A commodity in liquid form shall be sold only by liquid measure or by weight, and a commodity not in liquid form shall be sold only by weight, by measure of length or area or by count; provided, that the provisions of this section shall not apply to a commodity sold for immediate consumption on the premises of sale, to vegetables sold by the head or bunch, to cotton seed sold to cotton gins or to a commodity when in package or container form standardized by law. The board shall issue such regulations as are required to carry out the provisions of this section.