It shall be unlawful for any person, either for himself or another, to falsely manipulate or underread or overread or take inaccurate samples or make any false determinations by Babcock test or any other contrivance used to determine the quantity of fat in milk or cream or the value of milk or cream delivered to a creamery, cheese factory, condensory, ice cream plant, milk plant or milk depot or when sold or purchased. The test shall be clear oil, free from sediment, solids or other foreign substance, and must be read at a temperature of 125 degrees to 140 degrees Fahrenheit. Test cream shall be weighed. The scales must be sensitive and accurate. The tester and owner or owners are jointly responsible for their accuracy. All licensed receiving stations, conducted for the purchase of butterfat either in the form of cream or milk shall retain in a cool, clean, sanitary place and in tightly stopped bottles or tightly covered jars the exact, properly labeled samples of cream or milk from which the butterfat test has been conducted, until 4:00 P.M. of the day following the application of the test where daily testing is practiced, and until 4:00 P.M. of the second day following the application of the test where composite testing of individual deliveries is practiced.