1. Control of Microorganisms by Physical and Chemical Agents LECTURE 9: Microbiology and Virology; 3 Credit hours Atta-ur-Rahman School of Applied Biosciences (ASAB) National University of Sciences and Technology (NUST)

2. Control of Microorganism The goal is two fold: 1.to destroy pathogens and prevent their transmission, and 2.to reduce or eliminate microorganisms responsible for the contamination of water, food, and other substances.

3. Important Definitions Disinfection: The destruction or removal of vegetative pathogens but not bacterial endospores. Usually used only on inanimate objects. Sterilization: The complete removal or destruction of all viable microorganisms. Used on inanimate objects.

4. Important Definitions Antisepsis: Chemicals applied to body surfaces to destroy or inhibit vegetative pathogens Chemotherapy: Chemicals used internally to kill or inhibit growth of microorganisms within host tissues

5. Important Definitions Sanitization is closely related to disinfection. In sanitization, the microbial population is reduced to levels that are considered safe by public health standards Germicide kills pathogens (and many non- pathogens) but not necessarily endospores. Bactericide, fungicide, algicide, or viricide Bacteriostatic and fungistatic

6. Microbial Control Methods