Characterization of Aspergillus species associated with dried cocoa beans in Peninsular Malaysia

Cocoa ( Theobroma cacao ) is a key agricultural commodity that is highly susceptible to fungal and mycotoxin contamination, particularly during post-harvest processes such as fermentation, drying, and storage. This study aimed to characterize Aspergillus species associated with dried cocoa beans from 12 farms across six states in Peninsular Malaysia using morphological, molecular, phylogenetic, and toxigenicity analyses. Fungal isolation and enumeration were performed, followed by identification based on morphological characteristics, DNA sequencing, and phylogenetic analysis targeting the internal transcribed spacer (ITS) region and β-tubulin ( tub2 ) gene. Mycotoxin-producing potential was assessed using coconut cream agar (CCA), where fluorescence under ultraviolet (UV) light indicated the presence of secondary metabolites. A total of 43 Aspergillus isolates were identified as A. flavus (10 isolates), A. niger (nine isolates), A. tamarii (nine isolates), A. tubingensis (eight isolates), and A. aculeatus (seven isolates). One sample exceeded the hygienic threshold, with a fungal load of 2.9 × 10⁵ CFU/g, surpassing the permissible limit of 1 × 10⁴ CFU/g. All isolates exhibited fluorescence, indicating potential mycotoxin production. Moderate fluorescence intensity was observed exclusively in A. niger , while all other species showed low fluorescence levels. These findings underscore the importance of improved post-harvest handling practices to mitigate fungal contamination and mycotoxin risks. The results offer valuable insights for enhancing food safety, supporting cocoa trade, and informing agricultural policy in cocoa-producing regions.