Brewing spoilage - rapid microbial methods
Beer is relatively microbiologically stable. Brewers are mostly concerned with spoilage organisms such as anaerobic bacteria and fermentative yeast species.
Rapid technologies have been developed to enable brewers to act more quickly on microbiological issues. Many of these are DNA-based and employ polymerase chain reaction (PCR) to amplify a specific DNA target sequence which then allows detection of the target organism. In the last few years there have been developments to simplify result interpretation and minimise sample handling. A disadvantage of this technology is that there is no differentiation between live and dead cells so false positive results are possible.
Rapid detection of organisms present in beer can also be done using other techniques, such as micro-colony counting. Alternatively, live cells can be detected by methods employing “in situ hybridisation”, the binding of labelled DNA probes to a target RNA sequence. Another innovation is Matrix-Assisted Laser Desorption/Ionisation Time of Flight Mass Spectrometry (MALDI TOF MS) which is now also available for rapid identification of microbes. This produces a speciesspecific fingerprint that can be used to identify the microbes.