A Guide To Store Breast Milk Safely In The Fridge or Freezer


The process of breastfeeding isn’t an easy one and many moms who choose to breastfeed go through pumping breastmilk challenges on a daily basis.

Breastmilk storage is a question many new mothers face, such as what to do with your freshly pumped milk and how long is it good for?

This post will cover how to express your milk, what to do with your milk, breastmilk storage tips and the best breastmilk storage bags for your precious liquid gold.

Having the right knowledge and tools on hand will make you have a much smoother pumping experience.

(This post contains affiliate links. Our full disclosure policy is really boring, but you can find it here.)

How to Collect And Express Breastmilk

Many new moms start pumping breastmilk soon after the birth of the baby. Some reasons may be because they are planning a return to work in a few weeks, or they simply want to build a freezer stash. whatever the reason for your breast expression journey, there are a few different ways to achieve your goals.

You can also check this article for the 5 Best Breast Pumps For Breastfeeding Moms

Electric pumps are very common options but you can also hand express, use a suction pump, or try a manual pump as well.

Electric Breast Pump: An Electric breast pump will be the fastest way to get the milk from your body. If you have access to a double electric breast pump you can pump both breasts at the same time. If you have a single electric breast pump, you can pump one side at a time.

Manual Breast Pump: A great sidekick to your electric pump is the manual breast pump. Some mothers like to have a manual pump on hand so they can quickly express breastmilk without having to be hooked up to a machine. These are great for on-the-go pumping and they are small and fit nicely into any diaper bag.

Suction Pump: A newer way to pump is to use a suction pump. A suction pump attaches to your breast while the baby eats from the other side and collects all the let down from the unused breast. The silicone suction pump will collect any milk that would otherwise be leaking out of you while you baby is eating.

Catchers: Milk catchers are shells which sit in your bra and catch milk that leaks from your breasts throughout the day. Instead of wasting your milk in a breast pad, these allow you to keep all the milk which your body produces so you can feed it to your baby later.

Hand expression: This is not the most efficient method of expressing breastmilk but sometimes it’s all you have. Simply warm your breast with a warm cloth and massage your breast to encourage the milk to flow. You can collect your milk into a cup if you need to.

When you have decided on which milk expression method you will you, you’ll need some sort of a way to catch and collect all that milk. Your options are breastmilk storage bags, or simply using sterilized baby bottles.

Electric and manual breast pumps often have bottles that you can attach to the pump and then put a lid onto that bottle and store the milk in the fridge. If you are using a catcher or a suction pump, then you will have to transfer your milk into bottles or bags.

Transferring Breastmilk

When you pump your milk, you are not able to pump directly into a storage bag, and most bottles are not meant to be stored in the freezer. To transfer breastmilk without making a sticky mess and losing precious liquids gold there are some things you should note.

There are 3 transfer methods you can use from pump to storage bag, from bag to bottle and from bottle to bottle. You can use the Bokee to help keep your bottle sturdy on the counter to prevent spills.

Transferring from pump to storage bag: when transferring your milk from the pump into the storage bag, use your pump flange as a funnel to guide the milk into the bag.

Transferring from bag to bottle: Breast milk bags are a great way to efficiently store your breastmilk in the fridge or freezer. To transfer breastmilk from a storage bag into a bottle without spilling you should try this. Place your bottle into the Nokee then carefully pour the milk into the bottle. You may have to cut the bag to get all the milk out.

Transferring from bottle to bottle: When you need to combine milk from bottle to bottle, you can use something like the bokee to help keep the bottle secure on the counter while you pour from the other bottle. You can also keep the bottle from falling over by securing it with your hand. You can use your breast pump flange as a funnel in this case as well.

Safe Storage For Breastmilk

Storing breastmilk is easy, but storing breastmilk SAFELY is a whole other ballgame. Here are the top guidelines to follow when you are learning how to store breast milk.

Store in a sterilized container: Make sure your bottle is sterilized and your bags have not been previously used when pouring breastmilk for storage. Freezer-safe glass bottles must be cleaned well with soap and water and sterilized as well.

Store Breastmilk in proper numbers: It’s better to store breast milk in 2-3oz portions as that is how much the baby will eat for the first little while in one sitting. You cannot refreeze thawed breastmilk so if you fill your bags with 6 oz, you might lose 3oz if your baby doesn’t eat it all. If you are not sure how much milk your baby eats in a day, that’s ok! Just freeze your milk in smaller numbers such as 2-3oz portions. You might use more bags this way, but you’ll also waste less milk.

