Aspergillus spp. and their secondary metabolite production in grape berries from Slovakia

Occurrence of Aspergillus spp. in grapes from Slovak has been surveyed during 2 years, to assess their ability to produce secondary metabolites, in vitro and in berries. A large number of Aspergillus spp., including A. flavus, A. japonicus, A. niger, A. carbonarius and A. Ibericus, have been identified, and strains randomly selected and analysed to verify their potential ability to produce secondary metabolites. A broad spectrum of fungal metabolites has been observed in vitro and have been analysed using HPLC-MS/MS. Aspergillus niger, the most frequently isolated species, produced ochratoxin A (in a range from 104 to 1745 μg L-1) and fumonisin B2 (93 μg L-1). Aspergillus carbonarius produced ochratoxin A in the range 138 to 2031 μg L-1. Ochratoxin A and fumonisins were not detected in grape berries. Other secondary metabolites, including emodin, 3- nitropropionic acid, kojic acid and malformin C, were also detected at different concentrations in berries, but their occurrence was dependant on the geographic area of origin and on the year of berry collection.