ITew Yokk Agkicultueal Experiment Station. 135 



upon mLxed milk brought from the creamery, should not be over- 

 looked. 



In this as in their other acts regarding the suppression of tuber- 

 culosis the Danes have shown a laudable moderation and consid- 

 eration of the rights of all concerned. The legal enactment as to 

 the temperature to be used was not made until the pasteurizing 

 process had been voluntarily adopted and the necessary machinery 

 installed in joractically every creamery in the country. 



The American promoters of the Danish method, knowing from 

 their previous experiences with the other form of pasteurization 

 that a heating above 70° C. (158° F.) produces a disagreeable 

 flavor in the milk, were either not willing to trust the practical 

 experience of the Danes or hopelessly confused the two problems 

 and recommended 6T.3° C. (155° F.) to the American experi- 

 menters when the Danish practice is to employ a temperature at 

 least 12.7° C. (25° F.) higher. 



The points in which their reasoning went astray were two : 

 First, the cooked taste in milk, at least for the most part, is not 

 a matter of absolute temperature at which the milk is heated, but 

 rather the result of an exposure of hot milk to oxygen. Milk 

 that has been highly heated in a Danish pasteurizer and imme- 

 diately and thoroughly cooled as is their practice has surpris- 

 ingly little of the cooked taste. Second, the cooked flavor does 

 not attach itself tenaciously to the fat of w^hich the butter is 

 almost exclusively prepared and butter made from highly heated 

 milk that may have a slightly cooked taste immeditely after 

 churning losses this objectionable flavor in a very short time. 



Believing that a failure to properly heat the milk might be a 

 factor in the lack of success of past American experiments our 

 investigations began with this point. 



THE PROBLEM STUDIED. 



The objective point was to determine the effect upon the germ- 

 life when milk was passed through a continuous pasteurizer at 



