Rapid Methods for DetectingSaccharomyces Diastaticus, a Beer Spoilage Yeast, Using the Polymerase Chain Reaction

We have devised rapid methods for detecting Saccharomyces diastaticus, a beer spoilage microorganism, using polymerase chain reaction (PCR). We have designed primers to detect S. diastaticus by PCR, paying attention to sequential differences between the glucoamylase genes of S. diastaticus and S. cerevisiae. An examination of primer reactivity showed the forward primer, SD-5A, and the reverse primer, SD-5B, to react with S. diastaticus (seven strains tested); however, they did not react with other microorganisms, including the brewing yeast used by our company, two strains of Saccharomyces spp. 10 strains of Brettanomyces spp., four strains of wild yeast, four strains of fungus, and 23 strains of various bacteria. The DNA extracted enzymatically from cell numbers as low as 101 worked successfully as templates for the PCR method. Time required to extract DNA from cells and to detect S. diastaticus was only ≈5 hr. The combination of the rapid microbe detection system and PCR led to high accuracy of analysis. For a test of beer product, these combined procedures for the detection of S. diastaticus may be useful and, even from one cell which becomes one micro-colony (one to two day old colony), a test can be completed in 30 hr.