Week 3 P2 Sterilisation Y

Question 1

Why would we want to control microbial growth?

Answer 1

To prevent unwanted growth

Question 2

Compare disinfection and sterilisation

Answer 2

Disinfection removes all bad microbes
Sanitisation reduces the no of microbes

Question 3

Some factors affecting the influence of killing microbes

Answer 3

Temperature, size, composition, concentration, exposure

Question 4

Dead cell

Answer 4

A cell that is unable to reproduce

Question 5

Name physical methods of sterilisation

Answer 5

Heat
Filtration
Radiation

Question 6

To raise BP of water you must

Answer 6

Raise the pressure

Question 7

Tyndallisation definition

Answer 7

Type of sterilisation, boiling goods in cans/jars at BP for 15-20mins for 3 days in a row, kills endospores and MO

Question 8

What is the D value

Answer 8

The time taken under defined conditions to reduce a
population by 90%

Question 9

What is pasteurisation

Answer 9

Use of mild heat to decrease microbial population

Question 10

Autoclaves

Answer 10

Type of pasteurisation, removes air from chamber adds steam to reach desired temp + Pressure

Question 11

Membrane filters uses :

Answer 11

Sterilisation, samples vols of Liq, supports growth of bacteria

Question 12

Bacterial and Fungicidal

Answer 12

Kills B and F both

Question 13

Bacteriolytic

Answer 13

Kills organism and disrupts membranes

Question 14

Bacterio and fungistatic

Answer 14

Stops growth

Question 15

Phenolics adv + dis

Answer 15

long lasting , kills tb dis; toxic , accumulative

Question 16

What technique could we use to sterilise liquid media containing heat sensitive components?

Answer 16

Filtration

Question 17

In an autoclave heat sterilisation is achieved under a temperature of ————– and for a minimum recommended duration of …………………..

Answer 17

121 for 15 mins

Question 18

Pasteurisation can be carried out at:

Answer 18

63 for 30 mins

Question 19

The most difficult problem in sterilization is to kill

Answer 19

endospores

Question 20

The bacterium that is currently under investigation for it’s possible role in Crohn’s disease and spread via milk is:

Answer 20

myobacterium paratuberculosis

Question 21

Heat sterilization is normally undertaken in an autoclave. The most usual conditions are:

Answer 21

15mins 121 degrees

Question 21

In phototrophic metabolism light energy leads to electron generation and electron flow. These electrons are mainly produced from

Answer 21

Water