In September 1999 Illinois Department of Public Health traced a large outbreak of E. coli O157 infections to beef served at an annual Downstate Labor Day party held in Petersburg, Illinois. The party organized by farmer, Tom Baird, was the fourth annual "Cornstalk" musical bash held on a small field beside Baird's clubhouse. An indistinguishable genetic strain was isolated in patients, cattle droppings, and in leftover meat. As many as 329 people who attended the party became ill. Beef served at the party came from a steer slaughtered at CA Processing of Athens, Illinois which slaughters meat for the private use of farmers. Health officials identified the slaughtering process as the point when the original contamination occurred. Many people who attended the event described the beef as being undercooked.