Inactivation of Spores of Bacillus Species by Wet Heat: Studies on Single Spores Using Laser Tweezers Taman Spectroscopy

We have investigated the aspects of the release of Ca-dipicolinic acid (DPA), protein denaturation and cellular heterogeneity of single Bacillus spores during wet-heat treatment that are commonly used in spore killing and inactivation. Achievements include: (1) determined kinetic change in spore state and Ca-DPA levels in single spores of Bacillus and Clostridium species during heat activation; (2) measured the rates of Ca-DPA release and protein denaturation of individual spores when incubated in water at elevated temperatures; (3) determined the effects of wet heat-treatment on the germination of individual spores and identified the damages of key proteins; (4) developed useful methodologies to analyze multiple individual spores during wet-heat treatment and germination.