chapter 10 objectives Flashcards
sterilization
process that destroys and removes all viable microorganisms and viruses
disinfection
physical/chemical process to destroy VEGETATIVE pathogens but not bacterial endospores. removes toxins from microorganisms
decontamination
cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to SAFE LEVELS
sanitization
cleansing technique that mechanically removes microorganisms as well as other debris to reduce contamination to SAFE LEVELS
Antisepsis
reduces number of microbes on human skin
degermation
reduces number of microbes on human skin
microorganisms most resistant and least resistant to control measures
most resistant: prions
least resistant: enveloped viruses
microbial vs microbiostatic agents
microbial kills microbes and micro biostatic agents
four categories of cellular targets for physical and chemical agents
heat, radiation, gases/liquids, filtration
6 methods for physical control of microorganisms
incineration, dry oven, steam under pressure, boiling water, ionizing, nonionizing
moist vs dry heat methods
thermal death time vs thermal death pt
tdt: shortest length of time it takes to kill specific bacteria at a specific temperature
tdp: the lowest temperature required to kill all microbes in a
sample in 10 minutes
why is moist heat more effective than dry heat at lower temperatures
Moist heat is more effective than dry heat at lower temperatures because it more easily penetrates microorganisms and denatures their proteins.
2 methods of dry heat control
direct flaming (incineration) and hot air sterilization
pasteurization
technique in which heat is applied to liquids to kill potential agents of infection (spores survive; it does not sterilize)
cold vs desiccation advatages
bacteriostatic meaning it slows growth but it does not kill bacteria
ionizing and non ionizing control methods
ionizing: short wavelengths, high energy
nonionizing: long wavelengths, short energy (not as effective)
desirable characteristics of chemical control agents
rapid action even in low concentrations, long term stability
broad spectrum action
halogens used for microbial control
iodine and chlorine
heavy metals control microbial growth
disrupt cellular metabolism which kills microbes
aqueous chemical
chemicals dissolve in pure water
tincture
chemicals dissolve in pure alcohol
disadvantages of aldehyde agents
highly toxic
70% alcohol is more effective than 100% alcohol
water helps it penetrate microbes and 100% evaporates too fast
applications for ehtylene oxide sterilization
used for heat-sensitive items like medical devices and spices
pryogen free liquid by filtration
Filtration removes pyrogens (fever-causing substances) to make liquids safe for injection or eyes.
