Sherman Produce of St. Louis, MO, is voluntarily recalling 241 cases of bulk walnuts packaged in 25-lb. bulk cardboard boxes and Schnucks brand 10-oz. trays because the products are potentially contaminated with Listeria monocytogenes. The trays of walnuts have UPC 00338390032 with best by dates 03/15 and 04/15. These products were sold to retailers in MO and IL from March through May 2014. No illnesses have been reported to date. The recall was initiated after FDA inspectors detected Listeria monocytogenes in walnuts sampled at the facility. All walnuts processed in the facility during the same time frame as the product found positive are being recalled. Consumers who have purchased the walnuts are urged not to consume them but are advised to dispose of them or return them to the place of purchase for a full refund. Consumers with any questions may call Sherman Produce at 314-231-2896, 8:30 a.m. to 5 p.m. CDT, Monday through Friday. Listeria monocytogenes is an organism which can cause serious and sometimes fatal infections in young children, frail or elderly people, and others with weakened immune systems. Although healthy individuals may suffer only short-term symptoms such as high fever, severe headache, stiffness, nausea, abdominal pain and diarrhea, Listeria infection can cause miscarriages and stillbirths among pregnant women.