BACTERIA IN THE INDUSTRIES 2OI 



that they are mixed, consisting of several lactic-acid microbes or organisms 

 and yeast organisms. These foods or drinks therefore contain lactic acid 

 and a small amount of alcohol. 



As soon as it was determined experimentally that the beneficent action 

 of sour milk, thick or clabbered milk and the above-named special prepara- 

 tions was largely due to the lactic acid formed by specific microbes, efforts 

 were made to isolate these organisms in pure culture and to induce them 

 to act in sterile or pure milk. This has been done, and there are now upon 

 the European and American market several patented preparations con- 

 sisting of the lactic acid bacillus. 



Our knowledge of the relative importance of the several organisms 

 which are said to produce the fermentative changes in the milk is as yet 

 incomplete. Bacteriologists have thus far not succeeded in disclosing 

 all of nature's secret processes involved. It is supposed that the microbe 

 of Bulgarian sour milk, the Bacillus bulgaricus, is the most vigorous and 

 active of all organisms concerned in the lactic-acid fermentation of milk. 



It is not definitely determined whether or not the fermentations of 

 milk induced by the mixed and often filthy "yeasts" employed in 

 making koumys, kefir, yoghurt, matzoon and other similar fermented 

 foods, are superior or inferior to those of lactone and other pure 

 culture milk ferments. It is, however, very evident that the mar- 

 keted preparations in tablet form give very satisfactory results, as 

 used by pharmacists and in the home. Full directions for using 

 the tablets are found on every package. As is naturally to be sup- 

 posed, these tablets deteriorate in a comparatively short time and all 

 reliable manufacturers place the age-limit on each package. 



Pharmacists can prepare a marketable kefir ferment powder from milk 

 activated by kefir, provided care is observed to guard against outside 

 infection in the several steps of procedure. The following is the method 

 of preparing a kefir powder: 



A. Securing the Kefir. The kefir known as kefir grains or kefir seeds 

 may be secured from the large dealers in drugs in New York City or in 

 other large Eastern port cities. The kefir is a solid of a tough gelatinous 

 consistency, brittle when dry, of grayish-yellow color. It is a conglomera- 

 tion of various organisms, as Dispora caucasica, several species of other 

 microbes, a yeast organism, and other undetermined organisms. 



B. Washing the Kefir. Place two or three drams of the kefir in a mix- 

 ture of equal parts of milk and water, enough to cover the kefir. Allow 

 to stand for four hours, decant off the liquid and renew at intervals of 

 about one hour. Repeat this four or five times at a temperature of about 

 82 F. 5 



This process serves a cleansing purpose and initiates the fermentative 



