WASHINGTON (AP) — After nearly two decades of study, the Food and Drug Administration announced rules Thursday designed to make sure that infant formula is safe and nutritious.

Most formula makers already abide by the practices, but the FDA now will have rules on the books that ensure formula manufacturers test their products for salmonella and other pathogens before distribution. The rules also require formula companies to prove to the FDA that they are including specific nutrients — proteins, carbohydrates, fats, vitamins and minerals — in their products.