Occurrence of ochratoxin A in wine and ochratoxigenic mycoflora in grapes and dried vine fruits in South America

Abstract

Grape and wine production in South America represents about 6.6% and 10% respectively of the world grape and wine production. The available information on the ochratoxigenic mycoflora and ochratoxin A (OTA) presence in wine grapes, wines, grape juices and dried vine fruits is limited. Surveys have been carried out in Argentina and Brazil which showed that Aspergillus niger aggregate are predominant in the Argentinean varieties while from the Brazilian varieties the species A. niger, Aspergillus ochraceus and Aspergillus carbonarius were isolated. A mycobiota survey from wine grapes in Argentina showed that while Alternaria alternata was predominant, Aspergillus section Nigri species were isolated from 60% of samples. About 41% of black Aspergilli isolates produced OTA with levels ranging from 2 to 24.5 ng mL(-1). In another study, about 83% of A. carbonarius isolates from dried vine fruits produced OTA, with levels ranging from 2 to 5200 ng mL(-1). A survey of grape juices and wines of Brazilian, Argentinean and Chilean origin were found to contain very low levels of OTA. Studies are in progress in Latin America on the ecophysiology of ochratoxigenic fungi and OTA occurrence to reduce the impact of this toxin in the food chain.