Detection of Beer Spoilage Organisms by Polymerase Chain Reaction Technology. Youichi Tsuchiya, Hirotaka Kaneda, Yukinobu Kano, and Shohei Koshino, Brewing Research Laboratories, Sapporo Breweries, Ltd. 10, Okatohme, Yaizu-shi, Shizuoka, 425, Japan. J. Am. Soc. Brew. Chem. 50:0064, 1992.

A sensitive detection and identification method for beer spoilage organisms was developed. The procedure involves the electrophoretic analysis of DNA fragments amplified by the polymerase chain reaction. When genomic DNA of Lactobacillus brevis was amplified, using a set of primers, to give a 117-base pair fragment encompassing the 5S rRNA gene (rDNA) and then electrophoretically analyzed, a single cell of L. brevis was detected. When various populations of L. brevis were added to 250-ml volumes of pasteurized beers, collected by a membrane filter, and then analyzed by this method, the detection limit was about 30 cells. It was expected that these primers could specifically be used to detect lactic acid bacteria. Another set of primers encompassing the 100-base pair fragment of 5S rDNA of Saccharomyces cerevisiae was synthesized, and using the two sets of primers in mixtures, L. brevis and S. cerevisiae were detected and distinguished. These results suggested that the detection and identification of beer spoilage organisms can be done at the same time using suitable primers.

Keywords: Beer spoilage organisms, Contamination, Detection, Lactic acid bacteria, PCR, Yeast