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61 Cards in this Set
- Front
- Back
What is sterilization?
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the destruction of all microbial life, including viruses and endospores
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What does disinfection do?
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destroys most microbial life, reducing contamination on inanimate surfaces
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What is antisepsis?
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destroys most microbial life, reducing contamination on a living surface
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What is decontamination?
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the mechanical removal of most microbes from an animate or inanimate surface
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When does decontamination take place? and Give an example?
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Used when actual sterilization isn’t needed but need to decrease the risk of infection or spoilage (ex. food industry)
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What is sanitization?
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any cleansing technique that mechanically removes microorganisms to reduce contamination to safe levels
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Give an example of sanitizer
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compound such as soap or detergent
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What does suffix -cide mean?
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to kill
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What is a germicide and microbicide?
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chemical agents that kill microorganisms
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What is a bacteriacide?
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chemical that destroys bacteria (not endospores)
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What is fungicide?
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a chemical that can kill fungal spores, hyphae, and yeasts
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Virucide
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a chemical that inactivates viruses
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Sporicide
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can destroy bacterial endospores
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Stasis and static definition:
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to stand still
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Bacteristatic
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prevent the growth of bacteria
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Fungistatic
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inhibit fungal growth
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Primary targets of microbial growth
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microorganisms that can cause infection or spoilage that are constantly present in the external environme
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Highest resistence
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Bacterial endospores; prions
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Moderate resistance
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Protozoan cysts, fungal sexual spores, naked viruses, resistant vegetative bacteria
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Least resistance
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Most bacterial vegetative cells, fungal spores, enveloped viruses, yeasts, protozoan trophozoites
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Factors that Influence the Action of Antimicrobial Agents
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- number of microorganisms
-nature of the microorganisms in the population -temperature and pH of the environment -concentration of the agent -mode of action of the agent -presence of solvents, interfering organic matter, and inhibitors |
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3 Modes of Action for Protein and Nucleic Acid Synthesis
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Binding to ribosomes to stop translation
Bind irreversibly to DNA preventing transcription and translation Mutagenic agents |
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Autoclave
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-Steam under pressure
-Pressure raises the temperature of steam -Kills endospores |
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Pasteurization definition
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Heat is applied to liquids to kill potential agents of infection and spoilage, while retaining the liquid’s flavor and food value
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What is the most efficient pressure-temp combination for sterilization?
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Most efficient pressure-temperature combination for sterilization: 15 psi which yields 121°C
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What is flash method for pasteurization?
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expose to 71.6°C for 15 seconds
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What is batch method for pasteurization?
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expose to 63°C to 66°C for 30 minutes
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What real life purpose does pasteurization serve?
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used to disinfect beverages
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What does pasteurization not kill?
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endospores or thermoduric microbes
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What does boiling water do?
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Kills vegetative bacteria and fungal pathogens, almost all viruses within 10 minutes
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Some survivors of boiling waterm and for how long?
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endospores (20hrs), some viruses (Hepatitis – 30 min.)
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What is the rate for dry ovens?
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Exposure to 150°C to 180°C for 2 to 4 hours
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What id a dry oven used for?
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Used for heat-resistant items that do not sterilize well with moist heat
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Why does the dry oven work?
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The heat in water is more readily transferred to a cool object than is the heat in air.
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What is dessication?
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dehydration of vegetative cells when directly exposed to normal room air
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What is Lyophillization
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a combination of freezing and drying; used to preserve microorganisms and other cells in a viable state for many years
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What can freezing do?
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perserve cultures
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cold does not do what?
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kill most microbes
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What is radiation?
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energy emitted from atomic activities and dispersed at high velocity through matter or space
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Radiation for microbial control
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Gamma rays
X rays Ultraviolet radiation |
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Wavelength of ultraviolet radiation
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200-300 nm
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Ultraviolet radiation has what kind of penetrating power?
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poor
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What happens to mutations in ultraviolet radiation?
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they are induced
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What are tinctures
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solutions dissolved in pure alcohol or water-alcohol mixtures
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Examples of Halogen Microbial Agents
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Fluorine, bromine, chlorine, and iodine
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Examples of chlorine compounds?
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liquid and gaseous chlorine, hypochlorites, chloramines, household bleach
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What do chlorine compounds do?
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Kills bacteria, fungi, viruses and endospores
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Examples of iodine compounds
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Topical antiseptic, betadine
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What do phenol and phenolics do?
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Disrupts cell membrane and denatures enzymes
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What is rarely used due to irritation?
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phenol
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What do phenolics do?
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kills wide range of microbes, remains active in the presence of organics, used primarily to disinfect surfaces (Lysol®)
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Where are bisphenols found?
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found in hand soaps and skin lotions (Triclosan)
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What do bisphenols do?
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kills wide range of microbes
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What do Chlorhexidines target?
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cell membranes and protein structure
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3 characteristics of Chlorhexidine
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Mild, low toxicity, rapid action
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What alcohols are suitable for microbial control?
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Only ethyl and isopropyl alcohols
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What does alcohol destroy
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resistant vegetative forms
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What does alcohol not kill at room temp?
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bacterial spores
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Drawbacks of using metals in microbial control
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-very toxic to humans
-cause allergic reactions -Large quantities of biological fluids and wastes neutralize their actions -Microbes can develop resistance to them |
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What do Aldehydes do?
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denature proteins
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What effect does very low or high ph levels do?
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destroy or inhibit microbial cells
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