Kefir. Kephyr. N. N. R. 1917. (See also Lactic Acid Therapy.)—From time immemorial the Tartars and the Balkan peoples have employed as a food and beverage one or another form of fermented milk. The Tartars prepared from mare's milk a drink known as koumiss or kumys. This is prepared by the action of a peculiar ferment known as kephir (kepir) and called also by the Mohammedans "the prophet's millet." In Western Europe, mare's milk not being available, an imitation of kumys has been made from cow's milk, to which the term "kephir milk" should be applied, limiting the word kumys to the genuine Tartar drink. The Armenians employed a fermented milk, madzonn or matzoon. Giaourdi is a fermented milk prepared in Greece from sheep and goat's milk with an enzyme obtained from fermented figs. The Bulgarians use a fermented milk known as yoghourt (yaowite). The Arabians have a fermented milk called leben.
The kefir grains (or seeds) are white, irregular, roundish bodies about the size of a walnut with a rough, ferruled surface, of gelatinous or, when dried, cartilaginous consistency. Despite considerable investigation, their composition is not yet definitely settled. They probably contain several micro-organisms as follows: (1) a yeast fungus which Spivak (N. Y. M. J., 1896) believes identical with the ordinary yeast, Saccharomyces cerevisiae, but which Beyerinck believes to be a distinct species, S. Kefir, (2) Bacillus Dispora Caucasica (Kern) or Bacillus Kephir (Sorokin), (3) Bacillus acidi lactici, (4) other bacteria which are probably of little importance to the process of fermentation.
There are a number of directions for preparing kephir milk, varying more or less in the details. The following is a simple one: About 120 grains of kephir grains are softened by soaking over night in a pint bottle full of water. The following morning the water is poured off and the bottle is three-quarters filled with unboiled milk and tightly stoppered. This is kept at a temperature of 20° C. (68° F.) for from one to three days. The milk is strained through cheese cloth immediately before use and the residue recovered may be used for fermenting other milk. For various other processes see Kobert (Zeitsch. f. Krankenpflege, 1904, p. 377; Ph. Ztg., 1904, 819 and 1912, 277), Drasler (Med. Klin., 1908), and Spivak (N. Y. M. J., 1896). According to Spivak, the changes in milk during kephirization are as follows: 1. Fat, salts, and water remain unchanged. 2. The quantity of lactose is gradually lessened from 30-50 per mille to 16-30 per mille in the second-day kephir, and to 12-20 per mille in the third-day kephir. 3. Lactic acid is increased from 3.5-8.6 per mille in second-day kephir to 6.3-9.0 in third-day kephir. 4. Alcohol is produced from 5.3-8.0 mille in second-day kephir to 6.0-10.0 in third-day kephir. 5. Carbon dioxide is generated in quantities approximately 10 per cent. 6. A part of the casein—namely, about 10 per cent.—is transformed into acid albumin and peptone, 10 per cent. into hemialbumose, and the rest loses its lime, and therefore becomes more easily digestible.
There is largely sold, under the name of kumys, a spurious drink which is made by fermenting sweetened milk with ordinary yeast. It is a pleasant beverage, but differs in important regards from the true kephir milk. The following formula has been suggested by L. Wolff (A. J. P., 1880, 291): "Grape sugar, half an ounce. Dissolve it in four ounces of water. Dissolve twenty grains of compressed yeast, or well-washed and pressed out brewer's yeast, in two ounces of milk. Mix the two solutions in a quart champagne bottle, which is to be filled with good cow's milk to within two inches of the top. Cork well, secure the cork with wire, and place in a cellar or ice chest, where a temperature of 10° C. (50° F.) or less can be maintained, and agitate three times a day. In three or four days the koumys is ready for use, and should not be kept longer than four or five days; it should be drawn only with a champagne tap." A beer bottle with patent stopper may be substituted for the champagne bottle.
The composition of true koumys, according to Stalberg, is given below; other analyses may be found in the J. P. G., 1875, 62.
Koumys of June. In 100 parts, alcohol 1.65, fat 2.05, sugar of milk 2.20, lactic acid 1.15, casein 1.12, salts 0.28, carbonic acid 0.75.
Koumys of September. Carbonic acid 1.86, alcohol 3.23, fat 1.05, lactic acid 2.92, casein and salts 1.21. Stalberg gives the following as the result of an analysis of Swiss koumys, made from cow's skimmed milk to which sugar had been added. Alcohol 3.622, lactic acid 0.256, sugar 2.376, albumin 2.099, butter 2.008, mineral salts 0.574, carbonic acid 1.997. Warnikiewicz found in koumys from cow's milk 6.32 per cent. of solid material, casein 3.08, butter 0.22, milk sugar 1.77, salts 0.33, lactic acid 0.62, alcohol 1.23 parts per hundred. (See also Konig's Nahrungs- und Genussmittel, 416-419.)
These fermented milks vary in composition with the milk they are prepared from. In the following analyses, the first three columns are taken from A. J. P., 1887; the matzoon analysis is by Uffelmann.
|Sugar of milk||41||22.0||20||16.2|
|Water and salts||873||918.3||905||926.2|
Gordon Sharp (P. J., 1892, 512) stated that the composition of koumys is complex, and that the decomposition which its proteids undergo is closely allied to putrefaction.
Kephir milk is useful either as an accessory or sole food in various conditions of malnutrition. Not only does it offer the nutritive elements of milk in a partially digested form, but it is claimed that the living ferments which are contained in it have an influence in aiding digestion in the alimentary canal, and that it also stimulates the appetite. It first came into Europe as a remedy in pulmonary tuberculosis, but has also been recommended in various forms of dyspepsia, whether functional or organic, in anemia and chlorosis, in rachitis, chronic rheumatism, and other conditions of impaired nutrition. It has also been employed as an infants' food with asserted remarkable results. Its value in phthisis has been extraordinarily lauded by Uroganski. (Wiener Med. Wochens., 1907.)
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.