Ochratoxin A production by Aspergillus carbonarius on some grape varieties grown in Italy

Fungi responsible for the presence of Ochratoxin A (OTA) in grapes have been identified as belonging to the black aspergilli, Aspergillus section Nigri, among which Aspergillus carbonarius is the main producer. Despite the widespread occurrence of OTA in various types of wine, there is no specific information on the ability of black aspergilli to infect berries and to produce OTA in different grape varieties. The aim of this study was to investigate the susceptibility to A. carbonarius of twelve grape varieties representative of a wide range of characteristics, including geographical distribution. In all the conditions of berry status (intact and damaged) and temperature (20 and 25 degrees C) tested, the incidence of colonised berries and their OTA contents were always low in 'Bianco d'Alessano', 'Pampanuto' and 'Uva di Troia'. In contrast, 'Cabernet Sauvignon', 'Trebbiano' and 'Verdeca' showed high fungal incidence and OTA content. The information gathered is relevant for defining risk factors for OTA presence in grapes, even if these data need to be confirmed by observations in vineyards.