2.4 Control of Microbial Growth

Question 1

asepsis

Answer 1

maintenance of sterility by preventing contamination

Question 2

difference between complete sterilization and commercial sterilization.

Answer 2

elimination of all viable microbes including endospores

elimination of microbe that cause foodborne disease or spoilage

Question 3

Disinfection

Answer 3

destruction of vegetative pathogens but not endospores

Question 4

Antisepsis

Answer 4

reduction of microbes on the skin through the use of chemicals

Question 5

Degerming

Answer 5

reduction of microbes on the skin through scrubbing and chemicals

Question 6

Sanitization

Answer 6

mechanical removal of microbes and debris to safe levels

Question 7

Factors that influence the selection of a method of microbial control

Answer 7

Types of microbes present
Number of microorganisms present
Nature of the material to be treated
Presence of other materials
Exposure:  time and concentration
Toxicity

Question 8

Targets of Physical and Antimicrobial Agents in the Cell

Answer 8

Cell Wall:  blockage of synthesis or digestion of cell wall
Cell Membrane:  damage to lipid bilayer
Protein synthesis:  inhibition
DNA:  damage to bases or double helix
Proteins:  denaturation

Question 9

Phenolics

Answer 9

denature proteins and disrupt membranes

Question 10

Heavy Metals

Answer 10

bind to proteins and inhibit enzyme activity

Question 11

Halogens

Answer 11

oxidize and destabilize cellular macromolecules

Question 12

Ethyl and Isopropyl Alcohol

Answer 12

denature proteins and disrupt membranes

Work best at 70% solution

Question 13

Surfactants

Answer 13

lower surface tension to facilitate physical removal

Anionic detergents: soaps and detergents

Question 14

Chlorhexidine

Answer 14

: disrupts cell membranes

Found in surgical scrub, antiseptics, and oral rinses

Question 15

Alkylating Agents

Answer 15

inactivate enzymes and nucleic acid

Question 16

Peroxygens

Answer 16

oxidize and destabilize cellular macromolecules