MARKET MILK 175 



which is gradually replacing the flash process, is more effective 

 and is superior in every way. 



Pasteurization in bottles is the latest development of the 

 process to be used on a practical scale. This process, as first 

 practiced, consisted in putting the raw milk into bottles with 

 water-tight seal caps, then immersing them in hot water until 

 heated to 145° F. and holding them at that temperature for 

 twenty or thirty minutes. The cooling was accomplished by 

 gradually lowering the temperature of the water until that of 

 the milk reached 50° F. This method is now in use in several 

 milk plants. The advantage of this process is in the fact that 

 the milk after heating is not exposed until it reaches the con- 

 sumer, thereby eliminating any danger of reinfection with dis- 

 ease-producing organisms through handling. For this process 

 to be successful it is necessary, of course, that the seals be ab- 

 solutely water-tight, as the bottles are submerged in water, 

 and, during cooling, a defective cap might allow infection by 

 polluted cooling water. The disadvantage of this process is 

 in the increased cost of pasteurization, caused by the cost of 

 the seal caps. It is claimed, however, that the saving in milk 

 losses by pasteurization in bottles makes up for the added 

 expense of caps. It is now possible to pasteurize milk in this 

 manner without using water-tight caps. This is accomplished 

 by the aid of devices which fit over the tops and necks of the 

 bottles, thereby protecting the ordinary paper caps from the 

 water which is sprayed on the bottles for the purpose of heat- 

 ing or cooling. This method of protecting the tops permits 

 the use of the ordinary caps and removes the possible danger of 

 polluted water infecting the milk. 



Another method of pasteurization, or, rather, a modification 

 of the present holder process, is that of bottling hot pasteurized 

 milk. Work on this process was begun in 1911, and the 

 process was first suggested by the author in 1912; further 

 work on this subject may be found in an article published 



