The Food &amp; Drug Administration, which controls packaged foods and drugs, only requires a use-by, or expiration, date on infant formula and some baby foods. That's because formula must contain a certain quantity of each nutrient that is described on the label. And if formula is stored too long, it loses its nutritional quality. It also separates or form lumps that will clog the bottle nipple. Except for infant formula and some baby foods, product dating is not required by federal regulations.