USE OF PURE CULTURES. 1 97 



countries. Since the public taste for butter is different in 

 different sections of the world it is evident that no type of 

 ripening, even though satisfactory in one country, will 

 necessarily meet the demands of another. The use of 

 pure cultures has been satisfactory in Denmark and pro- 

 duces a butter which exactly meets the demands of the Euro- 

 pean public; but the same cultures do not meet the condi- 

 tions at present existing in the United States. The demand 

 for a highly flavored butter in this country makes it neces- 

 sary, if pure cultures are to be used for this purpose, that 

 some form of culture should be obtained that will give a 

 stronger flavor than that which is developed in Denmark. 

 Hence it happens that the use of pure cultures may be 

 quite successful in one locality and unsuccessful in a second. 

 But with the possibility of change in the public taste, it is 

 quite possible, or even probable, that the continued use of 

 such cultures would, in time, develop a taste for the peculiar 

 kind of butter which they produce. 



Use of Pure Cultures. In the use of these cultures the 

 first step necessary is that of building up the culture. The 

 bacteria culture is furnished to the purchaser in quite small 

 quantity. It is commonly in the form of a powder or a 

 liquid, and although it contains many billions of bacteria, 

 the number is quite insufficient to inoculate properly a large 

 quantity of cream. It is, therefore, necessary to increase 

 the supply. This is usually done by a simple method. A 

 small quantity of cream or milk, perhaps a quart, is sterilized 

 by heating to a temperature of boiling, and then to it 

 is added the culture purchased from the market. The 

 material is covered to keep out the dust, and placed in a 

 moderately warm locality for a couple of days. During this 

 period the bacteria increase in numbers, and there is obtained 

 a quart of culture well impregnated with the bacteria. Then 

 a larger quantity of milk or cream, five or six gallons, is 

 heated to a pasteurizing temperature of about 155 and 



