Mo. Rev. Stat. § 34.070
In making purchases, the commissioner of administration or any agent of the state with purchasing power shall give preference to all commodities and tangible personal property manufactured, mined, produced, processed, or grown within the state of Missouri, to all new generation processing entities defined in section 348.432, except new generation processing entities that own or operate a renewable fuel production facility or that produce renewable fuel, and to all firms, corporations or individuals doing business as Missouri firms, corporations or individuals, when quality is equal or better and delivered price is the same or less. The commissioner of administration or any agent of the state with purchasing power may also give such preference whenever competing bids, in their entirety, are comparable. For purposes of this section, "commodities" shall include forest products and bricks or any agricultural product that has been processed or otherwise had value added to it in this state.
§ 34.070, RSMo