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65 Cards in this Set
- Front
- Back
Who thought of the first aseptic techniques during WW2? |
Joseph Lister |
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Sterilization |
removal of ALL microorganisms (living and non living except prions) |
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Sterile |
describes an item free of microbes including endospores and viruses |
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Disinfection |
elimination of most or all pathogens (some viable microbes may remain) |
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Disinfectants |
biocides, germicides, bactericides |
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Antiseptics |
disinfectants used on living tissues |
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Pasteurization |
Brief heating to reduce number of spoilage organisms, destroys pathogens |
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Decontamination |
reduce pathogens to levels considered safe to handle |
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Sanitize |
substantially reduce microbial population that meets accepted health standards. (non specific levels) |
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Preservation |
process of delaying spoilage of food and other perishable goods |
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Bacteriostatic |
a growth-inhibiting preservatives |
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How come soap does not affect the beneficial skin mictobiota? |
They reside deeper on underlying layers of skin and in hair follicles. |
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How long to wash hands for? |
at least 20 seconds |
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What does the FDA regulate the risk of? |
Toxicity |
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Describe the standards of drinking water. |
free of pathogens, not sterile |
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What chemical is usually used to clean drinking water? |
Chlorine |
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What is the downside to chlorine? |
Forms DBPs, disinfection by-products, which are linked to long-term health risks |
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What is the downside of only chemical water treatment? |
Some organisms resist chemical disinfectants |
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What are the 4 factors considered when selecting and antimicrobial procedure? |
1. type and # of microbes 2. Environmental conditions 3. risk of infection 4. composition of infected items |
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Why are endospores highly resistant? |
Only extreme heat or chemicals can completely destroy them |
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Why are protozoan and oocysts highly resistant? |
resistant to disinfectants (causes diarrheal disease) |
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Why are Mycobaterium spp. highly resistant? |
Their wall are made of mycolic acid which cause a waxy cell wall resistant to many chemical treatments |
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Why are Pseudomonas spp. highly resistant? |
resistant to and can grow in disinfectants |
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Why are naked viruses highly resistant? |
they lack a lipid envelope and are more resistant to disinfectants (alcohols dont work) |
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Even supplies that have been autoclaved have........ on it. |
prions |
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Decimal reduction time |
The time it takes to to kill of x amount of microbes (exponential decay) |
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What is one way to speed up decimal reduction time on the body? |
Wash your hands! and body. |
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What environmental conditions interfere with cleaning the body of germs? |
dirt, grease, body fluids, heat penetration |
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What can influence the effectiveness of a cleaning procedure? |
pH and temperature |
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What are the pros to heat treating? (Autoclaving) |
reliable, safe, relatively fast, inexpensive, nontoxic, can be set to sterilize or disinfect, and can use moist or dry heat |
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What does heat do to "kill" a microbe? |
irreversibly denatures it's proteins. |
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Describe how to check an autoclave if it is running properly. |
You insert a crushable capsule which contains bacteria. Run through the autoclave. Then crush the capsule. If bacteria grows then it does not work properly. |
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True or False: The canning process has procedure which include eliminating endospores? |
False: to REDUCE the number of endospores to about 1 |
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What is a reason why you would use dry heat? |
Powders, and other material which would be affected chemically by the moisture |
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What is a con of dry heat? |
1. it takes longer 2. higher temperature 3. Things get could get so oxidized that they become incinerated |
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What are some pros of Gamma and X ray radiation a sterilizer? |
can be used for heat sensitive materials can be used after packaged because of penetration abilities is FDA approved |
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What can Ionizing radiation do to microbes? |
1. destroys DNA 2. damages cytoplasmic membranes 3. reacts with O2 to produce reactive oxygen species |
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What is the downside to Ultraviolet radiation? |
can now penetrate through much. Only kills where it shines directly. |
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How do microwaves work? |
They don't actually kill the cell specially, the heat does. It also heats the water inside of the (food) and acts like a moisture heat autoclave |
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Why is high pressure preferred over radiation? |
1. It doesnt scare the general public 2. Food keeps it taste and color |
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Sterilants |
destroy all microorganisms. used for critical instruments |
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High level disinfectants |
destroy viruses and vegetative cells (NOT endospores) used in semi-critical instruments. (touches mucus membranes) |
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Intermediate-level disinfectants |
destroy vegetative bacteria, mycobacteria, fungi, and most viruses. used on non-critical instruments |
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Low-level disinfectants |
Destroy fungi, vegetative bacteria except mycobacteria, and enveloped viruses (NOT naked viruses) Used on floors, furniture, and walls. |
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What are some on the considerations in choosing a germicide? |
Toxicity, activity, compatibility, residues, cost, storage, environmental risk. |
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What is the preferred dilution of alcohol and why? |
60-80%. Less than 60 is too weak. You need at least 20% water because it helps dissolve proteins which alcohol can then get into contact with and denature proteins. |
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What is the preferred % of alcohol concentration in hand-sanitizers? |
60% or more |
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Why do we not use aldehydes as sterilants alot? |
Inactivates proteins and nucleic acids (of human cells too!) |
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What is the popular gaseous sterilant? |
Ethylene oxide |
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What specific chemicals on the periodic table are good germicides? |
Halogens |
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What are the the metal compound made of? |
metal combined with sulfhydryl groups of enzymes and proteins. |
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What is the downside of using metal compounds? |
1. Expensive 2. Not environmentally friendly |
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What is an alternative of chlorine to disinfect drinking water? |
Ozone |
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What are the downsides of ozone? |
1. unstable 2. decomposes quickly so must be made on site |
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Peroxygens |
powerful oxidizers used as sterilants, readily biodegradeable, no residues, less toxic than ethylene oxide, can be used on surfaces |
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Phenolic compounds |
Denature proteins and destroys cytoplasmic membranes. destroy most vegetative bacteria but not reliable on viruses. |
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Quats, Quaternary Ammonium compounds |
positively charged detergents, nontoxic, and used on the surfaces of food prep |
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How do Quads work? |
Charged hydrophilic and uncharged hydrophobic regions 1. reduce surface tension of liquids 2. aids in removal of dirt, organic matter, and microorganisms |
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How do Quads affect cells? |
1. react with membranes 2. destroy vegetative bacteria and enveloped cells 3. Pseudomonas can grow in Quads |
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Describe a dilution test for disinfectants |
A rings has bacteria that is dried. The ring is then placed in disinfectant for 10 minutes at 20 C. Ring placed in media to see if the bacteria can survive the disinfectant or not. |
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Describe a disk diffusion test for disinfectants. |
A disinfectant spot is marked in a petrie dish that is fully streaked. If it doesn't grow there than it works. |
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As a preservation a for food, weak organic acids are used for what? (Benzoic. sorbic, propionic) |
Inhibit metabolism and alter cell membrane function.
Control molds and bacteria in foods and cosmetics |
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What are nitrates used for? |
inhibit endospore germination and vegetative cell growth within meat |
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What does low-temperature mean for bacteria? |
It slows the growth and sometimes the ice crystal formation can kill the cells |
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What is the purpose of adding salt as a preservative ? |
To remove the water from the system and causes cell to shrink! |