UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 739 



Contribution from the Bureau of Animal Industry 

 JOHN R. MOHLER, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



December 30, 1918 



THE SIGNIFICANCE OF THE COLON 

 COUNT IN RAW MILK 



By 



S. HENRY AYERS and PAUL W. CLEMMER 

 Bacteriologists, Dairy Division 



CONTENTS 



Page 



Present status of the question 1 



Do organisms of the colon-aerogenes group indicate the presence of manure in fresh 



milk? 3 



Can milk be produced commercially without contamination by organisms of the 



colon-aerogenes group ? -. 9 



How many organisms of the colon-aerogenes group can be introduced into milk 



during milking ? 12 



Why are high colon counts often found in raw milk ? 19 



Are both the B. coli and B. aerogenes types present in milk and if so is their relative 



proportion of any value ? 27 



Has the colon count any significance in raw milk ? 31 



Significance in fresh milk 31 



Significance in milk that has been held 31 



Summary 32 



literature cited 33 



WASHINGTON 



GOVERNMENT PRINTING OFFICE 



1918 



