Tyson Foods Inc. expanded its portfolios of value-added foods and specifically Mexican foods with the June 1 acquisition of Circle Foods LLC. Price was not disclosed. The purchase includes a159,000-sq.-ft. plant in San Diego, built in 2008. Circle Foods, which has been in business for 25 years, makes frozen and refrigerated handheld Mexican foods, uncooked tortillas and Indian flatbreads under the Nuevo Grille, Tortillaland and Rotiland brands, as well as some private label. The operation has 600 full-time employees, and Tyson said it will make no changes. The seller was Claridge, an investment firm headed by Stephen Bronfman, grandson of the founder of spirits-maker Seagram.