DETECTION OF SALMONELLA CELLS WITHIN 24 TO 26 HOURS IN POULTRY SAMPLES WITH THE POLYMERASE-CHAIN-REACTION BAX SYSTEM

BAX, a commercial polymerase chain reaction-based system, was evaluate d to determine the efficacy of the system with different concentration s of Salmonella cells in mixed cultures and compared to conventional m ethods for detection of inoculated Salmonella cells from poultry sampl es. When present in enrichment broths at levels of 10(5), 10(4), and 1 0(3) CFU/ml, Salmonella cells were detected in 100, 93, and 41% of sam ples, respectively Salmonella cells were detected in 23 of 150 (15%) p rocessed chicken rinse samples with the BAX system compared to 18 of 1 50 (12%) samples with conventional methods. Salmonella cells were dete cted in 28 of 50 (56%) ground turkey samples with the BAX system compa red to 25 of 50 (50%) samples with conventional methods. Overall there was a 97% method agreement. One false-negative and two false-positive results were obtained with the BAX. Band sizes and intensity of the p olymerase chain reaction product were shown to be correlated with esti mated numbers of Salmonella CFU present in the enriched and inoculated samples. The assay was able to detect 10(4) Salmonella CFU/ml of enri chment medium, which allows consistent detection of Salmonella cells w ithin 24 to 26 h. The high degree of sensitivity and specificity of th e BAX system make it a reliable alternative to conventional bacterial cultural methods.