General Mills Inc., Mars Inc. and Mc Kee Foods Corp. joined a growing list of food manufacturers and grocers in antitrust litigation that alleges top US sugar producers colluded to inflate prices for the sweetener used in many of the snacks and drinks Americans consume every day. In a lawsuit filed in Chicago federal court, the companies claim the vertically integrated producers American Sugar Refining Inc. and United Sugar Producers & Refiners effectively coordinated by reporting “competitively sensitive” data pricing and sales to an independent market analyst, Commodity Information Inc., which then published the information to sugar company subscribers. The case adds to mounting legal pressure on major sugar suppliers amid rising input costs for packaged goods manufacturers across the United States.