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94 Cards in this Set
- Front
- Back
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_____ refers to the removal or destruction of all microbes includeing viruses and bacterial endospores, in or on an object.
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sterilization
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True or False
Sterilization destroys prions. |
False. Prions (infections proteins) is not destroyed by standard sterilization techniques.
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True or False
Sterilization can leave behind some innocuous microbes. |
True- as in commercial sterilization does not kill all hyperthermophilic microbes
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____ describes an environt or procedure that is free of contamination by pathogens.
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aspetic
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____ refers to the use of physical or chemical agents knowns as disinections.
Give some examples. |
disinfections
examples: UV light, heat, alcohol |
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What is the difference between disinfection and antisepsis?
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Disinfection refers to treatment of inanimate objects whereas as antisepsis is used when referring to the chemical application on tissues.
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____ is the removal of microbes from a surface by scrubbing.
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degerming
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____ is the process of disinfecting places and utensils used by the public to reduce the number of pathogenic microbes to meet accepted public health standards.
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sanitization.
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___ is the use of heat to kill pathogens and reduce the number of spoilage microorgansims in food and beverages.
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Pasteurization
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What suffices indicate the inhibition, but not complete destruction of a type of microbe?
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-stasis
-static |
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Define microbial death.
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The permamnent loss of reproductive ability under ideal environemental conditions.
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How can the efficact of an antimicrobial agent be evaluated?
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By calculating the microbial death rate
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What is the term used for removing microbes by mechanincal means?
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degerming
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True or False
The microbial death rate is usually found to be constant over over time. |
True
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What are the two classifiucations of the actions of antimicrobial agents?
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1. Alteration of cell walls and membranes
2. Damage to proteins and nucleic acids |
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What portion of the ribosome is responsible for catalyzing the synthesis of proteins?
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Ribozyme
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What are the three factors that affect the efficacy of antimicrobial methods?
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1. Site to be treated
2. Relative susceptibility of microoganisms 3. Environmental conditions |
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List microbes in order of those most susceptible to those most resistant
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Enveloped viruses
Gram-positive viruses Fungi Gram-negative bacteria Active stage protozoa (which are aka trophozoites) cysts of protozoa Mycobacteria Bacterial Endospores |
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List 3 of the MOST hardiest organisms from lesser to greater.
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Cysts of protozoa- cell wall prevents disinfectant entry and protects against drying, radiation, and heat.
Mycobacterial (such as mycobacterium tuberculosis) has large amounts of waxy lipids that protect against drying and most water-bassed chemicals Bacterial endospores- (such as bacillus and clostridium) and can survive harsh environmental extremes of temperature and acidity as well as chemical disinfectants |
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The effectiveness of ____ can be measured as high, intermediate, and low.
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Germicides
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What does an intermediate level germicide kill?
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fungal spores, protozoan cysts, viruses, and pathogenic bacteria, but NOT endospres.
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True or False
Warm disinfectants work better than cool ones |
True
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True or false
Antimicrobial effect of heat is decreased by an acididc environment. |
False, it is enhanced by an acidic environment.
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___ is the use of heat to kill pathogens and reduce the number of spoilage microorgansims in food and beverages.
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Pasteurization
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What suffices indicate the inhibition, but not complete destruction of a type of microbe?
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-stasis
-static |
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Define microbial death.
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The permamnent loss of reproductive ability under ideal environemental conditions.
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How can the efficact of an antimicrobial agent be evaluated?
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By calculating the microbial death rate
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What is the term used for removing microbes by mechanincal means?
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degerming
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True or False
The microbial death rate is usually found to be constant over over time. |
True
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What are the two classifiucations of the actions of antimicrobial agents?
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1. Alteration of cell walls and membranes
2. Damage to proteins and nucleic acids |
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What portion of the ribosome is responsible for catalyzing the synthesis of proteins?
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Ribozyme
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What are the three factors that affect the efficacy of antimicrobial methods?
