Iowa Code § 179.6
Every producer shipping milk to a first purchaser outside of Iowa who is not by agreement with the commission collecting the tax imposed by this chapter, and every first purchaser within the state, and every producer distributing milk directly to the consumer, shall keep a complete and accurate record of all milk produced or purchased by the person during the period for which an excise tax levy is imposed under this chapter. The records shall be in the form and contain the information prescribed by the commission, shall be preserved by the person charged with their making for a period of two years, and shall be offered or submitted for inspection at any time upon written or oral request by the commission or its duly authorized agent or employee.
Iowa Code § 179.6
85 Acts, ch 126, §12; 86 Acts, ch 1238, §8