No abstract

Listeria monocytogenes is a major foodborne pathogen of global health concern. Herein, the rapid diagnosis of L. monocytogenes has been achieved using loop-mediated isothermal amplification (LAMP) based on the phosphatidylcholine-phospholipase C gene (plcB). Colorimetric detection was then performed through the formation of DNA concatemers and a gold nanoparticle/DNA probe complex (GNP/DNA probe). The overall detection process was accomplished within approximately 1 h with no need for complicated equipment. The limits of detection for L. monocytogenes in the forms of purified genomic DNA and pure culture were 800 fg and 2.82 CFU mL−1, respectively. No cross reactions were observed from closely related bacteria species. The LAMP-GNP/DNA probe assay was applied to the detection of 200 raw chicken meat samples and compared to routine standard methods. The data revealed that the specificity, sensitivity, and accuracy were 100, 90.20, and 97.50%, respectively. The present assay was 100% in conformity with LAMP-agarose gel electrophoresis assay. Five samples that were negative by both assays appeared to have the pathogen at below the level of detection. The assay can be applied as a rapid direct screening method for L. monocytogenes.

A rapid and specific, hly-based, loop-mediated isothermal amplification (LAMP) was applied for the detection of Listeria monocytogenes in food and food products, using a real-time turbidimeter platform (LAMP-turbidity). The principle behind this method relies on an increase in a DNA yield, which correlates with the production of magnesium pyrophosphate, and the results can be determined via an amplification curve within 1 h. The specificity test revealed that L. monocytogenes (DMST 17303) was observed from 34.1 to 38.3 min, while thirty strains of non-L. monocytogenes demonstrated no crossreactions. The limits of detection for purified genomic DNA and pure culture were 800 pg mL À1 and 2.82Â 10 3 CFU mL À1 , respectively. Investigation on 200 raw chicken meat samples indicated that the specificity, sensitivity, and accuracy of LAMP-turbidity were 100%, 62.75%, and 90.50%, respectively.These data suggest that an hly-based, real-time, quantitative LAMP-turbidity assay can be an applicable tool for the epidemiological screening of L. monocytogenes in food and food products.

No abstract