RAPID METHODS FOR DETECTING SACCHAROMYCES-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 atten tion to sequential differences between the glucoamylase genes of S. di astaticus and S. cerevisiae. An examination of primer reactivity showe d the forward primer, SD-5A, and the reverse primer, SD-5B, to react w ith S. diastaticus (seven strains tested); however, they did not react with other microorganisms, including the brewing yeast used by our co mpany, two strains of Saccharomyces spp. 10 strains of Brettanomyces s pp., four strains of wild yeast, four strains of fungus, and 23 strain s of various bacteria. The DNA extracted enzymatically from cell numbe rs as low as 10(1) worked successfully as templates for the PCR method . Time required to extract DNA from cells and to detect S. diastaticus was only approximate to 5 hr. The combination of the rapid microbe de tection system and PCR led to high accuracy of analysis. For a test of beer product, these combined procedures for the detection of S. diast aticus may be useful and even from one cell which becomes one microcol ony (one to two day old colony), a test can be completed in 30 hr.