Every stockyard, slaughterhouse, tobacco warehouse or loose floor, dairy products plant, cotton gin or compress, and agricultural grain or seed buying/receiving station which buys or sells commodities on a bulk basis shall have in its employ one or more public weighmasters. All livestock, tobacco, milk, cream, cotton, and agricultural grains or seeds which are purchased, processed, or sold on a bulk weight basis at the above mentioned establishments shall be weighed only by a public weighmaster. Any individual acting on behalf of such individual or an establishment that charges a fee, commission, or any type of payment to perform public weighing, shall also be licensed under this part.