SOURCES OF THE CONTAMINATION OF MILK. 45 



Sources of the contamination of milk. The means by which 

 typhoid fever bacilli are disseminated by the individual offer 

 frequent opportunity for the infection of milk. The typhoid 

 patient is believed by some to disseminate the disease during 

 the incubation period and early stages of the disease. Certain 

 it is that patients, long before taking to bed, disseminate ba- 

 cilli through the urine and feces. This is equally true of walk- 

 ing cases that never take to bed. The danger is augmented 

 by the fact that diagnosis may be delayed until the second or 

 third week, and in the mild cases no diagnosis is made, and 

 thus no warning is given. 



The patient in bed is a menace through the careless disposal 

 of excreta. Thus, infection may be disseminated through the 

 nurse, by flies when allowed access to discharges on the ground 

 or in open vaults, and by the contamination of the well or 

 stream. All these factors may play a part in milk infection 

 on a dairy farm. 



The convalescent may return to work while yet dissemin- 

 ating infection. A considerable number of those recovering 

 from typhoid for years afterwards continue to disseminate 

 infection. Such cases or others harboring bacilli, with no 

 previous history of typhoid fever, are called bacilli carriers, 

 and are believed to be significant factors in the spread of the 

 disease (25). Adequate means for protecting the public from 

 this source of danger have not yet been put into general prac- 

 tice. 



In the dairy there are certain practices that facilitate the 

 infection of milk. The failure to wash the hands before milk- 

 ing and the common practice of wetting the hands with milk 

 are particularly dangerous. As likely as not the milker may 

 be acting as nurse in the sick room. 



Conditions that would permit flies to come in contact with 

 milk or the cans are common in dairies. 



Common practice in connection with the care of utensils 

 leaves many opportunities for contamination by polluted water. 

 Oftentimes, the milking utensils are not scalded after the even- 

 ing's milking, but are merely rinsed in cold water. The 

 scalding given utensils is very apt to be inefficient and does 



