American College of Veterinary Nutrition – ACVN has excellent discussions in their FAQ. Organic ingredients, raw foods, homemade diets, a lot of valid information.
AVMA Pet Food Recall Listing - recall food listing, site currently re-opening in Aug 2012, has the link to their twitter feed that is current on the subject.
Hill’s Science Diet Veterinary Prescription Diets - information on Hill’s prescription diets, routine dog and cat health care, common diseases affected by diet.
How to Read a Pet Food Label – FDA’s site with informative article on what the requirements and wording are for pet food labels.
Purina Veterinary Prescription Diets - information on Purina’s prescription diets, routine dog and cat health care, and common diseases affected by diet.
Royal Canin Veterinary Prescription Diets - very nice library of disease information, RC’s prescription diets, and routine health care information for dogs and cats.
Cat and Dog Nutritional Needs – Science based discussion of actual nutritional needs for dogs and cats. Easy read, intended for owners.