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 hospital needs to sterilize heat-sensitive plastic instruments. Which method would be most appropriate?

Accepted Answer

Ethylene oxide gas sterilization

Question 3

Which of the following statements about the 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 is NOT a physical method for controlling microbial growth?

Accepted Answer

Alcohol-based hand sanitizer

Question 5

A laboratory needs to remove bacteria from a heat-sensitive vitamin solution. Which method should be used?

Accepted Answer

Filtration through a membrane filter

Question 6

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

Accepted Answer

Prions

Question 7

Why is it important to consider the composition of an item before selecting a microbial control method?

Accepted Answer

Some methods can damage the item if it is not compatible, such as heat melting plastics or liquids damaging electronics.

Question 8

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

Accepted Answer

HPP can destroy microbes by altering their proteins but does not always sterilize because some endospores can survive.

Question 9

Which of the following is a FALSE statement about ozone as a chemical agent?

Accepted Answer

It is a surfactant.

Question 10

Which of the following best explains why refrigeration preserves food?

Accepted Answer

Low temperatures slow or inhibit the growth of most pathogens and spoilage microbes.

Question 11

Which of the following is the correct order of effectiveness for surfactants from most to least antimicrobial activity?

Accepted Answer

Quats, detergent, soap

Question 12

Which of the following chemical agents is commonly used to disinfect swimming pools?

Accepted Answer

Chlorine

Question 13

Which of the following is NOT a factor to consider when selecting a germicidal chemical?

Accepted Answer

The color of the chemical

Question 14

Which of the following statements about alcohols as disinfectants is TRUE?

Accepted Answer

Alcohols are not reliably effective at destroying endospores and non-enveloped viruses.

Question 15

Which of the following is the main function of nitrites in processed meats?

Accepted Answer

Inhibit the germination of Clostridium botulinum endospores

Question 16

Which of the following methods physically removes microbes from liquids or air without necessarily killing them?

Accepted Answer

Filtration

Question 17

Which of the following is a disadvantage of using chlorine as a disinfectant?

Accepted Answer

It can react with organic matter to form potentially carcinogenic trihalomethanes.

Question 18

Which of the following statements about glutaraldehyde is TRUE?

Accepted Answer

It can destroy all forms of microbial life, including endospores, if given enough time.

Question 19

Which of the following is NOT considered a peroxygen?

Accepted Answer

Phenol

Question 20

Which of the following methods is most effective for killing microbes on heat- and moisture-tolerant laboratory instruments?

Accepted Answer

Autoclaving (moist heat under pressure)

Controlling Microbial Growth in the Environment: Methods and Principles

Study Guide - Practice Questions