446 THE BACTERIA OF FOOD POISONING 



Although B. aertrycke has been isolated in typical outbreaks of food poisoning 

 more frequently than any other paratyphoid bacillus, little has been ascertained 

 about its source. In the fourteen instances in which this organism was found by 

 Savage and White, generally in necropsy material, the suspected foods cover a wide 

 range, such diverse articles as canned tomatoes, canned salmon, canned apricots, 

 milk, and shellfish (cockles) being among them. In but three of the fourteen out- 

 breaks did direct bacterial examination of the food give a clue to the origin. In one 

 instance B. aertrycke was isolated from suspected steak and liver gravy, in one from 

 beef brawn, in one from ice-cream. In a fourth outbreak, occurring in Glasgow and 

 due to milk, B. aertrycke was isolated from an apparently healthy cow at the impli- 

 cated dairy. In the remaining ten outbreaks not much can be safely inferred regard- 

 ing origin, especially since in several cases the evidence incriminating particular food 

 articles seems highly conjectural. Many other reports fail to trace infection with 

 B. aertrycke to a definite source.' In certain instances investigators have surmised 

 that contamination of food by rats or mice gave rise to the outbreak.^ 



While B. aertrycke and B. enteritidis are the organisms of the paratyphoid group 

 that have been most commonly isolated in connection with food-poisoning outbreaks, 

 B. suipestifer has been occasionally reported.^ It is remarkable that no connection 

 has ever been traced between the relatively frequent outbreaks of hog cholera in 

 which B. suipestifer is found abundantly and outbreaks of human disease. This may 

 be due to marked variations in virulence or to the fact that a very massive dosage is 

 necessary to produce infection. 



Other bacilli of the paratyphoid group do not appear to have been definitely 

 implicated in food poisoning outbreaks, although they should be regarded as poten- 

 tially dangerous. Numerous outbreaks attributed to horse meat are reported in Ger- 

 many,'' but do not seem to have been adequately investigated bacteriologically. 

 At least two outbreaks due to horse meat have been described with considerable 

 detail,^ but in neither case, unfortunately, was the causal organism certainly identi- 

 fied, so that it remains unknown whether the equine paratyphoid strain (B. abortivo- 

 equinus) was concerned. 



Neither is it known whether the various avian paratyphoid strains, B. sanguinari- 

 um, B. pullorum, and B. anatum, are capable of giving rise to food poisoning. As yet 

 they have never been definitely incriminated. These organisms, however, must be 

 looked upon as possible sources of danger.** It is of great interest that B. aertrycke 

 has been found to be the cause of epidemics in canaries, parrots, and squabs." 



The studies summarized above on the differentiation and distribution of the 



' E.g., Perry, H. M., and Tidy, H. L.: Med. Research Com., Spec. Rep. Ser., No. 24. 



=* E.g., Savage, VV. G., and White, B.: op. c'U., Outbreak No. 51; Burgess, W. L.: Proc. Roy. Soc. 

 Med., Sec. Epid.b° SlateMed., 18, 61. 1924-25; Salthe, O., and Krumwiede, C, Jr.: J.IIyg., 4, 23. 

 1924. 



3 Krumwiede, C, Jr., Provost, D. J., and Cooper, G. M.: J. Med. Research, 43, 53. 1922; Scott, 

 W.M.: J. Hyg., 25, 406. 1926; Shaw, F.W.: /. Lab. &° Clin. Med., 12, 141. 1926. 



4 Meyer, R.: Rekhs-Gesimdheilsbl., i, 1027. 1926; Ahstr., Bull. Hyg., 2, 469. 1927. 

 sFederschmidt: MUnchen. med. Wchnschr., 67, CS14. 1920; Harms: ibid., 73, 777. 1926. 



6 Smith, T., and Ten Broeck, C: J. Med. Research, 31, 52^,. 1914-15; Rcttger, L. F., Hull, T. G., 

 and Sturges, W. S.: J. Exper. Med., 23, 475. 1916. 



'Beaudette, F.: /. Am. Vet. M.A., 68, 642, 644. 1926. 



