Fast and Reliable Screening and Identification of the Most Relevant Beer Spoilage Bacteria Plus Detection of Spoilage Yeasts in Beer By Real-Time PCR

Introduction:  In general, beer is a hostile environment for most microorganisms. Only a few kinds of bacteria are able to grow under such conditions and are able to spoil beer. The detection of beer spoilage bacteria by conventional methods is a time consuming and laborious task.

Purpose:  This study attempts to clarify that real-time PCR provides an easy, fast, and reliable alternative testing solution.

Methods:   For this study, foodproof^® Beer Screening Kit hybridization probes were used.

Results:  This kit allowed the detection of 31 beer-spoilage bacteria, including identification of 12 species, in one test within 24-48h. The range of detected organisms includes the most beer-relevant species of the genera Lactobacillus, Pediococcus, Pectinatus and Megasphaera. The method was adjusted to the routine lab with throughput up to 94 samples per PCR run. The absence or presence of beer spoilers was detected immediately after the PCR run. Subsequent melting curve analysis allowed the identification of the most important spoilage bacteria, such as Lactobacillus brevis, Lactobacillus lindneri, or Pediococcus inopinatus from a positive result without further testing. Lactobacillus acetotolerans, another beer spoiling bacteria, was the most recent addition to the list of target organisms.

The new foodproof^® Beer Screening LyoKit is, also, available and allows the detection of the above mentioned 31 different beer-spoilage bacteria. In addition, it detects hop tolerance genes in a separate fluorescence channel. Lactobacillus brevis, the most important bacterial beer spoiler can be identified. To detect the most important spoilage yeasts, BIOTECON Diagnostics has developed the foodproof Spoilage Yeast Detection 1 and 2 Kits, which detect the most important genera using two tests.

Significance: The combination of the foodproof^® Beer Screening Kits, liquid and lyophilized, and the foodproof Spoilage Yeast Detection Kits provides the most complex testing solution available to brewers.