A New Method For Rapid Detection Of Beer Spoilage Bacteria By Using Chromatography

Beer is easily to be contaminated in the production process, which will further influence the quality of beer and the sales of beer. The traditional method used for detection beer spoilage bacteria is of low sensitivity, and time-consuming and labor-intensive, which cannot meet the actual production requirements. The contaminated beer can be detected with the characteristic peaks in the profiles of organic acids and biogenic amines by using liquid chromatography, while in the profile of flavor compounds by using gas chromatography.In this research, we firstly established the standard LC and GC chromatogram database of each component in beer without spoilage. Then the beer spoilage bacteria of Lactobacillus brevis( 49#), Bacillus( 3012#), Lactobacillus plantarum( JSB), Lactobacillus parabuchneri( Bai), Staphylococcus saprophyticus( Qiu) were forcely inoculated into the beer respectively. Finally, the components of beer were detected with GC or LC. The characteristic peaks corresponding to each component were found by comparing the experimental chromatograms with standard chromatograms, which can be used to confirm whether the production process was contaminated and which bacteria were the exact beer spoilage bacteria. The results showed: When Xin Dong beer was as the experimental material, the significant differences between JSB and Bai were not many. Qiu was significantly different from other four beer spoilage bacteria, so did 3012# and Qiu. This phenomenon was almostly consistent with the species category that each bacteria were belonging to. JSB and Bai were all belonging to Lactobacillus,49# was the different though it was also belonging to Lactobacillus. 3012# and Qiu were belonging to Bacillus and Staphylococcus saprophyticus respectively. In general, the beer spoilage bacteria belonging to the close species influence similarly on the profiles of organic acid, biogenic amine and flavor compound in beer. On the contrary, the influences of the beer spoilage bacteria belonging to the far species on the components of beer were different from each other.As 49# was most different from other four bacteria, 49# was inoculated into many different brands of beer for further study. The component of each brand of beer was analyzed by LC or GC in the way as mentioned above. The results showed: the contamination of 49# did not significantly influence the profiles of organic acid and flavor compound, but influenced the profile of biogenic amine remarkably.In future, this method can be applied for actual production process to rapidly and easily detect whether the beer is contaminated with beer spoilage bacteria.