IDENTIFICATION OF YOGURT-SPOILING YEASTS WITH 18S RIBOSOMAL-RNA-TARGETED OLIGONUCLEOTIDE PROBES

18S rRNA-targeted oligonucleotide probes were designed for rapid and r eliable identification of yeasts involved in spoilage of dairy product s. Candida parapsilosis, Candidal glabrata, Clavispora lusitaniae, Deb aryomyces hansenii, Dekkera bruxellensis, Hanseniaspora uvarum, Pichia anomala, Pichia membranaefaciens, Rhodotorula glutinis, Saccharomyces cerevisiae and Saccharomycopsis capsularis were identified by dot blo t hybridization assays using species-specific, digoxygenin-labeled pro bes which were deduced from comparative analysis of highly variable re gions of 18S rRNA. The eucarya-specific probe EUK516 gave intense sign als detected by epifluorescense microscopy when hybridized in situ to all yeast species tested. Whole cell hybridization experiments reveale d that the 3'-end of the target molecule is a. suitable site for fluor escently labeled species-specific nucleic acid probes which detect S, cerevisiae, P. anomala, D. hansenii and D. bruxellensis in situ. Other variable regions of the 185 rRNA tested for species-specific probes a pparently were not accessible to in situ hybridization. S, cerevisiae and P. anomala were detected in yoghurt using the fluoressently labele d probes Sce1711 and Pan1710.