(a) No person purchasing or selling milk or cream or both by weight or measure or butterfat test, and no agent or servant of any such person, shall use as a basis of payment for such purchase any weight or measure or butterfat test other than the approved weight or measure or butterfat test of the milk or cream purchased or sold.
(b) Only procedures approved by the Association of Official Analytical Chemists or the American Public Health Association and adopted or prescribed by the State Department of Agriculture may be used. The Babcock test or the automated light scattering method for determining fat content of raw unhomogenized milk are hereby adopted as procedures for the determination of the fat content of milk as a basis of payment to producers.