Routine microbiology with PCR—What’s new?

GUDRUN J. VOGESER (2), Corina R. Nuber (1)
(1) Georg-Simon-Ohm Hochschule Nürnberg, University of Applied Sciences, Nürnberg, Germany; (2) PIKA Weihenstephan GmbH, Pfaffenhofen, Germany

Brewing microbiology is still known to generate results which are available typically way later than desirable for production needs. The traditional analyses are more or less still the same as they were 200 years ago: enrichment and visual inspection for microbial growth. In the past 15 years, different approaches have been made to use molecular biology, mainly detection of genetic material (DNA), for the fast and specific detection of spoiling microorganisms. The results of those analyses such as polymerase chain reaction (PCR) are generally accepted, but the method itself has not yet reached every brewer’s lab. The general opinion is that PCR analysis is too complicated to be used in a mid-sized brewery. This study compares traditional microbiological methods in a brewer’s lab involving conventional enrichment methods with results from real-time PCR. Comparison includes reliability of methods, time from sample to result, as well as practical aspects like handling and cost. A special focus lies on the necessities and possibilities for implementation of PCR analysis into small and medium-sized breweries which require a low-budget system with minimal operator intervention. Examples from PCR applications in small breweries are shown as well as the variation of beer-spoiling microorganisms monitored over some years. The composition of the microbial flora and changes in their composition within particular breweries and beer types are evaluated.

Gudrun Vogeser received a diploma in microbiology from Eberhard Karls University in Tuebingen, Germany, and afterward worked at the Technical University of Munich, Germany, where she finished her doctoral thesis in 1992. She was then employed as a scientist at the Chair of Brewing Technology at TU Munich–Weihenstephan, where she examined the use of molecular biology methods, mainly PCR, to detect and analyze beer-spoiling microorganisms. In 2000 she founded PIKA Weihenstephan, Pfaffenhofen, where she is working as a managing partner. Gudrun is a founding member and, since 2009, chair of the European Brewery Convention (EBC) Microbiology Committee.

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