UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 940 «Sb 
Contribution from the Bureau of Animal Industry *^J 
JOHN R. MOHLER, Chief J&p'^^U 
sw^su 
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. 
Present status of the sporogenes test- 
The Savage method 
The "Weinzirl method 
Defects in the sporogenes test 
Attempts to improve the characteris- 
tic stormy reaction 
Use of 20 c. c. quantities of milk in 
the' sporogenes test 
The sporogenes test in relation to 
milk produced under extreme con- 
ditions of cleanliness and of filth_ 
Page. 
1 
11 
12 
Conditions of production of pasteur- 
ized milk as indicated by the spo- 
rogenes test 
The source of the majority of spores 
of B. enteritidis sporogenes found 
in milk 
Summary and conclusions 
Literature cited 
Page. 
14 
16 
19 
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. perfringens (Veillon and Zuber) ; 
and B. Sac char obutyHcus 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 
