It depends how old the milk is to start with. If you have 2 bottles with different expiration dates, even if left out the longer dated one will last longer. I would not worry too much as bad milk smells bad, so you throw it away.
Breast milk can stay out at room temperature for up to 4 hours after being refrigerated.
Milk can stay at room temperature for about 2 hours before it starts to spoil. After that, it should be refrigerated to keep it fresh.
Breast milk can stay out at room temperature for up to 4 hours after being in the fridge. It is important to discard any leftover milk after this time to ensure safety for the baby.
Expressed breast milk can safely stay out at room temperature for up to 4 hours before it needs to be discarded.
Frozen breast milk can stay out at room temperature for up to 24 hours before it needs to be discarded.
Breast milk can stay out at room temperature for up to 4 hours before it needs to be refrigerated or discarded.
Thawed breast milk can stay out at room temperature for up to 2 hours. After that, it should be refrigerated or used within 24 hours.
Previously refrigerated breast milk can stay out at room temperature for up to 4 hours before it needs to be discarded.
Expressed breast milk can be safely stored at room temperature for up to 4 hours. After that, it should be refrigerated or discarded.
Thawed breast milk can stay out at room temperature for up to 2 hours before it needs to be discarded. After that, it should be refrigerated or used within 24 hours.
Used breast milk can stay out at room temperature for up to 4 hours before it needs to be discarded. After that, it should be refrigerated or frozen to maintain its quality and safety.
Breast milk can be safely stored at room temperature for up to 4 hours. After that, it should be discarded to prevent bacterial growth.