Natural dog food comes in many different forms, including dry kibble, canned, freeze dried, refrigerated and fresh frozen. Dry kibble and freeze-dried food does not need to be refrigerated, even after opening the bag, though it should be stored in an airtight container. Canned food should be refrigerated after opening the can. Refrigerated food should be refrigerated before and after opening the package. Fresh frozen food should be thawed in the refrigerator and leftovers should be refrigerated.