Washington, D. C. 



UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 782 



Ckuitribation from the Bureau of Animal Industry 

 JOHN R. MOHLER, Chief 



PROFESSIONAL PAPER 



A STUDY OF THE ALKALI-FORMING 

 BACTERIA FOUND IN MILK 



By 



S. HENRY AYERS, PHILIP RUPP, and WM. T. JOHNSON, Jr., 

 of the Dairy Division, Bureau of Animal Industry 



CONTENTS 



Historical Reriew 1 



Definition of the Aikali-Forming Groups 



. of Bacteria '2 



Cause of the Alkaline Reaction in MOk . 3 



Sources of the Alkali-Forming Bacteria . 9 



Morphology and Growth 10 



Sources of Nitrogen ........ 11 



Fermentation of Carbohydrates .... 



Fermentation of Alcohols • 



Fermentation of Salts of Organic Acids . 



Reduction of Nitrates and Nitrites . . 



Arbitrary Grouping of Alkali-Forming 



Bacteria From Milk ....... 



Summary and Conclusions . . > . . 



12 

 17 

 19 

 30 



35 



WASHINGTON . 

 GOVERNMENT PRINTING OFFICE 

 1919 



