Rapid detection and identification of spoilage bacteria in beer

New products trends towards nonpasteurized beer, low or nonalcohol beers and alcopops (sweetened beer mixtures) 

In recent years, diverse rapid methods have been publicized and there are several systems in use today. For some applications and organisms, optimized methods are available which can detect bacteria within 8h and most of them can do it within 24h. Some rapid methods are even able to detect several organisms in one step. 

Today s systems are in most cases based on the bioluminescence with ATP and luciferase from the firefly. As an alternative system it is also possible to use a colour test nicotinamide adenine dinucleotides (NAD/NADH) and nicotinamide adenine dinucleotide phosphates (NADP/NADPH), which are also compounds used for the energy transfer in the metabolism in living cells or compounds found in food debris. 

If NAD(P) and/or NAD(P)H is present in the sample, glucose dehydrogenase converts 3-D-Glucose into D-gluconolactone, then diaphorase converts a tetrazolium salt into a coloured formazan salt (HY-RiSE system from Merck). Any colour development on the test strip indicates a positive result (not clean). 

It is also possible to use a method with horseradish peroxidase and NAD(P) and/or NAD(P)H. The result of the reaction is the production of H2O2 (hydrogen peroxide), which can be detected with the addition of luminol. The luminol reacts with H2O2, resulting in bioluminescence (Anand, 2004). 

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Rapid detection and identification of spoilage bacteria in beer... 

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