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Bavarian Wheat Beer, an Example of a Special Microbe Habitat Cultivation, Detection, Biofilm Formation, Characterization of Selected Lactic Acid Bacteria Hygiene Indicators and Spoilers - WINNER OF LUDWIG-NARZISS-AWARD 2018
Riedl, R., Goderbauer, P., Brandl, A., Jacob, F. and Hutzler, M.

For the food industry, hygiene conditions within production plants are of high relevance to product quality. Most microbiological quality issues can be traced back to inadequate plant hygiene. In particular, the formation of mature biofilms is highly connected with product spoilage. The formation of biofilms depends on the provision of nutrients and therefore on the product. With a wider range of beer types and beer-like products, new spoilage organisms are becoming relevant. For Bavarian Wheat Beer types, other low-hopped beer types and beer mix beverages, the potential beer-spoiling bacteria Lactobacillus acetotolerans, Lactobacillus rossiae, Lactococcus lactis and Leuconostoc mesenteroides can be critical, either because of the spoilage potential or because of the biofilm formation potential. The majority of strains of the above-mentioned species proved that they could develop biofilms de novo in MRS, which makes them important hygienic indicator germs. An adapted media to detect Bavarian Wheat Beer spoiling bacteria (Wheat Beer media by Hutzler and Riedl (WBM-HR)) was developed. For rapid detection and identification, real-time PCR systems with compatible standard protocols were developed for the specified species. The detection of obligate slow-growing Bavarian Wheat Beer-spoiling species Lactobacillus acetotolerans was modified. The developed methods can be applied to specific contamination tracking and to evaluating the hygiene status of breweries that produce Bavarian Wheat Beer.

Descriptors: Bavarian Wheat Beer spoilage, Lactobacillus rossiae, Lactobacillus acetotolerans, Lactococcus lactis, Leuconostoc mesenteroides

BrewingScience, 70 (January/February 2017), pp. 39-50