separator, cream, dairy machine used to separate fresh whole milk into cream and skim milk. Formerly the separation was made by the gravity method, allowing the cream to rise to the top of a pan and then skimming it off. C. G. de Laval of Sweden devised the first mechanical cream separator c.1880, based on the principle of centrifugal force. Whole milk is conducted into a bowl, commonly through a central tubular shaft. A spindle rotates the bowl at a rate of from 6,000 to 9,000 rpm, and a series of identical conical disks separates the milk into vertical layers. The heavier skim milk collects on the outer circumference of the rapidly whirling bowl, and the lighter cream tends to remain in the center. The pressure of the whole-milk supply above the bowl then forces the cream and skim milk out of the machine and into separate collecting vessels. The cream separator makes it possible to control the amount of fat (called butterfat) remaining in the milk. The gravity method ordinarily leaves one fourth of the fat in the milk, while the cream separator leaves only 0.01% to 0.02% of the fat in the skim milk. Since the latter process is much faster than the gravity method, there is less chance for harmful bacterial action.

ice cream, sweet frozen dessert, made from milk fat and solids, sugar, flavoring, a stabilizer (usually gelatin), and sometimes eggs, fruits, or nuts. The mix is churned at freezing temperature to attain a light, smooth texture. Water ices existed in the Roman Empire, and Marco Polo brought back from East Asia reports of iced, flavored foods. From Italy the confection spread to France and England, reaching America early in the 18th cent. Ice cream sundaes had become popular by the 1890s, and the ice cream cone was introduced in 1904. The manufacture of ice cream in the United States on a commercial scale began in 1851 in Baltimore and has become an important industry. Commercial ice cream is pasteurized and homogenized. Federal, state, local, and industry regulations as to percentage of milk fats and solids, purity of ingredients, and cleanliness of preparation and dispensing are designed to maintain the dietary value of ice cream and to inhibit bacterial multiplication, for which ice cream is a favorable medium. Similar frozen confections include the fat-rich bisque (with added bakery products), parfait (containing eggs), and mousse; frozen custard, generally low in fat; frozen yogurt, also low in fat; and ices and plain or milk sherbets, based on fruit juices and sugar.

cream of tartar, white crystalline powder. Chemically it is potassium hydrogen tartrate, KC₄H₅O₆, the acidic potassium salt of tartaric acid. It is used as the leavening agent in baking powders. An impure form, called tartar or argol, forms naturally during the fermentation of grape juice into wine and crystallizes in the wine casks.

cream cup: see poppy.

Frozen dairy food. Ice cream is made from cream or butterfat, milk, sugar, and flavourings. Fruit ices (nondairy frozen desserts) were introduced into Europe from the East sometime after being first described by Marco Polo in his journals. Creation of the first true cream ice is credited to a Parisian café owner named Tortoni in the late 18th century. The ice-cream cone originated at the 1904 World's Fair in St. Louis, Mo., U.S. Commercial ice cream is made by heating and blending its ingredients to form a mix, which is then pasteurized and homogenized. The mix is ripened for several hours and then agitated while being frozen to incorporate air; the highest-quality ice creams incorporate the least air. Ice cream is now available in hundreds, if not thousands, of flavours.

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Edible seed of a large South American tree, Bertholletia excelsa (family Lecythidaceae), and one of the major commercially traded nuts in the world. The hard-walled fruit, resembling a large coconut, contains 8–24 nuts (seeds) arranged in it like sections of an orange. Each nut has a very hard shell and is three-sided in shape. Brazil nuts are high in fat and protein and taste somewhat like almond or coconut. The tree grows wild in stands in the Amazon River basin, reaching heights of 150 ft (45 m) or more.

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Yellowish part of milk, rich in butterfat, that rises to the surface naturally if milk is allowed to stand. In the dairy industry, cream is separated mechanically. Cream is graded by percentage of fat content. In the U.S., half-and-half, a mixture of milk and cream, contains 10.5–18percnt butterfat; light cream, commonly served with coffee, contains no less than 18percnt; and medium and heavy creams (the latter including whipping cream) contain about 30percnt and 36percnt respectively. Commercial sour cream, about 18–20percnt butterfat, is inoculated with lactic-acid-producing bacteria. Seealso ice cream.

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