Growth Characteristics and Contamination Source of Ethanol Tolerant Mold Isolated from Spoiled White Bread

Abstract

Orange mold isolated from spoiled white bread was morphologically and physiologically identified as Moniliella suaverolens. When the M. suaverolens was inoculated on white bread, and incubated at 25°C for 2 weeks, the white bread formed an orange spot during storage. The assimilation of ethanol by this isolated mold and its growth in a 2% yeast extract and 1% malt extract with 15% sucrose (15% SY) broth contaning 0.5-10% ethanol was investigated. This isolated mold assimilated ethanol and grew better in the 15% SY broth containing 0.5-2.0% ethanol than in medium without ethanol and grew even in 15% SY broth containing 10% ethanol at 25°C. The predominant strains of airborne molds detected in the white bread manufacturing process were Cladosporium, M. suaverolens, Aspergillus, Penicillium, Aureobacidium. M. suaverolens was detected in all manufacturing processes. The survival ratio of M. suaverolens was found to decrease with increasing dissolved ozone concentration ranging from 1 to 15mg/l and all mold cells (2.7×10⁵/ml) were completely killed with ozonated water containing 15mg/l dissolved ozone at 25°C for 5 min.