RAPD-PCR Characterization of Brewery Yeast and Beer Spoilage Bacteria. Thomas A. Tompkins (1), Robert Stewart, Louise Savard (2), Inge Russell, and Terrance M. Dowhanick (3), Research and Technical Services Department, Labatt Breweries of Canada, 150 Simcoe Street, London, Ontario, Canada N6A 4M3. (1) Present address: Lallemand Inc. Laboratoire R&D, 6100 Royalmount, Montreal, Quebec, Canada H4P 2R2. (2) Present address: Institute IRBV, 4101 Sherbrooke St. E., Montreal, Quebec, Canada H1X 2B2. (3) Author to whom all correspondence should be addressed: 519/667-7338; Fax 519/667-7350. J. Am. Soc. Brew. Chem. 54(2):91-96. Accepted September 13, 1995.

Commercially available oligonucleotide primers (10-mers) were used in a random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) to screen and characterize potential beer-contaminating bacteria. The species identification of Lactobacilli, Pediococci, Leuconostoc, and others was achieved using four different primers in the RAPD-PCR. For each bacterial species, each primer produced a unique and characteristic "core" fingerprint pattern. Using the core patterns as a guide, we were able to distinguish and recognize unknown contaminants obtained during regular testing by our quality control laboratories. The procedure is faster than traditional characterization techniques—the identification of a single colony was typically achieved in less than 10 hr. Keywords: Beer spoilage microorganisms, DNA fingerprinting, PCR, RAPD.