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1. Site to be treated
2. Relative susceptibility of microoganisms 3. Environmental conditions |
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List microbes in order of those most susceptible to those most resistant
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Enveloped viruses
Gram-positive viruses Fungi Gram-negative bacteria Active stage protozoa (which are aka trophozoites) cysts of protozoa Mycobacteria Bacterial Endospores |
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List 3 of the MOST hardiest organisms from lesser to greater.
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Cysts of protozoa- cell wall prevents disinfectant entry and protects against drying, radiation, and heat.
Mycobacterial (such as mycobacterium tuberculosis) has large amounts of waxy lipids that protect against drying and most water-bassed chemicals Bacterial endospores- (such as bacillus and clostridium) and can survive harsh environmental extremes of temperature and acidity as well as chemical disinfectants |
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The effectiveness of ____ can be measured as high, intermediate, and low.
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Germicides
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What does an intermediate level germicide kill?
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fungal spores, protozoan cysts, viruses, and pathogenic bacteria, but NOT endospres.
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True or False
Warm disinfectants work better than cool ones |
True
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True or false
Antimicrobial effect of heat is decreased by an acididc environment. |
False, it is enhanced by an acidic environment.
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What are the three methods for evaluating disinfectants?
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1. Phenol coefficient
2. use dilution test 3. in-use test |
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Define phenol coefficient
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a ratio that compares an antimicrobial agent's efficacy against a microbe to that of phenol's
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A phenol coefficient greater than ___ indicates that an antimicrobial agent is more effective than phenol
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1.0
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Which of the following bacteria is not used in a use-dilution test?
a. Salmonella cholerasuis b. Salmonella enterica c. Staphylococcus aureus d. Psuedomonas aeruginosa |
b. Salmonella enterica
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Which of the following tests is used as a current standard test for evaluating disinfectants and antispetics?
a. phenol coefficient b. in-use test c. use-dilution test d. all of the above |
c. use-dilution test
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Which of the following test applies to more real life situations and why?
a. phenol coefficient b. in-use test c. use-dilution test d. none of the above |
b. in-use test because the antimicrobial agent is compared to a range of microbes found in biofilms as opposed to just one or a few microbes used in the other tests.
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What are the 5 physical methods of microbial control?
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Exposure to the microbes to extremes of heat and cold, dessication, filtration, osmotic pressure, and radiation
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______ is the lowest temperature that kills all cells in a broth in 10 minutes.
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Thermal death point
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_____ is the time it takes to completely sterilize a particular volume of liquid at a set temperature
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Thermal death time
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Define decimal reduction time.
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It is the time required to destroy 90% of the microbes in a sample
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Which endospore is used as a reference for heat sterilization in foods?
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clostridium botulinum
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Which is more effective at killing microbes: moist or dry heat? Why?
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Moist heat is more effective because water is a better conductor then heat.
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Boiling kills vegetative cells of bacteria and fungi, the trophozoites of protozoa, and most viruses within ____ minutes at sea level.
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10
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Autoclaves use ___ in conjunction with steam to achieve sterilization.
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Pressure
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In autoclaving, temperature, pressure, and time for sterilization are:
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121 degrees celsius, 15 lbs of pressure, 10 minutes
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What is a biological indicator used to assess sterilization in autoclaving?
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Bacillus stearothermophilus
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Which of the following are controlled in pasteurization?
a. Brucella melitensis b. Mycobacterium Bovis c. Escherichia coli d. All of the above |
d. all of the above
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True or False
Pasteurization = sterilization |
False, Thermoduric (heat tolernt) and thermophilic (heat loving) survive
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Milk used to be pasteurized using the ____ method for 30 minutes at 63 degrees celsius.
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batch
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List two types of pasteurization used today.
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Flash pasteurization-milk flows through tubes heated to 72 for 15 minutes
Ultrahigh-temperature pasteurization- milk is heated to 140 degrees celsius for 1-3 seconds |
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Dry heat sterilization occurs at ___ degrees celsius for 1 hour or ___ degrees celsius for 2 hours.
