Question 1

Which of the following terms best describes the process of removing and destroying all microbial life from an object?

Accepted Answer

Sterilization

Question 2

A hospital uses an autoclave to sterilize surgical instruments. What is the primary mechanism by which moist heat sterilization kills microbes?

Accepted Answer

Denaturation of proteins

Question 3

Which physical method of microbial control is most appropriate for sterilizing heat-sensitive liquids such as vaccines?

Accepted Answer

Filtration

Question 4

A food processing plant uses pasteurization to reduce spoilage organisms and pathogens in milk. What is the standard high-temperature short-time (HTST) condition for pasteurization?

Accepted Answer

$$72\ ^\circ\mathrm{C}$$ for 15 seconds

Question 5

Which of the following statements about bacteriostasis is correct?

Accepted Answer

It inhibits microbial growth without killing

Question 6

A researcher is testing the effectiveness of a new disinfectant using the disk-diffusion method. What result indicates the disinfectant is effective?

Accepted Answer

A large zone of inhibition around the disk

Question 7

Which chemical agent is most effective against both endospores and mycobacteria according to Table 7-7?

Accepted Answer

Glutaraldehyde

Question 8

Why do low temperatures generally have a bacteriostatic effect rather than a bactericidal effect?

Accepted Answer

They slow down bacterial metabolic rate

Question 9

Which of the following is NOT a factor that affects the rate of microbial death during disinfection?

Accepted Answer

Color of the microbes

Question 10

A patient with a wound is treated with an antiseptic. What is the main difference between antisepsis and disinfection?

Accepted Answer

Antisepsis is used on living tissue, disinfection is used on inanimate objects

Question 11

Which of the following actions by microbial control agents can result in cell death by causing cell contents to leak out?

Accepted Answer

Alteration of membrane permeability

Question 12

A laboratory technician uses a membrane filter with pore size $$0.22\ \mu\mathrm{m} to $$sterilize a solution. Which type of microorganism is most likely to pass through the filter?

Accepted Answer

Viruses smaller than $$0.22\ \mu\mathrm{m}$$

Question 13

Which of the following is a real-world example of degerming?

Accepted Answer

Washing hands before surgery

Question 14

Which principle of effective disinfection explains why bleach is less effective in the presence of blood or organic matter?

Accepted Answer

Organic matter

Question 15

Which chemical agent acts by denaturing proteins and is effective due to its oligodynamic action?

Accepted Answer

Heavy metals (Ag, Hg, Cu, Zn)

Question 16

A sample of bacteria is exposed to a chemical agent that inhibits growth but does not kill the cells. What term best describes this effect?

Accepted Answer

Bacteriostasis

Question 17

Which of the following is true regarding the microbial death curve when using a constant rate of killing?

Accepted Answer

It takes longer to kill a larger population than a smaller one

Question 18

Which surface-active agent is most effective for degerming and emulsification but not for killing microbes?

Accepted Answer

Soap

Question 19

Why are thermoduric organisms able to survive pasteurization?

Accepted Answer

They are resistant to high temperatures

Question 20

A scientist wants to kill Clostridium botulinum endospores in canned food. Which process should be used?

Accepted Answer

Commercial sterilization

Control of Microbial Growth: Principles and Methods

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