An in vitro and in vivo evaluation of peroxyacetic acid as an alternative sanitizer for wine barrels

Peroxyacetic acid is a common sanitizer used in the food and wine industry, but its use as a sanitizer for wine barrels has not been reported. We are reporting the findings for in vitro studies using three different concentrations of peroxyacetic acid (0, 60, and 120 mg/L) as sanitization challenges against seven strains of wine spoilage yeast representing three different species: Dekkera /Brettanomyces bruxellensis (three strains), Saccharomyces cerevisiae (three strains) and Zygosaccharomyces bailii (one strain). In vitro sensitivity to peroxyacetic acid concentration varied within and between species. A post hoc study (in vivo ) using the highest concentration from the in vitro studies (120 mg/L) as well as 200 mg/L was performed to validate a sanitization method for wine barrels. Exposure of barrels to 200 mg/L of peroxyacetic acid for one week resulted in no detectable levels of wine spoilage microorganisms after treatment. These findings are crucial for establishing protocols to assure the maximum reduction of microbial contaminants.