Aspects related to the presence of toxigenic fungi in grapes and ochratoxin A in wines

The infection of grapes by 'black aspergilli' in the field is the main source of ochratoxin A (OTA) in the wine. Aspergillus carbonarius and A. niger fungi are the main producers of this mycotoxin in grapes. They are opportunistic fungi that develop mainly on damaged berries at ripening. The production of OTA in grapes is influenced by climatic conditions, geographical location, grape varieties, crop system, berries damage caused by insets, fungal infection or excessive irrigation and rainfall. Control measures for toxigenic mycoflora in the vineyards must consider these critical control points. OTA in grapes is transferred to wine during vinification and an increase of OTA concentration in must was observed during maceration. The toxin remains stable during wine aging because the same OTA concentration is found in wine after 1 year. Good Agriculture Practices including balanced soil tillage, irrigation, nitrogen fertilization and pruning associated with Good Manufacturing Practices, such as separation of rot bunches helps considerably to reduce OTA-producing fungi and levels of mycotoxin in wine.