Chapter 7 Quiz
Oxidizing agents include all of the following EXCEPT
glutaraldehyde
Which one of the following is most resistant to chemical biocides?
mycobacteria
Bone and tendons for transplant are decontaminated by
supercritical fluids
Which concentration of ethanol is the most effective bactericide?
70%
Which of the following regarding antimicrobial control agents is false?
A true antimicrobial control agent is equally effect against both bacteria and viruses
Which of the following is a limitation of the autoclave?
Cannot be used with heat-liable materials
Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?
gamma radiation
Which of the following results in lethal damage to nucleic acids?
heat, radiation, and some chemicals
An iodophor is a(n)
iodine mixed with a surfactant.
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 121C for 15 minutes
The fate of E. coli O157:H7 in apple cider held at 8°C for 2 weeks, with and without preservatives, is shown below: Bacteria/mlCider only 2.2Cider with potassium sorbate 2.0Sodium benzoate 0Potassium sorbate + sodium benzoate 0In the table, which preservative is most effective?
sodium benzoate
All of the following substances are used to preserve foods EXCEPT
biguanides
All of the following are effective for destroying prions EXCEPT
boiling
A disk-diffusion test using Staphylococcus gave the following results:Disinfectant Zone of inhibition (mm)A 0B 2.5C 10D 5In the table, which compound was the most effective against E. coli?
cannot be determined
The following data were obtained by incubating gram-positive bacteria in nutrient medium + disinfectant for 24 hr, then transferring one loopful to nutrient medium (subculturing). (+ = growth; - = no growth) In the table, which disinfectant was bactericidal?
cannot be determined
Application of heat to living cells can result in all of the following EXCEPT
decreased thermal death time
The preservation of beef jerky from microbial growth relies on which method of microbial control?
desiccation
An agent used to reduce the number of bacteria on a toilet would most accurately be called a(n)
disinfectant
In the figure, the decimal reduction time (D value) for the culture is approximately
10 minutes
In the figure, what is the thermal death time?
60
Assume 109 E. coli cells/ml are in a flask. Which graph in the figure best depicts the effect of placing the culture in an autoclave for 15 minutes at time x?
B
A disk-diffusion test using Staphylococcus gave the following results: Disinfectant Zone of inhibition (mm)A 0B 2.5C 10D 5In the table, which compound was the most effective against Staphylococcus?
C
Which graph in the figure best depicts the effect of placing the culture at 7°C at time x?
D
Which of the chemical agents is used for sterilization?
Ethylene Oxide
The antimicrobial activity of chlorine is due to which of the following?
Formation of hypochlorous acid
Which of the following regarding antimicrobial control agents is false?
Some agents inactivate viruses by attacking cell membrane lipids
All of the following substances are effective against nonenveloped viruses EXCEPT
alc
Which of the following pairs is mismatched?
alcohols open wounds
Which of the following pairs of terms is mismatched?
bacteriostatic kills vegetative bacterial cells
Which of the following treatments is the most effective for controlling microbial growth?
equivalent treatments
Which of the following is the best method to sterilize heat-labile solutions?
membrane filtration
All of the following are methods of food preservation EXCEPT
microwaves
Which of the following does NOT achieve sterilization?
pasterurization
