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, the autoclave operates at 15 psi above atmospheric pressure. What temperature does the steam reach under these conditions?

Accepted Answer

$$121\ ^\circ \mathrm{C}$$

Question 3

Which term refers to the absence of significant microbial contamination?

Accepted Answer

Asepsis

Question 4

A food processing plant uses pasteurization to reduce spoilage organisms and pathogens. Which of the following is NOT an equivalent treatment for pasteurization?

Accepted Answer

$$100\ ^\circ \mathrm{C}$$ for 5 min

Question 5

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

Accepted Answer

Filtration

Question 6

A microbial death curve plotted logarithmically shows a straight line. What does one log decrease represent?

Accepted Answer

90% of the population killed

Question 7

Which of the following factors does NOT affect the thermal death point (TDP) of bacteria?

Accepted Answer

Type of microscope used

Question 8

Which microbial control agent action is described as damaging cellular proteins by breaking hydrogen and covalent bonds?

Accepted Answer

Damage to proteins

Question 9

If a bacterial population is subjected to heat and dies at a constant rate, what mathematical model best describes the death curve?

Accepted Answer

Logarithmic model

Question 10

Which of the following is true about thermoduric organisms after pasteurization?

Accepted Answer

They survive pasteurization but do not grow at storage temperature

Question 11

A laboratory technician needs to sterilize a solution that contains heat-sensitive enzymes. Which method should be used?

Accepted Answer

Filtration through a $$0.22\ \mu\mathrm{m}$$ membrane

Question 12

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

Accepted Answer

Color of the microbial colony

Question 13

What is the decimal reduction time (DRT) in microbial control?

Accepted Answer

Minutes to kill 90% of a population at a given temperature

Question 14

Which of the following statements about autoclaving is correct?

Accepted Answer

Steam must directly contact the material to be sterilized

Question 15

Which physical method of microbial control kills by oxidation?

Accepted Answer

Dry heat sterilization

Question 16

A cell placed in a hypertonic solution will undergo which process?

Accepted Answer

Plasmolysis

Question 17

Which of the following is NOT a method of low temperature microbial control?

Accepted Answer

Incineration

Question 18

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

Accepted Answer

To compensate for lower atmospheric pressure and achieve sterilizing temperatures

Question 19

Which microbial control method is best for removing microbes from air in hospital rooms?

Accepted Answer

HEPA filtration

Question 20

Which of the following is a plausible reason why organic matter may interfere with heat treatments?

Accepted Answer

Organic matter absorbs heat, protecting microbes from lethal temperatures

Chapter 7: The Control of Microbial Growth – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards