RECOVERABILITY OF HEAT-INJURED BACILLUS SPORES BY LYSOZYME AND EDTA OR ALKALINE THIOGLYCOLATE

The D-95 degrees C value of Bacillus thuringiensis spores plated in th e presence of lysozyme increased from 3.0 min to 3.6 min by post-treat ment of heat-injured spores with 50 mM EDTA. In the case of Bacillus a lvei and Bacillus polymyxa spores D-values decreased from 4.9 to 4.3 m in and from 4.7 to 4.1 min respectively. Post-treatment of heat-injure d spores treated with alkaline thioglycollate increased D-95 degrees C values of Bacillus alvei from 4.2 to 5.3 min, B. thuringiensis 3.6 to 4.7 min, and Bacillus polymyxa from 4.2 to 5.0 min when spores were p lated in the presence of lysozyme. Electron micrographs of heat-injure d B. alvei spores treated with sodium thioglycollate indicated that th e coat layers of the treated spores were granulated and less intact th an the control spores.