CHANGES IN THERMORESISTANCE OF SOME BACILLUS SPORES AFTER SUBLETHAL HEAT PRETREATMENT

Experimentation was designed to check if heat-induced resistance occur ed at increasing heating temperatures in four Bacillus species spores: B. stearothermophilus CNCH5781, B. stearothermophilus NCTC10007, B, c ereus F3748 and B. cereus (lab) in distilled water. Heat-induced resis tance was observed in these species and, the rate of temperature rise appeared to influence the amount of increase in heat resistance. The p henomenon was more stressed in thermophilic strains than in mesophiles . It suggests that the temperature of sporulation could play a role in the elevation of heat resistance after sublethal heating since a ther mophilic strain sporulated at 45 degrees C did not display heat-induce d resistance phenomenon.