1 62 BACTERIA IN MILK. 



Tuberculosis. This subject will be considered in a separate 

 chapter. 



Typhoid Fever. Typhoid fever is produced by a well-known 

 bacterium primarily inhabiting the human intestine (Fig. 40). 

 Inasmuch as the cow is not subject to typhoid fever, milk, when 

 freshly drawn, will never contain typhoid bacilli. This disease, 

 therefore, bears quite a different relation to dairy matters from 

 tuberculosis. Milk, if infected with tuberculosis bacilli, contains 

 them when freshly drawn, and secondary infection is 

 a matter of no significance. But fresh milk never 

 contains typhoid bacilli, and if they are present in the 

 milk, they come wholly from secondary contamination. 

 FIG. 40. The chief sources of these secondary contaminations 

 baciHuJ. P are: I - Direct contact with persons who have or are 



recovering from the disease. It is well known that 

 patients may, after recovery from this disease, carry around the living 

 bacilli for a long time; "bacillus carriers" they are called. In other 

 cases the patient may be so slightly sick with the disease as to keep 

 about his work, having what is called "walking typhoid." If people 

 from either of these classes are employed in the dairy, they will be 

 pretty sure to infect with typhoid fever germs whatever dairy utensils 

 they handle. 2. Patients who are sick enough to be confined in 

 bed eliminate large numbers of bacilli in their excretion, and this, 

 together with clothing soiled by it, may be carelessly handled by 

 some one who is employed in the dairy. The chance of milk infec- 

 tion from such persons is, then, very great, and no one who has 

 anything to do with the care of a typhoid fever patient should be 

 allowed to have any contact with the dairy. 3. Infected water is 

 a common source of contamination. This does not mean that 

 the milk is necessarily watered; but milk may become infected 

 by simply allowing the cans to stand in impure water while they are 

 cooling or by rinsing the cans in such water after they have been 

 washed. There are also other secondary sources. That the danger 

 from these sources is real and not imaginary, may be judged from 

 the fact that already at least three hundred typhoid epidemics have 

 been traced to milk. 



