Control Of Microbial Growth

Question 1

What is sterilization?

Answer 1

destruction of all forms of life

Question 2

What is disinfection?

Answer 2

destruction of only vegetative pathogens

Question 3

What is antisepsis?

Answer 3

destruction of vegetative pathogens on living tissue

Question 4

What does bactericidal mean?

Answer 4

kills microbes

Question 5

What does bacteriostatic mean?

Answer 5

temporarily inhibits growth

Question 6

What are the five physical methods of control?

Answer 6

1. heat 2. cold 3. filtration 4. desiccation 5. radiation

Question 7

Wha are the two types of heat?

Answer 7

1. dry heat 2. moist heat

Question 8

What is the action of dry heat?

Answer 8

oxidizes cell components

Question 9

What does dry heat achieve?

Answer 9

sterilization

Question 10

What are two examples of dry heat?

Answer 10

incineration and dry oven

Question 11

What are the parameters of a dry oven?

Answer 11

171C for 1 hour

Question 12

What is the action of moist heat?

Answer 12

steam coagulates cell components

Question 13

What are three examples of moist heat?

Answer 13

1. autoclaving 2. boiling 3. pasteurization

Question 14

What is autoclaving?

Answer 14

steam under pressure

Question 15

What does autoclaving achieve?

Answer 15

sterilization

Question 16

What are the parameters of autoclaving?

Answer 16

121C for 15 minutes with 15 psi

Question 17

What does boiling achieve?

Answer 17

disinfection

Question 18

What are the parameters of boiling?

Answer 18

100C for 30 min

Question 19

What is pasteurization?

Answer 19

high temperatures to kill microbes in food

Question 20

What does pasteurization achieve?

Answer 20

reduction of microbes

Question 21

What is the classical method of pasteurization?

Answer 21

63C for 30 min

Question 22

What is the HTST method of pasteurization?

Answer 22

High Temp. Short Time; 72C for 15 sec

Question 23

What is the UHT method of pasteurization?

Answer 23

Ultra High Temp 140C FOR 3 SEC

Question 24

What does cold do to bacteria?

Answer 24

Bacteriostatic; reduces metabolic rate

Question 25

What are examples of cold and their parameters?

Answer 25

refrigerator: 0-7C; freezer: -5C or lower

Question 26

What is filtration?

Answer 26

removal of microbes from a suspension using a porous barrier

Question 27

What are the two types of filtration?

Answer 27

High Efficiency Particulate Air filters and membrane filters

Question 28

Where do High Efficiency Particulate Air Filters remove microbes from?

Answer 28

the air

Question 29

Where do Membrane filters remove microbes from?

Answer 29

liquid

Question 30

What is desiccation?

Answer 30

removal of water

Question 31

Is desiccation bacteriostatic or bactericidal?

Answer 31

bacteriostatic

Question 32

What are two examples of desiccation?

Answer 32

drying, hypertonic environments

Question 33

In tradition ____ the wavelength, _____ the energy

Answer 33

shorter, greater

Question 34

What are the two types of radiation?

Answer 34

ionizing radiation and non-ionizing radiation

Question 35

What is ionizing radiation?

Answer 35

produces high energy ions that damage the cell

Question 36

What are two examples of ionizing radiation?

Answer 36

X-rays and gamma rays

Question 37

What is non-ionizing radiation?

Answer 37

UV

Question 38

What are the wavelengths of UV?

Answer 38

15-400 nm

Question 39

What does UV target?

Answer 39

DNA at 260nm

Question 40

What is the action of UV?

Answer 40

induces thymine dimers in DNA which causes mutation or death

Question 41

What does UV achieve?

Answer 41

disinfection

Question 42

What is the limitation of UV?

Answer 42

doesn’t penetrate well

Question 43

What are the three actions of anti-microbial agents?

Answer 43

1. alteration of membrane 2. damage proteins 3. damage nucleic acids

Question 44

What are the 9 types of disinfectants/antiseptics?

Answer 44

1. phenol and phenolics 2. biguanides 3. aldehydes 4. ethylene oxide 5. halogens 6. alcohols 7. heavy metals 8. peroxides 9. surface- active agents