7 C.F.R. § 46.19
Sales tickets shall bear printed serial numbers running consecutively and shall be used in numerical order so far as practicable. No serial number shall be repeated within a 90-day period. The sales tickets shall be prepared and all the details of the sale shall be entered on the tickets in a legible manner in order that an audit can be readily made. Erasures, strike-outs, changes, etc., should be held to the minimum. When errors are made in preparing sales tickets, the tickets should be voided. Each sales ticket shall show the date of sale, the purchaser's name (so far as practicable), the kind, quantity, the unit price, and the total selling price of the produce. Each sales ticket shall show the lot number of the shipment if the produce is being handled on consignment or on joint account. Sales tickets on all other lots of the same commodity which are on hand at the same time shall also show a lot number. The original or a legible carbon copy of each sales ticket, including those voided or unused, shall be accounted for and shall be filed or stored either by dates of sales or in the order of the serial numbers for a period of two years.
7 C.F.R. §46.19