Breast milk is an essential source of nutrients for breast-fed babies, but, like all milk, it’s also vulnerable to spoiling.
How long does it take for breast milk to expire?
Breastmilk stays fresh at room temperature for about 4 to 6 hours, and in the fridge for about 4 to 6 days. If you’re just not sure if you’ll use it soon or you are busy with lots of tasks, it’s better to put it in the fridge for safekeeping. You worked hard for that milk, don’t let it accidentally spoil!
But before you pump, it’s great to keep some safe pumping guidelines in mind:
- Squeaky clean
All soon-to-be-filled baby bottles should be washed by hand or run through a dishwasher before any pumping session. They also need to be very dry. You’ll want to give your hands a good, long wash with soap and hot water to get rid of any bacteria that could get into your milk during the pumping and bottling/bagging process. - Get into cold storage, STAT!
Breast milk may be stored at room temperature for a short time, but it does more easily spoil at room temperature, so sticking it in the fridge or freezer as soon as possible helps prevent milk loss. - Know your milk’s limits
Breast milk can be stored at room temperature for around 4 to 6 hours safely, but that’s only true if the room temperature isn’t too warm. Milk containers should be covered and kept out of direct sunlight. Ideally, it isn’t warmer than 77 degrees Fahrenheit or 25 degrees Celsius where the milk is sitting out.
Breast milk can be refrigerated for up to five days, but for longer-term storage, parents can also choose to freeze milk for use later. This option is safe and often more convenient, but it should only be done within safety guidelines for freezing. The U.S. Centers for Disease Control (CDC) says if your fridge has one door to both the refrigerator and freezer compartments, be sure to thaw any frozen milk within two weeks. But if your freezer has its own separate door, you can safely store frozen breast milk for up to 3 to 6 months, and if you have a chest freezer or deep freezer, breast milk can be safely frozen for 6 months to a year.
- Unrefrigerated: 4 to 6 hours
- Refrigerated: 5 days
- Frozen (depending on which freezer you use): 6 months to a year
If you’ve read conflicting information, that’s because different organizations related to health and breastfeeding offer varying numbers of hours and days that milk can be stored in different locations.
When in doubt, look at and smell your milk. Although milk will separate and have a fatty layer on top, it should not be clumpy (chunks of ice during a thaw are okay). It should have a faint or sweet smell when fresh, or will smell pretty awful and rotten if it’s spoiled. If you notice a soapy or metallic smell in expressed milk, it could be high lipase. This is an enzyme, and although it changes the smell of milk over time, high lipase milk is perfectly safe, and happens to folks for reasons we don’t quite understand. The only risk with high-lipase milk is that your baby won’t like the taste. Rest assured, there are many ways to work around this, but offering this milk early on can let you know if you have a flexible baby or need some support.
Sources
- “How long does expressed breast milk keep?” Mayo Clinic. Mayo Clinic, April 27 2022. http://www.mayoclinic.org/healthy-lifestyle/infant-and-toddler-health/in-depth/breast-milk-storage/art-20046350?pg=2.
- “Proper Handling and Storage of Human Milk.” Centers for Disease Control and Prevention. U.S. Department of Health and Human Services, November 27 2023 https://www.cdc.gov/breastfeeding/recommendations/handling_breastmilk.htm.
- DiMaggio, D. “Tips for Freezing and Refrigerating Breast Milk.” Healthy Children. American Academy of Pediatrics, March 3 2023. https://www.healthychildren.org/English/ages-stages/baby/breastfeeding/Pages/Storing-and-Preparing-Expressed-Breast-Milk.aspx.
- “Storing Human Milk” La Leche League International. La Leche League International, July 2024. https://llli.org/breastfeeding-info/storing-human-milk/
