508 MANUAL OF MILK PRODUCTS 



results are obtained by using with the Bact. caucasicum a 

 culture of an ordinary lactic acid organism such as is used in 

 making buttermilk. Bact. caucasicum growing alone in milk 

 forms usually a rather slimy, tenacious curd which cannot be 

 broken up into the smooth, creamy condition essential to a 

 good buttermilk. If this organism is grown in combination 

 with the ordinary lactic acid organism, a more friable curd is 

 obtained, and the sliminess is not so evident. The two organ- 

 isms can be carried in mixed culture only with great difficulty, 

 as the high acid soon suppresses the ordinary form. The most 

 satisfactory results can be obtained by making buttermilk in 

 the ordinary way and churning it with an equal quantity of 

 milk curdled with the yogurt organism. This procedure gives 

 the desirable texture of buttermilk and a distinctive flavor. 



If a culture can be obtained, yogurt can be made in the 

 home. If a reasonably active dry or fluid culture can be 

 obtained, the following procedure should be satisfactory : 



(1) Heat one-half pint of milk in a double boiler, holding it 

 one-half hour after the water begins to boil. 



(2) Cool this milk to about 100 F. (about blood heat). 

 At this temperature the container will feel warm, but not hot, 

 to the touch. 



(3) Add a considerable quantity of the culture to this milk. 

 If it is in the form of tablets, three or four should be used. 



(4) Transfer the milk to a bottle or fruit- jar or, better 

 still, a vacuum-insulated bottle which has been rinsed with 

 boiling water, and keep overnight in a warm place. Good 

 results may be obtained by placing the bottle or jar, containing 

 the milk, in a dish of water warmed to about 100 F. The 

 most favorable temperature for the fermentation is at or a 

 little below blood heat. At a little higher temperature the 

 organism grows faster, but the curd is likely to separate from 

 the whey as a tough mass. At a lower temperature the growth 

 may be so slow that other bacteria gain the ascendency. By 



