Mo. Rev. Stat. § 416.420: Discrimination in price between localities — evidence.

1. No processor or distributor shall, with the intent or with the effect of unfairly diverting trade from a competitor, or of otherwise injuring a competitor, or of destroying competition, discriminate in price in the sale of any milk product furnished from the same plant between any of the towns, cities, municipalities or counties of this state; except that no violation results from different prices which reflect, in the case of a processor, the actual transportation cost from point of processing to point of sale, and, in the case of a distributor, the actual transportation cost from point of purchase to point of resale.

2. Proof of the advertising, offer for sale or sale of any milk products furnished from the same plant in any town, city, municipality, or county at prices less than advertised, offered for sale, or sold in any other town, city, municipality or county by the processor or distributor, which cannot be accounted for by the difference in the transportation costs is prima facie evidence of a violation of this section.