106 THE BOOK OF BUTTER 



coagulation of the curd during the pasteurizing process. 

 It has been found by experience that if the cream con- 

 tains 40 per cent fat or above, the " mealy " condition will 

 not be noticeable even though the cream may be fairly sour. 



One of the sources of most difficulty in the operation of 

 the " holder " pasteurizer is the boxings that hold the coil 

 tube and in which it rotates. When the boxing itself, or the 

 packing in it, wears the least bit, the oil flows back along 

 the tube and into the cream. Some machines are so con- 

 structed that the bear ings are not in contact with the cream. 

 All pasteurizers should be safeguarded in this respect. 



76. Cost. Bowen 1 finds that the flash process 

 of pasteurization requires approximately 17 per cent more 

 heat than the " holder " process. In addition to this there 

 is a correspondingly wider range of temperatures through 

 which the cream must be cooled. This adds to the 

 cost of pasteurization. He computes the cost of pasteuriz- 

 ing cream to be $0.0756 to 100 pounds. This would 

 amount to .216 cents a pound of fat when calculating 35 

 pounds of milk-fat in 100 pounds of cream. Mortensen 2 

 makes the following summary of the expenses of pasteuriz- 

 ing a pound of milk-fat : 



TABLE XVIII 



1 Bowen, John T., The Cost of Pasteurizing Milk and Cream, 

 U. S. Dept. of Agri., Bui. 85, p. 12, 1914. 



2 Mortensen, M. t Cost of Pasteurization, Butter, Cheese and 

 Egg Jour., Vol. 7, No. 22,,p. 22, 1916. 