Refrigerate quickly: Once you express your breastmilk it should be in the fridge or freezer within 4 hours of pumping.

Freeze the milk: Freezing breastmilk ensures that you can keep your breastmilk for a longer period of time. Breastmilk can be frozen for up to 9 months in a fridge freezer and up to 12 months in a deep freezer. Breastmilk does change its nutrients as your baby grows, so be sure to use the breastmilk in a reasonable time frame to ensure you are giving your baby the needs they have at this moment.

Use thawed milk: Use the thawed milk within 24 hours.

When you thaw breastmilk and are ready to provide it to your baby, then you’ll have to look at the transfer process when preparing the milk. A bottle warmer that is safe for breastmilk will properly heat up the baby milk properly.

How to store breast milk in the refrigerator

To store your breastmilk in the refrigerator you should follow these important guidelines. always refrigerate your breastmilk as soon as possible after it has been pumped. Use proper clean and sterilized bottles and bags which are made from BPA-free materials. BPA has negative long-term effects and is slowly being phased out of the markets. You can combine pumped milk as long as both portions of milk are at the same temperature. Do not add body temperature milk to cold milk. Store your breastmilk in the back of the fridge and not in the fridge door to ensure the temperature is the most consistent.

How to store breast milk in the freezer

To safely store your breast milk in the freezer you should cool it first as soon as possible after expressing and then add the milk to a freezer-safe storage solution. Your breastmilk containers or bags could crack in low temperatures so be sure to use the proper equipment. Do not overfill your breastmilk bags as milk will expand when it’s frozen. Always store the breastmilk in the back of the freezer and in the door racks.

More Storage Tips

Always label your breast milk with the date it was expressed

Avoid storing the breastmilk in the door of the fridge or freezer

If you do not use the expressed milk within 4 hours, put it into the freezer.

Freeze breastmilk in smaller numbers 2-3oz to avoid wasting and overfilling.

Breastmilk can be stored in an insulated cooler bag with frozen ice up to 24 hours.

  • Clearly label the breast milk with the date it was expressed.
  • Do not store breast milk in the door of the refrigerator or freezer. This will help protect the breast milk from temperature changes from the door opening and closing.
  • If you don’t think you will use freshly expressed breast milk within 4 days, freeze it right away. This will help to protect the quality of breast milk.
  • Freeze breast milk in small numbers of 2 to 4 ounces (or the number that will be offered at one feeding) to avoid wasting breast milk that might not be finished.
  • When freezing breast milk, leave about an inch of space at the top of the container because breast milk expands as it freezes.
  • If you will be delivering breast milk to a childcare provider, clearly label the container with the child’s name and talk to your childcare provider about other requirements they might have for labelling and storing breast milk.
  • Breast milk can be stored in an insulated cooler bag with frozen ice packs for up to 24 hours when you are travelling. Once you arrive at your destination, milk should be used right away, stored in the refrigerator, or frozen.

How to warm your refrigerated breast milk

Full-term babies can safely drink breastmilk at body or room temperature. Some babies don’t like cool milk while others don’t mind so much.

Warm your breastmilk by placing the milk bottle into a cup or bowl of warm water for a few minutes until it reaches body temperature. Do not use a microwave. You can use a bottle warmer.

If your milk has separated fat in the bag or bottle, gently swirl the milk to mix it back together. Do not shake the bag or bottle.

Using frozen breast milk

To use your frozen breastmilk simply take the bag out of the freezer and place it in to the fridge or counter to thaw. You can speed this process up by placing the bag or bottle into warm water, making sure not to use hot water which can spoil the milk.

Once the milk has thawed, simply place the milk into a jug or bowl of water and wait for the milk to reach room temperature. You can use a bottle warmer once the milk has been transferred from a bag to a bottle.

Frequently asked questions on storing breastmilk

Breast milk storage for NICU and hospitalized babies

Breastfeeding a NICU baby is even harder than a full-term baby, but it’s not impossible. If you are facing the challenge of providing your NICU baby with breastmilk you can feed your little one from a tiny cup or bottle, or a feeding tube. How to store breast milk for NICU babies will look a little different than storing breastmilk for full-term babies because the rules are more strict for their health and safety. NICU babies will have weaker immune systems so here are some things to keep in mind.

  • Freshly expressed milk for a premature baby should be used within 1 hour or refrigerated within 1 hour. The bacteria which grows when the milk is left at room temperature is dangerous to them. You can store freshly expressed breastmilk in the fridge for up to 48 hours.
  • Thawed milk must be used within 24 hours when you thaw within the refrigerator or 2 hours if you have warmed it up. If you have not used the milk but was previously frozen, you have to throw it away.
  • Label the milk with the baby’s name, date, time of day you pumped and any medication which you have taken that day.

