Whosoever violates this act by not grading potatoes as herein required, or by not stenciling or branding containers as herein required or by removing any department notices placed upon said containers or by removing or altering any stencils or brands placed upon or attached to any container as in this act required, unless ordered to do so by the commissioner of agriculture or his duly appointed inspector or inspectors shall be guilty of a misdemeanor and subject to a fine of not more than 50 dollars and costs for the first offense and not more than 100 dollars and costs for each subsequent offense, or by imprisonment in the county jail for not more than 30 days in default of paying the fine and costs, or both such fine and imprisonment in the discretion of the court.