After notice of the establishment of grades or standards and the determination of brands and labels, it shall be unlawful to use a brand or label to identify farm products and fish as being of a grade established before a permit is granted or after the revocation of the right to use such brand or label by the commissioner, with the approval of said board. Violations of this section shall be punishable for the first offense by a fine of not more than $50.00 and for subsequent offenses by a fine of not more than $200.00.