Recombinase Polymerase Amplification-Based Assay for Rapid Detection of Listeria monocytogenes in Food Samples

Listeria monocytogenes (L. monocytogenes) is a Gram-positive microbe and is reported to be potentially pathogenic for both humans and animals, exhibiting a high mortality rate of up to 30%. The invention of a fast and sensitive method of point-of-care testing (POCT) is of great significance for the field of food safety of the rapid detection of harmful microbes and prevention of food contaminated by such microbes from reaching the markets. A novel isothermal molecular amplification technique, recombinase polymerase amplification (RPA), has been used to detect L. monocytogenes in food combined with a highly sensitive end determining method, lateral flow dipstick (LFD) technology. RPA-LFD was implemented at 37 degrees C, and amplification only took 20 min. By optimizing the primers and probes, the system had no cross-reaction with seven other pathogens, and it was proven to have a 100 times higher sensitivity (1360 cfu/mL) than a real-time PCR for L. monocytogenes testing. Also, RPA-LFD was applied without complex or expensive equipment, only a thermostatic heater such as the Thermomixer Comfort was required. Thus, RPA-LFD was found to be a solution for POCT for L. monocytogenes, especially for low-resource locations with little available laboratory equipment.