Description : Sour milk contains – (1) acetic acid (2) tartaric acid (3) citric acid (4) lactic acid
Last Answer : (4) lactic acid \ Explanation: Lactic acid, also known as milk acid, is a chemical compound that plays a role in various biochemical processes and was first isolated in 1780 by the Swedish ... kefir, and some cottage cheeses. The casein in fermented milk is coagulated (curdled) by lactic acid.