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41 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Antisepsis
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Inhibition or killing of microorganisms (pathogens on skin or tissue by the use of a chemical antiseptic
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Asepsis
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Practice to reduce or eliminate contaminants (microorganisms) from entering the operative field in surgery or medicine to prevent infection
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Sanitization
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Process of disinfecting surfaces and utensils used by the public. Reduction of microbial life to bring to a safe level
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Disinfection
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Use of physical or chemical agents to inhibit or destroy microorganisms on inanimate objects
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Sterilization
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Refers to the removal or destruction of all microbes (but prions) in or on an object.
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-stasis/-static
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Indicates that a chemical or physical agent inhibits microbial metabolism and growth, but doesn't necessarily kill microbes
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-cide/-cidal
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refers to agents that destroy or permanently inactivate a particular type of microbe
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Bacteriostatic
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Inhibits growth of bacteria without killing them. For example: refrigeration is bacteriostatic for most bacterial species but they resume metabolism when temperature is restored
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Beacteriocidal
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Kill bacteria
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Fungicide
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Kill fungal hyphae, spores, and yeasts
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Alcohols
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Denature proteins and disrupt cell membranes (phospholipid bilayer)
Disinfectants, antiseptics, and as a solvent in tinctures |
characteristics
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Aldehydes
(glutaraldehyde and formaldehyde) |
Denature proteins
Very effective of killing microbes at low doses Can't use on living tissues Liquids but can be aerosol to sterilize rooms Disinfectant and embalming fluid |
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Detergents (surfactants)
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Inactivate the lipid bi-layer surfactants and essentially make water wetter. They make the lipids soluble. They remove microbes rather than killing them.
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Halogens (iodine, chlorine, bromine, and fluorine)
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Presumably denature proteins. They interfere with protein configuration
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Heavy Metals (arsenic, zinc, mercury, silver, and copper, ect.)
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Denature proteins. Get in the way of proper enzyme function. Hg used in mummification. AgNO3 was used to prevent babies from blindness against gonorrhoeae. Also used for burns to keep them pathogen free
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Phenol (carbolic acid)
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Denature proteins and disrupts cell membranes. Original surgical antiseptic, now replaced by less odorous and injurious phenolics
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Peroxides (oxidizing agents)
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Oxidizing agents that interfere with protein configuration and enzyme activity. For deep wounds, water purification, sterilization of food-processing and medical equipment.
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Variables affecting performance
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• Concentration – some work at low concentration or high
• Timing – quickly or longer time. Concentration and time are inversely related • Temperature – higher temperature, faster chemical reactions • pH – halogen containing compounds, higher pH • Nature of material – most common disinfectant is a halogen compound (bleach). In order to disinfect or get rid of blood for example, you first have to wipe area and then wipe with bleach. You can’t just add it on top of the blood to properly rid. |
Of the disinfectants.
5 of them |
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Heat
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one of the older and common techniques. Used to denature proteins, interfere with the integrity of cytoplasmic membranes and cell walls, and disrupt the function and structure of nucleic acids.
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Be able to explain the ways of controlling microbes by this physical mean
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Thermal death point
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lowest temperature that kills all cells in a broth in 10 minutes.
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Thermal death time
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time it takes to completely sterilize a particular volume of liquid at a set temperature.
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Dry Heat
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baking 180 °C in glassware, mostly for metals. Incineration is the ultimate means of sterilization, burning contaminated bags and carcasses. Takes a lot longer than moist heat because it penetrates more slowly.
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Be able to explain the ways of controlling microbes by this physical mean
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Moist Heat
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boiling water at 100 °C but does not effect endospores or viruses. More effective than dry heat because water is a better conductor…. Effective for sanitizing but not for true sterilization.
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Be able to explain the ways of controlling microbes by this physical mean
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Steam: autoclave:
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121C for 15 minutes – achieving true sterilization… you must increase the pressure to increase the temperature. That’s what happens in the autoclave. Increasing the pressure to another 15psi, so you can get the stream to 121C, kills all endospores and viruses for 15 minutes. They used Baccillus stearothermophilus’ spores as a basis because they are thermophiles and it was effective. We can only use this with material that can withstand this high temperature.
