222 MODERN DAIRY PRACTICE. 



with a further description of the nature and character- 

 istics of the different lactic-acid bacteria. 



The methods of applying these pure cultures in the 

 creamery business were vague and uncertain until of late; 

 the solution of the problem was only a couple of years 

 ago in its first stage of development. 



Storch (Copenhagen) recommends the following method 

 of procedure for the application of pure cultures : " The 

 starter is to be prepared daily by means of a pure 

 culture; the latter may best be supplied to the creamery 

 in especially-arranged vessels, from which it may be 

 drawn in small portions without danger of contamination ; 

 the creamery-man adds a sufficient quantity to as much 

 new milk (or perhaps preferably separator skim-milk) as 

 the creamery is in the habit of using for a starter. Before 

 adding the pure culture the milk is heated above 158 F., 

 and at once cooled to the temperature at which the ripen- 

 ing will take place safest and quickest. It is possible that 

 another heating of the milk to 158 F. after a day's in- 

 terval will be found necessary. When sufficiently acid 

 and completely curdled this milk is ready to be used as a 

 starter." 



Weigmann (Kiel) gives the following method: "The 

 pure culture is to be ordered from a bacteriological labora- 

 tory; full-skimmed separator skim-milk is used in prepar- 

 ing the starter. The bacteria found in the same are 

 weakened or partially destroyed by cooling or heating; if 

 cooling be applied it must be very effective (37-30 F.). It 

 is, however, better to heat the milk to 140 F., cooling it at 

 once afterwards to 68-77 F. A portion of the pure culture 

 is then added, at the same time stirring the milk carefully. 

 The starter will be ready the following day, and should be 



