UNITED STATES DEPARTMENT OF AGRICULTURE 



b BULLETIN No. 940 { 



Contribution from the Bureau of Animal Industry > ^ 



J&9*^&1* JOHN R. MOHLER, Chief sZ&p'^&U 



Washington, D. C. 



PROFESSIONAL PAPER 



April 25, 1921 



THE SPOROGENES TEST AS AN INDEX OF THE 

 CONTAMINATION OF MILK. 



By S. Henry Ayees and Paul W. Clemmer, of the Dairy Division. 



CONTENTS. 



Page. 



Present status of the sporogenes test- 1 



The Savage method 3 



The Weinzirl method „_ 6 



Defects in the sporogenes test 7 



Attempts to improve the characteris- 

 tic stormy reaction 9 



Use of 20 c. c. quantities of milk in 



the sporogenes test 11 



The sporogenes test in relation to 

 milk produced under extreme con- 

 ditions of cleanliness and of filth_ 12 



Page. 



Conditions of production of pasteur- 

 ized milk as indicated by the spo- 

 rogenes test 14 



The source of the majority of spores 

 of B. enteritidis sporogenes found 

 in milk 16 



Summary and conclusions 19 



Literature cited 20 



PRESENT STATUS OF THE SPOROGENES TEST. 



The sporogenes test is based on the characteristic milk reaction 

 produced by certain anaerobic spore-forming bacteria which are 

 widely distributed in nature and which are particularly common in 

 fecal material. 



Numerous names have been given to anaerobic bacteria that give 

 the typical milk reaction, some of which are the following: B. ente- 

 ritidis sporogenes (Klein) ; B. aerogenes capsulatus (Welch), syno- 

 nym B. welchii (Migula) ; B. per f ring ens (Yeillon and Zuber) ; 

 and B. Saccharobutyricus immobilis (Schattenfroh and Grass- 

 berger). It is generally believed that the organisms bearing these 

 names are either identical or very closely related species. 



In milk, under anaerobic conditions, these organisms produce 

 what is known as the " stormy " fermentation. In a characteristic 

 reaction the casein is coagulated and the curd torn by gas within 24 

 hours at 37° C. The whey is usually quite clear and the odor of 

 butyric acid is noticeable. When the milk in a test tube is covered 

 with a paraffin plug the latter is usually forced up almost to the top 

 of the tube and sometimes entirely out of the tube. 

 25154°— 21 1 



