Chapter 11 Study Questions
[Note: These questions are meant to be a study guide, not a
substitute for a thorough reading of the book and careful review
of your notes from class. However, if you review this list and
answer all of the questions, it will help prepare you for EXAM
3. All of these questions can be answered by referring to your
book or your lecture notes. No answers will be posted].
1. What are the three major methods of controlling
2. What is meant by the terms sterile and sterilization?
3. How does a bactericidal agent differ from a
4. How do antiseptics differ from disinfectants? Give an
5. What do we mean when we say a bacterial culture is
6. What is the standard temperature for an autoclave? How
temperature be reached if steam is only 100C?
7. In an autoclave, what kills microorganisms, heat or
8. Does boiling a growth medium make it sterile? Why or why
9. How does heat kill microorganisms?
10. What do we mean by thermal death time?
11. Which is the more effective killer, moist heat or dry
12. What happens to a protein when it denatures?
13. Is freezing a good means of killing microorganisms?
14. What is pasteurization? Is it the same as sterilization?
Give an example
of a pasteurized product.
15. Distinguish between ionizing and nonionizing radiation
and give an
example of each. Which is the stronger form of
16. How can meat be made sterile by “cold sterilization”?
17. How does UV radiation kill microorganisms? Why would UV
ineffective as an agent for cold sterilization of food
18. What is the radura and what does it tell you?
19. Describe a situation in which you would use filter
20. Describe an unusual property of the bacterium Deinococcus
22. When might a germicidal agent that claims to kill
99.99% of germs on
a surface, not be an effective agent?
23. Why would be want a germicidal agent to be “broad
24. From a chemical standpoint, all phenols contain
________ and _______.
25. What chemical is used to disinfect drinking water?
How does it kill
26. Give an example of something that would be
sterilized by ethylene
27. What are “quats” and why are they germicidal?
28. What halogen is used to disinfect skin prior to a
29. What is a coliform? Which coliform in particular is
used as an indicator
organism in drinking water analyses and why?
30. How does formaldehyde kill microorganisms?