Except as provided in section 34.044, all requests for bids and proposals for supplies to be purchased shall be made in general terms and by general specifications and not by brand, trade name or other individual mark, provided such article to be purchased can be definitely described without the designation of such brand, trade name or other individual mark. All such requests and bids shall contain therein a paragraph in easily legible print, reading as follows: “By virtue of statutory authority, a preference will be given to materials, products, supplies, provisions and all other articles produced, manufactured, made or grown within the state of Missouri.”.