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28 Cards in this Set
- Front
- Back
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Sterilize
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to kill or remove all living organisms as well as viruses...sterility is the complete absence of living organisms.
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Disinfect
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to kill the harmful living microorganisms
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-cidal
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having the effect of killing.
ie) clorox bleach |
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-static
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having the effect of retarding growth, but not killing
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CTA chemotherapeutic agent
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any drug (chemical agent) used to treat a patient.
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Types of radiation to sterilize
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1. Ultraviolet light (UV light)
2. Ionizing radiation (X-rays, gamma rays) |
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UV light (can sterilized slightly)
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Forms thymine dimers in DNA and blocks ability of microbe to replicate.
Effective only on thin films or surfaces b/c UV rays do NOT penetrate well (low energy) |
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Ionizing Radiation (better way to sterilize)
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Generation of free radicals, such as OH which damage macromolecules, especially DNA, blocking microbes' ability to replicate.
Effective for many substances (plastics, cloth) b/c high energy rays penetrate well. Good means of Sterilization!! |
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Heating to sterilize
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1. dry heat
2. moist heat |
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Dry Heat
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good only for items that are not themselves destroyed by heat.
Requires high temps and long exposure times for sterilization (140 C for 2 hr) |
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Moist Heat
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Sterilizes better and penetrates better.
Pasteurization Canning Autoclaving |
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Cooling for sterilization
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cooling retards microbial growth and extends holding times but is not an effective way to sterilize anything. NOT A GOOD WAY TO STERILIZE! doesn't kill anything just retards growth. Cooling 10 C kills microbes in 1/2.
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Filtration
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Removes bacteria and larger microbes
Effective for fluids only... liquids or gasses Used as a means of disinfection, not sterilization, because it does not remove viruses. |
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Dehydration
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Limits H2O availability to retard microbial growth.
Not an effective means of disinfection or sterilization |
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Food Spoilage
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Highly perishable (meat, eggs, milk, fruit, veggies)
Semi-perishable (potatoes, apples, nuts) Non-perishable (rice, flour, sugar) |
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Factors underlying perishability
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Moisture content (high)
pH ( above 5 and below 8) Salinity (low) Storage temp (below 4C, above 60C) |
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Chemical preservatives retard microbial growth such as:
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sodium benzoate
Sorbic acid Sodium Nitrite, nitrate Sulfites, sulfur dioxide |
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Germicide
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a chemical agent that kills microbes
ie) disinfectants, antiseptics |
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Antiseptic
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a chemical agent that kills harmful microbes and is selectively toxic enough that it can be used on human skin.
ie) silver nitrate, iodine, alcohol, hydrogen peroxide |
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Disinfectant
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a chemical agent that kills harmful microbes, but is too harsh to be used on human skin.
ie) chlorine gas, chlorine compounds, copper sulfate |
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Alexander Flemming
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discovered a mold that makes penicillin.
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Waksman
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discovered streptomycin
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Dogmagk
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synthesized protosil and sulfa (anti-microbials) synthetic is less expensive $$
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CTA's work by damaging:
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1. Metabolites (sulfa)
2. Membranes (amphotericin B) 3. Cell Walls (penicillin) 4. Proteins (erythromycin) 5. Nucleic acids (AZT) |
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Antibiotics
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are naturally occurring substances made by certain bacteria and fungi
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antimetabolites
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are synthetic substances made from chemicals by humans in factories.
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Selective toxicity
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This is Crucial!! harmful to one thing (microbe) but not to another (host)
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Effectiveness
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Route and Concentration
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