Ultrastructural and Chemical Changes in Spores of Bacillus cereus after Action of Disinfectants

Spores of Bacillus cereus subjected to 5% NaOH at 50° and 0.25% NaOCl at 20° undergo a 99% loss in viability in 11 and 19.5 min, respectively. Kinetic studies show that the release of Ca 2+ and dipicolinic acid occur at different rates and that extensive loss of both ribonucleic and deoxyribonucleic acids occur under these conditions of disinfection. Electron micrographic studies reveal a progressive degradation of the spore integuments. Both chemical and ultrastructural observations made in this study lead to the conclusion that the primary lethal effect of either disinfectant is the modification of outer spore coats leading to a disruption of normal permeability barriers.