Soured milk denotes a range of food products produced by the acidification of milk. acidification, which gives the milk a tart taste, is achieved either through bacterial fermentation or through the addition of an acid, such as lemon juice or vinegar. the acid causes milk to coagulate and thicken, inhibiting the growth of harmful bacteria and improving the product's shelf life. soured milk that is produced by bacterial fermentation is more specifically called fermented milk or cultured milk. traditionally, soured milk was simply fresh milk that was left to ferment and sour by keeping it in a warm place for a day, often near a stove. modern commercial soured milk may differ from milk that ...

Source: Wikipedia