Sour cream

Sour cream (sometimes known as soured cream in British English) is a dairy product obtained by fermenting regular cream with certain kinds of lactic acid bacteria. The bacterial culture, which is introduced either deliberately or naturally, sours and thickens the cream. Its name comes from the production of lactic acid by bacterial fermentation, which is called souring. TraditionalTraditionally, sour cream was made by letting cream that was skimmed off the top of milk ferment at a moderate temperature.