Occurrence of toxin-producing fungi in intact and rotten table and wine grapes and related influencing factors

The current study investigated mycotoxin-producing fungal contamination of grapes grown in Shaanxi province, China. Intact berries and rotten berries from three table grape cultivars and five wine grape cultivars were tested. A total of 187 isolates were obtained that belonged to seven genera. A total of sixteen isolates, including twelve Aspergillus spp., three Penicillium spp., and one Cladosporium spp. were able to produce ochratoxin A. Seventeen isolates, including four Aspergillus spp. and thirteen Penicillium spp. produced patulin. Three Aspergillus spp. isolates had evidence of aflatoxin B1 production. The occurrence of mycotoxin-producing fungi was mostly observed in Thompson seedless grapes but was also observed in intact grapes and table grapes, as well as rotten and wine grapes. High aerial contamination in vineyards and reducing sugar content in berries was related to high fungal contamination in grapes. Aspergillus sp. and Penicillium sp. found in intact grapes had a high probability of producing toxins.

► Toxigenic fungi were found in both rotten and intact grapes, and more in rotten ones. ► Toxigenic fungi were found in both wine grape cultivars and table grape cultivars. ► Diversity of fungal contamination was significant among different grape cultivars. ► Correlation between fungal contamination and properties of grape berries was found.