List three physical agents and three chemical agents used for microbial control.
Physical agents: temperature (high temperature and dry heat have the best effect), radiation (X-rays or UV-rays can induce mutations which cause imbalance in the vital processes), moist pressure (causes coagulation of proteins);
Chemical agents: alcohols (cause denaturation of proteins and dissolve lipids), surface-active agents (emulsify fats), quaternary ammonium compounds (disrupt plasma membrane, and the cytoplasm leaks out).