UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 240 



Contribution from the Bureau of Animal Industry 

 A. D. MELVIN, Chief 



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Washington, D. C. 



PROFESSIONAL PAPER 



July 13, 1915. 



PASTEURIZING MILK IN BOTTLES AND BOTTLING 

 HOT MILK PASTEURIZED IN BULK. 



By S. Henry Ayers, Bacteriologist, and W. T. Johnson, Jr., Scientific Assistant, 



Dairy Division. 



CONTENTS. 



Page. 



Introduction 1 



Method of bacteriological analysis __ 3 



Method of pasteurizing in bottles 3 



Bacterial reductions by pasteuriza- 

 tion in bottles 3 



Advantages and disadvantages of 



pasteurization in bottles__ 7 



Machinery for pasteurizing milk in 



bottles 7 



Method of pasteurizing in bulk and 



bottling while hot 11 



Comparison of bacterial reductions in 

 milk pasteurized in bottles and 

 milk pasteurized in bulk and bot- 

 tled while hot 12 



Page. 



Prevention of bottle infection by 

 bottling hot milk and by pasteur- 

 ization in bottles 14 



Cooling milk which has been bottled 



hot 10 



The cream line and flavor of pas- 

 teurized milk cooled by various 

 methods 23 



Bottles to be used in the process of 



bottling hot pasteurized milk 24 



Process of bottling hot pasteurized 



milk under commercial conditions. 24 



Summary 25 



Citation to literature 27 



INTRODUCTION. 



The process of heating milk in bottles is by no means a new one, for 

 it probably dates back to the work of Soxhlet (1) ,* from 1886 to 1891. 

 In general, however, the object has been partially or completely to 

 sterilize the milk by the use of high temperatures rather than simply 

 to pasteurize it at low temperatures. While the practice of steriliz- 

 ing or partially sterilizing milk in bottles has been extensively prac- 

 ticed in several countries in Europe, the pasteurization of milk in 

 bottles has not been so common. 



1 The figures in parenthesis refer to the list of citations to literature at the end of the 

 paper. 



Note. — This paper is of interest to milk dealers, health officials, and all who have to do 

 with the milk supply of cities ; it is suitable for distribution in all parts of the country. 

 94289°— 15 1 



