Beer-Spoiling Bacteria

The actual frequency of occurrence of particular beer-spoiling bacteria in different beer types and in different areas of the beer production chain is reported in this investigation of 150 samples from the ongoing production of a south German brewery. The recently approved rapid detection system, VIT® Bier plus L. brevis, was used for the detection of beer-spoiling bacteria. This study reveals that the composition of beer types, especially with regard to the level of beer haze as measured in EBC units, has a large impact on the sensitivity of beer to contamination with beer-spoiling bacteria. In particular, the beers with a low level of haze showed higher contamination rates than did the beers with a high level of haze. The study confirms that Lactobacillus brevis is the most frequently occurring beer-spoiling bacterium, regardless of the type of beer. It led to spoilage in all analyzed beer types. Other beer-spoiling bacteria were only detected in the beer type helles, which interestingly contains a low level of haze (18 EBC units). Beer-spoiling bacteria were found in many areas throughout the production process. However, contamination occurred most frequently within the yeast propagation, filtration room, bright beer cellar, and filling area. All other sampled production stages were free of contamination. These results show that weak spots in the production process can be located and that they need to be regularly controlled by using fast and reliable detection systems in order to prevent the spread of beer-spoiling bacteria.

Publikation language: English