Contamination of freshly harvested Bambara groundnut (Vigna subterranea) seed from Mpumalanga, South Africa, with mycotoxigenic fungi

Abstract

Freshly harvested Bambara groundnut (BGN) is occasionally consumed raw and can potentially become infected with mycotoxingenic field fungi. In this study, BGN samples were obtained from 12 farms in three districts of Mpumalanga in South Africa. Eight pooled samples were screened for multi-mycotoxin contamination using Ultra Performance Liquid-Chromatography tandem mass spectrometry (UPLC-MS/MS). To identify mycoflora, 12 samples were screened using conventional and molecular methods. Selected potential mycotoxin producing isolates were screened for mycotoxins using UPLC-MS/MS. No mycotoxins were detected on the freshly harvested BGN samples, but they were infected with various mycotoxin producing fungal species namely Aspergillus flavus (50%), Penicillium citrinum (25%), Penicillium oxalicum (17%), Penicillium citreoviridin (0.8%), and Fusarium verticillioides (0.8%). Following screening of selected fungal cultures, aflatoxin B 1 (0.4, 0.45 and 0.4 ppm) and fumonisin B 1 (0.7 ppm) were detected from A. flavus and F. verticillioides, respectively. Identification of mycotoxigenic fungi on freshly harvested BGN presents a potential health risk.