Natural Pet Food Definitions
May refer to the whole product or individual ingredients and simply means that the traditional chemical preservatives have been replaced with natural preservatives, most commonly Vitamins C and E.
A variation of this is "with added vitamins and minerals", so you can't assume that 'all-natural' is equal to 'all-satisfying' with regard to your pet's nutritional requirements.
Includes meat, vegetables and herbs that are free of pesticides, insecticides, hormones, antibiotics, or any other non-animal or non-vegetable elements. A cat food might be totally organic or it may contain one organic ingredient in an otherwise 'un-natural', unhealthy product.
This seems to imply that the ingredient is fit for human consumption; a variation on this is USDA approved. Ingredients called human-grade must be processed in human food processing plants. If they are processed in pet food processing plants, they cannot be called 'human-grade', even if the original product has come from a human food plant. The AAFCO apparently prohibits the use of this term on labels, but you can find out about the many human-grade dog foods and cat foods on suppliers' web sites.
Many ingredients (natural or otherwise) found in pet foods have been linked to allergies in pets, and many manufacturers promote their products as being free of one or any number of these ingredients: rice, corn, soy, wheat, barley, sorghum, dairy products, etc.