Sour cream



 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 or naturally, sours and thickens the cream. Its name stems from the production of lactic acid by bacterial fermentation, which is called souring. The taste of sour cream is only mildly sour.

Traditional
Sour cream, made out of cream, contains from 18 to 20 percent butterfat — about 22 grams per 120 milliliter serving;— and gets its characteristic tang from the lactic acid created by the bacteria. Commercially produced sour cream often contains additional thickening agents such as gelatin, rennet, guar gum and carrageenan, as well as acids to artificially sour the product.

Light varieties
Light, or reduced-fat, sour cream contains about 40 percent less butterfat than regular sour cream, because it is made from a mixture of milk and cream rather than just cream. Fat-free "sour cream" contains no cream at all, and is made primarily from non-fat milk, modified cornstarch, thickeners and flavoring agents.

Storage
Sour cream is not fully fermented, and as such must be stored under refrigeration. As with other dairy products, it is usually sold with an expiration date stamped on the container, though whether this is a "sell by", a "best by" or a "use by" date varies with local regulation. Food authorities, such as the United States Department of Agriculture, advise that sour cream with visible mold should be discarded, as it may be contaminated below the surface and could contain dangerous mycotoxins such as aflatoxin.

Uses
Sour cream is used primarily in the cuisines of Europe and North America, often as a condiment. It is a traditional topping for baked potatoes, added cold along with chopped fresh chives. It is used as the base for some creamy salad dressings and can also be used in baking, added to the mix for cakes, cookies, American-style biscuits, doughnuts and scones. It can be eaten as a dessert, with fruits or berries and sugar topping. Also, it is sometimes used on top of waffles in addition to strawberry jam. In Central America, crema (a variation of sour cream) is a staple ingredient of a full breakfast.

Sour cream can also provide the base for various forms of dip used for dipping potato chips or crackers, such as onion dip.

In Tex-Mex cuisine, it is often used as a substitute for crema in nachos, tacos, burritos, taquitos or guacamole. It is one of the main ingredients in chicken paprikash and beef Stroganoff.