48 SHELLFISH CONTAMINATION FROM SEWAGE-POLLUTED WATERS. 



The examination made of water and food samples for E. coli has 

 resulted in diagnosing the presence of this organism only after iso- 

 lation and making a thorough study of its morphological and bio- 

 logical characters; even under these conditions many minor differ- 

 ences are found as to the quantity and character of gas produced, 

 the time required for coagulating milk, the amount of indol and 

 nitrites formed, its reaction on various culture media, and other 

 detailed considerations. 



Unless isolated and carefully studied in pure culture, no reliable 

 means are yet available for distinguishing the true colon bacillus, 

 by presumptive tests alone, from other gas-forming organisms, such 

 as B. lactis aerogenes, B. cloacse, etc. However, the presence of any 

 of these organisms in water is indicative of fecal matter. 



There seems to be no question regarding the undesirability of the 

 presence of the colon bacillus and allied organisms in water used in 

 any way for food purposes. The relation of this germ to the pollu- 

 tion or purity of water supplies seems to be now pretty well established 

 and there can be no doubt that water harboring this germ may be a 

 constant source of great danger, for where B. coli is found the spe- 

 cific cause of enteric 'fever, namely, B. typhosus, and also the cholera 

 spirillum, etc., may be present in sufficient numbers to produce infec- 

 tion when introduced into susceptible individuals. 



SUMMARY. 



(1) There is undisputed evidence to show that shellfish become 

 contaminated when placed in sewage-polluted water, and that B. coli 

 and B. typhosus will survive for variable lengths of time in the liquor 

 and the body contents of such shellfish after their removal from 

 infected water. 



(2) The presence of sewage organisms in oysters and other shell- 

 fish, even in small numbers, may be indicative of great danger; for, 

 where such organisms exist, the specific cause of enteric fever and 

 allied disorders may also be found. 



(3) The results of many investigators show that sewage-polluted 

 shellfish have been responsible for the production of typhoid fever 

 and other intestinal diseases. The most noteworthy cases appear to 

 have occurred from eating oysters which had been floated in sewage- 

 polluted water, although instances are cited where shellfish infected 

 by polluted water, either in their natural or artificial beds, have also 

 been the vehicle of disease transmission. 



(4) The shellfish industries of this country are extensive and 

 important, comparing favorably with other industries concerned 

 with the production of food materials. A valuable article of food is 

 furnished to millions of people by these industries, and thousands of 



