Preserving Your Liquid Gold: Best Practices for Storing Breast Milk

JUN 23 , 2023


  • Let's be honest, while breastfeeding is a beautiful process, it's not always convenient. There will be times when you're away from your baby or simply need a break, and that's where properly stored breast milk comes into play.

Hey there, mama-to-be! If you're planning on breastfeeding your little one, you might be wondering what to expect. Breastfeeding is a natural process, but it's not always a walk in the park. That's why it's important to know about the different stages of breastfeeding and how to prepare for them.

Before we delve into the heart of the matter, let's quickly go over the basics. Freshly expressed breast milk can stay fresh up to 4 hours at room temperature, 4 days in the refrigerator, and 6 months in the freezer. It's important to note that these are just basic guidelines and proper storage practices, which we'll dive into more detail later, can significantly affect the quality and safety of your stored breast milk.


The first thing to consider when storing breast milk is the choice of storage containers. Trust me, all containers are not created equal when it comes to storing your precious breast milk. You'll want to opt for BPA-free plastic bottles or bags designed specifically for breast milk storage. These are usually pre-sterilized and have a sealable top to prevent any leaks. They're not only safe but also handy for noting down important details like dates and quantities.

Speaking of dates, this brings us to our second point - the importance of labelling your stored milk. I can't emphasize this enough, always, always label your breast milk with the date it was expressed. Time can fly by, especially when you're juggling the myriad tasks of parenthood, and it's all too easy to lose track of when each batch was pumped. Proper labelling helps ensure that you use the oldest milk first (a principle known as 'first in, first out') and prevents any milk from staying stored past its safe usage period.

But it's not just about the date. Including other details like the quantity of milk and your baby's name (especially important if your little one attends daycare) on the label can be super helpful.

And remember, while it may be tempting to fill each bottle or bag to the brim, it's a good idea to store milk in small quantities (about the amount your baby consumes in a single feeding). This prevents waste and makes thawing quicker and more efficient.


A. Room Temperature Storage

Let's begin with room temperature. Surprisingly, freshly expressed breast milk can stay at room temperature (around 77°F or 25°C) for up to 4 hours. However, it's always best to refrigerate or freeze the milk as soon as possible after pumping. If the room temperature is above 77°F, it's recommended to store the milk sooner.

B. Refrigerator Storage

Moving on, the fridge is often the go-to spot for storing breast milk. Breast milk can be stored safely in the refrigerator for up to 4 days at a temperature of 39°F or 4°C. Make sure to place the bottles or bags of milk at the back of the fridge where it's coldest, not in the door where the temperature fluctuates.

One of my favorite tips? Consider a designated area or container in your fridge for breast milk storage. It helps keep everything organized and ensures that other items in the fridge don't accidentally puncture the milk storage bags.

C. Freezer Storage

Lastly, for longer-term storage, the freezer is your best friend. Breast milk can be frozen for up to 6 months, and for optimal quality, should be stored at 0°F or -18°C or lower. Always remember to leave a little space at the top of your storage container when freezing, as breast milk tends to expand as it freezes.

Just a little heads up, my fellow mamas and papas, thawed breast milk that was previously frozen should not be refrozen. We'll cover thawing and warming in an upcoming section, but keep this in mind when deciding how much milk to freeze in each container. 

Whether you're storing your breast milk at room temperature, in the refrigerator, or in the freezer, proper storage practices are critical to maintaining its quality and nutritional content. After all, this 'liquid gold' deserves the very best care!


A. Thawing Frozen Breast Milk

If you've been storing your breast milk in the freezer, you'll need to thaw it before feeding it to your little one. The safest way to thaw frozen breast milk is to move it from the freezer to the refrigerator the night before you plan to use it. Breast milk usually thaws in the refrigerator within 12 hours.

If you need to use the milk sooner, you can thaw it quickly by placing the sealed container in a bowl of warm water. Remember, never use a microwave or stovetop to thaw or heat breast milk, as it can create hot spots and risk burning your baby's mouth.

A vital point to remember: once thawed, the breast milk should be used within 24 hours and should never be refrozen.

B. Warming Refrigerated Breast Milk

While breast milk does not necessarily need to be warmed before feeding, some babies prefer it at body temperature. If your little one is one of them, the safest way to warm breast milk is to place the bottle in a bowl of warm water for a few minutes.

A gentle shake will help distribute the heat evenly. Always test the temperature of the milk by dropping a small amount on your wrist before feeding it to your baby. It should feel comfortably warm, not hot.

C. The Role of Gentle Swirling

When thawing or warming your breast milk, a gentle swirl can work wonders. Why? Well, the fats in the breast milk can separate and rise to the top when stored. Swirling (not shaking) helps mix the fat back into the milk without damaging the milk's cellular structure.

