Storage Stability of Brettanomyces bruxellensis-Spoiled Pinot Noir After UV-C Treatment

The application of ultraviolet-C (UV-C) light has emerged as a promising non-thermal alternative to chemical preservatives in winemaking. This study investigates the efficacy of UV-C treatment on the microbial stability of Pinot noir wine during a 12-week storage period at 20 °C, with a focus on the spoilage yeast Brettanomyces bruxellensis. Microbiological analysis demonstrated complete and sustained inactivation of 10⁵ CFU/mL Brettanomyces bruxellensis after UV-C treatment with no detectable regrowth during the 12-week storage period. Untreated wine showed 1-log increase in Brettanomyces bruxellensis during the 12-week storage period and significant production of volatile esters and 4-ethylguaiacol. At the same time, a significant reduction in coumaric acid concentration was determined and attributed to Brettanomyces bruxellensis metabolism. UV-C-treated wine showed marginal increases in 4-ethylguaiacol attributed to the residual activity of Brettanomyces bruxellensis after UV-C treatment. Volatile esters did not significantly change during the 12-week storage period. The findings of this study demonstrate that UV-C treatment can ensure the microbiological storage stability of red wine.