[Direct PCR detection of food-borne bacteria from mixed human feces]

Mixed human feces were evaluated for simultaneous direct PCR detection of 3 food-borne bacteria--verotoxin-producing bacteria, Salmonella, and Shigella. Mixed feces concentrated approximately 2.5% in distilled water, were heated at 95 degrees C for 5 min. The heated suspension was then centrifuged and 5 microL of the supernatant poured into a 45 microL PCR mixture prepared to neutralize PCR inhibitors originating in biological samples. As a result of PCR under the above conditions followed by melting curve analysis (MCA), one positive fecal sample containing food-borne bacteria was detected from among 50 mixed fecal samples, showing the same sensitivity as individual cultivation. Results thus indicate that this method enables rapid, reliable, highly sensitive testing of many fecal samples--especially those of personnel handling food, which requires the simultaneous testing of many samples.