A rapid and colorimetric loop-mediated isothermal amplification (LAMP) based on HRP-mimicking molecular beacon for the detection of major 6 Listeria species in enoki mushroom

Abstract Since the contamination of Listeria species is considered as a serious problem in public health and food industries, a rapid, accurate, and easy-to-use detection method is highly demanded. The objective of this study is to develop a colorimetric loop-mediated isothermal amplification (cLAMP) assay using a molecular beacon for the rapid and sensitive detection of Listeria species in enoki mushroom. The detection limit of the method optimized at 59.7 °C for 6 Listeria species in buffer was all 1 × 100 CFU/mL, and the cLAMP was confirmed to be specific to 6 major Listeria species. The period required to complete the cLAMP was within 1 h. The cut-off value of the method for the artificially inoculated mushroom samples was 1 × 101 CFU/g. This study suggests that the cLAMP is expected to be used as a point-of-care molecular diagnostic technology because the method does not require any expensive instruments.