A Binary Logistic Regression Model as a Tool to Predict Craft Beer Susceptibility to Microbial Spoilage

• Published in: Foods 2021-08, Vol.10 (8), p.1926
• Main Authors: Rodríguez-Saavedra, Magaly, Pérez-Revelo, Karla, Valero, Antonio, Moreno-Arribas, M. Victoria, González de Llano, Dolores
• Format: Article
• Language: English
• Subjects: Alcohol; antimicrobial hurdles; Bacteria; Beer; beer intrinsic factors; Beverages; Bitterness; Breweries; Ethanol; Food science; Goodness of fit; Gram-positive bacteria; growth/no growth; Lactic acid; Lactic acid bacteria; Microorganisms; model development; Parameters; Physicochemical properties; Regression models; Software; Spoilage; spoilage microorganisms; Susceptibility; susceptibility prediction; Variance analysis; Yeast; Yeasts
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods10081926

Beer spoilage caused by microorganisms, which is a major concern for brewers, produces undesirable aromas and flavors in the final product and substantial financial losses. To address this problem, brewers need easy-to-apply tools that inform them of beer susceptibility to the microbial spoilage. In this study, a growth/no growth (G/NG) binary logistic regression model to predict this susceptibility was developed. Values of beer physicochemical parameters such as pH, alcohol content (% ABV), bitterness units (IBU), and yeast-fermentable extract (% YFE) obtained from the analysis of twenty commercially available craft beers were used to prepare 22 adjusted beers at different levels of each parameter studied. These preparations were assigned as a first group of samples, while 17 commercially available beers samples as a second group. The results of G/NG from both groups, after artificially inoculating with one wild yeast and different lactic acid bacteria (LAB) previously adapted to grow in a beer-type beverage, were used to design the model. The developed G/NG model correctly classified 276 of 331 analyzed cases and its predictive ability was 100% in external validation. This G/NG model has good sensitivity and goodness of fit (87% and 83.4%, respectively) and provides the potential to predict craft beer susceptibility to microbial spoilage.