CREAM RAISED BY GEAYITY PROCESSES. 179 



In the ic< method the milk is creamed in high, usually 

 narrow tin cans. These cans are easily cleaned and 

 steamed, and it is therefore not difficult to keep them 

 sterile. 



Without entering into a general discussion of the ad- 

 vantages of this method in our creameries and dairies, I 

 desire to call attention to some points about it, the neg- 

 lect of which will largely influence the keeping quality of 

 the products. 



First of all, I will recall what was said on pp. 62-66 

 concerning the necessity of the rapid cooling of the milk 

 by the use of sufficient quantities of ice. It is necessary 

 not only to use ice liberally, but to use it in the right way. 

 It is therefore advisable to have finely-divided ice in the 

 creamer instead of large pieces, especially in the first cool- 

 ing of the milk, as the fine ice causes a more rapid cool- 

 ing of water and milk. When a sufficient decrease in the 

 temperature of the milk has been obtained, larger pieces 

 of ice may be used. A mistake often made is to place the 

 milk-cans very near one another, not allowing a sufficient 

 quantity of ice between them for the rapid cooling of the 

 milk. It may furthermore be well to remember that pure 

 water must be kept in the creamer. In many creameries 

 the same water is left in the tanks for weeks, although 

 milk is often spilled into them, thus improving the water as 

 a nutritive medium for bacteria. The water is, of course, 

 kept cold by the ice floating in it, and the bacteria are 

 thus prevented from increasing perceptibly; but water 

 often splashes into the milk from the creamer or is spilled 

 on the floor and walls, where it evaporates. The bacteria 

 coming from the evaporated water may then float in the 

 air, and thus easily infect the milk, 



