Question 1

Which of the following best describes the process of commercial sterilization in the food industry?

Accepted Answer

The destruction of Clostridium botulinum endospores in canned goods.

Question 2

A hospital is preparing surgical instruments for use. Which method should be used to ensure sterilization, and what are the standard conditions for this method?

Accepted Answer

Autoclaving at $$121\ ^\circ C$$ and 15 psi for 15 minutes.

Question 3

Which of the following statements about alcohol-based hand sanitizers is CORRECT?

Accepted Answer

They are effective against most bacteria but not against Clostridium difficile or Norovirus.

Question 4

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

Accepted Answer

Membrane filtration

Question 5

Which of the following is the best definition of decimal reduction time ($$D_{RT}$$)?

Accepted Answer

The time required to kill 90% of a specific population of bacteria at a given temperature.

Question 6

Which physical method of microbial control is most effective for sterilizing disposable plastic syringes?

Accepted Answer

Ionizing radiation (gamma rays)

Question 7

Why are Gram-negative bacteria generally more resistant to biocides than Gram-positive bacteria?

Accepted Answer

Their outer membrane contains lipopolysaccharides that restrict entry of biocides.

Question 8

A food processing plant wants to prevent the growth of Clostridium botulinum in packaged meats. Which chemical preservative should they use?

Accepted Answer

Nitrites

Question 9

Which of the following statements about the use-dilution test is TRUE?

Accepted Answer

It determines whether bacteria survive treatment with a disinfectant by transferring them to culture media.

Question 10

Which of the following chemical agents is considered sporicidal and is used for sterilizing medical equipment that cannot be autoclaved?

Accepted Answer

Glutaraldehyde

Question 11

A researcher is using a disk-diffusion method to test the effectiveness of several disinfectants. What does a large zone of inhibition around a disk indicate?

Accepted Answer

The disinfectant is more effective at inhibiting microbial growth.

Question 12

Which of the following statements about nonionizing radiation is correct?

Accepted Answer

It damages DNA by creating thymine dimers.

Question 13

Which of the following is a limitation of using alcohols as disinfectants?

Accepted Answer

They are not effective against endospores and nonenveloped viruses.

Question 14

Which of the following is the primary mechanism by which halogens such as iodine and chlorine exert their antimicrobial effects?

Accepted Answer

Inhibiting protein synthesis and oxidizing cellular components

Question 15

A laboratory is using a HEPA filter to sterilize air entering a clean room. What is the minimum particle size that a HEPA filter can remove?

Accepted Answer

$$0.3\ \mu m$$

Question 16

Which of the following statements about quaternary ammonium compounds (quats) is TRUE?

Accepted Answer

They are cationic detergents that disrupt plasma membranes.

Question 17

Which of the following is a reason why prions are difficult to destroy using standard sterilization methods?

Accepted Answer

They are resistant to heat, chemicals, and radiation.

Question 18

Which of the following is a correct statement about the effect of container size on autoclave sterilization times for liquid solutions?

Accepted Answer

Sterilization time increases as container size increases due to longer heating times.

Question 19

Which of the following best explains why pasteurization does not sterilize milk?

Accepted Answer

It reduces spoilage organisms and pathogens but thermoduric organisms survive.

Question 20

A patient is being treated for a skin infection caused by Staphylococcus aureus. Which of the following chemical agents would be most appropriate for antisepsis of the skin prior to surgery?

Accepted Answer

Chlorhexidine

Chapter 7: The Control of Microbial Growth – Comprehensive Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards