Question 1

Which of the following best describes the process of sterilization?

Accepted Answer

Removal of all microbial life including endospores

Question 2

A hospital uses an autoclave to sterilize surgical instruments. At sea level, what pressure and temperature are typically used to achieve sterilization?

Accepted Answer

$$15$$ psi and $$121^\circC$$

Question 3

Which of the following terms refers to the absence of significant microbial contamination?

Accepted Answer

Asepsis

Question 4

A food processing plant uses pasteurization to reduce spoilage organisms. Which of the following is an equivalent treatment for pasteurization?

Accepted Answer

All of the above

Question 5

Which of the following best explains why boiling is not always sufficient for sterilization?

Accepted Answer

Boiling only kills vegetative cells and some viruses, but not all endospores

Question 6

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

Accepted Answer

Filtration using a $$0.22\mum $$membrane filter

Question 7

Which of the following is NOT a factor that affects the effectiveness of antimicrobial treatment?

Accepted Answer

Color of the microbial colony

Question 8

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

Accepted Answer

Microbial populations die at a constant logarithmic rate

Question 9

A solution contains $$1,000,000$$ bacteria. If the decimal reduction time (DRT) is $$1$$ minute, how many bacteria remain after $$2$$ minutes?

Accepted Answer

$$10,000$$

Question 10

Which of the following best describes the action of a biocide?

Accepted Answer

Kills microbes

Question 11

Why must the pressure in an autoclave be increased at higher altitudes to achieve sterilization?

Accepted Answer

Because water boils at a lower temperature at higher altitudes

Question 12

Which of the following is the main mechanism by which moist heat kills microbes?

Accepted Answer

Denaturation of enzymes

Question 13

Which of the following is true regarding thermoduric organisms?

Accepted Answer

They survive pasteurization but do not grow at storage temperatures

Question 14

Which of the following is an example of dry heat sterilization?

Accepted Answer

Hot-air oven at $$170^\circC $$for 2 hours

Question 15

Which of the following best describes the effect of high osmotic pressure on microbial cells?

Accepted Answer

Cells undergo plasmolysis due to water loss

Question 16

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

Accepted Answer

Deep freezing

Question 17

Which of the following is the best definition of decimal reduction time (DRT)?

Accepted Answer

The time required to kill 90% of a microbial population at a given temperature

Question 18

Which of the following is a limitation of filtration as a sterilization method?

Accepted Answer

Some bacteria such as spirochetes and mycoplasmas can pass through certain filters

Question 19

Which of the following is NOT a typical action of microbial control agents?

Accepted Answer

Increase in microbial metabolic rate

Question 20

A nurse swabs a patient's skin with alcohol before an injection. This is an example of which process?

Accepted Answer

Degerming

The Control of Microbial Growth: Principles and Physical Methods

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