a microscopic fungus of the class Fungi Imperfecti; it is an aerobe that forms white downy colonies on thick nutrient mediums. The mycelium is divided by transverse partitions into individual cells, or oidia. Geotrichum candidum appears on the surface of fermented milk products (yogurt, acidophilus milk) and cucumber brine. It forms, primarily in children, a white film on the mucous membranes of the mouth.