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Problem SA5
Why are Gram-negative bacteria more susceptible to heat than Gram-positive bacteria?
Problem V1
Calculate the decimal reduction time (D) for the two temperatures in the following graph.
Problem MC14
A sample of E. coli has been subjected to heat for a specified time, and 90% of the cells have been destroyed. Which of the following terms best describes this event?
a. Thermal death point
b. Thermal death time
c. Decimal reduction time
d. None of the above
Problem MC15
Which of the following substances is least toxic to humans?
a. Carbolic acid
b. Glutaraldehyde
c. Hydrogen peroxide
d. Formalin
Problem MC16
Which of the following chemicals is active against bacterial endospores?
a. Copper ions
b. Ethylene oxide
c. Ethanol
d. Triclosan
Problem MC17
Which of the following disinfectants acts against cell membranes?
a. Phenol
b. Peracetic acid
c. Silver nitrate
d. Glutaraldehyde
Problem MC6
The endospores of which organism can be used as a biological indicator of sterilization?
a. Bacillus stearothermophilus
b. Salmonella enterica
c. Mycobacterium tuberculosis
d. Staphylococcus aureus
Problem MC7
A company that manufactures an antimicrobial cleaner for kitchen counters claims that its product is effective when used in a 50% water solution. By what means might scientists best verify this statement?
a. Disk-diffusion test
b. Phenol coefficient
c. Filter paper test
d. In-use test
Problem MC9
The preservation of beef jerky from microbial growth relies on which method of microbial control?
a. Filtration
b. Lyophilization
c. Desiccation
d. Radiation
Problem MC10
Which of the following types of radiation is more widely used as an antimicrobial technique?
a. Electron beams
b. Visible light waves
c. Radio waves
d. Microwaves
Problem MC11
Which of the following substances would most effectively inhibit anaerobes?
a. Phenol
b. Silver
c. Ethanol
d. Hydrogen peroxide
Problem MC12
Which of the following adjectives best describes a surgical procedure that is free of microbial contaminants?
a. Disinfected
b. Sanitized
c. Degermed
d. Aseptic
Problem MC13
Biosafety Level 3 includes __________:
a. Double sets of entry doors
b. Pressurized suits
c. Showers in entryways
d. All of the above
Problem MC18
Which of the following disinfectants contains alcohol?
a. Iodophor
b. Quat
c. Formalin
d. Tincture of bromine
Problem MC19
Which antimicrobial chemical has been used to sterilize spacecraft?
a. Phenol
b. Alcohol
c. Heavy metal
d. Ethylene oxide
Problem MC20
Which class of surfactant is most soluble in water?
a. Quaternary ammonium compounds
b. Alcohols
c. Soaps
d. Peracetic acids
Problem MC1
In practical terms in everyday use, which of the following statements provides the definition of sterilization?
a. Sterilization eliminates all organisms and viruses.
b. Sterilization eliminates harmful microorganisms and viruses.
c. Sterilization eliminates prions.
d. Sterilization eliminates hyperthermophiles.
Problem MC2
Which of the following substances or processes kills microorganisms on laboratory surfaces?
a. Antiseptics
b. Disinfectants
c. Degermers
d. Pasteurization
Problem MC3
Which of the following terms best describes the disinfecting of cafeteria plates?
a. Pasteurization
b. Antisepsis
c. Sterilization
d. Sanitization
Problem MC4
The microbial death rate is used to measure the effectiveness of:
a. A detergent
b. An antiseptic
c. Sanitization techniques
d. All of the above
Problem MC5
Which of the following statements is true concerning the selection of an antimicrobial agent?
a. An ideal antimicrobial agent is stable during storage
b. An ideal antimicrobial agent is fast acting
c. Ideal microbial agents do not exist
d. All of the above are correct
Problem SA1
Describe three types of microbes that are extremely resistant to antimicrobial treatment, and explain why they are resistant.
Problem SA2
Compare and contrast four tests that have been developed to measure the effectiveness of disinfectants.
Problem SA3
Why is it necessary to use strong disinfectants in areas exposed to tuberculosis patients?
Problem SA4
Why do warm disinfectant chemicals generally work better than cool ones?
Problem SA6
Describe five physical methods of microbial control.
Problem SA7
What is the difference between thermal death point and thermal death time?
Problem SA8
Defend the following statement: “Pasteurization is not sterilization.”
Problem SA9
Compare and contrast desiccation and lyophilization.
Problem SA10
Compare and contrast the action of alcohols, halogens, and oxidizing agents in controlling microbial growth.
