RELATION OF BACTERIA TO DAIRY PRODUCTS 553 



milking time. When this trouble occurs, a thorough steriliz- 

 ing of all utensils will usually be effective in getting rid of it. 



Milk as a carrier of disease 



It has long been known that certain diseases may be carried 

 by milk, and the history of many milk-borne epidemics is 

 on record. 1 Certain diseases such as tuberculosis, foot-and- 

 mouth disease, and anthrax may be transmitted through the 

 milk directly from a cow suffering with the disease. There is 

 another group of diseases, such as typhoid fever, diphtheria, 

 scarlet fever, and septic sore-throat, in which the specific organ- 

 isms do not come from the cow, but get into the milk from 

 some human source, the milk acting simply as a carrier of the 

 organisms. Still another group of diseases, more or less indefi- 

 nite in nature, but in general represented by intestinal disorders, 

 may be caused by organisms which are carried in milk. 



Of the diseases which may be transmitted directly from the 

 cow, tuberculosis is by far the most important. The extent 

 to which this disease is transmitted by milk to human beings is 

 not definitely known, but the frequency with which the bovine 

 type of tubercle bacilli has been found in children indicate 

 that there is a considerable number of such cases. Fortunately, 

 the tubercle bacilli do not multiply in milk, so that the number 

 at the time the milk is consumed is no greater than when it 

 left the cow. 



Of the diseases which are transmitted from man to man by 

 way of the milk supply, typhoid fever is the most important. 

 The organisms which cause this disease gain entrance to the 

 milk in a number of ways, the more important probably being 

 direct contamination of the milk, by some person suffering with 

 the disease or having recovered, but still carrying the organ- 

 isms, or through contamination of the milk utensils by infected 



1 Bulletin 56 — Public Health and Marine Hospital Service. 



