(AP) — In this Sept. 29, 2006, file photo, an E. coli screening test for "O" antigens is seen in the Gastroenteric Disease Center at Pennsylvania State University's Wiley Lab in State College, Pa.
The USDA is expected to announce Tuesday, Sept. 13, 2011, that it is expanding its testing of E. coli in meat, a move that will hasten recalls and help authorities identify more foodborne illnesses. (AP Photo/Carolyn Kaster, File)
