The term “yeast”, which is similar to mold, is often used, but it can be difficult to define. It refers to fungi that are not filamentous, but unicellular, ovoid, or spheroid, and can reproduce by budding and fission. Yeasts can be beneficial or harmful to foods. Yeast fermentations play a role in the production of bread, wine, vinegar, and surface-ripened dairy products. Yeasts can be grown for enzymes or for food. When yeasts cause spoilage in sauerkraut, fruit juices and sirups as well as honey, jellies, meats and wine, they are considered undesirable.