How Long Can Breast Milk Sit Out at Room Temperature?

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

Breast milk at room temp

Verywell / Jessica Olah

Parents have many options when it comes to expressed breast milk storage. It can be stored in the refrigerator, freezer, insulated bag, and even at room temperature. In fact, pumped breast milk can sit out at room temperature for longer than infant formula and other foods before becoming unsafe for your baby, but parents and caregivers should still familiarize themselves with safe storage guidance.

For healthy full-term infants, here are the guidelines for keeping breast milk out at room temperature (up to 77 degrees F or 25 degrees C).

  • Freshly pumped breast milk: Approximately 4 hours
  • Previously refrigerated breast milk: Up to 4 hours
  • Frozen breast milk, thawed in the refrigerator, but not yet warmed up: Up to 4 hours
  • Frozen breast milk taken directly from the freezer: Do not store or thaw at room temperature
  • Frozen breast milk, thawed and warmed up: Do not store at room temperature; use immediately or store in the refrigerator

Breast Milk and the Growth of Bacteria

Bacteria are all around. They are on your hands, on the skin around your breasts, and on the parts of your breast pump. When you pump your breast milk, some of that bacteria gets into the milk. But don't worry: When you store your breast milk safely, this small amount of bacteria will not harm a healthy, full-term child.

Breast milk contains antibacterial and immune properties that can prevent bacteria from growing inside of it for many hours. However, the longer it is left out, the more time the bacteria has to multiply. Temperature also plays a significant role in the growth of bacteria. The higher the temperature of the room, the faster the bacteria can grow.

To be safe, you should ideally use room temperature breast milk within 4 hours.

While some sources state that due to the antibacterial properties found in human milk, it can remain at room temperature for as long as 10 to 12 hours, that is generally not the accepted recommendation.

The Centers for Disease Control and Prevention (CDC) and the Academy of Breastfeeding Medicine (ABM) recommend that breast milk should not stay out at room temperature for longer than 4 hours. The American Academy of Pediatrics (AAP) also recommends no longer than 4 hours.

Storing Breast Milk for Premature Babies or Babies With Health Issues

These guidelines, while safe for healthy, full-term babies, do not apply to premature infants or children who do not have healthy immune systems. The bacterial growth that occurs in breast milk that is left out at room temperature can be dangerous to these children, who are at a higher risk of infection. In general, breastmilk pumped for premature or hospitalized infants should be used within one hour or refrigerated. But you should discuss the recommended storage guidelines for your situation with your child's health care providers.

Tips for Storing Breast Milk at Room Temperature

In addition to following the guidelines above, keep these tips for safe breast milk storage in mind:

  • The temperature of the room should not be over 77 degrees F or 25 degrees C. The cooler the room, the better.
  • If the room temperature is greater than 77 degrees F (25 degrees C), do not let your breast milk sit out at all. Place it in the refrigerator or an insulated cooler with ice packs immediately.
  • Once you collect your breast milk in the storage container, put a top or cap (not a feeding nipple) onto the breast milk storage bottle or seal the storage bag.
  • Place a cold towel over the storage container to keep the milk cooler.
  • Keep breast milk away from heat, windows, and direct sunlight.
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Article Sources

  1. Centers for Disease Control and Prevention. Proper Storage and Preparation of Breast Milk. 2019.

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