Every proprietor of a milk gathering station shall keep, in any form that the director of environmental management may prescribe, a record of transactions of purchases of milk or cream by him or her and he or she shall, at least semimonthly, or weekly if so agreed upon by the parties to the transaction, deliver to each person from whom he or she receives or purchases milk or cream, and in the unit of measure used in computing the amount due, an itemized statement of the several amounts or quantities of the milk or cream received or purchased at that milk station from that person during the prior half month or, if statements are delivered more frequently than semimonthly, during that period of time which has elapsed since the delivery of the last prior statement.