Evaluation of two loop-mediated isothermal amplification methods for the detection of Salmonella Enteritidis and Listeria monocytogenes in artificially contaminated ready-to eat fresh products

Abstract

In the present study, the effectiveness of two loop-mediated isothermal amplification (LAMP) assays was evaluated. Samples of romaine lettuce, strawberries, cherry tomatoes, green onions and sour berries were inoculated with known dilutions (10⁰-10⁸ CFU/g of product) of <em>S.</em> Enteritidis and <em>L. monocytogenes</em>. With LAMP, assay pathogens can be detected in less than 60 min. The limits of detection of <em>S.</em> Enteritidis and <em>L. monocytogenes</em> depended on the food sample tested and on the presence of enrichment step. After enrichment steps, all food samples were found positive even at low initial pathogen levels. The developed LAMP assays are expected to become a valuable, robust, innovative, powerful, cheap and fast monitoring tool, which can be extensively used for routine analysis, and screening of contaminated foods by the food industry and the Public Food Health Authorities.