Maher, K., Stone Brewing, Escondido, CA, USA and Kahle, K., Invisible Sentinel, Philadelphia, PA, USA
Poster
A major challenge in maintaining beer quality is early detection of spoilage microorganisms before they have the ability to produce unintended flavors and aromas. Spoilage organisms can be diverse and present different quality risks based on their potential to thrive in beer and in the brewery. Early detection coupled with risk-based analyses can provide invaluable information to quality-centric brewers. A novel molecular diagnostic assay, Veriflow® brewPAL, was developed to provide accurate and sensitive detection of beer-spoiling Pediococcus and Lactobacillus species in under 3 hr. In this study, Veriflow® brewPAL technology was used to assess bacterial growth in beers having diverse properties. Numerous factors may influence the ability of Lactobacillus and Pediococcus species to metabolize and affect the quality of beer, including levels of hop resistance genes in bacterial isolates and percent ABV, IBU, gravity, malt builds and respective substrates in beer formulations. The effects of these factors on Lactobacillus and Pediococcus growth were evaluated with the ultimate goal of developing a comprehensive, validated model for beer spoilage risk assessment that could be used by breweries to preserve the quality and, therefore, the taste and value of the beer they produce. Lactobacillus and Pediococcus strains were isolated from different locations within a brewery setting. Each isolate was genetically characterized to determine strain identity and the hop resistance gene profile. Following characterization, select strains were grown in beers having distinct properties in order to determine the factors that are major predictors of spoilage risk. Bacterial growth in each beer was measured and quantified using the Veriflow® brewPAL system to determine overall risk of spoilage, which was subsequently correlated to the properties specific to each beer. While ABV and IBU are important factors that can influence the risk of beer spoilage, the results of these studies revealed additional properties are strong modulators of bacterial growth, including the utilization of specialty malts. These findings can be used as a guide to help predict whether conditions within a particular beer are favorable for rapid bacterial growth and subsequent spoilage, thereby providing brewers with the ability to make early and informed decisions to maintain the quality of their products.
Kelly Maher was born and raised on Long Island, NY. She graduated from Northeastern University with a B.S. degree in biology in 2012. She has been working in quality and product development for five years. Her love of craft beer came from her time working at Sam Adams, and her love of quality assurance came from her work at Estee Lauder Companies.
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