Development of a molecular diagnostic test for the specific detection of Brettanomyces bruxellensis in red wine

Brettanomyces bruxellensis is considered the main source of spoilage in red wine. This yeast, by producing volatile phenols, is responsible for the development of unpleasant aromas affecting the quality of final products and resulting in substantial economic losses for wine producers. This work therefore describes the development of an easy to-use colorimetric molecular diagnostic test for the rapid and specific detection of B. bruxellensis in wine. Detection was achieved using a sandwich hybridization format in which the target RNA was recognized by an immobilized DNA capture probe and a labelled DNA signal probe. The proposed device was highly specific to B. bruxellensis and showed a linear relationship between measured signal and target RNA concentration in the range 0.1-5 ng μL^-1, with a limit of detection value of 0.1 ng μL^-1 of total RNA. The colorimetric assay was validated on red wine samples, with a detection limit of 10² CFU mL^-1. This study suggests that the reported method could be used for early detection of spoilage yeasts in wine and other alcoholic beverages.