These one-celled microorganisms belong to the Fungi kingdom and are commonly used in the alcohol fermentation process and in baking. Some yeasts such as Candida albicans are mildly pathogenic to humans and others such as Saccharomyces boulardii have therapeutic uses.
Healthcare practitioners can find out more about Saccharomyces boulardii on the Probiotics Database.
A Yogurt Starter Kit is a combination of specific bacteria strains, known as yogurt cultures, selected for their ability to change milk into yogurt. The yogurt cultures (usually in powdered form) are added to the milk and allowed to incubate. The bacteria consumes the lactose in the milk, and uses it to produce lactic acid which cause the milk proteins to coagulate, resulting in yogurt. The yogurt culture bacteria strains each have certain properties and are selected for their effect on the finished yogurt. For example, some types of bacteria produce more lactic acid which will result in a sour tasting yogurt & some bacteria strains create different textures in the milk, resulting in a thicker or more solid yogurt.