CONDENSED AND EVAPORATED MILK 255 



made the concentration of nutrients so great that bacteria 

 did not develop in it, even if constantly exposed to the air. 

 Mr. Page started a factory in Switzerland. In 1866 he 

 was succeeded by the Anglo-Swiss Milk Company, which 

 located a large factory on Lake Zug in the canton of that 

 name. This company prospered and so far as known still 

 exists and has branches in the United States, Germany, 

 England and Switzerland. It supplied practically the whole 

 of Europe with condensed milk. The Borden Condensed 

 Milk Company is one of the largest in this country. 



Before the milk is put into the vacuum pan, it is heated 

 and run through a clariner to remove all physical dirt 

 and some of the objectionable odors. Then it is passed 

 on to the vacuum pan, where the condensation takes 

 place. 



Enough air is pumped out of the vacuum pan so that 

 it will show a vacuum or air pressure of 24 to 28 inches 

 as measured by a mercurial column vacuum gauge. In 

 such a vacuum, milk boils at a temperature of from 105 

 to 135 F. It is very essential to keep the vacuum pump 

 working uniformly in order to maintain a constant vacuum. 

 Should the vacuum be greatly lessened, evaporation would 

 cease, the temperature of the milk would rise, and the 

 entire batch of milk might be spoiled. Condensation is 

 continued until a sample drawn from the pan shows the 

 proper degree of concentration as determined by a Baume 

 hydrometer. 



Degree of Concentration. This is undoubtedly the 

 most important point in the process. When concentrated 

 too much, the result may be curdled milk. When not 

 sufficiently concentrated, the fat separates and may churn 

 in subsequent processes. In either case the commercial 

 value of the product is greatly lessened. 



