The investigation or testing of any product shall not be deemed to imply or indicate any endorsement of the qualifications or value of the product. No person shall make any representation that investigation or testing under this article 50 constitutes any approval or endorsement of his, her, or its activities by the department. The investigation or testing of any product shall not be deemed to imply or indicate that the product is useless or harmful, and during testing no person shall make any representation, except to the department, that the product under test is discredited or that it has been found useless or harmful.