New Microbiological Approach to Reduce Ochratoxin Levels in Alcoholic Beverages  Andrea Caridi 1  , Antonio Cufari 1 , Fabio Galvano 1 , Marco Geria 1 ,Santo Postorino 1 , Alessio Tafuri 2 and Alberto Ritieni 2 1 Dipartimento di Scienze e Tecnologie Agro-Forestali e Ambientali (STAFA), Università Mediterranea di Reggio Calabria, Piazza San Francesco 7, I-89061 Gallina (RC), Italia 2 Dipartimento di Scienza degli Alimenti, Università Federico II di Napoli, Parco Gussone ed. 84, I-80055 Portici (NA), Italia Summary The biodiversity of 20 strains of Saccharomyces cerevisiae, selected for winemaking, with respect to their capacity to remove ochratoxin A (OTA) in vitro was studied. The strains were chosen regarding their different aptitude to adsorb phenolics using a simple method for screening yeasts in Petri dishes. A weighed quantity (40-60 mg) of fresh biomass of each strain was placed in triplicate in test tubes containing 10 mL of physiological sterile saline and 1.1 ng of OTA/mL. Toxin was assayed in the supernatants after 15 days. The amount of bound toxin was calculated by subtracting the amount of toxin in experimental tubes from the amount found in control tubes. The binding capacity of the yeasts varied from 0 to 1.1 ng of OTA and was directly correlated with the strain ability to adsorb phenolics. Key words: adsorption, alcoholic beverages, ochratoxin, Saccharomyces cerevisiae Introduction Ochratoxin A (OTA) is a potently nephrotoxic, carcinogenic, teratogenic, and immunotoxic mycotoxin, that frequently contaminates various foods and beverages and poses serious threats to the human health. Different approaches to the risk assessment of OTA in diverse jurisdictions leaded to variable estimations of the tolerable daily intakes (1). In 1996, the Joint Expert Committee on Food Additives of the World Health Organization and the Food and Agriculture Organization, on the basis of the nephrotoxicity of OTA, proposed a provisional tolerable daily intake of 14 ng/kg bw (2). More cautious values (5 ng/kg bw) have been purposed by the Working Group of the Nordic Council of Ministers (3) and by the European Commission (4) whereas the Canadian authority purposed an OTA tolerable daily intake in the range 1.2-5.7 ng/kg bw (5). Available data (Table 1) regarding the presence of OTA in alcoholic beverages and in their substrata are discordant (6-20). In alcoholic beverages OTA is formed prior to the alcoholic fermentation (10), during which OTA is partially removed or degraded (21,22). It is interesting to note that the decrease is strain-dependent (23). OTA occurrence in wines is related to the growth of Aspergillus carbonarius and other black Aspergilli on grapes during cultivation (8,20). Recently (24) it has been demonstrated by plate assay that Bacillus thuringiensis has the potential to inhibit the growth of several filamentous fungi associated with the spoilage of grapes (Botrytis cinerea) and ochratoxin A production on grapes (A. carbonarius).  Corresponding author; Phone. ++39 0965 682 816; Fax: ++39 0965 680 727; E-mail: acaridi@unirc.it  This paper was presented at the 19 th International ICFMH Symposium FoodMicro2004 in Portorož, Slovenia, September 12-16, 2004