CHAPTER XXXV 

 THE BACTERIA OF FOOD POISONING 



EDWIN O. JORDAN 



University of Chicago 



The term "food poisoning" has come to have a special technical meaning and is 

 today most commonly applied by public health workers to certain infections or 

 intoxications due to particular micro-organisms. The specific bacteria concerned in 

 food poisoning may be grouped broadly in three divisions: (i) paratyphoid bacilli; 

 (2) Clostridium bokdimim, varieties A, B, and C; (3) miscellaneous bacteria. While 

 such a grouping — like classifications generally — is for convenience only, it fairly re- 

 flects the present state of our knowledge. 



I. PARATYPHOID BACILLI 



In recent years the chief interest in these organisms has centered in the attempts 

 to unravel the tangled skein of host relationships, in the effort to determine more 

 exactly sources of infection, and in the study of toxin production. In all three lines 

 of investigation significant progress has been made. 



Paratyphoid bacilli may be readily distinguished, on the one side, from the B. coli 

 group through their inability to ferment lactose; and, on the other, from B. typhosus 

 through their gas production (not, however, absolutely invariable) in dextrose and 

 other carbohydrate media.' A more constant characteristic differentiating them from 

 typhoid bacilli is their abiUty to ferment rhamnose. So far as a single cultural char- 

 acter can have weight, rhamnose fermentation affords the readiest means of dis- 

 tinguishing paratyphoid bacilli from typhoid (and dysentery) bacilli. Other cultural 

 characters combine to give the group an independent and distinctive character.^ The 

 generic name Salmonella was bestowed by Lignieres upon the organisms of the "hog- 

 cholera group" in 1900 and, although open to objection, appears to be used with 

 increasing frequency. Bergey's MamiaP lists nineteen specifically named kinds. 



Within the group or "genus" a gay medley of names and "species" has long exist- 

 ed, partly because of preconceived ideas respecting identification, partly because of 

 the real lack of suitable differential tests coupled with the great variability of many 

 members of the group. One fertile source of error has lain in the institution of exten- 



' Non-gas-producing strains of various members of the group have been described by a number of 

 observers: Dorset: iSth Ann. Rep., Bur. An. Ind., p. 566. 1901; Bock, F.: Arb. a. d. k. Gesundh., 

 24, 238. 1906; Bainbridge, F. A.: /. Path, b" Bad., 13, 443. 1908-9; Ten Broeck, C: /. Exper. 

 Med., 24, 213. 1916. I have one such anaerogenic strain that has been under observation for over 

 twenty-five years without change in gas-producing power. Fluctuations in gas-producing power may 

 develop even after a long period of apparent stability. For a recently reported instance cf. Emmy 

 Klieneberger (Centralbl.f. Bakteriol., Abt. I, Orig., loi, 305. 1927). 



^Jordan, E. O.: /. Infect. Dis., 20, 457. 1917. 



3 Bergey, D. H., ef al: Manual (2d ed.). 1925. 



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