IDENTIFICATION OF SPOILAGE YEASTS IN A FOOD-PRODUCTION CHAIN BY MICROSATELLITE POLYMERASE CHAIN-REACTION FINGERPRINTING

A survey of yeast strains present in the production chain of mayonnais e and salad dressings was carried out over a period of 14 months. Atte mpts were made to identify the isolated yeasts with the API system, bu t identification of all species involved was not possible. In the inve stigation the performance of the microsatellite polymerase chain react ion (PCR) fingerprinting analysis with the microsatellite oligonucleot ide primers (GAC)(5) and (GTG)(5) appeared to be superior. Several yea st species were encountered in the production lines but only the speci es Zygosaccharomyces bailii and Zygosaccharomyces bisporus were presen t in the final products. Only microsatellite PCR fingerprinting analys is allowed discrimination between species of the Zygosaccharomyces gen us. In addition, the PCR-based technique allowed the discrimination of different types within the Z. bailii species. Z. bailii strains isola ted from spoiled products displayed PCR-fingerprinting types that appe ared to be identical to some of those generated by strains isolated fr om one specific production line. This suggested that microsatellite PC R fingerprinting is useful in tracing back the origin of spoilage outb reaks, and that it can be applied in microbiological quality assurance monitoring systems in industrial environments. (C) 1996 Academic Pres s Limited.