Control of Microbial Growth (Lec. 5) Flashcards
(18 cards)
Define sterilization
Complete elimination of any microbial life
Define disinfection
Removal of harmful microbial life from inanimate objects
Define antisepsis
Removal of harmful microbial life from animate objects
Define sanitization
lowering microbial counts on eating utensils to safe levels
Define bacteriostasis
Inhibiting, not killing microbes
Compare the effectiveness of moist heat and dry heat
Moist heat denatures proteins. Dry heat can also do that, but it’s more likely to damage the specimen more and just burn it.
Describe how filtration suppresses microbial growth
Physically removes microbes from entering an area
Describe how low temperatures suppress microbial growth
Reduced metabolic activity
Describe how high pressure suppresses microbial growth
Denatures proteins
Describe how desiccation suppresses microbial growth
Reduces water in the microbes and therefore slows down cell function
Describe how osmotic pressure suppresses microbial growth
Plasmolyzes cells
Explain how radiation kills cells
Damages the nucleic acids of the DNA, so it can’t encode proteins or reproduce
Identify the methods of action and preferred uses of chemical disinfectants
Microbiocidal germicides kill microbes. Microbiostatic germicides inhibit microbial growth. Disinfectants treat inanimate objects and antiseptics treat living tissue.
Identify gaseous chemosterilants
Ethylene oxide and chloride gas
Describe how endospore levels are controlled
Autoclaving, ethylene oxide and chloride gas
Describe how virus levels are controlled
Viruses with lipids in their viral envelope: gluteraldehyde-based detergents. Naked viruses: chlorine-based agents
Describe how protozoan levels are controlled
Different life stages require different methods of control
Describe how prion levels are controlled
Combination of chemical treatments and autoclaving
