Soured milk denotes a range of food products produced by the acidificationofmilk. 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. It is not good for making cheese.
Soured milk that is produced by bacterial fermentation is more specifically called fermented milkorcultured milk.[1] 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 has become sour naturally.[2][full citation needed]
Raw milk that has not gone sour is sometimes referred to as "sweet milk", because it contains the sugar lactose. Fermentation converts the lactose to lactic acid, which has a sour flavor. Before the invention of refrigeration, raw milk commonly became sour before it could be consumed, and various recipes incorporate such leftover milk as an ingredient. Sour milk produced by fermentation differs in flavor from that produced by acidification, because the acids commonly added in commercial manufacture have different flavors from lactic acid, and also because fermentation can introduce new flavors. Buttermilk is a common modern substitute for naturally soured milk.
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Sukhov, SV; Kalamkarova, LI; Il'chenko, LA; Zhangabylov, AK (1986). "Microfloral changes in the small and large intestines of chronic enteritis patients on diet therapy including sour milk products". Voprosy pitaniia (in Russian). Jul–Aug (4): 14–7. PMID3765530.
^US patent 3625702, Exler, Heinrich, "PREPARATION OF SOUR MILK DRINKS", published 1971-12-07, issued 1971-12-07, assigned to Heinrich Exler
^US patent 3978243, Pedersen, Jens Kristian, "Process for preparing gelled sour milk", published 1976-08-31, issued 1976-08-31, assigned to Kobenhavns Pektinfabrik
