Evaluation of Conventional Culture, invA PCR, and the Real-Time PCR iQ-Check Kit as Detection Tools for Salmonella in Naturally Contaminated Premarket and Retail Turkey

• Published in: Journal of food protection 2008-02, Vol.71 (2), p.386-391
• Main Authors: Nde, C.W, Fakhr, M.K, Doetkott, C, Logue, C.M
• Format: Article
• Language: English
• Subjects: Animals; bacterial contamination; Bacterial Proteins; Biological and medical sciences; Colony Count, Microbial - methods; Consumer Product Safety; Culture Media; DNA, Bacterial - analysis; enrichment culture; Food Contamination - analysis; Food industries; Food Microbiology; food pathogens; food processing plants; food safety; Fundamental and applied biological sciences. Psychology; General aspects; genes; Humans; isolation; Meat - microbiology; meat processing; Methods of analysis, processing and quality control, regulation, standards; microbial detection; plate count; polymerase chain reaction; Polymerase Chain Reaction - methods; Reproducibility of Results; retail marketing; Salmonella; Salmonella - isolation & purification; Salmonella Food Poisoning - prevention & control; selective media; Sensitivity and Specificity; turkey meat; turkey processing plant; Turkeys; virulence
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-71.2.386

This study was aimed at comparing the ability of conventional culture, the iQ-Check real-time PCR kit, and invA PCR to detect Salmonella in naturally contaminated premarket and retail turkey parts. Premarket (n = 120) turkey parts collected from a commercial turkey processing plant, and retail turkey parts (n = 138) were examined. Both PCR methods detected a significantly greater (P < 0.05) number of positive samples when compared with the conventional culture method for the premarket turkey parts. The indices of total agreement between the conventional culture method and the iQ-Check kit for the premarket and retail parts were 79.2% (95% CI: 70.8, 86) and 90.6% (95% CI: 84.4, 94.9), respectively. When the conventional culture method was compared with invA PCR for Salmonella detection in the premarket and retail parts, the indices of total agreement were 75.8% (95% CI: 67.2, 83.2) and 84.1% (95% CI: 76.9, 89.7), respectively. The rates of false positives (premarket: 31.9%, retail: 9.7%) and false negatives (premarket: 5.9%, retail: 9.7%) were determined between the culture method and the iQ-Check kit. When invA PCR was compared with the culture method, the rates of false positives (premarket: 37.7%, retail: 11.1%) and false negatives (premarket: 5.9%, retail: 18.3%) were obtained. The higher total agreement and the lower rates of both false positives and false negatives for the iQ-Check kit compared with invA PCR for both premarket and retail turkey parts corroborates the use of the iQ-Check kit as a screening tool for Salmonella in poultry meat.