84 



SCIENCE 



[N. S. Vol. XLVII. No. 1204 



outbreak of 93 eases of typhoid infection 

 due to a dish of 'baked spaghetti. Here it 

 was found 'by subsequent experiment that 

 the degree of heat reached in the interior 

 of the dish was an incubating rather than 

 a sterilizing temperature. Milk, which is 

 an excellent culture medium, is a food par- 

 ticularly liable to become dangerous through 

 the multiplication of bacteria. The mixing 

 of milk from many farms at a central 

 station tends to disseminate any contami- 

 nation present through the whole supply. 

 One typhoid carrier on a single farm may 

 therefore lead to the contamination of a 

 large volume of raw milk and to an exten- 

 sive epidemic. The pasteurization of milk 

 offers a satisfactory method of meeting 

 this danger. 



Besides the various modes of direct con- 

 tact there are more roundabout methods of 

 food contamination from human sources 

 of infection. One possibility is the trans- 

 mission of typhoid infection by vegetables 

 grown on land fertilized by night soil. The 

 practise of manuring truck gardens with 

 human excreta is not unknown in this 

 country and is believed by some to be in- 

 creasing. Melick* has shown that typhoid 

 bacilli may remain attached for several 

 weeks to lettuce and radishes grown in 

 contaminated soil, a period quite sufficient 

 for the maturing of these vegetables. He 

 also showed that the bacilli are not removed 

 from the surfaces of the vegetables by tlie 

 ordinary methods of washing used in pre- 

 paring such foods for the table. 



The second type of food-borne infection, 

 that in which the food itself is contami- 

 nated at its origin and does not simply pick 

 up contamination en route to the consumer, 

 is especially exemplified in the case of 

 certain infections of the ordinary food 

 animals. Food plants are not attacked 'by 

 any microorganism pathogenic to man, with 



i Jour. Infect. Bis., 1917, 21, p. 28. 



perhaps the single exception of the coconut 

 palm, in which a disease called bud-rot is 

 said to be caused by a variety of B. coli, 

 an organism usually harmless but under 

 some conditions slightly pathogenic for 

 man. The rather numerous species of bac- 

 teria that cause the diseases to which the- 

 common garden vegetables are subject are 

 none of them, so far as known, pathogenic 

 for man or other animals. On the other 

 hand, many food animals suffer from bac- 

 terial infections that may be communi- 

 cated to man. 



Milk is probably the animal food that 

 serves most commonly as the vehicle of this 

 type of infection. It has 'been definitely 

 established that the bacillus of bovine tu- 

 berculosis may be present in the milk of a 

 diseased cow and that the use of such milk 

 in a raw state is a source of human in- 

 fection, particularly in young children. 

 Milk from diseased animals may also pro- 

 duce infection in foot-and-mouth disease, 

 in Malta fever (goat's milk) and in some 

 other diseases. In many cases the condi- 

 tion of the animal is such as to give ample 

 warning, in others the danger is not so 

 readily apparent. Adequate pasteuriza- 

 tion of the milk is a safeguard against this 

 mode of infection as well as against in- 

 fection with milk contaminated from hu- 

 man sources. 



Other food products originating from 

 diseased animals may contain pathogenic 

 bacteria. A noteworthy number of out- 

 breaks of meat poisoning have been traced 

 to the use of meat from animals ailing at 

 the time they were slaughtered, and later 

 discovered to have been definitely infected. 

 Bacilli of the paratyphoid-enteritidis group 

 are found in a large proportion of these 

 cases, both in the meat of the diseased 

 animals and in the organs or excreta of the 

 persons affected. This class of food in- 

 fections is of special interest, since in their 



