Q. What are the Yeasts?

Like mold, the term "yeast" is commonly used but hard to define. As used here it refers to those fungi which are generally not filamentous but unicellular and ovoid or spheroid and which reproduce by budding or fission. Yeasts may be useful or harmful in foods. Yeast fermentations are involved in the manufacture of foods such as bread, beer, wines, vinegar, and surface-ripened cheese, and yeasts are grown  for enzymes and for food. Yeasts are undesirable when they cause spoilage  of sauerkraut, fruit juices, syrups, molasses, honey, jellies, meats, wine, beer, and other foods.