10 MASS. EXPERIAIENT STATION BULLETIN Z7c, 



interviewed, among those who had attended the banquet, only those who did 

 not eat the Hver paste escaped ilhiess. All of those who attended the con- 

 firmation party were infected. 



By the time the investigation was started, none of the liver paste was avail- 

 able for bacteriological examination. Consequently the evidence implicating 

 the paste was statistical and circumstantial, but hardly to be doubted. Bac- 

 teriological examination of the intestinal discharges of a number of the suf- 

 ferers, and of one of the persons who had helped to prepare the liver paste, 

 showed the presence of bacteria of the Salmonella group. 



This outbreak illustrates several characteristics of food poisoning outbreaks 

 in general: (1) It came from food prepared in large quantity, in a place 

 which served the public. (2) A large number of people were affected. It is 

 quite common for a large number of infections to follow a public function, 

 but infections can happen also among families in private homes. (3) The onset 

 was sudden and severe, and the symptoms were typical. (4) There were no 

 deaths, and recovery was relatively rapid. (5) By the time the outbreak was 

 reported to the authorities, none of the ofifending food was to be had for 

 examination. (6) A bacterium identical with that which contaminated the 

 food was isolated from one of the persons who prepared the food, so he may 

 have been a carrier. (7) Careless handling of the food was evident, especial- 

 ly the lack of refrigeration, on a warm day, that permitted rapid growth of 

 the bacteria. 



A wide variety of foods may carry bacteria of the Salmonella group. Meat 

 products, especially cold cuts and canned meat and fish, are common sources 

 of infection; and dairy products, including milk, cream, ice cream, and cheese 

 sometimes are sources. Infections frequently result from the eating of custard- 

 filled pastries, and occasionally from the eating of infected vegetables, especial- 

 ly beans and peas. Even such an unusual product as pineapple jelly has been 

 reported as having been the source of infection. It seems that almost any 

 kind of food can convey food poisoning if an infective germ is present, and 

 if the food has been improperly cooked or improperly handled after its prep- 

 aration. Tanner (16), in his book on food-borne infections and intoxications, 

 lists a number of outbreaks of food poisoning, and gives the number of cases 

 and the sources and circumstances of infection in each instance. 



The question arises: How do the responsible bacteria get into the food? 

 In the outbreak reported above in detail, a human carrier may have infected 

 the chicken-liver paste; and it is possible that human carriers may be as im- 

 portant in food poisoning infection as they are in typhoid fever. Where meats 

 and meat products are the sources of infection, the bacteria may come from 

 infected animals. It is unfortunate that, in most outbreaks, the remnants of 

 infected food have been destroyed before the illness is reported to health au- 

 thorities; and if fresh meat is the source, the butchered animal is even less 

 frequently available. Rats and mice are often considered responsible for food 

 poisoning, and a bacterium, Salmonella typhimurium, sometimes identified as 

 a cause of food poisoning, is also the cause of an intestinal disease among 

 rats and mice and may be spread to food from their droppings. Flour and 

 sugar bins could easily be infected that way, and it is thought that custard 

 and cream pastry fillings are often so contaminated. Insects, especially flies 

 and cockroaches, may help to spread bacteria from rodent droppings. 



Food Poisoning from Staphylococcus and Other Bacteria 



Another cause of food poisoning, now frequently recognized, is Staphylococ- 



