because once you use them, they are no longer sterile. 

So there is a high risk of contaminants getting into the breast milk bag and being transferred into your baby’s food supply. Reused plastic bags have bacteria in them that will get into the milk as soon as it is poured in. This creates a danger to your child because of the risk of exposure to dangerous pathogens or organisms. 

Also, the plastic that these bags are made of is not durable enough. Attempting to re-sterilize one-use milk bags also makes them lose their viability, weakening and making them easier to burst. Since liquids expand as they freeze, these bags often split, ruining all of the milk inside of them. Because of this, you should always throw away these pre-sterilized breast milk bags after they have been used, but since all of them are not created equal, there is a solution.

Reusable Silicone Breast Milk Bags

For the mom who is asking, “Can I reuse milk bags?” here is some good news! Pre-sterilized plastic throw-away bags are no longer your only option for breast milk storage. 

reusable breast milk bags

Instead, silicone bags are safe to use and reuse because they are very durable and don’t leak after being resterilized. They are also safer for the environment since they cut back drastically on the amount of plastic being tossed out daily.

Some mothers may balk at the price of a silicone reusable breast milk bag. After all, they are significantly more expensive than the disposable pre-sterilized plastic ones. However, you have to take into account the fact that disposable bags are a recurring purchase. In contrast, reusable silicone bags are only bought once and will usually last throughout your baby’s breastfeeding years. 

Do You Need Reusable Bags?

The truth is that both types of breast milk bags have their own purpose. If you are trying to store a large amount of breast milk in the freezer, the cost of disposable ones makes sense. They don’t need to be reusable for this since they will likely be stored and not used for some time, and they do not have to be sterilized.

Reusable bags are better for those who are pumping milk for the day or even a week. 

You can purchase enough of these silicone milk bags to last for the amount of time you need, whether for daily use or a few days. For example, if you try to store enough for the day while you are at work, then each night you can resterilize the same bags and fill them again for the next day. 

While both non-reusable plastic bags and reusable silicone bags can be stored in the freezer for a long time, disposable ones are a better bargain for storing large quantities.

Sterilizing Milk Bags

While the disposable plastic bags come sterilized and are tossed, the silicone ones have to be re-sterilized at home. You should always read the instructions that come with the bags before taking this step. That said, you can wash these in the sink or on your dishwasher’s top rack and allow them to air dry before sterilization.

Once your silicone milk bags are dry, you can sterilize them using the same method used for disinfecting your breast pump equipment. According to the CDC, the proper way to sterilize breast pumps is as follows.

Once all parts have been washed and dried, you can either use the steam method of sterilization or the boiling method, according to the manufacturer’s recommendations. 

Steam Method

For the steam method, you will need to purchase a microwave or plug-in steam sterilization system and follow the directions that come with the device.

Boiling Method

For the boiling method of sterilization, simply add all of the breast pump parts, silicone bags, bottles, nipples, etc., to a large pot of water and cover with a lid. Place the pot on the stove and slowly bring to a boil. Set the burner on a low setting that will allow the water to boil slowly without removing the lid. Keep for 5 minutes, and then remove the items with clean tongs.

All items should be placed on a clean dish towel or paper towel and allowed to air dry completely. Once they are dry, you can store them safely. It is important to make sure that there is no lingering moisture in order to avoid the risk of mold or bacteria forming. 

And once again, the breast pump parts and silicone milk bags are ready to use!

Pumping and Storing Breast Milk

In order to safely express and store your breast milk, it is a good idea to follow the guidelines set forth by the CDC. Before you begin pumping, be sure that you either wash your hands thoroughly with soap and water or use a hand sanitizer that is at least 60% alcohol. You might choose to express milk with your hands or use a breast pump.

Check over all of your sterilized breast pump parts and reusable silicone milk bags to ensure they are in pristine conditions. If any of the bags, tubes, or parts look moldy, they must be immediately thrown away and replaced. 

Once you are sure that all parts and bags are clean, you can use either hand express or machine pump your milk into the reusable bags.

The CDC also suggests that you make sure to store your milk in either reusable storage bags or food-grade containers made from plastic or glass. The containers should not contain BPA, as this can be dangerous for your baby. Also, you should never store breast milk in plastic bags that were not designed for this purpose unless you are sure that it is a BPA-free product.

Pumped Milk Storage

Your freshly pumped milk can be kept at room temperatures of 77 degrees Fahrenheit or less for about four hours. It can be safely stored in the refrigerator for as long as 4 days. While you can preserve breast milk in the freezer for up to a year, it is considered best to keep it for a maximum of six months. It is still safe for longer periods, but the quality of the milk may go down after the six-month period.

Can You Freeze Breast Milk?

Milk that you do not expect to use within the next 4 days should be immediately frozen; otherwise, quality may be hampered. Also, it should never be stored in the fridge or freezer door since the temperature there may vary.

In addition, you might benefit from storing it in small containers so that you don’t thaw out more than you need and end up having to throw some away. Many moms store milk in 2 or 4-ounce containers so that it is precise enough for a feeding.

Important Storage Tip

Make sure that you do not fill reusable silicone milk bags or other containers more than three-quarters of the way full before freezing. Liquids will expand in the freezer, and overfilling will lead to the breaking of the container, and ruining of the milk. 

It is vital to make sure that you label your breast milk containers as soon as it is expressed with a non-permanent marker. If you plan to take the milk to a daycare center or childcare provider where there are other children, be sure that your child’s name is also clearly printed on the bag. When traveling, breast milk can be stored with ice packs in insulated coolers for up to 24 hours. 


While plastic bags are meant to be disposable, you can reuse silicone breast milk bags. Be sure that they are washed, sterilized, and stored properly. It is also vital to pump and store the milk according to the CDC guidelines. Reusable bags should be clearly marked with a washable marker so that you can re-label them the next time you use them. 

We hope this helps explain why it is safe to reuse some milk bags but not others. Feel free to look over our site for more valuable information about keeping your baby safe, happy, and healthy.


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