Question 1

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

Accepted Answer

Sterilization destroys all microorganisms, including endospores, while disinfection eliminates most pathogens but not necessarily all microbes or endospores.

Question 2

A hospital needs to sterilize heat-sensitive medical equipment. Which method would be most appropriate?

Accepted Answer

Filtration through a membrane filter with pore size $$0.22 \ \mu m$$

Question 3

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

Accepted Answer

Microbial death occurs at a constant rate, and can be described by a logarithmic decline.

Question 4

Which chemical agent is most appropriate for disinfecting water in a municipal supply?

Accepted Answer

Halogens such as chlorine

Question 5

A laboratory technician needs to sterilize a solution of vitamins that cannot be heated. Which method should be used?

Accepted Answer

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

Question 6

Which of the following is a limitation of using UV radiation for microbial control?

Accepted Answer

It cannot penetrate surfaces or opaque materials.

Question 7

Which of the following best explains why moist heat is generally more effective than dry heat for sterilization?

Accepted Answer

Moist heat denatures proteins more rapidly due to better heat penetration.

Question 8

A food processing plant wants to prevent microbial growth in jams and jellies. Which method is most effective?

Accepted Answer

Osmotic pressure by adding high concentrations of sugar

Question 9

Which of the following is a correct statement about the use-dilution test?

Accepted Answer

It measures the effectiveness of a disinfectant against dried bacterial cultures on metal cylinders.

Question 10

Which of the following factors does NOT affect the efficacy of antimicrobial methods?

Accepted Answer

The color of the disinfectant

Question 11

Which of the following best describes the action of aldehydes as antimicrobial agents?

Accepted Answer

They denature proteins and inactivate nucleic acids.

Question 12

A hospital is concerned about the development of resistant microbes. Which practice would best help prevent this?

Accepted Answer

Rotating the use of different classes of disinfectants and antiseptics

Question 13

Which of the following is the most appropriate method for sterilizing plastic Petri dishes?

Accepted Answer

Gamma irradiation

Question 14

Which of the following is a correct application of the phenol coefficient test?

Accepted Answer

Comparing the effectiveness of a disinfectant to phenol against a standard organism

Question 15

Which of the following is a reason why alcohols are effective disinfectants?

Accepted Answer

They denature proteins and disrupt cell membranes.

Question 16

Which of the following is a limitation of using heavy metals as antimicrobial agents?

Accepted Answer

They can be toxic to humans and the environment.

Question 17

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

Accepted Answer

Filtration

Question 18

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

Accepted Answer

It decreases the rate of metabolic reactions in microbes.

Question 19

Which of the following is a correct statement about the use of enzymes as antimicrobial agents?

Accepted Answer

They can be used to target specific microbial structures, such as bacterial cell walls.

Question 20

A laboratory is testing a new disinfectant using the in-use test. What is the main advantage of this method?

Accepted Answer

It evaluates the disinfectant under actual conditions of use.

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

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