Rapid Detection of Shiga toxin-Producing E. Coli in Animal Origin Foods Using Loop-Mediated Isothermal Amplification (LAMP) Assay

The aim of this study was comparative evaluation of loop-mediated isothermal amplification (LAMP) and polymerase chain reaction (PCR) assay for rapid and inexpensive detection of shiga toxin-producing E. coli in animal origin foods by targeting stx1 and stx2 genes. The LAMP assay was performed using a water bath. The standardized LAMP assay was evaluated on 122 E. coli field isolates obtained from various animal origin food samples to ensure its reliability and usefulness. The result showed that conventional PCR could detect 68 (55.73%) and 75 (61.47%) positive E. coli isolates for stx1 and stx2 genes. Whereas, LAMP showed higher sensitivity by detecting 79 (64.75%) and 87 (71.31%) positive isolates of E. coli for stx1 and stx2 genes, respectively. LAMP assay was found to be highly specific and 10 times more sensitive as it could detect 1.11 × 10 2 cfu/ml for both stx1 and stx2 genes of E. coli isolates, whereas conventional PCR could detect 1.85 x 10 3 cfu/ml for both stx1 and stx2 genes of E. coli isolates. The rapidness, sensitivity, specificity, easiness and cost-effectiveness of LAMP assays will be very useful for the detection of foodborne pathogens for improving food sanitation and maintaining food safety.