How Long Can Breast Milk Stay Out?

Storage Tips for Freshly Pumped, Refrigerated, and Frozen Breast Milk

Breastmilk in bottles

Verywell / Photo Composite by Nusha Ashjaee / Getty Images

Breast milk can stay out for up to 4 hours after it's been expressed. So if you are traveling or working away from home and don't have access to a fridge for your pumped breast milk, or you've recently pumped and plan to feed your baby soon, rest assured that your milk can stay out.

Freshly pumped milk will be okay for 4 hours, but if you baby has some of it, the rest of the bottle can only stay out for 2 more hours. If you defrost frozen milk, it can stay out for 1 to 2 hours and it should never be refrozen.

Let’s take a look at what that time frame is, what the storage options are, and tips for keeping breast milk fresh and safe for your baby.

Can I Store Breast Milk at Room Temperature?

Both the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) agree that storing breast milk at room temperature—defined as 77°F or 25°C—for up to 4 hours is acceptable and safe.

The reason that breast milk can safely stay out of the fridge for this length of time has to do with the fact that breast milk has many inherent antibacterial characteristics, explains Molly O'Shea, MD, official pediatrician of Goldfish Swim School.

“Breast milk contains natural antibodies, so it is safe to store longer than you might store formula at room temperature,” Dr. O’Shea says.

Breast milk also has several other key components that are protective and that allow it to stay safe for a few hours on your kitchen counter or in your travel bag, says Ashley Georgakopoulos, IBCLC, lactation director at Motif Medical.

“Breast milk has leukocytes, along with enzymes, that prevent the growth of undesirable mold, viruses, and bacteria,” says Georgakopoulos.

Breast milk at room temp

Verywell / Jessica Olah

How Long Can I Store Breast Milk at Room Temperature?

The Academy of Breastfeeding Medicine (ABM) suggests that breast milk can stay out at room temperature for 4 hours. But if the room is cooler, it’s possible that you could leave freshly pumped milk for up to 6 to 8 hours without issues. Still, ABM advises refrigerating or chilling milk as soon as possible after pumping if you don’t plan on feeding it to your baby for several hours.

Georgakopoulos explains that the conditions in which you pumped your milk can affect how clean and bacteria-free your milk is likely to be. For example, pumping near someone who is ill or pumping in a hospital or healthcare provider's office might make your milk less sterile.

Of course, these are all just general guidelines. Talk to your baby's pediatrician if you have questions about the safety of pumped breast milk as each situation, and each baby’s needs, are unique.

Storage Guidelines for Thawed and Leftover Milk

The guidelines for storage at room temperature are for recently pumped milk. There might be other instances where you would want to keep breast milk that hasn't been recently pumped out of the refrigerator for some period of time. If that’s the case, there are slightly different guidelines.

“When discussing breast milk at room temperature, it’s important to iterate that [the guidelines are for] freshly expressed or pumped breast milk,” Georgakopoulos says. Here is what you need to know about the storage guidelines for all types of pumped breast milk.

Fresh Breast Milk

Freshly pumped breast milk can stay at room temperature for up to 4 hours. It also can stay in the refrigerator for up to 4 days. And if you freeze your breast milk, it will last for about 6 months. (Up to 12 months in the freezer is acceptable, but 6 months is recommended for best quality.)

Thawed Breast Milk

If you’ve thawed previously frozen breast milk but aren’t ready to give it to your baby, you can store it at room temperature for 1 to 2 hours. If you put it back in the fridge, you should plan to use it within 24 hours. You also should never refreeze thawed milk.

Leftover Breast Milk

If you have fed your baby breast milk from a bottle and then put that bottle back on the counter, the 4-hour rule does not apply. The CDC says your baby should consume leftover milk within 2 hours. If you want to avoid wasting breast milk, you may want to store, warm, and serve it in smaller amounts.

Risks of Storing Breast Milk at Room Temperature

We all want what is best for our babies and don’t want to feed them milk that is spoiled or contaminated in some way. Dr. O’Shea says that it is very unlikely for that to happen to breast milk, even if you leave it on the counter for several hours.

If your baby was born premature or has a health condition, your baby's pediatrician may recommend different breast milk storage guidelines. Talk to your baby's healthcare provider for more details about storing your milk at room temperature.

“Even if you have a premature infant, the four-hour rule can generally be followed for freshly expressed milk,” Dr. O’Shea says.

Keep Breast Milk Safe at Room Temperature

Following the general storage guidelines in terms of length of time and temperature considerations is typically all you need to do to keep breast milk safe out of the fridge.

“Room temperature breast milk doesn't require any special storage as long as you're maintaining that four-hour window,” says Dr. O’Shea. “You can continue to add freshly pumped milk as long as the clock starts with your first pumping."

As such, it’s good to note the time that you pumped your milk, in case you are pumping more than once in a 4-hour span.

If you are out and about and it’s a hot day, you might want to use some freezer packs or a thermal insulator bag, suggests Dr. O’Shea. It’s important that if you are storing milk outside of the refrigerator or freezer you do so at a temperature that is less than about 77 degrees F.

Whatever storage container you use, it should be clean and sterile. Georgakopoulos recommends milk storage bags, BPA-free plastic bottles, or glass bottles for optimal storage.

The CDC recommends using a container with a tight-fitting lid and avoiding plastics with recycling symbol 7, which means that the plastic may contain the potentially harmful chemical bisphenol A (BPA).

A Word From Verywell

It is normal to feel concerned about your breast milk becoming contaminated or that it would be unsafe for your baby if it is left out of the fridge. Fortunately, the storage guidelines are fairly simple. You can keep freshly pumped milk out for up to 4 hours at room temperature, and it will be safe for your baby.

If you have any questions about these guidelines, or if you have concerns pertaining to your baby's feeding, reach out to your pediatrician. A lactation consultant also can be a good resource for questions about breast milk storage and breastfeeding challenges.

5 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. Proper storage and preparation of breast milk.

  2. American Academy of Pediatrics. Tips for freezing & refrigerating breast milk.

  3. Witkowska-Zimny M, Kaminska-El-Hassan E. Cells of human breast milk. Cell Mol Biol Lett. 2017;22:11. doi:10.1186/s11658-017-0042-4

  4. Eglash A, Simon L, Academy of Breastfeeding Medicine. ABM Clinical Protocol #8: Human milk storage information for home use for full-term infants, revised 2017. Breastfeeding Med. 2017;12(7):390-395. doi:10.1089/bfm.2017.29047.aje

  5. Steele C. Best practices for handling and administration of expressed human milk and donor human milk for hospitalized preterm infants. Front Nutrition. 2018;5:76. doi:10.3389/fnut.2018.00076

By Wendy Wisner
Wendy Wisner is a lactation consultant and writer covering maternal/child health, parenting, general health and wellness, and mental health. She has worked with breastfeeding parents for over a decade, and is a mom to two boys.

Originally written by Donna Murray, RN, BSN
Donna Murray

Donna Murray, RN, BSN has a Bachelor of Science in Nursing from Rutgers University and is a current member of Sigma Theta Tau, the Nursing Honor Society.

Learn about our editorial process