DAIRYING 15 



become over-ripe, or tainted, and if some of it, or of the butter 

 milk from it, is added to the next lot of sweet cream, these 

 defects may be transferred from one churning to another. The 

 sour cream and the buttermilk starter should not, however, be 

 altogether condemned. They may sometimes be used with good 

 results, as they are not always bad. The principal objection to 

 such a starter lies in the fact that the butter maker has no choice 

 in selecting his starter, but must use the same thing each day. 

 Sour cream and buttermilk are not safe sources of new starters, 

 but after a good one has been obtained from some other source, 

 its good qualities may be carried along from one churning to 

 another, for a while, by saving some of the cream or the butter- 

 milk for ripening the next lot of sweet cream. 



542. When a desirable starter has been obtained, an attempt 

 is usually made to retain the bacteria it contains as long as 

 possible. This is done by saving a small quantity of it each day 

 and adding this as seed to a new lot of pasteurized skim milk. 

 In this way the good butter qualities, which are due to these 

 bacteria, are transferred from one churning to another. 



543. Best Condition of Starter for Use. The starter ought 

 to be used before there is a separation of whey from the curd, 

 as a coagulated starter is too sour for producing the best results 

 in cream. The object of a starter is to propagate the largest 

 possible number of selected bacteria in a vigorously growing 

 condition ; and from our present knowledge it is supposed that 

 this point is reached just as the milk coagulates and before the 

 whey separates from the curd. 



The method of controlling butter flavor by means of a 

 starter may seem to be an easy one to follow, but in general 

 dairy and creamery practice it has been found that there are 

 many ways in which the starter or the pure culture becomes 

 contaminated with undesirable bacteria. These are introduced 

 so easily by careless handling from day to day and by a lack of 

 knowledge regarding the propagation of starters that it is im- 

 portant for the buttermaker to understand not only the mechani- 

 cal manipulations, or how to make a starter, but he ought also 

 to be familiar with the reasons for each step taken in their propa- 



