In the US, pet food labeling is regulated at two levels: federal and state. Federal regulations, enforced by the Food and Drug Administration's (FDA) Center for Veterinary Medicine (CVM), establish standards applicable for all animal feeds (including pet food): proper identification of product, net quantity statement, manufacturer's address and proper listing of ingredients.
Some states also enforce their own labeling regulations. Many of these states have adopted the model pet food regulations established by the Association of American Feed Control Officials (AAFCO). These regulations are more specific in nature, covering aspects of labeling such as the product name, the guaranteed analysis, the nutritional adequacy statement, feeding directions and calorie statements.
The product name is the first part of the label noticed by the consumer and can be a key factor in the consumer's decision to buy the product. For that reason, manufacturers often use fanciful names or other techniques to emphasize a particular aspect. Since many consumers purchase a product based on the presence of a specific ingredient, many product names incorporate the name of an ingredient to highlight its inclusion in the product. The percentages of named ingredients in the total product are dictated by AAFCO rules (see AAFCO's Official Publication for details).
Net quantity statement
The net quantity statement tells you how much product is in the container. There are many FDA regulations dictating the format, size and placement of the net quantity statement. A cost-per-ounce or per-pound comparison between products is always prudent.
The "manufactured by..." statement identifies the party responsible for the quality and safety of the product and its location. If the label says "manufactured for..." or "distributed by...," the food was manufactured by an outside manufacturer, but the name on the label still designates the responsible party.
All ingredients are required to be listed in order of predominance by weight. The weights of ingredients are determined as they are added in the formulation, including their inherent water content. This latter fact is important when evaluating relative quantity claims, especially when ingredients of different moisture contents are compared.
For example, one petfood may list "meat" as its first ingredient and "corn" as its second. The manufacturer doesn't hesitate to point out that its competitor lists "corn" first ("meat meal" is second), suggesting the competitor's product has less animal-source protein than its own. However, meat is very high in moisture (approximately 75% water).
On the other hand, water and fat are removed from meat meal, so it is only 10% moisture (what's left is mostly protein and minerals). If we could compare both products on a dry matter basis (mathematically "remove" the water from both ingredients), one could see that the second product had more animal-source protein from meat meal than the first product had from meat, even though the ingredient list suggests otherwise.
At minimum, a pet food label must state guarantees for the minimum percentages of crude protein and crude fat and the maximum percentages of crude fiber and moisture. The "crude" term refers to the specific method of testing the product, not to the quality of the nutrient itself.
Some manufacturers include guarantees for other nutrients as well. The maximum percentage of ash (the mineral component) is often guaranteed, especially on cat foods. Cat foods commonly bear guarantees for taurine and magnesium as well. For dog foods, minimum percentage levels of calcium, phosphorus, sodium and linoleic acid are found on some products.
Guarantees are declared on an "as fed" or "as is" basis, that is, the amounts present in the product as it is found in the can or bag. To make meaningful comparisons of nutrient levels between a canned and dry product, they should be expressed on the same moisture basis. The most accurate means of doing this is to convert the guarantees for both products to a dry matter basis.
Nutritional adequacy statement
Any claim that a product is "complete," "balanced," "100% nutritious" or suggests that a product is suitable for sole nourishment that is not, in fact, nutritionally adequate is a potentially unsafe product. For this reason, an AAFCO nutritional adequacy statement is one of the most important aspects of a dog or cat food label. A "complete and balanced" pet food must be substantiated for nutritional adequacy.
Feeding directions instruct the consumer on how much product to offer the pet. At minimum, they should include verbiage such as "feed ___ cups per ___ pounds of body weight daily." On some small cans, this may be all the information that can fit. The feeding directions should be taken as rough guidelines, a place to start. Breed, temperament, environment and many other factors can influence food intake.
Petfoods can vary greatly in calorie content, even among foods of the same type (dry, canned) and formulated for the same life stage. In addition, feeding directions vary among manufacturers, so the number of calories delivered in a daily meal of one food may be quite different from another. The number of calories in a product roughly relates to the amount of fat, although varying levels of non-calorie-containing components, such as water and fiber, can throw this correlation off.
Other label claims
Many petfoods are labeled as "premium," and some now are "superpremium" and even "ultra premium." Other products are touted as "gourmet" items. However, products labeled as premium or gourmet are not held up to any higher nutritional standards than are any other complete and balanced products.
The term "natural" is often used on pet food labels, although that term does not have an official definition. The term usually is intended to mean a lack of artificial flavors, artificial colors or artificial preservatives in the product.
"Natural" is not the same as "organic." The latter term refers to the conditions under which the plants were grown or animals were raised. There are now official rules governing the labeling of organic foods (for humans or pets).