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Micro#7
| Question | Answer |
|---|---|
| Moderate resistance microbes | Pseudomonas spp, some fungal sexual spores, Mycobacterium tuberculosis, Staphylococcus aureus Staphylococcus aureus |
| Disinfection | destruction of vegetative microbes via physical or chemical methods, disinfection for inert substances, disinfection of living tissues is antisepsis, disinfection does not destroy bacterial endo spores, can be achieved by chemicals, ultraviolet radiation, |
| Degermination | Mechanical removal on most of microbes in a limited area ex: cleaning of skin with alcohol before receiving injection |
| Sanitization | - reduction of microbes in significant numbers to prevent infection disease and transmission of infection and disease. Ex : sanitization of glassware, tableware etc |
| Thermal death point | Lowest temperature at which all microbes will be killed in 10 minutes |
| Dry heat sterilization is _____ than moist/wet heat sterilization | Less efficient |
| Temperature required for dry heat sterilization or Sterilization using dry heat requires a temperature of __________° C for a period of __________. | 160-170 degrees Celsius for 2-4 hrs |
| Steam heated to ____ under pressure __ psi above normal pressure and The autoclave uses pressurized steam at approximately | 121 degrees Celsius ; 15 |
| Considerations for microbial control | Site to be treated, Environmental conditions, Suspectibility of the microorganisms |
| Least resistant organisms | Include most bacterial vegetative cells, most fungal spores and hyphae, yeast, enveloped viruses, protozoan trophozoites |
| Highest resistance microbes | bacterial endospores, prions, cysts formed mostly by protozoans |
| Moderate resistance organisms | Some fungal sexual spores, protozoan cysts , some viruses (pseudomonas, mycobacterium and staphylococcus |
| Endospores two phase life cycle | Vegetative state - cell is metabolically active and Endoscopes state - dormant |
| Dormant, highly resistant structure | Endospores |
| Sterilization | When all forms of microbial life (including Endospores and prions) are eliminated |
| Commercial sterilization | Temperatures are used to kill all living microbes. May also result in degrading the quality of food. Just enough heat is used to destroy endo spores of clostridium botulinum |
| Pasteurization | Using heat to kill vegetative bacteria and reducing the number of microbes that have potential for food spoilage |
| Microbidical | Microbes are destroyed |
| Microbiostatic | Microbial growth is at a standstill - prevents further growth |
| microbial death | -cells within a culture have different susceptibility depending depending on their level of metabolic activity-permanent loss of reproductive ability-permanent loss of all vital activities-lethal agents do not always alter the appearance of microbial cell |
| Factors of effectiveness of an agent | -presence of other materials-overall concentration of the agent-number of microorganisms dictates the amount of time required for destruction-temperature and ph-the nature of organism to be destroyed |
| Thermal death time | Length of time required to kill the micro organisms |
| Decimal reduction time | Bacterial resistance indicates time in minutes in which 90% of the bacterial population in question will be killed at a given temp. |
| dry heat sterilization | Sterilization by flaming the object-Incineration |
| Moist heat requires ______________ and _______ period of time than dry heat | Lower temperatures; shorter |
| Steam under pressure | •Autoclave is a widely used instrument •Can be achieved with steam under pressure •Sterilization using wet heat needs, Steam sterilization under pressure is the most effective control method temperatures above the boiling point |
| Steam under pressure usually takes ___ minutes | twenty |
| Flowing Steam tyndallization | -for substances that cannot withstand high temperature on the auto clave |
| methods for food preservation | Pasteurization, Irradiation, Ultrahigh-temperature pasteurization |
| A toxic, odorless gas often used as a sterilizing agent in hospitals and dental officials is | ethylene oxide |
| Autoclaving will usually destroy/inactivate all fungi, bacteria, viruses, and most bacterial spores but will not necessarily eliminate | prions |
| The effects of different kinds of radiation depend on | Time of exposure, wavelength |
| Ionizing radiation involves all of the following except | Gamma rays, Electron beams, X-ray |
| Chlorine belongs to which of the following chemical groups | Halogens |
| The term “zone of inhibition” is used in which of the following procedures? | Disk-diffusion test |
| The technique that combines freezing and drying to preserve microbes and other cells is | lyophilization |
| Boiling items in water for __________ minutes will kill most vegetative bacteria and viruses. | 10-15 |
| Which of the following methods is the simplest heat-related method to sterilize metal? | Direct flaming |
| Decontamination is defined as the | reduction or removal of unwanted chemical or biological agents. |
| Antimicrobial agents that are specifically designed to be used on living tissues are referred to as | antiseptics |
| Agents that kill microbes are classified as __________. | microbicidal |
| Food irradiation destroys the __________ of the cell. | DNA |
| The two types of pasteurization typically used today are __________ and __________. | high temperature short time, ultrahigh temperature (extremely short time) |
| High salt or sugar content/concentrations make use of ____________ to destroy or inhibit the growth of microorganisms. | osmotic pressure |
| The bioassay method for testing the effectiveness of disinfectants and antiseptics on microorganisms is the _____________________. | use-dilution test |
| Bacteria that thrive in extremely dry conditions are classified as | xerophiles |
| Describe the factors influencing the antimicrobial effectiveness of chemical agents | Population size, Population composition, Duration of exposure, Local environment, Concentration of agent, Temperature, Organic matter |
Created by:
rosalyngreen