Your healthcare provider should be able to give you specific instructions for your NICU baby if you need more help with how to store breast milk for your little one.

Breast milk storage on the go

If you have to store your breastmilk on the go, you should be using a cooler bag with ice packs. This will keep your breastmilk cool and usable. For travelling and pumping tips read this article from Medela.

How to tell if you shouldn’t use stored breast milk

Rotten milk has a distinct smell, just like any of the other milk in your refrigerator. If you aren’t sure, you can taste the breast milk and see if it is sour. If it is sour it needs to be discarded.

You can also watch how the breast milk flows. If the milk is good, it will be easy to mix the fat back together with the foremilk with a gentle swirl. If you notice chunks floating in the milk then it has gone bad. You can store your breast milk in the freezer for up to 12 months.

The Best Breastmilk Storage Bags

You may wonder why you can’t use kitchen bags to store breastmilk in. Most people have them at home all the time and they are really convenient to use.

While I would agree with their convenience, they are not designed for holding liquids and can spill your precious liquid gold milk out. These bags are not BPA-free and most are not thick enough to store the milk. It will be a lot easier to pour the milk out of a special breastmilk storage bag than a regular kitchen plastic bag.

Breastmilk bags are not the same as bottle liners. They are specially designed to hold the breastmilk in a sterile environment and are easy to freeze.

Choosing the best breast milk storage bags

Here are some things you’re going to want to keep in mind when choosing breast milk storage bags:

Durability: You don’t want bags that will be easy to get a hole in.

Size: Your bags don’t need to hold a lot of milk since you only should be storing 2-3oz of milk per bag.

Material: Look for recyclable BPA free bags to keep your baby healthy.

Medela Breast Milk Storage Bags

Our favourite breast milk storage bags are the Medela brand. Medela knows everything baby and makes great breastfeeding products for new moms.

These storage bags are made with durable double layer material and a double zipper seal which means the bag won’t leak even if it’s moving around a lot.

These bags can stand on their own or lay flat for easier freezing.

These bags can hold up to 6oz of breastmilk per bag and they are sold in 100 bag packs. These bags are also BPA-free.

Lansinoh Breastmilk Storage Bags

The Lansinoh Breastmilk Storage Bags are our second favourite because they have a patented double zipper seal to help seal the bag up properly.

We have noticed that these bags leak when not sealed properly so be sure to seal it up all the way tightly so your breast milk doesn’t end up all over your freezer shelf.

They also have a spout which makes pouring them ilk out easier.

These BPA-free and BPS-free bags are designed to lay flat in the fridge or freezer.

Kiinde Twist Pouch Breastmilk Storage Bags

The Kiinde Twist Pouch Breastmilk Storage Bags are convenient breastmilk storage bags which are a cross between bag and bottle.

These bags come with a twist cap which attaches to many breast pum models with a bottle converter. These bags are BPA, PVC and phtalate free which means they are safe for your baby.

You can pump directly into the back and store the milk without having to transfer it at all. It’s ready to feed anytime.

This system makes it easy because you don’t have to worry about transferring milk or cleaning extra bottles.

Unimom Breastmilk Storage Bags

The Unimom Breastmilk Storage Bags are leak proof self standing storage bags which parents are loving.

Protect your newborn baby from harmful chemicals like phthalate, bisphenol A (BPA) and lead. All Unimom products are 100% safe for you and your babies.

he top of the bag is designed to rip off easily so you can pour into a bottle simply without the milk spilling out the sides or making a mess. Pump, store and feed with ease.

The bags are matte material which makes it easy to write your information on them and the bags also don’t slide around when stacked on top of each other.

These bags do not have a double zip design so you’ll have to ensure you are closing it properly before laying it flat to freeze.


The first re usable storage bag, the Junobie comes in a pack of 4 silicone bags.

These bags are free of BPA, BPS, PVC, Latex, Phthalates. No more throwing away hundreds of plastic milk storage bags. Now you can reuse! Finally… storage bags that are good for your baby and the environment.

The silicone bag is created to stand on its own. It’s durability makes it Dishwasher safe, microwave safe, and boil safe.

Designed to grow with your baby beyond breastfeeding and is useful also as a baby food container and a snack pack pouch for toddlers 

Bumblebee Breastmilk Storage Bags

BumbleBee Breast Milk Storage Bags are made from food-grade silicone. Our storage bags are clean, which means that you can use them straight away. They are super flexible and seal tight thanks to the double zip lock mechanism, making sure that they won’t leak and retaining the beneficial nutrients of your breast milk.

