MICHIGAN ACADEMY OF SCIENCE. 135 



Most of them digested starch, many with the production of sugar, 

 although complete starch reduction was observed where no sugar test with 

 Fehling's solution was found. 



A number of these bacteria would not produce spores in broth, although 

 spores were produced both in peas and in gelatin agar. 



Nearly all organisms survived heating in the autoclave at 10 pounds pres- 

 sure for 20 minutes, but were killed when autoclaved at this pressure ..for 30 

 minutes. Again they withstood autoclaving at 15 pounds pressure for ten, 

 but not for twenty minutes. These tests were made with test tubes of neutral 

 or slightly alkaline broth, inoculated with the spores. 



I have not worked out as yet how long it would take to kill these organ- 

 isms when in a can of peas. Work has been done with tin cans along that 

 line, however, by A. W. Bitting and K. G. Bitting, who state in their bulletin, 

 "Bacteriological Examination of Canned Foods," that it takes over 20 minutes 

 for the center of a can of peas to reach 248° F.. which is the temperature at 

 15 pounds pressure. With a glass jar there would be a variation, as there 

 would be also with different cans of peas depending upon the proportion of 

 solid and liquid matter present. 



From these data and the results which I obtained, it is perfectly logical to 

 conclude that the time given in government bulletins for the processing of cold 

 pack canned vegetables is not sufDcient in many cases. It is known that in a 

 large number of cases these directions have worked satisfactorily, but many 

 instances are. also known where housewives have attempted to conserve food 

 by this method and had dozens of cans spoil when these directions had been 

 followed absolutely. I personally know of an instance where an organism 

 resembling B. botuUnus survived the three-hour hot water bath heating pre- 

 scribed. Food poisoning was caused in this case. How long a period of proc- 

 essing necessary for absolute safety, is still a problem to be solved. 



Michigan Agr. College. 



