Every farm warehouse for which there is a warehouse receipt outstanding shall be examined monthly by the commissioner. The cost of such examination shall be included in the annual license fee. The commissioner, at his discretion, may make additional examinations of any public grain warehouse at any time. If any discrepancy is found as a result of additional examination, the cost of such examination is to be paid by the farm warehouseman. The commissioner shall examine and inspect the grain stored in the farm warehouse, and shall determine the quantity of the grain stored in each container in the warehouse. The commissioner shall maintain a record and file of all inspections made of the warehouses and of the results of such inspections.