Αξιολόγηση κινδύνου επιμόλυνσης αμπελοοινικών προϊόντων με ωχρατοξίνη Α και διερεύνηση δυνατότητας διάσπασης ή απορρόφησης της από ζύμες

Abstract

Ochratoxin A (OTA) is a mycotoxin produced by several fungi (Penicillium and Aspergillus species) with carcinogenic, nephrotoxic, teratogenic, immunotoxic and possibly neurotoxic properties. It has also been associated with nephropathy in humans. The Commission Regulation (EC) No 1881/2006 set the maximum limit of the amount of OTA in wine and must at 2.0 ppb (μg/kg). In this study, we investigated the contamination of Cyprus red wines and samples of commandaria with OTA. Furthermore, we investigated the presence of OTA in musts from two grape varieties, Maratheftiko and Cabernet sauvignon after application of three fungicides and two biocontrol agents (two isolates of the yeast Aureobasidium pullulans) under field conditions. Additionally, we investigated the potential of degradation or adsorption of OTA by yeast cells belonging to the species Saccharomyces cerevisiae and Aureobasidium pullulans. OTA production by Aspergillus isolates from Cyprus grapes (season 2010) was also investigated by liquid chromatography (HPLC) since it is known that fungi belonging to the genus Aspergillus spp. are responsible for the production of OTA in must and wine. The results of this study showed that the wine samples tested were negative for the presence of OTA as well as the must samples from two grape varieties, Maratheftiko and Cabernet sauvignon. Furthermore, some of the yeasts that were tested were able to absorb OTA on their cells but none of the isolates tested could break down the toxin. HPLC analysis revealed that from the 161 Aspergillus isolates, two species were able to produce OTA, the Aspergillus carbonarius (1 isolate) and Aspergillus tubingensis (16 positive isolates out of 148). Interestingly enough, none of the Aspergillus niger isolates (12 isolates) was able to produce OTA. The results of this work show that the tested Cyprus wines and the grape must from Maratheftiko and Cabernet sauvignon were OTA free, at least for the regions that the samples were collected. This study does not reflect all the wine-producing regions of Cyprus since the samples of the survey originated from 4 regions of Limassol district. However, we gained valuable information about the status of the OTA problem for the vineyards and wine of Cyprus. The results of this study are particularly interesting given that the contamination of red wine with OTA is a major problem in almost all countries of the Mediterranean basin.