Abstract Sanelle van WykFilipa V. M. Silva

New Impedance Method Reduces the Enumeration Time of Brettanomyces Yeast Contamination in Red Wine

Sanelle van Wyk* and Filipa V. M. Silva 
*Department of Chemical and Materials Engineering, University of Auckland, 20 Symonds Street, 1010, New Zealand (svan508@aucklanduni.ac.nz)

Brettanomyces yeasts are a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties with subsequent economic losses. Red wines are most often afflicted with this type of spoilage. Currently, the industry employs time-consuming plate counting to detect and monitor Brettanomyces bruxellensis contamination in wines. B. bruxellensis, a fastidious, slow-growing or-ganism, requires five days or more of incubation for visible growth on agar plates. Consequently, a need exists to develop a quicker, feasible method to detect and monitor this yeast. The aim of this study was therefore to determine the feasibility of using “direct” and “indirect” impedance methods to detect and enumerate B. bruxellensis in red wine. A reduction in incubation time from 120 hr down to 0.8 or 57.7 hr for samples with 4.2 × 107 or 1.8 × 102 cfu/mL, respectively, was achieved using the impedance methods. The “indirect” method proved more suitable than the “direct” method, offering faster detection times for a comparable level of accuracy. Overall, the “indirect” impedance method is a viable alternative to plate counting to detect and enumerate Brettanomyces contamination in the wine industry. Impedance technology decreases preparation and incubation times,thereby increasing throughput, reducing economic risk, and decreasing the chance of sample contamination.

Funding Support: University of Auckland