Chapter 7

Question 1

Sepsis

Answer 1

microbial contamination

Question 2

Asepsis

Answer 2

absence of significant contamination

Question 3

biocide/germicide

Answer 3

kills microbes

Question 4

bacteriostasis

Answer 4

inhibits growth of microbes, but doesn’t kill them

Question 5

After the removal of a bacteriostatic agent, microbial growth _______________.

Answer 5

can resume

Question 6

What are three ways that control agents affect microbial cells?

Answer 6

1. Alter membrane permeability 2. Damage proteins 3. Damage nucleic acids

Question 7

4 Factors that Influence the Effectiveness of Control Treatment

Answer 7

1. Number of microbes 2. Amount of time exposed to treatment 3. Environment 4. Microbial Characteristics

Question 8

Why does the number of microbes affect the effective on control treatment?

Answer 8

takes longer to kill them all

Question 9

Examples of Environmental Influences on the effectiveness of control treatments:

Answer 9

organic matter, temperature, biofilms

Question 10

What microbial characteristics makes it harder to kill microbes?

Answer 10

Being mycobateria, or having endospores

Question 11

Sterilization

Answer 11

complete elimination of all living organisms, including endospores

Question 12

Disinfection

Answer 12

Killing or removal of pathogens from inanimate objects; typically does not kill spores

Question 13

Antisepsis

Answer 13

Killing or removal of pathogens from living tissues; typically does not kill spores

Question 14

Sanitation

Answer 14

reduction of microbes on eating and drinking utensils to safe levels

Question 15

4 Types of Physical Control

Answer 15

high temperature, low temperature, filtration, radiation

Question 16

_____ heat is more effective than ___ heat

Answer 16

Moist; dry

Question 17

Killing spores and thermophiles usually requires _____ heat and _____ temperature.

Answer 17

high; high

Question 18

How does an autoclave kill microbes?

Answer 18

Denatures proteins

Question 19

Commercial Sterilization

Answer 19

enough heat to kill Clostridium botulinum endospores; not completely sterile

Question 20

Botulism

Answer 20

Clostridium botulinum; rare but serious paralytic disease caused by a nerve toxin

Question 21

Pasteurization

Answer 21

reduces spoilage organisms and pathogens

Question 22

What is a common method of pasteurization in the US?

Answer 22

HTST (High Temperature Short Time) 72C for 15 sec

Question 23

What is a common method of pasteurization in Europe?

Answer 23

UHT (Ultra High Temperature) 140C for

Question 24

Are these all equivalent treatments?
63C for 30 min
72C for 15 sec
90C for 0.5 sec

Answer 24

Yes

Question 25

Ultra-High Pasteurization

Answer 25

138 C for at least 2 sec; done before or after packaging; extended shelf life under refrigerated conditions

Question 26

3 Types of Dry Heat Sterilization

Answer 26

Flaming, Incineration, Hot-air sterilization

Question 27

Low temperatures ______ _______ and preserve strains -stasis

Answer 27

slow down growth

Question 28

Your refrigerator is what temp?

Answer 28

4-8C

Question 29

Lyophilization

Answer 29

freeze drying

Question 30

membrane filtration

Answer 30

physical removal of microbes from solutions

Question 31

2 common pore sizes for filtration:

Answer 31

0.22 micrometers and 0.45 micrometers

Question 32

UV light has poor penetration. It is used for _______ sterilization

Answer 32

surface

Question 33

Microwaves kill by heat, but _____ antimicrobial

Answer 33

aren't

Question 34

High pressure ___________ __________

Answer 34

denatures proteins

Question 35

Dessication

Answer 35

prevents metabolism by removing water

Question 36

Osmotic pressure causes _________

Answer 36

plasmolysis

Question 37

Phenols and Phenolics cause ________. In other words, they disrupt the _______ _________.

Answer 37

leakage; plasma membrane

Question 38

phenols are useful against _______________

Answer 38

mycobacteria

Question 39

Iodine

Answer 39

alters protein synthesis and membranes

Question 40

Iodine is used for:

Answer 40

skin disinfection

Question 41

Chlorine

Answer 41

oxidizing agents that inhibit enzyme activity

Question 42

Chlorine is used for:

Answer 42

disinfection of water

Question 43

3 main parts to ethanol

Answer 43

1. denatures proteins 2. dissolves lipids 3. requires water

Question 44

Heavy metals have oligodynamic properties meaning:

Answer 44

They denature proteins

Question 45

Aldehydes ________ proteins by ____-_________ with functional groups. They damage nucleic acids.

Answer 45

inactivate; cross-linking

Question 46

2 Uses of Formaldehyde

Answer 46

1. Disinfectant that kills bacteria and fungi | 2. Tissue preservative

Question 47

Oxidizing Agents like perozygens:

Answer 47

denature proteins and lipids

Question 48

Hydrogen peroxide is good for ______________ of contaminated surfaces but not a good __________ for wounds.

Answer 48

disinfection; antiseptic

Question 49

What's used to preserve meats like hot dogs?

Answer 49

Sodium nitrite

Question 50

What are organic acids used for?

Answer 50

the control of molds and bacteria in foods and cosmetics

Question 51

What two antibiotics prevent the spoilage of cheese?

Answer 51

nisin and natamycin

Question 52

What are the most resistant to chemical biocides?

Answer 52

prions

Question 53

What are the least resistant to chemical biocides?

Answer 53

viruses with lipid envelopes