A rapid monoclonal antibody-based direct immunoassay and a lateral-flow device for on-site sensitive analysis of the mycotoxin alternariol

Alternariol is an emerging mycotoxin that may be present in many foods at relatively high concentrations. Therefore, sensitive analytical methods are needed to reduce human exposure to this secondary fungal metabolite. The aim of the present study was to develop alternative immunochemical methods for the rapid analysis of alternariol using novel homemade monoclonal antibodies. In this study, a direct competitive enzyme-linked immunosorbent assay for alternariol is reported for the first time, with an IC50 value and a detection limit of 0.020 ng/mL and 0.004 ng/mL, respectively. Under the optimized immunoassay conditions, alternariol could be accurately and precisely quantified in fruit juice samples in only 25 min. In addition, a nanoparticle-based lateral-flow immunochromatography assay with an IC50 value and a visual detection limit of 0.24 ng/mL and 1 ng/mL, respectively, was developed. This immunoassay was validated according to European guidelines for portable semiquantitative analytical methods. Thus, juice samples with alternariol levels above 4 ng/mL were detected by this rapid method in only 15 min, with a negligible false suspect rate.