The grades of butter shall comply with the United States department of agriculture’s 1989 "Standards for Grades of Butter." "Undergrade" butter is butter scoring less than 90 under this standard. It is hereby declared to be unlawful to sell, or offer for sale any butter within the state of Idaho unless the wrappers and containers in which said butter is packaged are conspicuously labeled as to grades. Any butter that scores less than 90 and is sold or offered for sale within the state of Idaho must be conspicuously labeled with the words "undergrade butter" upon the wrappers and container in which said butter is packaged.