Chapter 8- Control of Microorganism in Environment Flashcards
any physical or chemical agent that kills microorganisms or inhibits their growth
antimicrobial agent
antibacterial, antiviral, antifungal, and anitprotozoal are all examples of ______________
antimicrobial agents
antimicrobial agent that kills
microbiocidal
bacteriocidal, fungicidal, virocidal
microbiocidal examples
antimicrobial agent that inhibits the growth of microorganisms
microbiostatic
free of all viable microorganisms, removed or killed
sterile
process of removal or killing microorganisms, includes any spores
sterilization
decrease the number of viable microorganisms on surface to the minimum transmission rate
disinfection
disinfection of living tissue
antiseptis
reduction of microbial population to safe levels
sanitization
microorganisms die because they loose the ability to _________
reproduce
alter physical state of cytoplasm, inactive enzymes destroy proteins, cell wall or membrane disrupted, DNA damaged, transport affected
mechanisms of death
not instant, occurs exponentially, measure agents killing efficiency, persister (VBNC) cells must be dead
pattern of microbial death
time to kill 90% of microorganisms
decimal reduction time
effectively used to kill microorganisms, moist more effective than dry, an use steam or hot water
heat
mild heating to kill vegetative microbes, does not sterilize, disinfection, slows micro growth in food to last longer, flash is at higher temps and lower time than bulk
pasteurization
kills vegetative bacteria, kills some spores, doesn’t kill all endospores
boiling water
higher boiling point of water when heated under pressure, device that steam at higher temps with pressure, greater penetration of the spore, sterilize
autoclave steaming
cause oxidation of organic constituents of cell, use when no moisture wanted, oven for higher temps and longer exposure time, incineration for burning and sterilization
dry heat
-4C, inhibit growth to extend shelf life, some slow growth by psychotolerant mesophiles, doesnt kill most vegetative cells
refrigeration
-20C, stops growth, extends shelf life of food, no killing of vegetative or spore cell
standard freezing
-80C, no microbial growth, more killing, cells survive in cyrtoprotectants, long term
ultra low temperature freezing
-196C, no growth, long term storage
liquid nitrogen
pass liquid or gas through screen like subs with pores, let gas or liquid pass through w/o bacteria, cellulose or nitrocellulose membrane filters
filtration
surgical masks, cotton plugs, HEPA filters
filtering air
ionizing radiaiton can damage or denature proteins and DNA, can penetrate packaging, sterilize sealed medical equipment, food and other things that can get hot or wet
radiation
treat water, lower level, non ionizing, no ion production, kills vegetative cells, decontaminates and disinfects
UV radiation
gamma radiation penetrates deep into objects, destroys endospores, not always virus effective
ionizing radiation
remove water from microorganisms, drying vegetative cells stops metabolic activity, preserve food and chemicals, dry grains and beef jerkey, gonorrhoeae die within minutes, mycobacterium viable for days and hours
dessication
dry with vacuum, lower temps
lyophilization
heat, drying plus toxic combustion products
smoking and cooking
chemical that sterilizes something
sterilant
chemicals that kill vegetative forms of microorganisms, reduce viability
disinfectant
prevents multiplying of microorganisms, kill or inhibits overall growth
anti-septic
kills 99.99% of microorganisms, for public health purposes
sanitizer
effective against wide variety of infections agents and low concentration, effective in presence of organic matter, overuse of antiseptics can lead to resistance
chemical agents
derived from phenol, lab and hospital disinfectants, act by denaturing proteins and disruption of cell membrane, disagreeable odor can cause skin irritation,
phenolics
widely used, concentrations of 70% ethyl alcohol most effective, no endospore killing and doesn’t sterilize, also common used skin antiseptic, propyl and isopropyl alcohols bacteriocidal for vegetative cells, overall inhibit by denaturing proteins and damage lipids
alcohols
skin antiseptic, oxidizes and denatures cell constituents and iodinates protein, increased concentration may kill spores, skin damage staining and allergies can be a problem,
halogens
iodine with organic carrier, released slowly to minimize burns
iodophore
iodine dissolved in ethanol
tincture
oxidizes cell constituents, produces hyperchlorate which is a strong oxidizer that kills proteins, destroys vegetative bacteria and fungi, can react with organic matter to form carcinogenic compounds
chlorine
use on organic forms
mercury
once used as antiseptic of newborns eyes
silver nitrate
include emulsifying agents (ampipathic) make lipids more water soluable, physically able to remove
soaps and detergents
detergents with antimicrobial activity are effective disinfecting agents, ampipathic organic cleansing agent, cationic detergents are effective disinfectants, kill most bacteria, easy and safe to use
quaternary ammonium compounds
commonly used agents are formaldehyde and glutaraldehyde, highly reactive molecules, sporocidal and can be used as chemical sterilants, combine with inactive nucleic acids and proteins
aldehydes
sterilize heat and sensitive materials, microbicidal and sporocidal, combine with and inactive DNA proteins
sterilizing gases