Designed with a wide bottom to let them self-stand, even if you only fill them with a small number of breast milk. You can also flatten the milk storage bags to use your limited fridge and freezer space more efficiently. The double zip lock seals tightly to become perfectly leak-proof, letting you store your milk bags in any orientation without worrying about messy spills.

These bags are made in the USA and have a thick and firm design to keep your breastmilk safe.

Haakaa Silicone Milk Storage Bag

The Haakaa Silicone Milk Storage Bag is the perfect eco friendly solution for safely storing your precious breast milk.

They are made of food grade silicone and can be reused over and over again, reducing the impact that single-use plastic makes on our environment.

aakaa Silicone Milk Storage Bags are fridge and freezer safe and can be stored laying down or standing up. Made with food grade silicone. BPA, PVC and phthalate-free. Dishwasher safe.

You can also store other liquid and paste food, such as juice and rice cereal. Once you have expressed your breast milk, pour the milk into the bag and firmly push in the leakproof stopper. When you are ready to use it, place the bag in warm water to heat the milk and prepare it for drinking.

Nanobébé Milk Storage Bags

Fit the whole family’s food in the freezer again! Declutter with your 50-count refill of stackable breast milk savers, specially designed to stack evenly inside nanobébé’s “first in, first out” vertical breastmilk storage container or for use on their own.

Rather than stress about running out of breast pump bags, plan ahead and cherish more bonding moments during infant feeding. Stocking up on breastfeeding storage bags saves you much-needed mommy time and creates future peace of mind.

These breast milk storage bags defrost and warm 2 times faster than standard freezer bags to preserve the powerful, unique-to-you nutrients within your breastmilk.

Cozytots Breastmilk Storage Bags

The pre-sterilised breast milk storage bags are made from food grade material with BPA free.

They also have a secure seal with double zipper is safe for fridge and freezer storage. The storage bag can stand upright on any flat for convenient holding, storage and filling.

The write-on area on the milk bag is for labeling the date, time & volume, to keep track of your milk storage.

This bag has an easy pour spout so you can pour your breastmilk into a bottle without spilling it all over the place. Overall these are a great choice for breastmilk storage bags.

Papablic Breastmilk Storage Bags

Coming with 2 kinds of Direct-Pump adapters that locks onto ALL major breast pump brands. Pump directly into bag for convenience and reduced waste. Less bottles to wash and save time. All parts that come into contact with breastmilk are BPA and BPS free.

Ideal for storing and freezing precious breastmilk securely. This pre-sterilized breastmilk storage bags are made of durable double-layer material and built-in double secure zipper seal to prevent leakage.

This unique spout design of the breastmilk storage bags allows you to tear it off or cut it easily for easier transferring to nursing bottles. No more spilling accidents.

A Few More Notable Breasts Milk Storage Bags To Check Out

Can I Just Use Cheap Plastic Bags?

You don’t want to pick your breastmilk storage bags based on price. Just because they are the cheapest doesn’t mean they will do the best job. You’ll need to look our for quality and pick out somethng that suits your needs the best.

Some of these bags have great features such as double zip close top. All the breast milk storage bags are properly sterilized and are safe to use.

If you want to use cheap plastic bags, then your baby’s milk may not be stored in a sterilized environment, and you might get gross freezer particles into your baby’s milk.

Breast milk bags aren’t very expensive, so if you’re going to store breastmilk, they are a must-have item for your registry.

How Do I Use Breast Milk Storage Bags?

You should always wash your hand when handling your baby’s milk.

To use a storage bag, simply open the bag and pour your milk in. Be sure to seal it tight to prevent any milk from spilling out. You can store your bag in the fridge or freezer. Make sure you lay your bag down so the milk can freeze flat, allowing you more room for storing more milk.

Make sure you don’t overfill the bag because your milk will expand. You will have to throw away any bags which pop in the freezer due to overfilling. Freeze 2-3oz at a time in your breast milk storage bags.

Safe Cleaning of Infant Feeding Items and Pumping Equipment

When feeding your baby you should be sanitizing and storing your pump equipment properly. Your baby’s breastmilk needs to be free of contamination to avoid things like thrush. Here are some guidelines on how to clean sanitize and store infant feeding essentials.

How To Store Breast Milk Guidelines

We hope this guide on how to store breast milk was helpful to you. You now know how to keep your baby safe while pumping breastmilk and how to use breast milk storage bags, as well as which brands we recommend like the Medela Breast Milk Storage Bags.

how to store breast milk

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