Baby Bottle Basics

That depends somewhat on what's in the bottle. If it's formula, you can keep it around for up to an hour (counting from the time the baby's mouth first touched the nipple), but it should be tossed after that. And if your baby takes longer than an hour to finish? Dr. Sears recommends ending the feeding, since bacteria can start to grow in the formula. "Chances are, he's falling asleep and the feeding is over anyway," he says. Or, you could try a faster-flowing nipple.

Dr. Sears says breast milk from a feeding can be saved for two to three hours—and you don't have to refrigerate it because breast milk contains antibodies formula doesn't.