A HIGHLY RESISTANT THERMOPHILIC ORGANISM 



P. J. DONK 



Research Laboratory, National Canners Association, Washington, D. C. 

 Received for publication February 10, 1920 



An examination of spoilage samples of "Standard Maine 

 Style" corn which had been packed in the usual manner and 

 processed at 118°C. for 75 minutes showed the presence of a 

 thermophile. The same organism was later found in spoiled 

 cans of string beans and corn on the cob. It appears to be an 

 unknown species and the name Bacillus stearothermophilus is 

 proposed for it. 



Its cultural characteristics are as follows : 



Name proposed: B. stearothermophilus. (N. S.) 



Source: Canned corn. 



Date of isolation: October 3, 1917. 



Vegetative cells: Medium used, agar; temperature, 60 to 65°C; age, 

 twenty-four hours; form, large rods; arrangement, majority single, 

 some in pairs end to end and few in chains of three or four. Size of 

 majority 0.8 by 3.5 micra; ends rounded. 



Relation to oxygen: Aerobic, facultative anaerobic. 



Endospores: Present; location, polar. Size of majority 1 by 1.5 

 micra. 



Motility: None. 



Flagella: None. Muir's modification of Pittfield's method, and 

 Loeffler's method. 



>Gram stain: Negative. 



Nutrient broth: Surface growth, none; no pellicle or ring; clouding of 

 medium uniform, odor, absent; sediment, compact, abundant. 



Agar stroke: Growth, moderate; form of growth, generally filiform, 

 sometimes slightly beaded, never spreading; elevation of growth, quite 

 regular; optical character, translucent; chromogenesis, none; color, 

 dirty white; odor, absent; consistency, butyrous. 



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