176 MODERN DAIRY PRACTICE. 



and as far as possible to prevent the fermentation bacteria 

 from developing their specific functions. We shall here 

 dwell mainly on the latter object. 



As we have seen, the milk always contains a larger or 

 smaller number of bacteria when set. According to my 

 experiments the number of bacteria in cream from 

 Swartz's cans may vary from less than 1 00 to several tens 

 of thousands per cubic centimeter the conditions of 

 creaming being the same in all cases. The variation de- 

 pended entirely on the handling of the milk before setting. 

 If the milk has been handled with the greatest cleanliness 

 and according to the principles previously dwelt on, the 

 number of bacteria in the cream will not only be smaller, 

 but the bacteria found will not as a rule be of such unde- 

 sirable forms as will otherwise be the case. 



The means at hand for the checking of the fermenta- 

 tion bacteria during cream-raising are, of course, the same 

 as stand at our disposal in the keeping of the milk, viz. : 



1. Scrupulous cleanliness throughout the dairy, es- 

 pecially as regards the creaming-vessels, etc. 2. Cooling 

 the milk as quickly as possible; and, 3. Light, fresh, and 

 dry creaming-rooms. 



The lactic-acid organisms are generally best fought by 

 the first two methods, but the last method also tends to 

 check them, though not to the extent in which it checks 

 putrefactive and similar bacteria. 



The oldest method of creaming of this kind is the 

 Holstein system. In this method the complete rising of 

 the cream is secured by the thinness of the layer of milk 

 and by a rather high temperature, at which the milk-serum 

 is but little viscous. The development of the bacteria 

 is rather incompletely checked. The temperature sinks 



