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60 Cards in this Set

  • Front
  • Back
What are 3 types of controling microbial growth?
Growth inhibition
removing from an environment
What is an example of growth inhibition?
Freezing, refrigeration; decreasing temp= enzymes cant function= reactions stop
What is an example of removing from the environment?
Filtering, washing
What are the type of physical methods?
Heat, irradiation (kill)
filtration, washing (remove)
What are the types of chemical methods?
antiseptics (applied on skin)
disinfectants (applied on objects)
What are the two categories that antimicrobial agents can be divided into?
germicidal: agents that kill (heat, irradiation, chemical)
germostatic: inhibit growth, remove agent, bacteria grows again (preservatives, cooling, freezing)
What is an antiseptic?
a disinfectant that is non toxic on skin
What is aseptic technique?
use of specific methods to exclude contaminating microorganisms from an environment
What is bacteriocidal?
kills bacteria
What is bacteriostatic?
inhibits growth of bacteria
What is disinfectant?
a chemical used to destroy many microorganisms and viruses
What is disinfection?
process that eliminates most disease causing microorganisms and viruses on a product
What is a fungicide?
kills fungi
What is germicide?
kills microorganisms, and inactivates viruses
What is pasteurization?
a brief heat treatment used to reduce # of spoilage treatments and kills disease causing microbes
What is preservation?
process of inhibiting growth of microorganisms in products to delay spoilage
What is sanitize
to reduce the # of microorganisms to a level that meets public health system
What is sterilant?
a chemical used to destroy all microorganisms and viruses in a product, becoming sterile
What is sterile?
completely free of microorganisms and viruses.
What is sterilization?
detroying or removing all microorganisms and viruses through physical or chemical means
What is a viricide?
inactivates viruses
What are the factors to selecting an antimicrobial feature?
-type of microorganism
- # of microorganisms
- environmental conditions
- potential risks of infection
What are the types of microorganisms to consider?
- bacterial endospores
- waxy cell wall (mycobacterium)
- grows in presence of disinfectants
- viruses that lack a lipid envelope
What is D value?
decimal reduction time, time required to kill 90% of population. varies with method used
What are the environmental conditions to consider?
PH= lower PH easier to kill with heat
Temp= increase heat shorter time to kill
Organic matter= presense of fat and organic compounds interfere with heat and chemical disinfectants
What are critical items?
direct contact with internal body tissues, needles, scalpels, need to be sterilized
What are semi-critical items?
contact with mucous membranes. (endotracheal tubes) must be free of vegetative bacteria. mucus membranes block endospores
What are non-cricital items?
pose no risk of infection, come in contact with unbreached skin, (stethoscopes)
What are the 4 methods of heat to control microorganisms?
-pressurized steam
-dry heat
What is boiling?
fast, reliable, inexpensive method to destroy most microbes. does not kill endospores, used to treat H20
What is pasteurization?
use high heat for a brief period of time reduces most spoilage micro organisms and pathogens. used on milk and juices
What is pressurized steam?
kills endospores, heat above 100'C, used on surgical items and canned food
What is dry heat?
high temp for long periods of time, flame sterilizes bacterial loops, ovens sterilize glassware and items not penetrated by steam
What is HTST method?
High temp, short time, used for milk and juices
What is UHT?
ultra high temp, increases shelf life of products, removes growth factors. packaged with H202 (biodegradable)
What is autoclaving?
sterilization using pressurized steam, pressure increases temp of steam, killing occurs by heat. kills endospores
What is commercial canning?
food is sealed and heated so as to kill all living organisms.
What is the main aim of commecial canning?
to kill endospores of clostridium botulinum that produces very lethal toxin.
What is dry heat good for?
to use on metals that wouold corrode or sterilize a powder (which can contain spores; does not destroy)
takes longer than steam and higher temp
What does a sterilant kill?
mycobacteria= yes
vegetative bacteria=yes
all fungi
all viruses
What does high level kill?
everything and some endospores
What does intermediate level kill?
vegetative bacteria=yes
viruses=lipids yes, non-lipid varies
What does low level kill?
some vegetative bacteria, some fungi, some lipid viruses
What are the factors in selecting a germicide?
toxicity, activity in presence of organic matter, compatability with material being treated, corrosion, cost, storage, availability
What are alchohols used for?
disinfectant and antiseptic for surface sterilization; removes dirt, evaporates quickly
What are Quaternary ammonia compounds used for?
benzocalium chloride (lysol); disinfects and antiseptics, preserves non food substances
What are phenolics used for?
hexaclorophene (floor disinfectant); highly effective against s. aureus
What are peroxigens used for?
oxidants used for disinfecting juice containers
What are halogens used for?
disinfect non-living objects, surface drinking water, and waste water, don't work with organic compounds
What does ozone do?
biodegradable, breaks into O2, disinfects drinking and waste water, replaces chlorine
What are ethylene oxide gas used for?
gaseous sterilizing agent, kills endospores, replaced by gamma radiation
What are aldehydes used for?
preserve animals, inactivates proteins and nucleic acids
What is formaldehyde used for?
inactivating viruses and bacteria, used in vaccine preparation
What are the two types of filtration?
fluid and air
What are the types of fluid filtration?
depth filters= uses paper layers placed in layers
membrane filters= filters wine to get rid of souring bacteria, liquid that cant be autoclaved
What is air filtration?
HEPA: used in special hospital rooms prevents spread of airborne pathogens.
What is radiation used for?
surface sterilization. kills bacteria by mutating DNA by removing electron. does not kill endospores
What is ionizing radiation?
gamma and x rays, can cross thru food, more penetrating. kills endospores
What are the types of preservation?
chemical, pickling, low-temperature, reducing water availability
HOw do we reduce water availability?
adding salt or sugar= draws water out of cell preventing growth.
drying food= lyphophilization= 1st frozen then dried