how long does a formula bottle last at room temperature

A prepared formula bottle can last at room temperature for up to two hours if untouched. Once a baby starts feeding from the bottle, it should be used within one hour, and any leftover formula must be discarded after that time. This is because bacteria can grow quickly once the baby's saliva contaminates the formula. If the formula is prepared but not yet fed, it should be refrigerated within two hours and can then last up to 24 hours in the fridge. These guidelines apply to formula made from powder, liquid concentrate, or ready-to-feed formulas.