Ch 9 Controlling Microbial Growth in the Environment Flashcards
What is sterilization?
remove all living cells and viruses
What is commercial sterilization?
Kills only harmful microbes
What is aseptic?
No microbe contamination, only normal organisms
What is disinfection?
Physical/Chemical agents to treat objects
What is antisepsis?
Antiseptics to clean skin/tissue
What is degerming?
remove microbes form surface by scrubbing
What is sanitization
Disinfect according to public standards
What is pasteruization?
Heat to kill pathogens & reduce spoilage
Define the suffix -statis/-static
Slow/inhibit growth
Define the suffix -cide/-cidal
Kills the microbe
What happens if you alter the cell wall/membrane?
Cells burst and content leaks out
What happens if you damage proteins & nucleic acids?
Denature proteins, destroy DNA/RNA
What does a high level germicide kill?
All pathogens & endospores
What does a intermediate level germicide kill?
All pathogens but endospores
What does a low level germicide kill?
vegetative bacteria, fungi, protozoa, some virus (no cyst & spore)
What germicide would you use in a BSL 1 lab?
Low level
What germicide would you use in a BSL 2 lab
Intermediate level
What germicide would you use in a BSL 3 or 4 level?
High level
What characteristic defines the relative susceptibility of prions, endospores, and mycobacteria?
Prions: misfolded proteins
Endospores: thick protective coat
Mycobacteria: mycolic acid
What characteristic defines the relative susceptibility of cysts and active protozoa?
Cysts: have shell.
Active protozoa: no shell.
What characteristic defines the relative susceptibility of small non enveloped viruses, large non enveloped viruses, and enveloped viruses?
Small: less surface area.
Large: more surface area
Enveloped: phospholipid membrane
What characteristic defines the relative susceptibility of fungal spores and vegetative fungi?
Fungal spores: protein shells
Vegetative fungi: No shell
What characteristic defines the relative susceptibility of gram-negative and gram-positive bacteria?
Gram-Pos: No protein pumps
Gram-Neg: Has protein pumps
What is a phenol coefficient?
Eval efficacy of disinfectants & antiseptics (<1 = effective)
What is the Use-Dilution test?
How much to dilute and still be effective
What is the Kelsey-Sykes Capacity test?
How long does it take to destroy or if it destroys?
What is the in-use test?
Eval. effectiveness on surface of object
How does heat control microbial growth?
denature protein, disrupt cytoplasmic membrane, cell wall, and nucleic acid
What is thermal death point?
Lowest temp to destroy all cells
What is thermal death time?
Time to destroy all cells
What is decimal reduction?
Time to destroy 90% of cells
What is moist heat?
Using boiling H20 to kill cells
What is more effective, dry or moist heat? Why?
Moist, H20 is a better heat conductor
T/F H20 boils at a lower temp at higher elevation
True
T/F Boiling temp. increases as pressure increases
True
What is pasteurization ?
Used in food, not sterilization
Why would dry heat be used if it isn’t effective?
things that can’t be sterilized w/ moist heat
How does refrigeration/freezing control microbial growth?
Cold slows metabolism, growth, and reproduction.
How does desiccation inhibit microbial growth?
Drys out moisture
How does lyophilization inhibit microbial growth?
freeze dry to preserve culture
How does filtering inhibit microbial growth?
Sieve catches microbe
How does osmotic pressure control microbial growth?
Hypertonic environments inhibit growth
How does radiation control microbial growth?
Ionizing radiation: ions denature mol.
Non ionizing: change shape of proteins and nucleic acid
How do phenol and phenolics impact microbial growth?
-Mid- low lvl.
-Denatures proteins/cell membrane
-good in organic matter
How does alcohol impact microbial growth?
-Mid lvl.
-Denature protein/cytoplas. mem
How do halogens impact microbial growth?
-Mid lvl.
-Denature enzymes
How do oxidizing agents impact microbial growth?
-High lvl
-Oxidize microbial enzymes
How do surfactants impact microbial growth?
-Degerming, not antimicrobial
-Quats disrupt cell membrane
How do heavy metals impact microbial growth?
-low lvl
-ions denature proteins
How do aldehydes impact microbial growth?
-Cross-link structures not normally connected
-Denature protein/inactive nucleic acid
How do gaseous agents impact microbial growth?
-Cross-link structures not normally connected
-Denature protein/inactive nucleic acid
How do enzymes impact microbial growth?
-act against microorganisms
How do antimicrobials impact microbial growth?
-Treatment of disease
