Sanelle van Wyk* and Filipa V. M. Silva 
*Department of Chemical and Materials Engineering, University of Auckland, 20 Symonds Street, Auckland, New Zealand (svan508@aucklanduni.ac.nz)

Brettanomyces bruxellensis is a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties and economic losses. Sulfur dioxide is currently the preferred method for wine preservation. However, due to its negative effects on consumers, new, alternative, non-thermal technologies are increasingly being investigated. Therefore, in this study, high-pressure processing (HPP) technology was used to treat different types of table wines. The effects of HPP pressure, yeast strain, alcohol content and pH on inactivation of B. bruxellensis were also determined. Additionally, the inactivation kinetics were modelled. Processing at 200 MPa for 3 min resulted in 5.8 log reductions. To achieve high throughput in the wine industry, HPP of 400 MPa for 5 sec (>6 log reduction) is recommended to inactivate B. bruxellensis. It was also found that yeast strain influenced HPP inactivation, with AWRI 1499 being the most resistant strain among three investigated. Wine type affected B. bruxellensis inactivation, with 200 MPa for 60 sec leading to log reductions ranging from 1.12 ± 0.01 (Dolcetto Syrah) to 5.05 ± 0.07 (Rosé). Alcohol concentration above 12.0% v/v had a significant effect on Brettanomyces inactivation increasing inactivation from 3.05 ± 0.08 (12% v/v) to 4.23 ± 0.05 (14% v/v) after 200 MPa for 180 sec. The Weibull model successfully described the non-linear HPP inactivation of Brettanomyces in different wines. HPP is a viable alternative for inactivation of B. bruxellensis in wine, with the potential to reduce the industry’s reliance on sulfur dioxide.

Funding Support: University of Auckland