Development and evaluation of ITS- and aflP-based LAMP assays for rapid detection of Aspergillus flavus in food samples

Aspergillus flavus is a common filamentous fungus that produces aflatoxins and presents a major threat to agriculture and human health. Previous studies focused mainly on the detection of A. flavus or aflatoxin separately. Here, we developed internal transcribed spacer (ITS)- and aflP-based rapid detection of A. flavus in food samples using the loop-mediated isothermal amplification (LAMP) method. The ITS1-5.8S-ITS2 rDNA region of A. flavus and the aflatoxin-encoding gene aflP were used as target regions. The detection limits of A. flavus and aflP were 10 fg and 1 pg pure DNA, respectively, which allows aflatoxin-contaminated samples to be differentiated from infected samples and reduces false-negative or false-positive results. For specificity testing, DNA extracted from 7 A. flavus, 5 different Aspergillus spp., and 21 other fungi were used, and our results showed that A. flavus strains are detected by ITS-based detection and aflatoxigenic A. flavus strains are detected by aflP-based detection. Furthermore, the ITS-and aflP-based LAMP assays were used for detection analysis of DNA from food samples artificially and naturally contaminated with A. flavus. Our results showed that the detection rate of A. flavus based on the multi-ITS-based LAMP detection is 100% and that the aflatoxigenic strains in all A. flavus are detected by the aflP-based LAMP assay. The LAMP protocol described in our study represents a rapid and highly specific and sensitive diagnostic method for A. flavus detection, which can be used as a diagnostic tool that simplifies A. flavus monitoring and guarantees the quality and safety of foods.