584 MICROBIOLOGY OF FOODS 



HUMAN INFECTIONS TRANSMITTED IN FOOD 



Food may serve as the passive carrier of the germs of any human in- 

 fectious disease capable of indirect transmission upon dead material. 

 In some foods, especially milk, these infectious agents may actually 

 multiply. Typhoid fever, diphtheria and scarlet fever appear to be 

 rather frequently disseminated through the agency of food, and para- 

 typhoid fever seems to be commonly transmitted in this way. Especial 

 precautions are advisable to prevent persons afflicted with dangerously 

 communicable diseases and those who are chronic germ-carriers from 

 engaging or continuing in occupations concerned with the immediate 

 preparation of food for consumption, particularly such occupations as 

 milk production and handling, market-dairying, cooking and serving 

 food. Numerous serious epidemics have been traced to such sources 

 in recent years. The history of Mary Mallon (Typhoid Mary)* has 

 become popular knowledge but instances of similar spread of infection 

 are but too common. 



FOOD POISONING DUE TO THE GROWTH OF SAPROPHYTIC BACTERIA IN 



THE FOOD 



Most food poisonings are due to food derived from perfectly healthy 

 and wholesome animals or plants, which has subsequently undergone 

 some bacterial decomposition giving rise to poisonous products. Our 

 knowledge of the specific causes of the poisonous changes is, however, 

 very incomplete, and on account of the difficult nature of investigation 

 in this field, some of the conclusions reached by careful men are still 

 open to question. The bacteria which have been most frequently 

 identified with various epidemics of food poisoning are the following: 

 B. enteritidis in meat poisoning; B. botulinus in meat, sausage and 

 vegetable poisoning; B. paratyphosus in poisoning with meat, chicken, 

 shellfish, and vegetables; B. coli in cheese poisoning and in milk poison- 

 ing; B. vulgaris in meat and in vegetable food poisonings. Doubtless 

 other microorganisms, as yet unrecognized, play an important part in 

 .many food poisonings, and there is reason to believe that some of these 

 important unknown forms are anaerobic bacteria. 



POISONOUS MEAT AND SAUSAGE. The flesh of a healthy animal is 

 ordinarily free from bacteria at the time of slaughter, and bacterial 



* Soper, George A.: Typhoid Mary. The Military Surgeon, July, 1919, Vol. 45, pages 1-15 



