OTA-producing fungi isolated from stored cocoa beans

Abstract

The aim of this study was to identify fungal populations in unroasted cocoa beans stored in Spain in order to evaluate the ochratoxin A (OTA)-production ability of certain Aspergillus isolates.Twenty batches of cocoa beans from different origins and with different OTA content were selected for this study. Three Aspergillus carbonarius and 13 Aspergillus niger aggregate strains isolated from these cocoa bean samples were selected to evaluate their OTA synthesis ability, being the only A. carbonarius isolates which are OTA producers [<limit of detection (LOD) = 3520 microg kg(-1) culture medium; LOD = 6 microg kg(-1) culture medium].No correspondence was found between the OTA levels in cocoa beans and the presence of OTA-producing fungi. Nonetheless, some samples contained A. carbonarius with a high OTA-producing ability and, consequently, specific fungal controls should be set up during storage to avoid this toxin.Toxigenic fungi in cocoa beans are not well understood. This study attempted to identify these fungi and evaluate their OTA-producing ability.