9-27-18 Lecture (anno)(1).pdf - CH 7 Controlling Microbial...

CH 7 Controlling Microbial Growth
– Sterilization:
– Disinfection:
– Antisepsis:
– Degerming:
– Sanitation:
removal/destruction of all living microbes
and spores and viruses
killing of vegetative pathogens on a surface
(inanimate objects); usually w/chemicals
reduction of pathogens from living tissue
(sepsis /asepsis)
removal of transient microbes from skin by mechanical
cleansing or by an antiseptic.
reduction of microbial populations on objects tosafe
levels
• The prevention, elimination, or control of microbes is
important in reducing the exposure to pathogenic microbes.

• Effect of antimicrobial treatments
 Bacteriostatic
 Bacteriocidal
• Exposure to antimicrobials reduces
cell numbers in an exponential
fashion  negative curve
• Factors influencing efficacy of
antimicrobial treatments:
– Number/types of microbes present
– Organic load
– Exposure time/dose
– pH, temperature

Physical & Chemical Agents of Control

Rate of Microbial Death
Data for bacterial culture
heated to 100°C ;
D ‐ value = ?