Texas Southern University - BIOL 347

Chapter 05

Control of Microbial Growth

Matching Questions

1)Which of the following best matches the description:

1. use of heat to eliminate pathogens/spoilage organisms        
2. removal of all life        
3. for use on skin              
4. elimination of most pathogens on a material             
5. reduction of microorganisms to meet health standards        

True / False Questions

2. Prions and viroids are easily destroyed by common sterilization procedures.

3. The endospores of Pseudomonas make that organism very difficult to kill.

4. Upon heat treatment, bacteria die at a constant proportion.
5. The more bacteria ones starts with, the longer it will take to kill them all.

6. Heat treatment is an effective method for sterilization or disinfection of all materials.

7. Boiling is very effective at removing most common waterborne pathogens.

8. Pasteurization results in the sterilization of food products.

9. Dry heat takes a much shorter time to sterilize material than wet heat.

10. 100% ethanol is twice as effective as 60% ethanol at controlling bacteria.

11. Generally, heavy metals, except silver, have been proven to be too toxic for use on human tissue and are no longer used medically.

12. Hydrogen peroxide may be used as a sterilant on living tissue.
13. Cold and freezing are very effective in killing bacteria.

14. Organic acids, such as benzoic acid, are often added to foods to prevent microbial growth.

Essay Questions

15. Sugar and salt have been used to preserve food. Explain how they work for this purpose.

16. Describe some potential problems with the overuse of antimicrobials.