Rapid Identification of Wine Spoilage Organisms

The scope of this project was to systematically analyze all enologically important organisms in the UC Davis wine microorganism collection for correctness of identification, and to create new differential media and a rapid method for identification of spoilage organisms in commercial wine production. During the first part of this project, the MEDI gas chromatography system has been completely set up including all necessary hardware and software upgrades. A variety of wine yeasts was selected and cultured under highly reproducible conditions followed by extraction and fatty acid profiling. The profiling has started on the genus level and the system was tested with Saccharomyces and Kloeckera, Pichia and Schizosaccharomyces strains. Due to the lack of wine-related yeast entries in the MIDI databases, the establishment of a special series of profiles based on cultures from the Department of Viticulture and Enology’s wine yeast collection was initiated. At this point, the system is able to produce well resolved fatty acids peaks that are recognized by the identification software, while the optimization of the cultivation and extraction techniques continues. The project has been part of the on-going long-term research program “Analysis of Saccharomyces during Normal and Problem Fermentations”. In addition to metabolic fatty acid profiling of wine yeast, the MEDI-based identifications will serve as a validation tool for concurrent PCR-based identifications