CHAPTER XIV 



THE CONTAMINATION OF FOODS WITH 

 PATHOGENIC BACTERIA 



The diseases of man and the lower animals that are due 

 to the growth of microorganisms in the body of the living 

 animal are propagated by the passage of the organism from 

 the body of the diseased individual into the body of a still 

 healthy individual. Many diseases are transmitted only by 

 very direct contact of the healthy with the diseased. With 

 others the organism may be transported over long distances 

 in time and space. Many objects may serve as transport- 

 ing agents. Prominent among them are certain foods. 



The causal organisms are usually contained in some of 

 the discharges of the body, which in one way or another 

 come in contact with food materials. Frequently the or- 

 ganisms are not resistant to desiccation, and in this case 

 can not be distributed on dry solid objects, but may be car- 

 ried by moist foods such as milk and water. There are a 

 number of reasons why these foods are especially important 

 in the causation of disease. In the case of milk, the prod- 

 uct of many farms is brought together and mixed in the 

 plant of the milk distributor. A contamination of the 

 product on any one farm may thus result in the introduc- 

 tion of the harmful organism into hundreds of city homes. 

 The original contamination may be slight, but by the time 

 the milk is consumed, it may contain an innumerable num- 

 ber of the organisms; for certain of the pathogenic bac- 

 teria find in milk a favorable nutrient medium, and can 

 grow at. the temperatures at which it is often stored. There 



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