Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
60 Cards in this Set
- Front
- Back
|
What are 3 types of controling microbial growth?
|
Growth inhibition
killing 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?
|
-boiling
-pasteruization -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?
|
endospores=yes
mycobacteria= yes vegetative bacteria=yes all fungi all viruses |
|
|
What does high level kill?
|
everything and some endospores
|
|
|
What does intermediate level kill?
|
endospores=no
mycobacteria=some vegetative bacteria=yes fungi=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 |
