It shall be unlawful for any person, acting individually or in concert with others, by mass picketing, force, coercion, physical obstruction at the entrance to any place of employment or physical obstruction in any street, sidewalk or railway, to prevent or attempt to prevent the delivery to any public, commercial or industrial enterprise of any supply, commodity or service necessary for the proper maintenance of any of the buildings, equipment, machinery or fixtures constituting such enterprise or necessary to keep any of such buildings, equipment, machinery or fixtures from deteriorating or being damaged by fire, freeze-up or other casualties, or the harvesting, the storing, the transportation to storage and market of a perishable food product. For the purpose of this section, “person” means any individual, corporation or unincorporated association, including partnerships and labor organizations. Whoever violates this section shall be punished by a fine of not more than $250 or by imprisonment for not more than 30 days, or by both.