Identification of yeasts isolated from high-sugar foods.

Abstract

Yeast strains were isolated from 265 samples of high-sugar foods and related materials, and 93 representative strains were identified. Fifty-four strains of ascosporogenous yeasts were identified as 12 species belonging to eight genera. Thirty-nine strains of asporogenous yeasts were identified as 26 species belonging to five genera. The major species identified wereZygosaccharomyces rouxii (23 strains), Hansenula anomala (eight strains), Debaryomyces hansenii (five strains), andSaccharomyces cerevisiae (four strains). More than 60% of the isolates were sugar- tolerant yeasts, and all strains of Zygosaccharomyces rouxii were osmophilic. Approximately 80% of the isolates fermented glucose. It is suggested that these yeasts cause pouch swelling and produce alcohol in gas-exchange packaged foods or vacuum-packaged foods.