Wine yeast species show strong inter- and intra-specific variability in their sensitivity to ultraviolet radiation

While the trend in winemaking is toward reducing the inputs and especially sulphites utilization, emerging technologies for the preservation of wine is a relevant topic for the industry. Amongst yeast spoilage in wine, Brettanomyces bruxellensis is undoubtedly the most feared. In this study, UV-C treatment is investigated. This non-thermal technique is widely used for food preservation. A first approach was conducted using a drop-platted system to compare the sensitivity of various strains to UV-C surface treatment. 147 strains distributed amongst fourteen yeast species related to wine environment were assessed for six UV-C doses. An important variability in UV-C response was observed at the interspecific level. Interestingly, cellar resident species, which are mainly associated with wine spoilage, shows higher sensitivity to UV-C than vineyard-resident species. A focus on B. bruxellensis species with 104 screened strains highlighted an important effect of the UV-C, with intra-specific variation. This intra-specific variation was confirmed on 6 strains in liquid red wine by using a homemade pilot. 6624 J.L-1 was enough for a reduction of 5 log(10) of magnitude for 5 upon 6 strains. These results highlight the potential of UV-C utilization against wine yeast spoiler at cellar scale.

Automated summary

The study focuses on the use of UV-C treatment for wine preservation and found that different yeast strains have varied responses to UV-C treatment at the interspecific level. Interestingly, cellar-resident Brettanomyces species were found to be more sensitive to UV-C compared to vineyard-resident species. Intra-specific variation in UV-C sensitivity was also observed, indicating the potential of UV-C utilization against wine yeast spoilage at the cellar scale.