How Long Can Breast Milk Stay Out of the Fridge
Whether you’re exclusively pumping, nursing and pumping, or just saving up for the occasional date night bottle, understanding how to safely store your milk is essential to ensure your baby gets the freshest and safest milk possible. I get messages every day from clients wanting to know the parameters surrounding breast milk storage.
Breast milk isn’t just a liquid - it’s a living substance full of changing nutrients and immune-boosting components. But once it leaves your body, it's subject to changes over time and temperature. Breast milk can only be left out of the fridge for a limited time before bacteria can start to grow, which may make it unsafe for your baby. In this post, I’m going to dive into how long breast milk can stay out of the fridge, what factors influence its safety, and what to do if you accidentally leave it out too long.
How Long Can Breast Milk Stay Out of the Fridge - Article Overview
This post is your go-to resource for understanding breast milk storage outside of refrigeration. I’ll answer key questions like:
Can you leave breast milk out of the fridge?
How long can breastmilk stay out of the fridge, depending on the container?
What happens if it’s left out too long?
What should you do if that happens?
Whether you’re a new mom, returning to work, or a caregiver handling pumped milk, this article will help you feel confident in your milk-handling practices. Knowing when to keep it, when to toss it, and how to safely store your milk can help reduce waste and ease your feeding journey.
Can You Leave Breast Milk Out of the Fridge?
Yes, you can leave freshly expressed breast milk out of the fridge for a short period of time, depending on the environment and how it’s stored. According to the CDC and other health organizations, breast milk can be kept at room temperature (up to 77°F or 25°C) for about 4 hours.
If you're storing it in an insulated cooler with frozen ice packs, it can last up to 24 hours, which is especially helpful for travel, workdays, or outings. This is where something like the Ceres Chill can come in handy as well.
Be sure to always wash your hands before handling breast milk or pump parts, and store it in clean containers like bottles, plastic bags made for breast milk storage, or disposable bottle liners when needed.
How Long Can Breast Milk Stay Out of the Fridge?
The amount of time breast milk can safely stay out of the fridge varies depending on where and how it’s stored. Let’s break it down by container and condition:
Bottles
When stored in bottles at room temperature (77°F or lower), breast milk can stay out for up to 4 hours.
Always cover the bottle with a lid or nipple cap.
Keep bottles in a shaded or cool spot if you’re not using them immediately.
Once your baby starts feeding from the bottle, use it within 1–2 hours or by the next feed.
Plastic Storage Bags
Plastic storage bags made specifically for breast milk storage can also hold milk at room temperature for up to 4 hours.
Be sure they’re labeled with the date and time.
Avoid reusing storage bags as they’re often meant for one-time use.
Place bags upright in a clean container to avoid spills.
Insulated Coolers
Using an insulated cooler with frozen ice packs can extend the life of freshly expressed breast milk to up to 24 hours.
This is ideal for work, travel, or situations where a fridge isn’t available.
Make sure the ice packs stay in direct contact with the milk container.
Keep the cooler closed as much as possible to maintain cold temperatures.
Again, I am a big fan of the Ceres Chill as well for storing breast milk at optimal temperatures for a longer period of time. Use code TBM15 for 15% off.
What Happens If Breast Milk Is Left Out Too Long?
Once breast milk has been left out past safe limits, the chances of bacterial growth increase, and it may become unsafe to feed. Here’s what can happen:
Bacterial Growth
Warm environments allow bacteria to multiply quickly, which can make the milk unsafe for your baby to consume.
Even though breast milk has antibacterial properties, it's not immune to spoilage.
Nutritional Decline
As milk sits out, its quality slightly declines. The immune properties and nutrients degrade over time, especially when the temperature is too warm.
Change in Smell or Taste
You may notice breast milk that’s been out too long smells sour or soapy. This could be due to lipase activity or spoilage.
Always do a sniff test if you’re unsure, but when in doubt, throw it out.What Happens If Breast Milk Is Left Out Too Long?
Once breast milk has been left out past safe limits, the chances of bacterial growth increase, and it may become unsafe to feed. Here’s what can happen:
Bacterial Growth
Warm environments allow bacteria to multiply quickly, which can make the milk unsafe for your baby to consume.
Even though breast milk has antibacterial properties, it's not immune to spoilage.
Nutritional Decline
As milk sits out, its quality slightly declines. The immune properties and nutrients degrade over time, especially when the temperature is too warm.
Change in Smell or Taste
You may notice warm breast milk that’s been out too long smells sour or soapy. This could be due to lipase activity or spoilage.
Always do a sniff test if you’re unsure, but when in doubt, throw it out.
What To Do With Breast Milk That Was Left Out Too Long
It’s always a bummer to toss milk, but safety comes first, especially with younger or immunocompromised infants. Here’s what you can do if your milk was left out past the safe time:
Don’t Feed It
If you suspect the milk is no longer safe, don’t risk feeding it. Babies have developing immune systems that are more vulnerable to bacterial infections.
Use for Milk Baths
Consider using it in a milk bath. It can be soothing for baby’s skin and is a great way to use breast milk in a topical way.
Add a few ounces to bath water for a gentle, nourishing soak.
Use for Diaper Rash or Skin Irritation
Apply a small amount of expired breast milk to areas of baby’s skin that are irritated or have a rash.
Let it air dry for a natural remedy.
Toss It
Sometimes, the best thing to do is let it go. I know how heartbreaking it can feel, but safe feeding is always the priority.
Additional Tips for Safely Handling Breast Milk
Always wash your hands before expressing, handling, or feeding breast milk.
Remember that breast milk expands, so leave room in containers when freezing breast milk.
Try not to add freshly expressed breast milk to already frozen breast milk unless the new milk has been cooled first (per CDC recommendations).
Never refreeze thawed milk (learn more in can you refreeze breast milk).
When thawing breast milk, make sure you use best practices
Use a bowl of warm water or warm running water to gently warm breast milk instead of microwaving.
Label every container with the date and time to keep track of your breast milk storage.
Only store expressed breast milk in clean bottles or breast milk-specific plastic bags.
Ideally, frozen breast milk should be used within 6 months but can be safe for up to 12 months when stored properly in a freezer.
For more comprehensive storage tips, check out our breastmilk storage guidelines.
Final Thoughts
Understanding how long breast milk can stay out of the fridge is one of the most common (and important!) questions I hear from pumping moms. Whether you’re prepping for daycare, pumping at work, or just building your freezer stash, these guidelines can help keep your milk safe, your baby healthy, and your sanity intact.
And if you ever forget how long it’s been sitting out—play it safe. A milk bath might be in your baby’s future, and a little peace of mind is always worth it.
Want to go deeper into everything you need to know about storing, thawing, and feeding your milk? Be sure to check out The Pumping Playbook - it includes my Fuss-Free Flange Sizing Guide and everything you need to make pumping work for you. Use the code BLOG10 for $10 off your purchase.
