Controlling growth

Question 1

Define sterilisation, and comercial sterilisation

Answer 1

Sterilisation: Killing or removal of all microorganisms.
Commercial sterilisation: Killing clostridium botulinum endospores (no pathogen left, growth stopped).

Question 2

define disinfection and antisepsis

Answer 2

Disinfection: Removing pathogens (inanimate objects)
Antisepsis: Removing pathogens from living tissue

Question 3

Define Degerming and Sanitization

Answer 3

Degerming: Removing microbes in a limited area
Sanitization: Lowering microbial counts (on eating utensils)

Question 4

Define Biocide/germicide and Bacteriostasis

Answer 4

Biocide/germicide: Kills microbes; inactivates viruses
Bacteriostasis: Inhibiting, not killing, microbes (stop them growing)

Question 5

Define sepsis and Asepsis

Answer 5

Sepsis: Refers to microbial contamination
Asepsis: absence of significant contamination

Question 6

Describe the patterns of microbial death caused by treatments with microbial control agents.

Answer 6

Death rate is consistent on a log scale.
Microbial control is dependent on the number of microbes, environment, time of exposure and microbial characteristics.

Question 7

Describe the effects of microbial control agents on cellular structures

Answer 7

Alteration of the membrane permeability
Damage to the proteins
Damage to the nucleic acid

Question 8

Interpret the results of the disk-diffusion method

Answer 8

Cover the agar plate with bacteria and add inhibitors/antibiotics. This tests the reaction to the chemical that bacteria has. The zone of inhibition is the visual zone around that indicates the death of microbes.

Question 9

Compare the effectiveness of moist heat, boiling, autoclaving, pasteurisation and dry heat

Question 10

Describe how filtration, low temperatures, high pressure suppress microbial growth