Merck

Detection of Brettanomyces spp. in red wines using real-time PCR.

Journal of food science (2012-08-23)
Rosanna Tofalo, Maria Schirone, Aldo Corsetti, Giovanna Suzzi
ABSTRACT

The question if the "Brett character" is a favorable wine attribute is one of the most controversial issues and it is currently addressed by many researches. Actually, the presence of Brettanomyces/Dekkera in wine during barrel aging is often associated to detrimental organoleptic characteristics depending on the release of volatile phenols (for example, 4-ethylphenol and 4-ethylguaiacol); for that reason the possibility to rapidly detect the yeast at the early stage of wine production could allow preventive actions to reduce wine spoilage. In this work, 25 and 5 samples from conventional and organic vineyards, respectively, all suspected to be spoiled by Brettanomyces/Dekkera spp., were analyzed using both culture-dependent and culture-independent techniques. In particular, a DNA extraction protocol and a real-time quantitative PCR (qPCR) assay to directly detect and quantify B. bruxellensis were optimized. Results showed that B. bruxellensis was present in 22 of 30 samples, ranging from 10 to 10(4) CFU/mL, lower values being found in organic wines (10 to 10(2) CFU/mL). Overall, qPCR was proved to be a useful and valuable wine control system, since 12 samples were recorded as positive for yeast presence when analyzed by qPCR and negative in case of plate count analyses. Brettanomyces cells were detected using a qPCR method, optimized in this study, which allows to obtain results quickly.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
4-Ethylguaiacol, ≥98%, FCC, FG
Sigma-Aldrich
4-Ethylphenol, 99%
Sigma-Aldrich
4-Ethylphenol, ≥98%, FG
Sigma-Aldrich
4-Ethylphenol, ≥97.0% (GC)
Supelco
4-Ethylphenol, PESTANAL®, analytical standard
Sigma-Aldrich
Guaiacol, oxidation indicator
Sigma-Aldrich
Guaiacol, natural, ≥99%, FG
Supelco
Guaiacol, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
4-Ethylguaiacol, natural, FG