How long can expressed breast milk be stored at room temperature?

Breast milk is the optimal food for infants, fully meeting all their nutritional needs during the first six months of life and supporting enhanced immunity, resistance to infection, and healthy development. So, how long can expressed breast milk be safely stored at room temperature? Below, we provide a detailed explanation.

How Long Can Expressed Breast Milk Be Stored at Room Temperature?

The shelf life of expressed breast milk depends directly on ambient storage temperature. Under typical room-temperature conditions (approximately 25°C), expressed breast milk remains safe for up to about 24 hours—but should generally not be kept overnight. When refrigerated at 2–4°C, it may be stored for up to 24 hours. In a freezer maintained at −18°C or colder, it can be stored for up to three months. To maximize freshness and safety, refrigerated breast milk should be placed toward the back of the refrigerator—away from the door—to maintain consistent low temperatures and minimize fluctuations caused by frequent door opening and closing. Additionally, when using frozen breast milk, it is recommended to follow a “first-in, first-out” principle—using the oldest stored milk first. For refrigerated milk, if discoloration (e.g., darkening) or floating particles appear after thawing and warming, this indicates spoilage, and the milk must not be fed to the infant. Since breast milk should only be thawed once, each storage bag should ideally contain a single feeding volume. Once thawed, breast milk must not be refrozen. Thawed milk should be gently warmed in warm water (up to 40°C); microwaving or direct heating over an open flame is strictly discouraged.

Additional Information: Key Considerations for Storing Breast Milk

1. Prior to expressing milk, thoroughly wash your hands. Each expression session should yield milk stored separately—never mix newly expressed milk with previously expressed (older) milk. Refrigerated milk that has exceeded its safe storage time should be promptly discarded to avoid accidental feeding of spoiled milk, which could cause infant discomfort or illness.

2. Use containers with excellent sealing properties for storage—preferably BPA-free plastic containers. Avoid metal containers, as they may degrade certain nutrients in breast milk, thereby reducing its nutritional value. Airtight containers also help prevent bacterial contamination.

The above outlines how long expressed breast milk can be safely stored at room temperature. We hope this information is helpful to you.