Fungal flora and ochratoxin A production during wine grape maturation in French vineyards during three years

Abstract

A survey was conducted in France over three years (2001-2003) in 10 vineyards from four winemaking regions with different geographical locations and climatic conditions. Aspergillus and Penicillium were isolated from the grapes. During 2001 and 2002, from setting to harvest, the total numbers of fungal isolates were respectively 721 and 711 increasing in 2003 to reach 1035. The Aspergillus genus was essentially represented by Nigri section (99%) and was predominant (80% ±4.6) when compared to Penicillium (20% ±4.6). Regardless of sampling year, 32.5% (±σ = 1.26) of the fungal isolates were OTA producers and 93% (±σ = 2.65) belonging to black aspergilli. The ochratoxigenic potential of the isolates and their occurrence on grapes revealed that A. carbonarius was the main OTA producer on French grapes. At harvest time, the fungal population was maximal and this was the most critical period influencing OTA contamination. Grapes from Languedoc-Roussillon region were most infested with ochratoxigenic fungi and had the highest concentrations of OTA. All these results could be of prime importance for further preventive action against ochratoxigenic species in vineyards to limit the contamination of grapes and grape products in France.