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.
Abstract
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.
S�ntesis
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
