Novel TaqMan® real-time PCR targeting invJ gene for 8-h detection of Salmonella from food matrices

<i>Salmonella</i>, a well-known food-borne zoonotic pathogen, is the causative agent of Salmonellosis affecting public health in both developed and developing countries. Traditional <i>Salmonella</i> detection methods are time-consuming, involving multiple steps like pre-enrichment, selective plating, and biochemical confirmation. In this study, a faster and sensitive TaqMan^® real-time PCR assay was developed with a 6 h enrichment paradigm for the direct detection of <i>Salmonella</i> from food matrices using a novel target gene, <i>invJ</i>, which is part of the <i>Salmonella</i> Type 3 Secretion System (T3SS). The assay was found to be highly specific and had a limit of detection of 10² CFU/mL <i>Salmonella</i> in pure culture. With a 6-h enrichment step, the assay was able to detect even low bacterial inoculum like 10⁰ CFU/mL of <i>S.</i> Typhimurium in both artificially contaminated raw foods (raw egg and frozen chicken) and cooked Indian food matrices (ready-to-eat chicken biriyani and chicken pulao). The assay demonstrated 100% relative sensitivity, specificity, and accuracy across 52 natural (raw and processed) food samples. In summary, the real-time <i>Salmonella</i> detection method developed is faster, specific, sensitive and a potential tool for regular <i>Salmonella</i> monitoring in diverse food matrices within 8 h.