All publications or public statements relating to the quality of milk or cream, or the condition of dairies or milk plants, shall be expressed in terms of percentage, 100 percent being considered perfect. In rating milk or cream this percentage shall be based upon an average of results obtained by the examination of at least four samples taken at intervals of at least a week. The method used for computing milk scores for publication shall be approved by the Department of Food and Agriculture of the State of California.
Cal. Code Regs. Tit. 3, § 605