You want to look for a food with quality animal protein, little or no grain, as sugarcatmom said. Beware of starches as some companies will use them to substitute for the grain.
I'm not big on the human grade label on pet food. there's really no meaning to it. I mean, the meat you get in grocery stores comes from the same slaughterhouse. It's the by-products you don't want. I guess by-products could also be the muscle and organ meats but they may also be other things like beaks and feet. If by-products are so good, then why not name them?
Give a dog food and make him prosperous, he will not bite you. That is the principal difference between a dog and man. (Mark Twain)