Upon receipt of the application for a license accompanied by the required fee, the department shall inspect the plant to be licensed and if it finds that such plant complies with the provisions of law, the department shall issue such license. The persons designated by the department to make such inspection shall be persons having practical knowledge of the operation of cold storage plants and the storage of food therein, and shall be thoroughly familiar with the provisions of the law applicable to locker plants and the applicable rules and regulations of the department. The department shall inspect all locker plants licensed under sections 196.450 to 196.515 at least once each six months, and may make such additional inspections as the department deems necessary. The department and its representatives shall have access to locker plants at all reasonable times for the purpose of making inspections.