Question 1

Which of the following best describes sterilization in the context of microbial control?

Accepted Answer

The complete destruction or removal of all microorganisms, including endospores and viruses

Question 2

A hospital is preparing surgical instruments for use in an operation. Which method would be most appropriate to ensure complete sterilization?

Accepted Answer

Autoclaving at $121^{\circ}C$ for 15 minutes at 15 psi

Question 3

Which of the following terms refers specifically to the disinfection of living tissue, such as skin, before an injection?

Accepted Answer

Antisepsis

Question 4

A food processing plant wants to reduce the microbial load on food-contact surfaces to meet public health standards. Which process should they use?

Accepted Answer

Sanitization

Question 5

Which of the following statements about microbial death rate is correct?

Accepted Answer

Microbial agents kill a constant percentage of cells over time

Question 6

Which factor does NOT affect the effectiveness of an antimicrobial agent?

Accepted Answer

The color of the disinfectant

Question 7

Why is moist heat generally more effective than dry heat for sterilization?

Accepted Answer

Moist heat denatures proteins and destroys membranes more efficiently due to better heat transfer

Question 8

A laboratory technician needs to sterilize a solution that is heat-sensitive. Which method is most appropriate?

Accepted Answer

Filtration through a $0.22\ \mu m$ membrane filter

Question 9

Which of the following is the ultimate means of sterilization, especially for heat-sensitive medical supplies?

Accepted Answer

Radiation (ionizing)

Question 10

Which of the following best explains why refrigeration inhibits microbial growth?

Accepted Answer

It decreases the rates of metabolism and reproduction

Question 11

A researcher wants to preserve a bacterial culture for several years. Which method is most suitable?

Accepted Answer

Lyophilization (freeze-drying)

Question 12

Which of the following statements about desiccation is correct?

Accepted Answer

Desiccation inhibits growth due to removal of water, which is necessary for metabolism

Question 13

Which of the following is a limitation of filtration as a method of microbial control?

Accepted Answer

It cannot remove toxins or dissolved molecules

Question 14

Which of the following is a correct statement about the use of masks in microbial control?

Accepted Answer

Masks reduce the transmission of respiratory pathogens by filtering airborne particles

Question 15

Which of the following is a primary mode of action for most antimicrobial agents?

Accepted Answer

Disrupting the structure and function of nucleic acids

Question 16

A nurse is preparing to inject a patient and must choose an appropriate method to reduce microbial load on the skin. Which is the best choice?

Accepted Answer

Antisepsis with an alcohol swab

Question 17

Which of the following is true regarding the effectiveness of chemical methods of microbial control?

Accepted Answer

Their effectiveness depends on temperature, pH, and concentration of the agent

Question 18

Which of the following best describes the difference between high-level and low-level germicides?

Accepted Answer

High-level germicides kill all pathogens, including endospores; low-level germicides kill only vegetative bacteria and some viruses

Question 19

A microbiologist is testing the effectiveness of a new disinfectant. Which method would be most appropriate for comparing its efficacy to other agents?

Accepted Answer

Diffusion susceptibility test (e.g., disk diffusion assay)

Question 20

Which of the following is a correct statement about pasteurization?

Accepted Answer

Pasteurization reduces the number of pathogens and spoilage organisms in liquids

Controlling Microbial Growth: Methods and Principles

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