Question 1

Which of the following best describes the main difference between sterilization and disinfection?

Accepted Answer

Sterilization eliminates all microbes (except prions), while disinfection eliminates most or all pathogens but not necessarily all microbes.

Question 2

A laboratory needs to sterilize heat-sensitive liquid media contaminated with bacteria. Which physical method is most appropriate?

Accepted Answer

Filtration using a membrane filter with small pore size.

Question 3

Which of the following statements about decimal reduction time ($$D-$$value) is correct?

Accepted Answer

The $$D-$$value is the time required to kill 90% of a microbial population under specific conditions.

Question 4

Which of the following microbes is most resistant to current human microbial control methods?

Accepted Answer

Prions

Question 5

A hospital is preparing surgical instruments for use in an operating room. What level of microbial control is required?

Accepted Answer

Sterilization

Question 6

Which of the following environmental factors can decrease the effectiveness of a chemical disinfectant?

Accepted Answer

The presence of organic matter such as grease or blood

Question 7

Which physical method of microbial control is most effective for sterilizing heat- and moisture-tolerant medical instruments?

Accepted Answer

Autoclaving (pressurized steam)

Question 8

Which of the following statements about high pressure processing (HPP) is true?

Accepted Answer

HPP can inactivate many microbes by altering protein structure but does not always sterilize because some endospores can survive.

Question 9

Which of the following is a disadvantage of using ethylene oxide gas for sterilization?

Accepted Answer

It is potentially carcinogenic and requires aeration after use.

Question 10

Which chemical agent is commonly used to disinfect swimming pools?

Accepted Answer

Chlorine

Question 11

Which of the following best explains why the composition of an item must be considered when selecting a microbial control method?

Accepted Answer

Some control methods can damage certain materials, making them unsuitable for use.

Question 12

Which of the following is NOT a peroxygen used for microbial control?

Accepted Answer

Phenol

Question 13

Which of the following statements about soaps and detergents is FALSE?

Accepted Answer

Soaps and detergents kill microbes and are effective sterilants.

Question 14

Which of the following is the correct order of effectiveness for antimicrobial activity among surfactants?

Accepted Answer

Quats \u003e Detergent \u003e Soap

Question 15

Which of the following is a real-world example of preservation as a microbial control method?

Accepted Answer

Refrigerating perishable foods to delay spoilage

Question 16

Which of the following is a reason why heavy metals are no longer widely used to prevent microbial growth in cooling water?

Accepted Answer

Their use contributes to serious pollution of natural waters.

Question 17

Which of the following is a key consideration when selecting a chemical agent for microbial control?

Accepted Answer

All of the above (toxicity, cost, compatibility, environmental impact)

Question 18

Which of the following best describes the action of aldehydes as microbial control agents?

Accepted Answer

They form cross-links with proteins and nucleic acids, inactivating them.

Question 19

Which of the following is true regarding the use of iodine as a disinfectant or antiseptic?

Accepted Answer

It may be used as an antiseptic or as a disinfectant, but does not readily kill endospores.

Question 20

Which of the following best describes the effect of refrigeration on microbial growth?

Accepted Answer

It slows or inhibits the growth of many pathogens and spoilage microbes.

Controlling Microbial Growth in the Environment: Methods, Principles, and Applications

Study Guide - Practice Questions