CHAPTER VIII 



MILK HYGIENE 



Milk as a distributer of disease. Milk frequently serves 

 as an agent for the transmission of communicable diseases. 

 Such distribution may be from one animal to another of the 

 same or different species ; from animal to man, when the 

 disease is one common to both ; from man to man, in case of 

 diseases that do not affect the cow, but whose nature is such 

 that milk may be infected with the causal organisms. 



The most important of the diseases common to man and 

 cattle is tuberculosis. The milk may contain the tubercle 

 bacilli before being drawn from the udder, as when the mam- 

 mary gland is one of the organs affected, and even when no 

 disease can be detected in the udder. The milk may be in- 

 fected after its withdrawal, through the pollution with dust 

 and manure during the milking process. 



In tuberculosis of the lungs the tubercular abscesses not 

 infrequently break and discharge their purulent contents into 

 the air passages. This material is coughed up and swallowed 

 by the animal. During the coughing a small part is ejected 

 from the mouth. In the passage through the alimentary tract 

 the tubercle bacilli are uninjured by the digestive juices, the 

 material of which the sputum is composed is digested, and 

 the tubercle bacilli are freed and mixed intimately with the 

 feces. During the milking process more or less manure 

 gains entrance to the milk, and may infect it with the 

 disease-producing organisms. 



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