S.D. Codified Laws § 5-18A-24
Grade A milk processors preferred
Any milk processor licensed pursuant to § 39-6-7 , bidding any milk or milk product under a competitive bid contract, shall receive the bid contract if the processor's bid is equal to, or within five percent or less, of any other bidder who is not a licensed processor.
Source: SL 2010, ch 31, § 27.