title: Validation of iQ-Check E. coli O157:H7 real-time PCR test kit for detection of Escherichia coli O157:H7 in selected foods.
abstract: iQ-Check E. coli O157:H7 (Bio-Rad Laboratories, Hercules, CA) is a real-time PCR kit for detection of E. coli O157:H7 from selected foods. Specific fluorescent oligonucleotide probes are used to detect target DNA during the amplification, by hybridizing to the amplicons. These fluorescent probes are linked to a fluorophore which fluoresces only when hybridized to the target sequence. Three foods (ground beef, apple cider, fresh spinach) were selected to compare the performance of iQ-Check E. coli O157:H7 to the U.S. Department of Agriculture-Food Safety and Inspection Service Microbiology Laboratory Guidebook (MLG) reference method for ground beef and the U.S. Food and Drug Administration/Bacteriological Analytical Manual reference method for apple cider and fresh spinach. Three protocols were tested in this study: a shortened 8 h primary enrichment in buffered peptone water (BPW), a 24 h enrichment in BPW, and an enrichment in appropriate reference method enrichment broth. The iQ-Check E. coli O157:H7 method was able to identify more true/confirmed positive samples than the reference method. Inclusivity and exclusivity rates of the method were 100%. iQ-Check E. coli O157:H7 performed as expected when minor procedural variations were introduced, validating the ruggedness of the method. There was no significant difference observed in performance over the shelf life of the kit.
authors.affiliation: Bio-Rad Laboratories, 2000 Alfred Nobel Dr, Hercules, CA 94564, USA. wendy_lauer@bio-rad.com
authors.forename: Wendy F
authors.initials: WF
authors.lastname: Lauer
authors.forename: Sylvie
authors.initials: S
authors.lastname: Tymciu
authors.forename: Caroline D
authors.initials: CD
authors.lastname: Sidi
authors.forename: Pierre
authors.initials: P
authors.lastname: Sonigo
mesh_terms: D000818:Animals; D002417:Cattle; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D019453:Escherichia coli O157 / Q000737:chemistry* / Q000235:genetics; D005516:Food Microbiology; D027845:Malus / Q000382:microbiology; D008460:Meat / Q000382:microbiology; D012015:Reference Standards; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018724:Spinacia oleracea / Q000382:microbiology
chemical_list: D004269:DNA, Bacterial