Throw away any formula left in the bottle after feeding. Do not feed a baby any formula that has been left out of the refrigerator or that smells sour. Do not microwave breast milk or formula. Milk heated in a microwave may burn the baby's mouth or throat because the milk can get too hot. Do not feed infants less than one year old honey.
Honey can cause infant botulism.
Honey used in cooking and baking is dangerous, too. The botulism spores that cause illness are not destroyed by regular cooking methods. Cover home-prepared baby food immediately and put in the refrigerator. Better still, freeze it in ice cube trays. Once the food is frozen, put the food cubes in a plastic freezer bag to prevent freezer burn.