Contaminated Perry in Patagonia Argentina: A Case Study

Perry is a beverage obtained by fermentation of pear juice, popular in the North Hemisphere. In Argentina it is an emerging market, particularly in the Patagonian region. The aim of this work is to describe and to evaluate the spoilage yeasts associated to six perry samples showing signs of microbiological contamination from a local craft perry company in North Patagonian region. Eighteen yeasts were isolated from four of the six perry samples where Brettanomyces custersianus, Brettanomyces bruxellensis and Zygosaccharomyces parabailii were identified. The growth capacity of these isolates in the presence of antimicrobial agents (sulfite and potassium sorbate) was analyzed in solid media. Growth parameters in sterile perry must was evaluated and the production of undesirable compounds were evaluated, products were characterized in terms of their aromatic and physicochemical features. The yeasts Z. parabailii NPCC1791 was able to grow on plates containing sulfite concentrations of up to 4 mM and produced high methanol concentrations in perry. Additionally, B. bruxellensis NPPC1792 was able to produce methanol as well as high concentrations of volatile phenols including 4-ethylphenol and 4-ethylguaiacol. These results demonstrate the potential of these species as perry contaminants. Given the lack of studies describing the contaminating yeasts in perry production, this work represents the first report about perry spoilage yeasts in Argentina, with this knowledge, control strategies can be developed to prevent microbiological contamination and minimize product loss.