1922 



UNITED STATES DEPARTMENT T)F AGRICULTURE 



BULLETIN No. 342 



Washington, D. C. 



Issued January 8, 1916; revised October 10, 1922 



THE PRESENT STATUS OF THE PASTEURIZATION 



OF MILK. 



By S. HENRY AYERS, 

 Bacteriologist, Dairy Division, Bureau of Ani, 



CONTENTS. 



Meaning of the term pasteurization- 

 Value of pasteurization 



Electrical and ultra-violet-ray treat- 

 ment of milk 



Extent of pasteurization in the 



United States 



Methods of pasteurization 



Advantages of low-temperature pas- 

 teurization 



Temperatures and methods most suit- 

 able for pasteurization 



Supervision of the process 



B 



7 



10 



11 

 33 



Handling milk after pasteurization- 



Cost of pasteurizing milk 



Bacteria which survive pasteuriza- 

 tion 



The colon test for efficiency of pas- 

 teurization 



Past and present theories of pasteur- 

 ization 



Pasteurization and vitamins 



The necessity for pasteurization 



References to literature- 



15 

 16 



16 



20 



20 

 22 

 24 

 25 



MEANING OF THE TERM PASTEURIZATION. 



The term "pasteurization" originated from the experiments of 

 Louis Pasteur, in France. From 1860 to 1864, in experiments on the 

 u diseases " of wine, he found that heating for a few moments at 

 temperatures of from 122 to 140 F. was sufficient to prevent abnor- 

 mal fermentations and souring in wine. A little later he found 

 that by a similar heating beer could be preserved from souring. 

 The application of the process gave rise to the term " pasteurization." 

 As applied under commercial conditions, pasteurization is the process 

 of heating for a short or a long period, as the different processes 

 demand, at temperatures usually between 140 and 185 F. As ap- 

 plied to milk for direct consumption, pasteurization should mean 

 a process of heating to 145 F. and holding at that temperature for 

 30 minutes. The process is followed by rapid cooling. 



elieved that the term pasteurization should be applied only 

 ocess of heating at 145 F. for a period of 30 minutes. 



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