Doane Pet Care Co. has issued a recall of some of its dog food sold exclusively at Wal-Mart Stores Inc. because of concerns about possible Salmonella contamination. The recall is unrelated to recent petfood recalls connected to tainted Chinese proteins used in some petfood production. Only a single batch of 55-pound bags of Ol' Roy Complete Nutrition dog food has been recalled. The dog food was produced at a plant in Manassas, Virginia, USA, and distributed to 69 Wal-Mart stores in Virginia, West Virginia, Maryland, Pennsylvania, North Carolina and Ohio. Forty of the stores are in Virginia. The company recalled the dog food after the Food and Drug Administration detected the presence of Salmonella . The company said no illnesses have been reported.