Detection of salmonella by flow-through immunocapture real-time PCR in selected foods within 8 hours.
This study investigated flow-through immunocapture (FTI), using the Pathatrix device, followed by plating on xylose lysine desoxycholate (XLD) agar (FTI-XLD) or analysis by real-time PCR (FTI-PCR) for the detection of Salmonella on smooth tomato surfaces and in potato salad and ground beef within 8 h. Food samples were inoculated with an appropriate dilution of a five-serovar Salmonella cocktail and enriched for 5 h. Following enrichment, samples were analyzed by the FTI-XLD and FTI-PCR methods. Food samples were also analyzed by a modified U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) Salmonella culture method for comparison. Salmonella inoculated at 10(0) CFU per tomato or 10(0) CFU/25 g was detected by the FTI-XLD method in 6, 8, and 4 of 10 samples for tomatoes, potato salad, and ground beef, respectively. Salmonella inoculated at 10(0) CFU per tomato or 10(0) CFU/25 g was detected by the FTI-PCR method in 8, 9, and 9 of 10 samples for tomatoes, potato salad, and ground beef, respectively. The FTI-PCR method achieved significantly higher (P < 0.05) detection of Salmonella on tomatoes, whereas the FTI-XLD method achieved significantly lower (P < 0.05) detection of Salmonella in ground beef when compared with the modified BAM Salmonella culture method; however, all other comparisons to the modified BAM method were not significantly different. The FTI-XLD method demonstrated the ability to isolate presumptive Salmonella colonies up to 48 hfaster than did the modified BAM Salmonella culture method.
Warren
Benjamin R
BR
ConAgra Foods, Incorporated, Six ConAgra Drive 6-350, Omaha, Nebraska 68102, USA.
Yuk
Hyun-Gyun
HG
Schneider
Keith R
KR
D001431:Bacteriological Techniques / Q000379:methods*; D015169:Colony Count, Microbial; D004269:DNA, Bacterial / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D018551:Solanum lycopersicum / Q000382:microbiology; D008461:Meat Products / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods*; D015203:Reproducibility of Results; D012475:Salmonella / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D011198:Solanum tuberosum / Q000382:microbiology; D013997:Time Factors
D004269:DNA, Bacterial