Through this journey, you're not only providing your child with the best possible nutrition but also learning to navigate the complexities of parenthood with grace and knowledge. These steps may seem intricate initially, but with a little practice, they will become as natural as your motherly instincts.


Preparing for Transportation: Before you set out, make sure your breast milk is stored in durable, leak-proof containers. Remember those BPA-free breast milk storage bags or hard plastic containers we talked about? They are perfect for this purpose.

Keeping it Cool: When transporting, keeping the breast milk cool is the name of the game. Use an insulated cooler bag with ice packs to maintain a low temperature, especially for longer journeys. If you're travelling with frozen breast milk, the ice packs will keep it frozen for several hours.

Handling Upon Arrival: Once you reach your destination, move the breast milk to a refrigerator or freezer as soon as possible. If you're going to use the milk within a day, the fridge will suffice. Otherwise, it's best to keep it in the freezer for longer shelf life.

At the Daycare or Workplace: If you're sending expressed breast milk to a daycare or bringing it to your workplace, remember to label each container clearly with your baby's name and the date of expression. It's a good practice that will help others handle your precious cargo with the attention it deserves.

Air Travel with Breast Milk: For the jet-setting moms out there, rest assured that most airlines allow you to bring a reasonable amount of breast milk in your carry-on luggage. It's always good to check with your airline for their specific policy.

Remember, frozen ice packs, gel packs, and other accessories required to cool breast milk are also typically allowed.

Traveling with stored breast milk may sound like a daunting task, but with a little planning and the right gear, it's absolutely doable. Remember, you're not just transporting milk, you're carrying love, nutrition, and comfort for your little one.


Leftover Milk from a Feeding: One common scenario is dealing with leftover milk after a feeding. It's always heartbreaking to throw away breast milk, but safety comes first. If your baby didn't finish a bottle, it's safe to use within two hours. After that, bacteria from your baby's mouth could multiply, and it's safer to discard the remaining milk.

Expired Milk: Always pay attention to the storage times we discussed earlier. If the milk has been stored longer than the maximum recommended time under optimal conditions - four hours at room temperature, four days in the fridge, or six months in the freezer - it's best to toss it.

Smell and Appearance: Breast milk can sometimes smell or look different after storage due to the lipase (an enzyme that helps break down fats) in it. But, if it smells rancid or sour, it's better to discard it. If your milk separates into a layer of cream and a layer of milk, it's normal - just swirl it gently to mix.

Thawed Milk: Remember, thawed breast milk that was previously frozen should not be refrozen. Once thawed, it should be used within 24 hours. If not used within this time, unfortunately, it's time to discard it.

During Illness: If you're sick with a common cold or a mild illness, it's generally safe to continue breastfeeding or pumping. But, if you have a serious illness or are on certain medications, consult with your healthcare provider about whether to discard your milk.

Discarding breast milk can feel disappointing, but remember, your baby's health and safety are the top priorities. Every drop of milk you provide is a gift to your little one, even if some of it ends up not being used.


Don't Mix Temperatures: A golden rule for storing breast milk is never to add warm milk to already cooled or frozen milk. Always cool the newly expressed milk before combining it with the previously stored milk.

Use a First-In-First-Out System: As we've mentioned before, always use the oldest milk first. This 'first-in, first-out' system ensures you are using your breast milk within its optimal freshness period.

Store in Smaller Quantities: Storing breast milk in smaller quantities helps prevent wastage. It's heartbreaking to discard breast milk because your little one couldn't finish a large serving. Plus, smaller servings thaw quicker!

Clean Pumping Equipment Thoroughly: The cleanliness of your breast pump and its parts directly affect the quality of your stored breast milk. Ensure you clean all pumping equipment thoroughly before each use.

Rotate the Freezer Stash: Remember to rotate the milk in your freezer regularly. Place the newly frozen milk behind the older milk to ensure you're using the oldest milk first.

Monitor Your Freezer's Temperature: Keep a thermometer in your freezer to ensure the temperature stays at 0°F or -18°C or lower. A small fluctuation in temperature can impact the quality of your stored breast milk.

Consider a Dedicated Storage Space: Having a designated area or container in your refrigerator or freezer for breast milk can help keep things organized and safe.

As we reach the end of this guide, I hope you feel more empowered and knowledgeable about breast milk storage. Our journey as parents is filled with a myriad of moments - moments of joy, moments of doubt, moments of discovery, and moments of deep, unconditional love. Every drop of breast milk you express is a testament to this incredible journey you're on. Even when you're fumbling with storage bags at 3 a.m., know that you're doing an amazing job. So, here's to all of you - the late-night warriors, the early morning nurturers, the tireless comforters, the givers of life, and love.

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