The commissioner or his duly authorized agents may inspect farm products and fish marked, branded or labeled in accordance with official grades or standards established and promulgated by the said commissioner, with the approval of the Board of Agriculture and Industries, for the purpose of determining and certifying the quality and condition thereof and other material facts relative thereto. Certificates issued in pursuance of such inspection and executed by the inspector shall state the date and place of inspection, the grade, condition and approximate quality of the farm products and fish inspected and such other pertinent facts as the said commissioner, with the approval of the said board, may require. Such a certificate relative to the condition or quality of said farm products and fish shall be prima facie evidence in all courts of the state of the facts required to be stated therein.