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14 Cards in this Set
- Front
- Back
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The usual definition of sterilization is the removal or destruction of all forms of microbial life; how could there be practical exceptions to this simple definition?
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Disinfectants and Antiseptics do not kill or remove all bacteria and viruses. Prions and endospores are also extremely resistant.
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How is it possible that a solution containing a million bacteria would take longer to sterilize than one containing a half-million bacteria?
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It takes longer for antimicrobials to kill larger populations
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Would a chemical microbial control agent that affects plasma membranes affect humans?
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Yes, since plasma membranes are present in human cells
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How is microbial growth in canned foods prevented?
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Osmotic Pressure causes plasmolysis- (high salt/sugar concentrations)
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Why would a can of pork take longer to sterilize at a given temperature than a can of soup that also contained pieces of pork?
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There is a greater mass of pork which requires sterilization when it is by itself, as opposed to when it is in soup
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What is the connection between the killing effect of radiation and hydroxyl radical forms of oxygen?
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Ionizing radiation Ionizes water to release OH• (highly active hydroxyl radical). It also damages DNA and causes mutations.
Low level ionization used in food industry |
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If you wanted to disinfect a surface contaminated by vomit and a surface contaminated by a sneeze, why would your choice of disinfectant make a difference?
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In these situations, organic material would be present that would inhibit the effectiveness of the disinfectant.
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Which is more likely to be used in a medical clinic laboratory, a use-dilution test or a disk-diffusion test?
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A disk-diffusion test.
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Why is alcohol effective against some viruses and not others?
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It does not kill endospores.
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Is Betadine an antiseptic or a disinfectant when it is used on skin?
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Antiseptic
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What characteristics make surface-active agents attractive to the dairy industry?
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CHECK
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What chemical disinfectants can be considered sporicides?
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CHECK
-Antibiotics -Sodium Nitrite, Nitrate |
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What chemicals are used to sterilize?
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-Aldehydes
-Alcohols -Halogens -Peroxygens |
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The presence or absence of endospores has an obvious effect on microbial control, but why are gram-negative bacteria more resistant to chemical biocides than gram-positive bacteria?
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Due to the external lipopolysaccharide layer
(Lipo, thin peptid, lipo) |
