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27 Cards in this Set
- Front
- Back
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Sterilization
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The eradication of organisms, including bacterial endospores and viruses, although not prions, in or on an object
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Aseptic
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Characteristic of an environment or procedure that is free of contamination by pathogens
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Disinfection/Disinfectants
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The use of physical or chemical agents to inhibit or destroy microorganisms on inanimate objects.
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Antisepsis/Antiseptic
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The inhibition or killing of microorganisms on skin or tissue by use of a chemical antiseptic
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Degerming
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The removal of microbes from a surface by scrubbing
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Sanitation
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The process of disinfecting surfaces and utensils used by the public
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Pasteurization
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The use of heat to kill pathogens and reduce number of spoilage microorganisms in food and beverages
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Microbial Death Rate
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Agents kill a constant percentage of cells over time rather then simultaneously killing all cells
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High Level Germicides
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Kill all pathogens, including endospores
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Intermediate Level Germicides
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Kill fungal spore, protozoan cysts, viruses and pathogenic bacteria
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Low Level Germicides
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Kill vegetative bacteria, fungi,protozoa and some viruses
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Action of Antimicrobial Agents
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Damaged Cell Wall: cannot prevent cell from bursting due to somatic effects
Damaged Cell Membrane: cannot contain cytoplasm or control passage of chemicals; cellular contents leak out; loss of proton gradient (NO ATP) Proteins Unfolded (denatured: extreme heat and certain enzymes are unable to function Nucleic Acids Altered (mutated): by heat, chemicals and radiation are fatal to reproductive cycles |
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Effects of High Temperatures
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Denaturation of proteins
Interference with integrity of cell walls and membrane Disruption of structure and function of nucleic acid |
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Incineration
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Ultimate means of sterilization; using great heat and burning the organisms
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Moist vs Dry Sterilization
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Moist is more effective; water is a better conductor of heat than air; 15 minutes at 121 C (Autoclave process applies pressure to boiling water, media and lab equipment
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Refrigeration and Freezing
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Inhibit growth by decreasing metabolism and reproduction
Only Static Process |
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Chemical reactions at lower temps
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Enzymes are less functional
Liquid water is less readily available |
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Lyophilization (freeze drying)
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can prevent ice crystal formation by removing water at cold temperatures
Long term preservation of microbial cultures |
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Desiccation
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Inhibits growth due to removal of water
Static process Salt induces desiccation |
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Radiation on Growth
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Shorter wavelength equals more energy and greater penetration
Uv: lab,surfaces and transparant fluid and glasses Gamma Rays: food |
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Chemical Methods of Microbial Control
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Affects microbes well walls, cytoplasmic membranes, proteins or DNA
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Chemical Methods of Microbial Control: Alcohols
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Denature proteins and disrupt cell membranes by removing water from cells
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Chemical Methods of Microbial Control: Halogens
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That they damage enzymes via oxidation or by denaturing them
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Chemical Methods of Microbial Control: Heavy Metals
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Present typically as ions that alter 3D shape of proteins inhibiting or eliminating their function
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Chemical Methods of Microbial Control: Surfactants
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"Surface active" chemicals that reduce surface tension of solvents to make them more effective at dissolving solutes
Soaps and detergents |
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Chemical Methods of Microbial Control: Aldehydes
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Containing terminal -CHO groups
Cross link with amino, hydroxyl, sulfhydryl and carboxyl groups to denature proteins and inactive nucleic acids Embalming tissues, disinfecting rooms and sterilize instruments |
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Chemical Methods of Microbial Control: Gaseous Agents
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Denature proteins and DNA by cross linking functional groups
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