Mo. Rev. Stat. § 413.095: Liquid form commodities, how sold — if not in liquid form, how sold — sale of commodity, duty of seller as to quantity.

1. Except as otherwise provided by the director, or by firmly established trade custom and practice:

(1) Commodities in liquid form shall be sold by liquid measure or by weight; and

(2) Commodities not in liquid form shall be sold by weight, measure or by count.

2. The method of sale of any commodity shall provide sufficiently accurate and adequate quantity information to permit the buyer to make reasonable price and quantity value comparisons.