Photo of Anne O'Keefe, MD, MPH

Dr. Anne O'Keefe is senior epidemiologist of the Douglas County Health Department in Omaha, Nebraska.

The German E. coli outbreak is demonstrating the difficulty of identifying a “smoking gun” in outbreaks of foodborne illness.

Some are asking, “Where is the evidence?” By “evidence,” I believe they mean identifying the outbreak strain of bacteria in a food source that is genetically identical to clinical isolates by Pulse-Field Gel Electrophoresis (PFGE).

There …