Starter cultures (also short starter ) are special, selected because of specific properties, viable microorganisms used in fermentation processes of food production. They may be in pure culture or controlled mixed cultures. They are usually present in concentrations higher than one million CFU per gram added to food to improve this in appearance, taste or shelf life. Starter cultures are traded in the form of suspensions or freeze-dried powders. Most lactic acid bacteria or yeasts are used, but also mixtures of the two groups - like leaven or kefir. The term " starter culture " is inspired by the fact that these microorganisms decompose the change process of the food going.
With the help of starter cultures approximately 35 percent of our food can be produced. Examples in this way produced foods are baked goods, sauerkraut, yogurt and sour milk products, cheese, fermented sausage, beer or wine. In the dairy industry bacterial starters are called lactic acid.