- Sour cream is a dairy product obtained by fermenting a regular cream with certain kinds of lactic acid bacteria.
- The bacterial culture, which is introduced either deliberately of naturally, sour and thickens the cream.
Quark is a type of fresh dairy product, common for the cuisines of German-speaking countries made by warming soured milk until the desired degree of coagulation (denaturation, curdling) of milk proteins is met, and then strained.