1. LECTURE 21: Control of Microorganisms by Physical and Chemical Agents 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: • to destroy pathogens and prevent their transmission, and • 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 killor 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 • Germicidekills pathogens (and many non-pathogens) but not necessarily endospores. • Bactericide, fungicide, algicide, or viricide • Bacteriostaticand fungistatic

6. Microbial Control Methods