Freshly expressed breast milk can last at room temperature (up to about 25°C or 77°F) for up to 6 hours if kept in a sterile, covered container. If the room temperature is warmer, around 29°C or higher, breast milk should not be left out for more than 2 hours. For optimal safety and to reduce the risk of bacterial growth, it is best to refrigerate or freeze the milk as soon as possible after expression. Premature babies have stricter guidelines, usually requiring breast milk to be used within 1 hour at room temperature. Signs of spoilage include a sour or off smell, and any milk left out too long should be discarded to avoid illness. In summary:
- Up to 6 hours at room temperature (25°C or below)
- No more than 2 hours if temperature is 29°C or above
- Shorter time for premature babies (1 hour)
- Refrigerate or freeze as soon as possible for safety
These recommendations have been consistently supported by multiple health sources and organizations.
