Application of a molecular beacon-real-time PCR technology to detect Salmonella species contaminating fruits and vegetables.
An oligonucleotide probe that becomes fluorescent upon hybridization to the target DNA (molecular beacon; MB) was evaluated in a real-time polymerase chain reaction (PCR) assay to detect the presence of Salmonella species. As few as 1-4 colony-forming units (CFU) per PCR reaction could be detected. The capability of the assay to detect Salmonella species from artificially inoculated fresh-cut produce such as cantaloupe, mixed-salad, cilantro, and alfalfa sprouts was demonstrated. A comparison of two commercially available kits utilizing MB-PCR (iQ-Check, Bio-Rad Laboratories) and conventional Association of Official Analytical Chemists (AOAC)-approved PCR (BAX, Dupont Qualicon) was performed on artificially inoculated produce. As few as 4 CFU/25 g of produce were detected after 16 h of enrichment in buffered peptone broth. These assays could be carried out entirely in sealed PCR tubes, enabling a rapid and high-throughput detection of Salmonella species in a large number of food and environmental samples. This is the first report of the application of MB probe being used for real-time detection of Salmonella species in whole and fresh-cut fruits and vegetables.
Liming
Samantha Hu
SH
Produce Quality and Safety Laboratory, Henry A. Wallace Beltsville Agricultural Research Center, Agricultural Research Service, USDA, 10300 Baltimore Avenue, Building 002, Room 117, BARC-W, Beltsville, MD 20705-2350, USA.
Bhagwat
Arvind A
AA
D015169:Colony Count, Microbial; D005453:Fluorescence; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D005638:Fruit / Q000382:microbiology*; D005798:Genes, Bacterial; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction / Q000379:methods*; D012475:Salmonella / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D014675:Vegetables / Q000382:microbiology*
D015345:Oligonucleotide Probes