Evidence of Cytoplasmic Membrane Injury in the Drying of Bacteria

The bacterial cell is extremely sensitive to drying or exposure to low levels of moisture, al-though there is much variation in the suscepti-bility of different species, some being quite re-sistant. Lyophilization, or freeze-drying, which is widely used for preserving a variety of bio-logical substances, has been found to be quite injurious to many species of bacteria (Fry, 1954). The loss of viability of bacteria in the aerosol state has been studied extensively (Ferry, Brown, and Damon, 1958). Moreover, in certain instances (Monk et al., 1956; Monk and McCaffrey, 1957) bacteria which have survived drying are found to die at a rapid rate when exposed to critical moisture levels.