Naturally Occurring Antifungal Agents and Their Modes of Action

Abstract

Yeast fermentations are involved in the manufacturing of foods such as bread, beer, wines, vinegar, and surface ripened cheese. Most yeasts of industrial importance are of the genus Saccharomyces and mostly of the species S. cerevisiae. These ascospore-forming yeasts are readily bred for desired characteristics. However, yeasts are undesirable when they cause spoilage to sauerkraut, fruit juices, syrups, molasses, honey, jellies, meats, wine, beer, and other foods (Frazier and Westhoff, 1988). Finishing process of the fermentation is usually either through filtration or pasteurization. However, the use of the latter is limited to certain foods since it is a heat treatment and hence denaturalizes proteins, and the former is also limited to clear liquids. Neither process can be applicable to some foods such as sauerkraut and “miso” (soy bean pastes). Zygosaccharomyces bailii, is a food spoilage yeast species. It is known for its capacity to survive in stress environments and, in particular, in acid media with ethanol, such as in wine. In addition, spoilage of mayonnaise and salad dressing by this osmophilic yeast is well described. Therefore, safe and effective antifungal agents are still needed.