(1) An artificial color may be used in a pet food or specialty pet food only if it has been shown to be harmless to pets or specialty pets. The permanent or provisional listing of an artificial color in the United States Food and Drug Administration regulations as safe for use, together with the conditions, limitations, and tolerances, if any, incorporated therein, shall be deemed to be satisfactory evidence that the color is, when used pursuant to such regulations, harmless to pets or specialty pets.

(2) Evidence may be required to prove the safety and efficacy or utility of a pet food or specialty pet food which contains additives or drugs, when used according to directions furnished on the label. Satisfactory evidence of the safety and efficacy of a pet food or specialty pet food may be established:

(a) When the pet food or specialty pet food contains such additives, the use of which conforms to the requirements of the applicable regulation in 21 C.F.R., or which are "prior sanctioned" or "informal review sanctioned" or "generally recognized as safe" for such use; or

(b) When the pet food or specialty pet food itself is a drug or contains a drug as defined in RCW 15.53.901 and is "generally recognized as safe and effective" for the labeled use or is marketed subject to an application approved by the United States Food and Drug Administration under 21 U.S.C. 360(b).

(3) When a drug is included in a pet food or specialty pet food, the format required by WAC 16-250-014(4) for labeling medicated feeds shall be used.

(4) Any pet food or specialty pet food ingredient or pet food or specialty pet food product must not contain materials that enhance the natural color of a food if it conceals inferiorities.