Lab 22

Question 1

generally, ___ kills microbes; ____ inhibits microbial growth

Answer 1

heat, cold

Question 2

name the 5 optimal growth ranges

Answer 2

psychrophilic, psychrotrophic, mesophilic, thermophilic, and hyperthermophilic

Question 3

0C-20C

Answer 3

psychrophilic

Question 4

20C-30C

Answer 4

psychrotrophic

Question 5

25C-40C

Answer 5

mesophilic

Question 6

45C-65C

Answer 6

thermophilic

Question 7

80C and higher

Answer 7

hyperthermophilic

Question 8

denatures enzymes, dehydrates microbes, and kills by oxidation effects

Answer 8

dry heat

Question 9

Standard application of dry heat in a hot-air oven is _____ for ___ hours.

Answer 9

170C, 2

Question 10

transfers heat energy to the microbial cell more efficiently than dry air, resulting in the denaturation of enzymes

Answer 10

moisture

Question 11

name the 3 moist heat methods

Answer 11

pasteurization, boiling, and autoclaving

Question 12

In _____, the temperature is maintained at 63 C for 30 minutes, or 72 C for 15 minutes to kill designated organisms that are pathogenic or cause spoilage

Answer 12

pasteurization

Question 13

______ (100 C) for 10 minutes will kill vegetative bacterial cells; however, it does not inactivate endospores

Answer 13

boiling

Question 14

most effective method of moist heat sterilization

Answer 14

autoclaving

Question 15

15 psi, at 121 C for 15 minutes. usually sufficient to kill endospores and render materials sterile

Answer 15

standard condition for autoclaving

Question 16

length of time required to kill all bacteria in a liquid culture at a given termperature

Answer 16

Thermal Death Time (TDT)

Question 17

the temperature required to kill all bacteria in a liquid culture in 10 inutes

Answer 17

Thermal Death Point (TDP)

Question 18

the time, in minutes, in which 90% of a population of bacteria at a given temperature will be killed

Answer 18

Decimal Reduction Time (DRT, or D value)