CHAPTER #7 STUDY GUIDE QUESTIONS
THE CONTROL OF MICROBIAL GROWTH:
Be sure you can answer the following questions before taking the test.
OBJECTIVES:
The Terminology of Microbial Growth:
1. Define the following terms and differentiate them in terms of microbial growth and control: disinfection, antisepsis, degerming, sanitization, biocide, germicide, bacteriostasis, and asepsis.
2. Differentiate between physical and chemical methods of microbial control.
The Rate of Microbial Death:
3. Describe the general pattern of death caused by treatments with microbial agents.
4. Identify and briefly describe the factors that influence the effectiveness of antimicrobial treatments.
Actions of Microbial Agents:
5. Describe the different effects of microbial agents on cellular structures.
Physical Methods of Microbial Control:
6. Several factors which must be considered when determining which method of microbial control is most appropriate – identify the factors and briefly describe why they are important.
7. Compare the effectiveness of moist heat techniques (boiling, autoclaving, pasteurization) and dry heat. Be sure to define the following: thermal death point, thermal death time, and decimal reduction time.
8. Describe how filtration is used to suppress microbial growth.
9. Describe how low temperature is used to suppress microbial growth.
10. Describe how high pressure is used to suppress microbial growth.
11. Describe how desiccation is used to suppress microbial growth.
12. Describe how osmotic pressure is used to suppress microbial growth.
13. Describe how ionizing and non-ionizing radiation kill cells, identify specific types of ionizing and non-ionizing radiation.
Chemical Methods of Microbial Control:
14. List the factors related to effective disinfection.
15. Describe the two methods used to test the effectiveness of disinfectants and antiseptics (use-dilution tests and disk diffusion method)
16. Review Table 7.8 in your textbook, note the methods of action and preferred uses of chemical disinfectants. Regarding Table 7.8: This is a great table which summarizes chemical agents used to control microbial growth, I do not expect you to memorize all of the information in this table, specifically each individual chemical agent. However, be sure you understand the general mechanism of action for each of the chemical agents (phenol compounds, halogens, alcohol, etc and the preferred use for the general classes listed).
17. Differentiate between halogens used as antiseptics and as disinfectants.
18. How do alcohols destroy microbes? Are they effective against all microbes, briefly explain.
19. Identify the appropriate uses for surface active agents.
20. List the advantages of glutaraldehyde over other chemical disinfectants.
21. Explain why chemicals are added to food.
22. Identify the method of sterilizing plastic labware.
Microbial Characteristics and Microbial Control:
23. Explain how the control of microbial control is affected by the type of microbe.