The role of processing on ochratoxin A content in Italian must and wine: a study on naturally contaminated grapes.

Available data show that ochratoxin A (OTA) is a possible contaminant of wine and its concentration is higher in red wines than in white and rose. The aim of this work was to study the fate of OTA during the main stages of the winemaking process (crushing, maceration, alcoholic fermentation, malo-lactic fermentation, bottle-aging) and the influence of technological treatments on OTA concentration in order to identify the critical process steps. Attention was focused on red winemaking, in different wineries in the south of Italy, with two naturally OTA contaminated grape varieties ('Negroamaro' and 'Primitivo') and on different vintages (2001-2002-2003). The results show that no OTA is produced during winemaking, but each operation during winemaking can modify OTA content. The OTA present in grapes to a certain degree is released to the juice during crushing. Maceration increases the OTA content, while alcoholic and malo-lactic fermentation cause a reduction in OTA in the wine.