Inspectors of the department shall conduct periodic inspections of approved markets. Any failure to meet prescribed standards shall be sufficient cause for the Commissioner to revoke market approval and to require return of the sign furnished to the market by the department, which sign shall at all times remain the property of the State of Georgia. Refusal to allow inspectors to make a full and complete inspection or refusal to disclose material facts to such inspectors shall be sufficient cause for revocation of market approval.