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Be able to explain the ways of controlling microbes by this physical mean
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Tyndallization
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atmospheric steam
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definition
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Pasteurization
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apply heat for a short period of time to decrease microbial load for the time. Doesn’t completely remove microbial life.
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Be able to explain the ways of controlling microbes by this physical mean
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Batch
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Louie Pasteur exposed a batch to 60-70 degrees centigrade for less than an hour. (63 degrees at 30 minutes) Needs to be done in a relatively closed container
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type of pasteurization
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Flash
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much higher temp for much shorter period of time like a minute (72 degrees centigrade for 15 seconds). You would need some type of technology of nozzles – this is for milk typically.
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type of pasteurization
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UHT
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temperature over a hundreds for a few seconds or 134 degrees centigrade for 1 second
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type of pasteurization
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UHS
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ultra high temp sterilization – getting rid of all living microbes. Pass liquid through superheated steam at 140 degrees centigrade for 1 second then cooling it rapidly. Used for dairy creamer.
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type of pasteurization
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Cold and Desiccation
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Cold can be used as a preservative but does not destroy living cells: only retards growth. Cold is used to preserve microbes. Psychrophilic microbes can multiply in refreigerated food and spoil taste and suitability for consumption. Freezing causes cell damage by ice crystal formation within individual cells punch holes in the membrane.
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Be able to explain the ways of controlling microbes by this physical mean
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Desiccation
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(removing water) can destroy vegetative cells but not endospores. It retards growth. Drying or salt preservation can preserve meat. Prevents microbes from growing and spoiling meat. Increase solute concentration, you decrease availability of water. Like in salted cod. In a hypertonic environment water is drawn out of the cells.
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Lyophilization
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combining freezing and drying to preserve microbes and other cells for many years. Instantly freeze and vacuum frozen water through sublimation where water is formed from a solid to a gas. Prevents formation of large damaging ice crystals.
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definition
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Ionizing radiation
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electron beams, gamma rays, and x-rays all have wavelengths shorter than 1 nm. They strike molecules with enough energy to create ions by ejecting electons from atoms. Disrupts hydrogen bonding, oxidize double covalent bonds, and create highly reactive hydroxide ions. Formation of ions leads to destruction of function in enzymes and nucleic acids..causing fatal mutations and cell death due to the changes in the molecules in the DNA.
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Under Radiation as a type of controlling microbes by physical means
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Gamma rays, X-rays
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remove microbial life present at the time. On the rise in popularity but is expensive. Gamma rays penetrate much farther than electron beams but require hours to kill microbes, prevents microbial spoilage and overripening of fruits. X-rays travel the farthest through matter but have less energy than gamma rays and require a prohibitive amount of time to make them practical for microbial control.
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Under Radiation as a type of controlling microbes by physical means
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Non-ionizing radiation (damages the DNA structure)
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UV radiation: damages the DNA. Only produce genetic changes. 1 or 2 changes does not really effect the cells.. but if enough is done then you have ultimate cell death. Widespread use, sterilization of air, UV lamps around packaging, sterilization of water. 1 problem, its not very penetrative.
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Under Radiation as a type of controlling microbes by physical means
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Filtration
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Traps microbes larger than the pore size allowing smaller microbes to pass through
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Filtration as a type of controlling microbes by physical means
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Exclusion filtration
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dependent on pore size and nature of material
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Filtration as a type of controlling microbes by physical means
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.45 µm
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yeast cells – limit in removing eukaryotic cells, viruses, small bacteria, and prions pass through
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Filtration as a type of controlling microbes by physical means
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.22 µm
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bacterial cells – Exclude microbes, but small viruses, pliable bacteria, and prions pass through
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Filtration as a type of controlling microbes by physical means
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.02 µm
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viral particles – exclude most viruses, but smallest viruses and prions pass
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Filtration as a type of controlling microbes by physical means
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