Soured Milk

Sour milk has long been a popular source of food and drink in many cultures around the world. Originally, soured milk products were produced naturally by the presence of lactic acid bacteria; a process which happily led to the discovery of yoghurt and cheese. However, now that the majority of milk is pasteurised - a procedure that destroys the lactic acid bacteria - when left, milk will simply go bad, rather than sour. This means that to make sour milk products at home, you will need to add a souring culture, such as Lactobacillus acidophilus.