Presenter: Gudrun Vogeser, PIKA Weihenstephan GmbH, Pfaffenhofen/Ilm, Germany.
During beer production, the growth of several microorganisms can cause spoilage. Well known are some representatives of the genera Lactobacillus and Pediococcus, in addition to anaerobic Megasphaera and Pectinatus species. Different bacteria species inherit different capabilities for spoilage. Besides generating turbidity by growing to high numbers, they may cause off-flavors such as diacetyl, acetic, lactic or propionic acid, hydrogen sulfide, etc. The brewer not only needs to detect these spoilers at a very early stage, but also has to know about their spoilage potential as soon as possible. By application of the PCR method it is possible to receive knowledge about the appearance of a spoiling microorganism at a very early stage and to identify the species. The microbiological flora in different breweries have been monitored with PCR applications, and the data from 2010 and 2011 (as far as available) will be shown. The influence of malt contamination with spoiler organisms on the microbiology in the following brewing process is examined. By comparison of different PCR applications that are commercially available for in-house analytics, an attempt is made to describe from the brewer’s point of view the requirements for the most valuable fast detection system—ease of use, worth of result, and costs.
Gudrun Vogeser is a specialist in microbiology and molecular biology techniques used for the detection of beer- and beverage-spoiling microorganisms. She is founding member and, since 2009, chair of the European Brewery Convention (EBC) Microbiology Committee. She received a diploma in microbiology and finished her Ph.D. thesis in 1992 at the Chair of Brewing Technology at Weihenstephan, Germany. As a post-doc she started working on molecular biology methods to be used for the fast detection of beer-spoiling bacteria, focusing on polymerase chain reaction. After working as a scientist at the Chair of Brewing Technology in Weihenstephan, she founded, in January 2000, the company PIKA Weihenstephan, Pfaffenhofen. The company specializes in serving the brewing industry in microbiological analytics, both with diagnostics and products.