(a) Any person or milk plant or agent thereof in the State or out of the State engaged in the business of buying milk on the basis of percentage of butterfat contained therein shall make a test of the milk at least once every 16 days. The milk purchased from each milk producer shall be represented by a composite sample taken from the entire delivery of each of the several lots purchased from the milk producer and shall cover a period of not more than 16 days. A composite sample shall contain a preservative and it shall contain aliquot parts from each lot of milk collected. The preservative must be capable of keeping the composite sample in suitable condition for testing for a period of at least 30 days. Each composite sample shall be held in an airtight bottle, to be labeled with the name or number of the milk producer.
(b) After the composite samples have been tested, their residues shall be held intact and in a suitable condition for retesting for a period of 15 days.
(c) All milk producers shall be notified within 5 days after the close of the period giving such producer the results of the butterfat test on the composite sample. If the producer desires a retest, such request shall be made directly to the milk plant or through the field man within 24 hours after the receipt of the butterfat test. The retest shall be made immediately and reported to the producer.
(d) The Department of Agriculture may at any time require out-of-state milk plants to deliver 1 or all composite samples to the Department of Agriculture laboratories for retesting purposes. An alternative shall be for the out-of-state milk plant to grant the Department of Agriculture or its agents permission to enter its plant for the purpose of taking samples for rechecking purposes. If the composite sample should in some manner be destroyed during the period and it becomes necessary to use fresh samples as the basis of settlement at least 3 fresh samples shall be taken from 3 separate deliveries of milk.
(e) Reports of all butterfat tests shall be made to the Department of Agriculture at the close of each testing period. If butterfat tests vary more than 0.02% from one testing period to the next testing period, a retest shall be made and reported.
(f) The Secretary of the Department of Agriculture may, by written permission, grant any person or milk plant or agent thereof engaged in the business of buying milk on the basis of percentage of butterfat contained therein the right to use a fresh sample method as approved by the Secretary.