EXPERIMENT STATION BULLETINS. 457 



SUMMARY 



An anaerobic themophile was isolated from several cans of one pack of 

 under-processed cold-packed string beans. 



The liquor from the under-processed string beans was not found definitely 

 to be poisonous to the experimental animals employed. 



An odor fruity, even disagreeable, accompanies the growth of the anaerobic 

 thermophile Str. BIC in all media, which odor, should this organism occur in 

 canned food, would render the product not liable to be eaten, especially as 

 the odor is intensified on heating. 



The colonies which form in shakes of various agar media have about the 

 same refractive index as the medium, and so are very difficult and in some 

 cases impossible to see. In such media their presence has always been de- 

 tected by the characteristic odor if the culture is old enough, and in many 

 media by active gas production. The anaerobic thermophile described grows 

 in practically all media tried experimentally. 



So far as the literature on the thermophiles has been searched no reference 

 has been found relating to an anaerobic thermophile, nor to an aerobic ther- 

 mophile, nor to bacteria growing at ordinary temperatures, which have the 

 above-mentioned peculiarity of growth, with the exception of those described 

 by Bronson BarloAV in his studies of thermophiles in canned corn. 



CONCLUSIONS 



So-called "fiat sours" may be caused by bacteria which form acid, and 

 perhaps so little gas that the ordinary glass-topped cans on opening by ordi- 

 nary methods may fail to show its presence to the housewife, and metal- 

 topped cans may fail to have the appearance of a "swell." It is improbable 

 that flat sours of this type may be due to an anaerobic thermophile such as 

 described in this paper since any considerable growth of this organism would 

 produce a swell and not a flat sour. 



Anaerobic thermophiles of this type are probably found in various places 

 ni nature; the fact that they have not been found previously is due to im- 

 proper incubation, poor choice of media and the wrong method of obtaining 

 anaerobic conditions. 



BIBLIOGRAPHY 



Barlow, Bronson. 



Spoilage of Canned Corn due to Thermophilic Bacteria. 

 Master's Thesis, U. of IlUnois, 1913. 



