chapter 7

Question 1

physical methods to control microorganisms (3)

Answer 1

– Low temperature storage
– Freezing
– Reducing available water

Question 2

Freeze drying aka ___________ is widely used for what?

Answer 2

LYOPHILIZATION

preserve foods like coffee milk and meats

Question 3

1. __________ and __________ used in
   processed meats have been shown to be a potent carcinogen
2. Numerous chemicals are
   used as _____________
   (Formaldehyde, phenols (animal tissues)

Answer 3

1. nitrates and nitrites
2. preservatives

Question 4

1. the suffix –cide means: to ____
2. _________: chemical that destroys bacteria (not endospores)
3. __________: a chemical that can kill fungal spores, hyphae, and yeasts
4. _____________: a chemical that inactivates viruses
5. _________: can destroy bacterial endospores
6. _________ : and microbicide: chemical agents that kill microorganisms

Answer 4

1. to kill
2. bactericide
3. fungicide
4. virucide
5. sporicide
6. germicide

Question 5

_________removing and destroying all microbial life
____________ eliminates MOST pathogens
___________ heat treatment to reduce organisms that cause food spoilage
_______________ process used to delay spoilage of perishable items

Answer 5

sterilization

disinfection

pasteurization

preservation

Question 6

Autoclaving, incineration and membrane filtration are all examples of what type of microbial control?

Answer 6

sterilization

Question 7

1. the suffix –static means: to _____ _____
2. ___________: prevent the growth of bacteria
3. _________: inhibit fungal growth
4. _____________: materials used to control the growth of microorganisms

Answer 7

1. stand still
2. bacteriostatic
3. fungistatic
4. microbiostatic

Question 8

Regulated by–FDA
1. ____________ (living/animate surfaces)

EPA
2. _______________ (non-living/inanimate surfaces)

Answer 8

1. antiseptics
2. disinfectants

Question 9

disinfectants and antiseptics are examples of what type of microbial control?

Answer 9

disinfection

Question 10

What is microbial death?

Answer 10

cell structures become dysfunctional and entire cell sustains irreversible damage

Question 11

germicidal agents cannot destroy ___________ while sterilants destroy all ____________

Answer 11

1. endospores
2. microorganisms

Question 12

In microbial death a cell can no longer do what?

Answer 12

reproduce/grow

Question 13

When does microbial death begin?

Answer 13

when a certain threshold of microbicidal agent is met.

Question 14

– Daily life
– Hospital
– Microbiology laboratories
– Food and food production facilities
– Water treatment

All of these factors can affect what?

Answer 14

Microbial control Methods

Question 15

T/F Selection of an effective antimicrobial procedure has drawbacks and procedural parameters

Answer 15

TRUE

Question 16

Effectiveness of treatment to kill microbes depends on what 4 things?

Answer 16

1. # of microbes
2. Environment (organic matter, temperature, biofilms)
3. Time of exposure
4. Microbial characteristics (endospores, cell wall)

Question 17

name 4 PHYSICAL methods of microbial control?

Chemical methods use a variety of what?

Answer 17

• Heat
• Irradiation
• Filtration
• Mechanical removal

antimicrobial chemicals

Question 18

What is the critical consideration for the type of microbe?

Answer 18

• resistant or susceptible to methods

Question 19

What are the 5 resistant microbes?

Answer 19

1. Bacterial endospores
2. Protozoan cysts and oocysts
3. Mycobacterium
   species
4. Pseudomonas species
5. Naked viruses

Question 20

what scientific term is being described below:

_______________
– Pasteur developed to avoid spoilage of wine
– Does not sterilize but significantly reduces organisms
– Used to increase shelf life of food
– Most protocols employ HTST method (High Temp Short Time)

Answer 20

pasteurization

Question 21

What resistant microbe is resistant to heat, drying, and numerous chemicals?

Answer 21

Bacterial endospores

Question 22

Protozoan cysts and oocysts are generally excreted in what?

• what does it cause?

