DISEASES CAUSED BY INFECTED MILK 113 



Typhoid fever 



Of the diseases which occur in epidemic form as a result 

 of infected milk, typhoid fever is the most frequent. 

 In fact, with a clean water supply milk is almost the only 

 remaining medium capable of causing violent and exten- 

 sive outbursts of this disease. Oysters and other foods 

 partaken raw are responsible occasionally for small out- 

 breaks. 



The typhoid bacillus grows well in milk. Therefore, if a 

 small particle of matter containing this micro-organism, 

 or even if one typhoid germ accidentally gets into milk, it 

 may undergo rapid multiplication and soon become dis- 

 seminated throughout the mass. The typhoid bacillus is 

 actively motile so that every drop of the milk will contain 

 some of these micro-organisms if it is infected; a tumbler- 

 ful of milk may contain countless myriads. 



Milk may appear to be perfectly fresh and sweet and yet 

 contain vast hordes of typhoid bacilli. In fact, this micro- 

 organism grows and multiplies in milk without producing 

 any material change in its color, odor, taste, or appearance.^ 1 

 Therefore the danger is insidious, and the phrase that "ty- 

 phoid lurks in milk," while trite and unpleasant, is never- 

 theless true. In view of the tremendous multiplication 

 which can take place in milk, especially when it is warm, it 

 is easy to appreciate how one bottle or less of infected milk 

 taken into a dairy may, when mixed with a large volume, 

 convey the infection to several thousand persons. We have 

 the instance of the Boston epidemic of 1908, which caused 

 over one thousand cases from a single source of contamina- " 

 tion. 



It is not milk alone but fresh milk products that are 

 occasionally responsible for typhoid fever. The disease has 

 been traced to infected ice cream, butter, and cream. We 

 know that the process of freezing does not destroy the 

 typhoid bacilli. In our experience in Washington several 



