How long can breastmilk be in the fridge before going bad?

November 27, 2025 •

4 min read

According to the Centers for Disease Control and Prevention (CDC), freshly expressed human milk is safe in the refrigerator for up to four days. However, several factors, such as refrigerator temperature and hygiene, can affect storage safety and quality. This guide will clarify exactly how long can breastmilk be in the fridge before going bad and how to store it correctly.

Quick Summary

The safe duration for storing freshly expressed breastmilk in the refrigerator is up to four days, but this can vary depending on guidelines and handling practices. Optimal storage involves using clean containers, placing milk in the coldest part of the fridge, and monitoring for signs of spoilage. Different rules apply to thawed milk and leftover milk after a feeding.

Key Points

Fresh milk lasts 4 days in the fridge: The Centers for Disease Control and Prevention (CDC) recommends using freshly expressed breastmilk within four days if stored in a refrigerator at 40°F (4°C) or colder.
Store milk in the back of the fridge: Avoid storing breastmilk in the refrigerator door, as temperature fluctuations occur more frequently there.
Previously frozen milk lasts 24 hours once thawed: Thawed breastmilk is good for up to 24 hours in the refrigerator once it is completely defrosted. It should never be refrozen.
Look for signs of spoilage: A sour smell, taste, or chunks that don't mix back into the milk after swirling are indicators that the breastmilk has gone bad and should be discarded.
Handle with care: Proper handling, including clean hands and clean storage containers, is crucial to prevent bacterial contamination and maximize storage time.

Understanding the Breastmilk Storage Timelines

Navigating the world of breastmilk storage can be overwhelming for new parents. While the standard recommendation is up to four days for fresh milk in a consistently cool refrigerator, it's essential to understand the nuances of this guidance. Variations exist depending on the source of the guideline, the milk's history, and the baby's health.

CDC and AAP Guidelines for Freshly Expressed Milk

Both the CDC and the American Academy of Pediatrics (AAP) provide conservative, reliable guidance for storing breastmilk for a healthy, full-term infant. For freshly expressed milk, the recommendation is to use it or freeze it within four days if stored in a refrigerator at or below 40°F (4°C). The storage time is shortened for premature or medically fragile infants, so always consult a healthcare provider for specific advice in those situations.

Best Practices for Refrigeration

To maximize the quality and safety of your breastmilk, follow these best practices:

Use Proper Containers: Always store milk in clean, food-grade containers or bags specifically designed for breastmilk storage. Avoid using general-purpose plastic bags or disposable bottle liners not intended for this purpose. Glass or BPA-free plastic is best.
Place in a Cold Spot: Store the containers in the back of the main refrigerator compartment, where the temperature is most consistent. The refrigerator door is the warmest area and should be avoided.
Label Correctly: Always label each container with the date and time of expression. This helps with the “first in, first out” method, ensuring you use the oldest milk first.
Don't Overfill: If you plan to freeze the milk later, leave a bit of space at the top of the container, as milk expands when frozen.

Can you refrigerate breastmilk that has been at room temperature?

If freshly expressed milk has been at room temperature (77°F or colder) for up to four hours, it is safe to put it in the refrigerator for later use. However, if it has been out longer than the recommended room temperature window, it should be discarded. It's crucial to put the milk in the fridge as soon as possible after pumping to maximize its safe storage time.

Reheating and Thawing Stored Breastmilk

Once you decide to use refrigerated breastmilk, it does not need to be warmed but can be served at room temperature or even cold, based on your baby's preference. If you choose to warm it, place the sealed container in a bowl of warm water or hold it under warm running water. Never heat breastmilk in a microwave, as this can destroy nutrients and create dangerous hot spots that could burn your baby's mouth.

Comparison of Breastmilk Storage Durations

Knowing the differences between storage methods is key for proper management. This table compares the general guidelines for healthy, full-term infants based on major health organization recommendations.


Storage Location	Temperature	Safe Storage Time (Fresh Milk)	Notes
Room Temperature	Up to 77°F (25°C)	Up to 4 hours	Use or store immediately, especially if warmer.
Refrigerator	40°F (4°C) or colder	Up to 4 days	Store at the back for optimal temperature stability.
Insulated Cooler	With ice packs	Up to 24 hours	Keep ice packs in contact with the container.
Freezer	0°F (-18°C) or colder	Up to 6-12 months	Use within 6 months is best for quality.
Thawed in Fridge	40°F (4°C) or colder	Up to 24 hours	Time starts once milk is completely thawed.

How to Tell if Refrigerated Breastmilk Has Spoiled

Even with proper storage, it's wise to check for signs of spoilage before feeding. While breastmilk separating into a creamy layer and a watery layer is normal (a simple swirl can mix it back together), there are clear signs it has gone bad.

Sour Smell: Spoiled breastmilk often has a strong, sour, or rancid odor. Fresh milk, even after chilling, should have a mild, slightly sweet smell.
Lumps and Chunks: If the fat and water layers do not mix back together after a gentle swirl, leaving behind persistent clumps or chunks, the milk may have spoiled.
Sour Taste: If you are unsure about the smell, a small taste test can confirm spoilage. If it tastes sour or off, discard it.

Conclusion

For a healthy, full-term infant, freshly expressed breastmilk is safe to store in the back of a consistently cold refrigerator for up to four days. It is important to adhere to proper handling and storage practices, such as using clean, food-grade containers and labeling with the date. By following guidelines from reliable sources like the CDC and AAP, parents can confidently manage their stored milk supply. Always remember that the quality of breastmilk, including its nutritional content, may slightly decrease the longer it is stored. For previously frozen milk, a separate 24-hour rule applies once it is fully thawed in the refrigerator. By staying vigilant and following these key principles, parents can ensure their baby receives safe and nutritious milk.

Additional Resource

For further reading and the most recent recommendations, you can consult the official CDC guidelines on breastmilk preparation and storage(https://www.cdc.gov/breastfeeding/breast-milk-preparation-and-storage/handling-breastmilk.html).

Frequently Asked Questions

Freshly expressed or pumped breastmilk is safe to store in the back of a refrigerator (40°F or colder) for up to four days.

Yes, leaving breastmilk in the fridge overnight is safe, as long as it is within the four-day storage guideline for freshly expressed milk.

Signs of spoiled breastmilk include a sour or rancid smell, a sour taste, or persistent clumps that do not mix back into the milk after swirling.

Once thawed in the refrigerator, breastmilk must be used within 24 hours. The 24-hour countdown begins once the milk is fully thawed, not when you take it out of the freezer.

The best practice is to use clean, food-grade storage containers, label them with the date, and place them in the back of the main refrigerator section to ensure consistent, cold temperatures.

Yes, but you should first cool the fresh milk in the refrigerator before combining it with already chilled milk. Always label the container with the date of the oldest milk.

Yes, it is completely normal for breastmilk to separate into a creamy, fatty layer at the top and a watery layer at the bottom. This does not mean it has gone bad; a gentle swirl before feeding will mix the layers back together.