Dean Foods, the nation''s largest dairy company agreed to sell a Wisconsin milk processing plant to settle an antitrust lawsuit filed by the Justice Department and three states, according to the Associated Press. The lawsuit filed last year objected to Dean Foods Co.''s 2009 purchase of two plants in Waukesha and De Pere from Foremost Farms USA. The purchase gave Dean Foods control over nearly 60 percent of milk sales in Illinois, upper Michigan and Wisconsin and raised concerns the company would quash competition and drive up milk prices. The attorneys general in those states joined the federal lawsuit. The proposed settlement filed in federal court calls for Dallas-based Dean Foods to sell the plant in Waukesha but doesn''t affect its ownership of the one in De Pere. The lawsuit portrayed Dean Foods'' purchase of the Waukesha plant as a strategic move to eliminate a strong competitor and said it left many school districts with only one milk supplier. The company''s sale of the plant will remedy that, and it will have to notify the Justice Department and Wisconsin attorney general''s office before it buys another plant worth $3 million or more.