All commercial dog food on sale should have certification on nutritional standards such as AAFCO. Do not buy the one that does not have nutritional standard. Reading your pet food label is the best way to determine the quality of the dog food you are feeding your dog. The ingredients on the label and the guaranteed analysis shows you the amount of protein, fat, carbohydrates, fiber and other nutrients contain in the dog food. All these information can be obtained from the food label. In addition to providing information about the amount and quality of protein and fat, the label will also alert you of any unwanted preservatives and give general feeding guidelines.

'AAFCO' stands for the Association of American Feed Control Officials. The AAFCO develops guidelines for the production, labeling, and sale of animal foods and it's called AAFCO standards. AAFCO has developed two standards which pet foods should meet and the pet foods which meet the AAFCO's requirements will include one of two statements on their food label. The first and lower standard states 'formulated to meet AAFCO's nutrient requirement.' which means the food was tested in the laboratory and was found to have the recommended amounts of protein, fat, etc. But any combination would easily meet this standard. The second standard states something like 'animal-feeding tests using AAFCO's procedures substantiate that this product provides complete and balanced nutrition.' For a pet food to be able to carry this label, it had to be tested on a population of animals for six months and shown to provide adequate nutrition. But even with this statement, there are problems with its interpretation. If one particular product in a manufacturer's line was tested and found to meet this standard, the company is allowed to include this same statement on other products in the same 'family' which provide equal or greater concentrations of all the nutrients. So even if the pet food carries this AAFCO food trial statement on its label, you can not be sure that specific product was actually tested in a food trial. In addition, testing a food for six months is not an adequate amount of time to determine if deficiencies or other long term effects may occur after feeding the product a year or more. Despite these problems with the interpretation of this AAFCO food trial statement, having the statement on a pet food label at least shows the company has made some attempt to develop a good food.