Answer 22

excreted in feces and cause diarrheal disease

Question 23

1. _________ method (High Temp Short Time)
   * Heated to ___ °C and held for 15 seconds
2. Other protocol _____ (Ultra High Temperature)
   * Heated to ____°C -150°C, held for several seconds then rapidly cooled

Answer 23

1. HTSA method
   heated to 72 °C
2. UHT Method
   heated to 140°C -150°C

Question 24

What resistant microbe has mycolic acid in their cell wall structure and initiates resistance?

Answer 24

Mycobacterium species

Question 25

Where do Pseudomonas species grow?

Answer 25

in presence of many chemical disinfectants

Question 26

What do naked viruses lack and what are they more resistant to?

Answer 26

Lack envelope and are more resistant to chemical killing

Question 27

Autoclave is _____________ steam and achieves sterilization at what temp, pressure and time? Autoclave is effective against vegetative cells and endospores but not ______ Prions are destroyed under what conditions?

Answer 27

pressurized steam 121°C and 15psi in 15 min prions Prions destroyed at 132°C and 15psi for 4.5 hours

Question 28

which heat is more effective between dry heat and moist heat.

Answer 28

Moist heat is more effective because of the steam

Question 29

T/F Hot air sterilization is more effective than moist heat?

Answer 29

FALSE, Not as effective as moist heat & Sterilization requires longer times and higher temperatures

Question 30

What type of radiation is described below? the radiation ejects orbital electrons from an atom causing ions to form

Answer 30

Ionizing radiation

Question 31

What type of radiation is described below? excites atoms by raising them to a higher energy state but does not ionize them – UV: modifications and breaks in DNA

Answer 31

Nonionizing radiation

Question 32

How do dry heat control conditions differ from autoclave control conditions? (temp/time)

Answer 32

* 200°C for 1.5 hours (dry heat) vs. * 121°C for 15 minutes (autoclave)

Question 33

1. T OR F: A-T bonds are harder to break than C-G bonds because A-T has 3 strands to bind while C-G only has 2 2. Non-Ionizing Radiation (ultraviolet, 260 nm) damages DNA by creating what?

Answer 33

1. FALSE, A-T bonds are easier to break than C-G bonds because A-T only has 2 strands to bind while C-G has 3 2. thymine dimers

Question 33

1. Solutions of 60% -80% isopropyl or ethyl alcohol kill vegetative bacteria and fungi but are not effective against what? 2. Mode of action: coagulation of __________ and essential ___________ – damage to lipid membranes 3. Alcohol is commonly used as what?

Answer 33

1. endospores and some naked viruses 2. coagulation of proteins and essential enzymes 3. antiseptic and disinfectant

Question 34

- Biguanides -phenolics -quats There 3 chemicals are used as controls to disinfect and sterilize what structure?

Answer 34

cytoplasmic membrane

Question 35

- Alcohols - Aldehydes - Halogens - Metals - Ozone - Peroxygens -Phenolics There chemicals are used as controls to disinfect and sterilize what?

Answer 35

proteins

Question 36

1. The effectiveness of Hydrogen peroxide depends on what? 2. Living tissue produces what that breaks down hydrogen peroxide to oxygen and water? 3. 2 reasons hydrogen peroxide is useful as disinfectant?

Answer 36

1. surface being treated 2. catalase enzyme 3.* Leaves no residue * Doesn’t damage most materials

Question 37

What 2 chemicals are used as controls for DNA?

Answer 37

- ethylene oxide -aldehydes

Question 38

________________ is a type of halogen that destroys all types of organisms and viruses (including spores) _____________ is a type of halogen that is not reliable with endospores and is used in tincture or iodophore on skin

Answer 38

chlorine iodine

Question 39

Heavy metal compounds combine with...?

Answer 39

enzymes and proteins

Question 40

1. Mode of action for phenol (carbolic acid) (2) 2. what does phenol kill? 3. Is phenol reliable? 4. what 2 phenols are used in soaps and lotions?

Answer 40

1. * Destroy plasma membrane * Denature proteins 2. most vegetative cells * Can kill mycobacterium at high concentrations. 3. No, not on all groups of viruses 4. Triclosan and hexachlorophene phenols

Question 41

Creams containing silver sulfadiazine are used for what? What are they available on?

Answer 41

prevent secondary infections bandages for wound care