436 Bacteria in Relation to Country Life 



swelled within twenty-four hours, and, in some instances, 

 the internal pressure was great enough to burst the can. 

 In order to determine its resistance to heat, a number 

 of inoculated cans were heated at 230° for varying lengths 

 of time, sealed in the usual manner, and kept under 

 observation. Nearly all of the cans heated for twenty or 

 twenty -five minutes swelled within ten days. Of the 

 cans heated for thirty minutes only 16 per cent swelled 

 in the same length of time, while none of the cans heated 

 for thirty-five or forty minutes showed any evidence of 

 swelling. 



Further tests with a temperature of 240° Fahr. 

 demonstrated that at least thirty minutes were neces- 

 sary for the efficient sterilization of the cans, although 

 even with this treatment, a very few showed signs of 

 sweUing. An examination of the spoiled cans showed 

 that those that had been heated for ten minutes contained 

 a mixture of several organisms, while those heated for 

 a longer time contained only the characteristic resistant 

 species. 



A less resistant form that caused the souring of the 

 peas without the production of marked quantities of 

 gas was also found. This form, when inoculated into 

 sterile peas, produced the characteristic souring of the 

 liquid, which assumed a milky appearance. We are 

 taught, thus, that there are organisms in canned goods 

 capable of withstanding temperatures of 230° or 240° 

 Fahr. for varying lengths of time, and that there may 

 be others not yet studied whose resistance to heat is 

 even greater. These organisms constitute, at times, 

 a serious problem for the canner, since he cannot afford 



