Control of Microbial Growth Flashcards
what is sterilization?
destruction or removal of all viable organisms
what is disinfection?
killing, inhibition, or removal of disease causing organisms`
what are disinfectants?
agents, usually chemical, used for disinfection on inanimate objects (typically)
what is sanitization?
reduction of the microbial population to levels deemed safe based on public health standards
what is antisepsis?
prevention of infection of living tissue by microorganisms
what are antiseptics?
chemical agents that kill or inhibit growth of microorganisms when applied to tissue
how is chemo used as antimicrobial agents?
use of chemicals to kill or inhibit growth of microorganisms within host tissue
what do -cidal agents do?
kills bacteria
what do -cidal agents do?
kills bacteria
what are examples of cidal agents?
bactericides, fungicides, and viricides
what does -static indicate?
a growth inhibiting agent
what is the pattern of microbial death?
microorganisms are not killed instantly
population death typically occurs exponentially
is a measure of an agents killing efficiency
make sure that viable but noncultural cells are dead
what is decimal reduction time?
the time it takes to kill 90% of cells
what does filtration do?
reduces microbial population or sterilizes solutions of heat-sensitive materials by removing microorganisms
also used to reduce microbial populations in the air
what are membrane filters?
porous membranes with defined pore sizes that remove microorganisms primarily by physical screening
what are some examples of air filters?
surgical masks
high-efiicienctb particulate air (HEPA) filters
what are some examples of using moist heat as control?
pasteurization
boiling
steam sterilization
what does moist heat destroy?
viruses, fungi, bacteria
NOT endospores
how does moist heat work?
degrades nucleic acids, denatures proteins, and disrupts membranes
steam sterilization
carried out above 100 degrees C which requires saturated steam under pressure
effective against all types of microbes
pasteurization
controlled heating at temperature well below boiling
used for milk, beer, and other beverages
process does not sterilize but kills pathogens present and slows spoilage y reducing the total load of organisms present
dry heat sterilization
less effective than moist heat sterilization, requires higher temperatures and longer exposure time
oxidizes cell constituents and denatures proteins
does not corrode glasswares and metal instruments as moist heat does
what is an example of dry heat sterilization?
flaming out inoculating loops
ultraviolet radiation
260 wavelength is most bactericidal
causes thymine dimers preventing replication and transcription
limited to surface sterilization because it doesn’t penetrate glass, dirt films, water, or other substances
used for water treatment