Comparative studies of the effect of physical factors on endospores and conidiospores of some thermopiles and mesophiles: effect of irradiation, freezing and thawing

ABSTRACT

The sensitivty of endospores and conidiospores of some thermophilic and mesophilic organisms to gamma-radiation and freezing and thawing was compared. Endospores were more resistant to gamma-radiation than conidiospores. Within each group, spores of Thermophiles were more radioresistant than spores of mesophiles. The reverse was mostly true for the effect of freezing and thawing, where endospores of Bacillus stearothermophilus were the most sensitive to freezing and thawing. The DR value for endospores of Thermoactinomyces vulgaris, B. stearothermophilus and B. subtilis are in respect 2.70, 2.25, and 3.0 KGY, while the DR value for conidiospores of Aspergillus fumigates, Penicillum sp., Streptomyces anadii and Streptomyces sp., are in respect, 0.6, 0.41, 0.708 and 2.25 KGY. Slow freezing and slow thawing is generally more damaging than fast freezing and fast thawing