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170
160 |
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Refigeration halts the growht of most pathogens that are predominately ____ with the exceptions of ___ and ___.
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mesophiles
listeria yersinia |
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____ us an antimicrobial technique which combines freezing and drying.
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lyophilization
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Give some examples where filtration is used.
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opthalamic solution, antibiotics, vaccines, liquid vitamins, enzymes, and culture media.
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What does HEPA stand for?
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High efficiency particulate air
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____ pressure inhibits microbial growth in foods by utilizing high concentrations of salt and sugar in foods.
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Osmotic
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What are the two types of radiation used?
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particulate radiation and electromagnetic radiation
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What symbol is used to show that foods in the US are irradiated?
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radura
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Wavelengths shorter than 1 nm are ____ forms of radiation.
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ionizing
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wavelengths greater than 1 nm in length are ____ forms of radiaiont.
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nonionizing
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True or False
UV light is a form of ionizing radiation |
False
UV light is a form of non-ionizing radiation |
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List some chemcial methods of microbial control
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phenol and phenolics, halogens, oxidizing agents, surfactants, heavy metals,aldehydes, gaseous agents
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What are two examples of bisphenolics?
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orthophenylphenol and triclosan
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True or False
Phenolics are intermediate to low-level disinfectants that denature proteins and disrupt cell membranes in a wide variety of pathogens |
True
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List some positives and negatives of phenol
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Positives: effective in the presence of contaminating organic material and are active on surfaces for long time
Negative: smelly and possible side effects |
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Alcohols are not effective against which of the following?
a. fungal spores b. bacterial endospores c viruses d. a and b |
d. a and b
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Alcohols are considered ___ level disinfectants
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intermediate
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Alcohols function in what way?
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Denature proteins and disrupt cytoplasmic membranes
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____ are solutions of other antimicrobial chemcials in alcohols.
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tinctures
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Give an example of a halogen disinfectant
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iodine
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How do oxidizing agents work and give some examples?
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Oxidizing agents such as peroxides, ozone, and peracetic acid work by oxidizng microbial enzymes which prevent metabolism.
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Oxidizing agents are ___ level disinfectants
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high
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How do surfactants work?
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They reduce surface tension which allows the solvent to become more effective at dissolving solute materials.
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What are two common surfactants used?
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Soap and detergens
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What are the most popular detergents for microbial control?
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Quaternary ammonioum compounds or quatas
-NH4, hydrogen atoms replaces by other functional groups or hydrocarbon chains. Examples: Zephiran and Cepacol |
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How do quats function?
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They disrupt cellular membrans and cause a loss of essential internal ions
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Which of the following are Quats effective against?
a. enveloped viruses b. non enveloped viruses c. mycobacteria d. nonenveloped viruses |
a. enveloped viruses
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What heavy metal is effective against Neisseria gonorhoeae?
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1% silver nitrate
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Aldehydes are compounds containing a termal ___ group
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CHO
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How do aldehydes function?
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They cross link amin, hydroxyl, sulfhydryl, and carboxyl organic functional groups thus causing the denaturization of proteins
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List two low level forms of microbial control?
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surfactants and metal (possibly phenol and phenolics as well)
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3 examples of high level microbial control includes:
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oxidizing agents, aldehydes, and gaseous agents
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Give some examples of gaseous agents used for microbial control.
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ethylene oxide, propylene oxide, and beta-propiolactone
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How do gaseous agents work?
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Denature proteins
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Which of the following microbial controls only denatures proteins and does not disrupt the cell wall?
a. phenolics b. alcohols c. aldehydes d. gaseous agents |
c and d (trick question!) the latter two ONLY denature protein whereas the upper two also disrupts cell membranes
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When a scientist chemically modifies an antibiotic it is called a ____?
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semisynthetic
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