PAPERS ON AGRICULTURE 119 
THE INFLUENCE OF UTENSILS ON THE GERM 
CONTENT OF MILK 
M. J. PRUCHA, UNIVERSITY OF ILLINOIS 
In the crusade for sanitary milk supply, the efforts have 
been centered largely upon the production of milk with a 
small number of bacteria. Milk, as it passes from the milk 
glands of the cow to the final vessel in which it is sold, is ex- 
posed to numerous sources of contamination, and before sani- 
tary milk production can be placed upon a rational basis it is 
necessary to have more definite information on the relative im- 
portance of the various sources of contamination. 
With this in view the investigation on the utensils as a 
source of bacteria in milk has been undertaken by the Dairy 
Department at the University of Illinois. The investigation 
has shown that utensils, when cleaned in the ordinary manner, 
and not sterilized, add very large numbers of bacteria to the 
milk. 
The extent of contamination of milk by the utensils is forc- 
ibly brought out by one of the experiments in this investiga- 
tion.* In this experiment all the utensils were steamed for 
each milking during fourteen days and the samples were taken 
from the milk as it passed into the respective utensils. During 
the following two weeks the utensils were washed, but were 
not steamed, and samples were again taken. The results are 
summarized in the following table. 
Utensils Sterile 
Bacteria per cc. 
Milk leaving barn 2,277 
Same milk, one hour later, bottled 3,875 
Utensils Not Sterile 
Increase due to 3 pails 57,077 
Increase due to strainer 15,353 
Increase due to clarifier 172,763 
Increase due to cooler 19,841 
Increase due to bottler 247,611 
Total in bottled milk one hour old 515,200 
In this experiment only 2,277 bacteria were due to all the 
barn conditions and over half a million bacteria were intro- 
duced into the milk by washed utensils. All other experiments 
lead to the same conclusion, namely, that the utensils as cleaned 
and cared for by the methods in vogue are a very important 
source of bacteria in the milk. 
•The results of the entire investigation are published in a bulletin by the Ag- 
riculture Experiment Station at the University of Illinois. 
