Fermented cereal doughs and porridges are traditional staple products in many countries. Fermentation improves the digestibility of the cereal as it breaks down the starch. It also preserves the dough by reducing the pH and gives the food a distinctive sour taste. Examples include steamed fermented maize dough known as kenkey in Ghana and bagone in Botswana. Fermentation of the dough takes place naturally, using lactic acid bacteria. The bacteria ferment the carbohydrate in the grain, breaking it down into simpler sugars and producing lactic acid. The acid gives the dough the sour taste. Starter cultures, usually a piece of fermented dough from a previous fermentation, are sometimes added to the dough or batter to speed up the rate of fermentation. Fermented cereal products carry a risk of food poisoning if the fermentation is not carried out properly or if non-desirable micro-organisms contaminate the product. Also, the products are not pasteurised after fermentation. Indigenous fermented foods are common in many parts of Africa. Some are used as beverages or snack foods while a fe aer consumed as staples and weaning foods.