Evaluation Study of the Frequency of Different Beer-Spoiling Bacteria Using the VIT Analysis

MBAA TQ vol. 43, no. 1, 2006, pp. 31-35  |  VIEW ARTICLE

Karin Thelen, Dr. Claudia Beimfohr, and Dr. Jiri Snaidr. vermicon AG, Emmy-Noether-Str. 2, 80992 Munich, Germany.

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.

Keywords: beer-spoiling bacteria, gene probes, quality assurance, rapid detection test, VIT

Figure 1 is in color in this online article. 

La frecuencia de ocurrencia de bacterias da�inas (a la cerveza) en diferentes tipos de cerveza y en diferentes sectores del proceso, es dada para 150 muestras de una cervecer�a en el sur de Alemania, utilizando el sistema r�pido de detecci�n VIT-Bier plus L. brevis, reci�n aprobado. El estudio demostr� que la composici�n de la cerveza, especialmente con respecto al nivel de turbieza, tiene un gran impacto sobre la susceptibilidad a la contaminaci�n con bacterias da�inas. Las cervezas con menor turbieza tuvieron una mayor contaminaci�n que aquellas con mayor turbieza. El estudio confirm� que Lactobacillus brevis es la bacteria da�ina m�s frecuente, sin importar el tipo de cerveza; da�� todos los tipos de cerveza analizadas. Otros tipos de bacterias da�inas s�lo fueron detectados en el tipo �helles Bier�, que por cierto ten�a un bajo nivel de turbieza (18 unidades EBC). Se encontr� contaminaci�n con estas bacterias da�inas en muchas �reas del proceso, pero fue m�s frecuente en las �reas de propagaci�n de levadura, en la filtraci�n, la cava de cerveza filtrada y en el envasado. Las otras �reas estaban libres de contaminaci�n. Estos resultados muestran que se pueden detectar puntos d�biles en el proceso productivo y que estos se pueden controlar mediante el uso de sistemas de detecci�n r�pidos y confiables para evitar la propagaci�n de bacterias da�inas a la cerveza.

Palabras claves: bacterias da�inas a cerveza, explorador de genes, aseguramiento de la calidad, prueba de detecci�n r�pida, VIT


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