Ch 7
In the figure, the decimal reduction time (D value) for the culture is approximately 40 min 60 min 30 min 0 min 10 min
10 min
Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper? ultraviolet radiation gamma radiation autoclave microwaves sunlight
gamma radiation
The antimicrobial activity of chlorine is due to which of the following? the formation of a hypochlorite ion the formation of hypochlorous acid disruption of the plasma membrane the formation of ozone the formation of hydrochloric acid
the formation of hypochlorous acid
Oxidizing agents include all of the following EXCEPT iodine chlorine hydrogen peroxide ozone glutarlydehyde
glutarlydehyde
All of the following are methods of food preservation EXCEPT high pressure ionizing radiation osmotic pressure microwaves desiccation
microwaves
Bone and tendons for transplant are decontaminated by glutaraldehyde .plasma sterilization. supercritical fluids. peroxygens. ethylene oxide.
supercritical fluids
In the figure, what is the thermal death time? The answer cannot be determined 60 min 100 C 150 C 120 min
60 min
Which concentration of ethanol is the most effective bactericide? 100% 70% 50% 40% 30%
70%
Which of the following regarding antimicrobial control agents is false? Some agents affect microbial cell membranes by dissolving lipids. Some agents kill by denaturing microbial cell proteins. Contaminating organic debris such as blood or sputum will decrease effectiveness. A true antimicrobial control agent is equally effective against both bacteria and viruses. Some agents are utilized as both an antiseptic and a disinfectant.
A true antimicrobial control agent is equally effective against both bacteria and viruses
In the table, which disinfectant was bactericidal? Aotus Gorb Komodo Tula The answer cannot be determined
Aotus
In the table, which compound was the most effective against Staphylococcus?
C
Which of the following is a limitation of the autoclave? It cannot be used with glassware It requires an excessively long time to achieve sterilization It cannot inactivate viruses It cannot be used with heat-labile materials It cannot kill endospores
It cannot be used with heat labile materials
Which of the following regarding antimicrobial control agents if false? Silver is used for treating antibiotic-resistant bacteria. Some agents kill by denaturing microbial cell proteins. Contaminating organic debris such as blood or sputum decrease effectiveness. Some agents inactivate viruses by attacking cell membrane lipids. Some agents affect microbial cell membranes by dissolving lipids.
Some agents inactivate viruses by attacking cell membrane lipids
Which of the following treatments is the most effective for controlling microbial growth? 63°C for 30 minutes 72°C for 15 seconds 140°C for 4 seconds They are equivalent treatments. None of the answers is correct.
They are equivalent treatments
In the table, which compound was bactericidal?
The answer cannot be determined
In the table, which compound was the most effective against E. coli?
The answer cannot be determined
In the table, which disinfectant was most effective against Salmonella? Doom Steri K.O. Mortum The answer cannot be determined
The answer cannot be determined
In the table, which disinfectant is the most effective at stopping bacterial growth? Tula Gorb Aotus Komodo The answer cannot be determined
Tula
All of the following substances are effective against non-enveloped viruses EXCEPT chlorine ozone ethylene oxide alcohol All are equally effective against non-enveloped viruses
alcohol
Which of the following pairs is mismatched? CuSO4 algicide organic acids food preservation alcohols open wounds H2O2 open wounds Ag wound dressings
alcohols open wounds
Which graph in the figure best depicts the effect of placing the culture in an autoclave for 15 minutes at time x?
b
Which of the following pairs of terms is mismatched? sterilant destroys all living microorganisms germicide-kills microbes fungicide kills yeast and molds virucide-inactivates viruses bacteriostatic kills vegetative bacteral cells
bacteriostatic kills vegetative bacterial cells
All of the following substances are used to preserve foods EXCEPT nisin calcium propionate potassium sorbat biguanides sodium nitrite
biguanides
All of the following are effective for destroying prions EXCEPT NaOH + autoclaving at 134°C. proteases. boiling. incineration .Each of the answers will destroy prions.
boiling
Which graph in the figure best depicts the effect of placing the culture at 7°C at time x?
d
Application of heat to living cells can result in all of the following EXCEPT alteration of membrane permeability damage to nucleic acids breaking of hydrogen bonds denaturation of enzymes decreased thermal death time
decreased thermal death time
The preservation of beef jerky from microbial growth relies on which method of microbial control? supercritical CO2 filtration lyophilization ionizing radiation desiccation
desiccation
An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n) aseptic antiseptic disinfectant fungicide virucide
disinfectant
Which of the following chemical agents is used for sterilization? ethylene oxide soap phenolics chlorine alcohol
ethylene oxide
Which of the following results in lethal damage to nucleic acids? heat radiation certain chemicals heat and radiation heat, radiation, and some chemicals
heat, radiation, and some chemicals
An iodophor is a(n) quaternary ammonium compound agent that reduces Oxygen form of formaldehyde phenol iodine mixed with a surfactant
iodine mixed with a surfactant
Which of the following is the best method to sterilize heat-labile solutions? pasteurization dry heat freezing membrane filtration autoclave
membrane filtration
Which one of the following is most resistant to chemical biocides? mycobacteria gram-positve bacteria protozoan cysts viruses with lipid envelopes gram-negative bacteria
mycobacteria
Which of the following does NOT achieve sterilization? supercritical fluids ethylene oxide dry heat autoclave pasteurization
pasteurization
If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar? pressure cooker at 121°C for 15 minutes boiling for 1 hour oven at 121°C for 1 hour bleach hydrogen peroxide
pressure cooker at 121 C for 15 min
In the table, which preservative is most effective? potassium sorbate sodium benzoate potassium sorbate + sodium benzoate no preservative
sodium benzoate
