The effect of sublethal injury by heating, freezing, drying and gamma‐radiation on the duration of the lag phase of Salmonella typhimurium

The duration of the lag phase of Salmonella typhimurium surviving heat, freezing, drying and gamma‐radiation was used to indicate the time needed to repair sublethal injury. Following equivalent lethal treatments, heat and freeze‐injured cells needed longer to repair than those injured by drying or gamma‐radiation. Measurement of repair on membrane filters showed that in a heat‐injured population having a lag time of 9 h, some individual cells needed up to 14 h to recover maximum tolerance to 3% NaCl.