The presence of coliform bacteria in water is widely accepted as an indication of contamination that is potentially of fecal origin. The E. coli strain O157:H7 is particularly virulent and is characterized by its low infectious dose and severity of illness. For example, E. coli O157:H7 was determined to be the causative agent for a 1989 waterborne outbreak in Cabool, Missouri that resulted in 243 cases of illness and four deaths. Another widely publicized outbreak occurred in Walkerton, Canada in 2000 where 21 deaths were reported.? Traditional E. coli O157:H7 detection procedures are tedious, time consuming, and, most importantly, lack the specificity for accurate determination in a timely manner to allow water utilities to employ contingency measures where contamination with this pathogen exists. The goal of this research was to develop a rapid (< 8 hours) analytical method to detect the presence of E. coli O157:H7 in raw water sources and treated drinking water.?