New Fast and Innovative Detection of Beer Spoilage Organisms

By: Manuela FabienkeScanbec GmbH and Jvo Siegrist, Microbiology Focus Edition 1.4

Product Manager Microbiology, Sigma-Aldrich…. ivo.siegrist@sial.com

HybriScan® an innovative screening method for beer spoilage organisms based on the detection of rRNA

The popularity of beer remains high but the quality of beer has to be very high to survive in a competitive market. Beer spoilage organisms are either lactic acid bacteria belonging to the genera Lactobacillus and Pediococcus or they are obligate anaerobes of the species Pectinatus and Megasphaera (see table 1). Within the species of lactobacilli known to cause spoilage of beer, only certain strains can grow in the beer and are responsible for spoiling (exception: Lactobacillus lindneri all strains cause spoilage). L. brevis is the most common beer spoilage bacterium followed by L. lindneri [1]. Additionally many wild yeasts are responsible for beer spoilage such as Saccharomyces cerevisiae and Candida pelliculosa [2]. One of the biggest problems is biofilm formation in beer plants, which makes it very difficult to remove spoilage organisms.

Table 1: Species of beer-spoilage microorganisms that can be detected with the HybriScan®D Beer–Kit (Cat. No. 62533 , 96 assays)

 

Highly skilled lab staff perform microbiological analysis in specific quality control laboratories. Most of the laboratories still use conventional standard based cultivation methods, which are very time consuming and take 3 to 5 days for beer to be released to the market.

HybriScan® Beer kit, a rapid test system developed by Scanbec GmbH in collaboration with Sigma-Aldrich, could lead to a faster product release of beer and could act as an alternative for the detection of beer spoilage contaminants. After as little as two hours (pre-enrichment for 24 h, if necessary) the brewery could have the first reliable results.

A variety of applications have been developed for HybriScan including the detection of bacteria and yeast in non-alcoholic beverages. The robustness of the HybriScan assay enables it, in contrast to other rapid test systems, to detect bacterial contamination in brewer’s yeast and leads to efficient use of this valuable resource. Furthermore HybriScan test system is a perfect tool for microbiological control of dispensing equipment. The legal standard for sterility control of dispensing equipment is 100,000 cfu/mL; a fast, direct determination of beer spoiling bacteria is possible without pre-enrichment-procedure delivering results within two hours.

Comparison of HybriScan and other rapid test systems: Performing quality control by using the standard cultivation based method takes a long time. In recent years many companies have developed rapid test systems to hasten this procedure. For quality control of beer and beverages three main technologies are available:

  • HybriScan (sandwich hybridization)
  • PCR (Polymerase Chain Reaction)
  • VIT (Vermicon Identification Technology)

A comparison of these different technologies is given in Table 2. Comparing HybriScan to PCR or VIT –technology the benefits of this rapid test system are:

  • Fast and cost efficient analysis
  • Inexpensive read-out technology
  • High sensitivity and specificity

Using two different probes for detection of microbial RNA, false-positive results are almost impossible. In Figure 1 results of quantification of Lactobacillus buchneri within a starter culture (silage) of three different samples are presented. Comparison of the HybriScan test with a cultivation based analytical method (MRS agar) displays the equivalent results within the limits of microbiological sample variability.

Table 2. Comparison of different technologies for detection of beer spoilage bacteria

Figure 1. Lactobacilli (beer spoilage organisms)

 

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Materials

     

References

  1. E. StorgArds, M.-L. Suiiiko, Detection and identification of Lactobacillus linderi from Brewery Environments, J. Inst. Brew., Vol. 104, p. 47-54 (1998)
  2. Markus Timke, et al., Identity, beer spoiling and biofilm forming potential of yeasts from beer bottling plant associated biofilms, Springer Science+Business Media B.V. (2007)

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