Control of Brettanomyces bruxellensis on wine grapes by post-harvest treatments with electrolyzed water, ozonated water and gaseous ozone

In this study, we investigated the possible effect of electrolyzed water (EW), aqueous ozone (WO) and gaseous ozone (GO) on Brettanomyces bruxellensis DSM 7001 strain artificially inoculated on the grape surface and on its evolution during the subsequent, inoculated must fermentation. Culture-dependent and -independent techniques were used to evaluate the effectiveness of treatments against B. bruxellensis, as well as its presence during fermentation. Particularly, GO treatment of 24 h decreased its presence by about 2.1 Log, making it possible to reduce significantly the concentration of ethylphenols in the wine in relation to the control wine. EW and WO treatments caused less relevant reductions. The results showed that all the treatments reduced the presence of this yeast on grapes. However, in these experimental conditions it was not possible to achieve a complete removal of this undesirable yeast. Industrial Relevance: Brettanomyces spp. is considered a wine spoilage yeast due to its ability to produce off-flavors (described as Brett character) and high levels of acetic acid. Broad disinfectant action against microorganisms, eco-friendliness and easiness of on-site application are among the main advantages of the ozone and the electrolyzed water. This study demonstrated the antimicrobial potential of the EW, WO and GO treatments against B. bruxellensis inoculated on post-harvest grapes.