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Test 2- Chapter 5: Controlling Bacterial Growth - Flashcards

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Class:BIOL 3200 - GENERAL MICROBIOLOGY
Subject:Biology
University:Auburn University - Main Campus
Term:Fall 2011
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2 important people that helped in the control of bacterial growth

- Joseph Lister

- Ignaz Semmelweiss

4 physical approaches to controlling bacterial growth

1. heat

2. irradiation

3. filtration

4. mechanical removal - washing

3 reasons for wanting to control growth of bacteria

1. stop spread of infectious disease

2. stop food spoilage

3. stop transmission of food borne illnesses

sterilization can be achieved through? (4)

- removal of ALL microorganisms

"nothing like a little bit sterile"

 

heat, irradiation, chemicals, and filtration

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_____ item is absolutely free of endospores, microbes, and viruses - sterile
disinfection 2 types

- eliminates MOST pathogens

---->some viable microbes may exist

 

 

-disinfectants and antiseptics

disinfectants are used on? - inanimate objects and surfaces
antiseptics are used on? - living tissues
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pasteurization - brief heat treatment used to reduce organisms that cause FOOD SPOILAGE
discontamination -treatment to reduce pathogens to level considered safe
degerming -mechanism used to decrease number of microbes in an area (particularly the skin)
sanitized

- implies a substantially reduced microbial population

-not a specific level of control

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preservation - process used to delay spoilage of perishable items
preservation often includes the addition of _______ ingredients - growth inhibiting
bactericidal - agents that KILL vegetative cells, but not endospores
bacteriostatic - agents that prevent of retard the multiplication of bacteria but do NOT kill the cell
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2 disinfectants that kill endospores

1. sterilants- chemical that sterilizes something

2. sporocides- kill spores

How can you control bacterial growth in daily life? - WASH with soaps and detergents
nosocomical infection - a disease acquired in the hospital
instruments in hospitals are ___ to aviod introducing infection to deep tissues - sterilized
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___ __ and ___ ___ are techniques used in labs to eliminate unwanted organisms. - aseptic technique and sterile media
How is contamination of the environment controlled in the lab? - contaminated material is treated for disposal
Food ____ is enhanced through prevention of microbial growth and contamination. - quality
__ treatment is most common mechanism when controlling bacterial growth on food. - heat treatment
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___ is generally used to disinfect water. - chlorine
Selection of antimicrobial removal procedure depends on what 5 factors? most critical?

1. type of microbe*******most critical

2. extent of contamination

3. environment

4. risk of infection

5. composition of infected item

most resistant bacteria?
3 factors affecting killing of microorganisms

1. time if application of agent

2. concentrations of agent

3. conditions (temp, nature of material (porus/nonporus), and presence of extraneous materials

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porours/nonporous materials are more difficult to kill. - porous
large population of organims means what in terms of killing them - going to take much longer
Explain "D value"

- unit given to the commercial effectiveness of antimicrobial procedure

-time required to kill 99% of population

Environmental conditions like (3), strongly influence effectiveness of antimicrobial p. - pH, temp,and presence of organic materials
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Chemicals are most effective at killing microbials at ___ temps and ____ pH. - high temps and lower pH
Effectiveness of antimicrobial agent can be hampered by the presence of? - organic materials
critical items 2 examples.

- come in contact with body tissues

 

- needles and scalpels

semicritical instruments 1 example

- contanct mucous membranes but do NOT penetrate body tissues

 

-endoscope

 

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non-critical instruments 1 example

- contact with unbroken skin only

-show little risk of transmission

 

-stethoscope

___ ___ is most useful for microbial control. - heat treatment
Heat can be used to ___ or ____. Methods include? (2)

-sterilze or disintect

 

 

1. moist heat

2. dry heat

moist heat detroys through what? methods include? (3)

- irreversible coagulation of proteins

"denatures proteins"

 

1. boiling

2. pasteurization

3. pressurized steam

 

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boiling destroys ___ and ___ but not _____. Not effective method of ____.

- does destroy most microorganims and viruses

-does NOT destroy endospores

-sterilization

Pasteurization was developed by __ ___ as a means to avoid spoilage of ____.

- Louis Pasteur

- wine

Pasteurization does not ___ but does do what? Used to increase what?

- NOT sterilize but does significantly reduce organisms

- increase shelf life of food

Most pasteurization uses the ____ method but some use the ___ method.

- HTST =high temp short time

- UHT =ultra high temp

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____ is used to sterilize using pressurized steam. Preffered method of _____.

- autoclave

-sterilization

___ heat is not as effective as ___ heat.

- dry

-moist*** better

Sterilization when using dry heat requires ___ times and ___ temps.

- longer times and higher temps

 

Example of dry heat sterilization - incineration burns carcasses and destroys medical wastes
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Example of dry heat sterilization used in lab - flaming lab inoculation loop incinerates organism = sterile loop
Other methods of bacterial control other than heat. (3)

- filtration

-irradiation

-high pressure treatment

___ filtration is used to remove microbes from fluids and air. - membrane filtration
Explain HEPA

- high efficiency particulate air filter removes nearly all microbes from air

 

 

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In electromagnetic radiation the range of the wavelenght is called the ___ ____. - electromagnetic spectrum
In electromagnetic radiation ___ wavelenght and ____ frequency= more energy.

- shorter wavelenght and high frequency

 

____ radiation is able to strip electrons from atoms via (3)...

- ionizing

 

1. gamma rays

2. x-rays

3. electron accelerators

Ionizing radiation does what? (3)

1. strips electrons from atons

2. causes damage to DNA and plasma membrane

3. used to sterilize heat resistant materials

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What method is used to sterilze heat resistant materials like disposble medical supplies? - ionizing radiation
What type of radiation causes damage to DNA producing thymine dimers?

- ultraviolet radiation

------>non-ionizing

ultraviolet radiation

- a nonionizing type of radiation that is used to destroy microbes in air, drinking water, and surface

-causes thymine dimers

high pressure processing (3)

1. used in pasteurization of commercial foods

2. doesn't use high temps, rather high pressure

3. destroys all microbes by denaturing proteins and altering cell membrane permeability

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What is a disadvantage of using UV radiation? - it has poor penetrating power
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 2 important people that helped in the control of bacterial growth

- Joseph Lister

- Ignaz Semmelweiss

 4 physical approaches to controlling bacterial growth

1. heat

2. irradiation

3. filtration

4. mechanical removal - washing

 3 reasons for wanting to control growth of bacteria

1. stop spread of infectious disease

2. stop food spoilage

3. stop transmission of food borne illnesses

 sterilization can be achieved through? (4)

- removal of ALL microorganisms

"nothing like a little bit sterile"

 

heat, irradiation, chemicals, and filtration

 _____ item is absolutely free of endospores, microbes, and viruses- sterile
 disinfection 2 types

- eliminates MOST pathogens

---->some viable microbes may exist

 

 

-disinfectants and antiseptics

 disinfectants are used on?- inanimate objects and surfaces
 antiseptics are used on?- living tissues
 pasteurization- brief heat treatment used to reduce organisms that cause FOOD SPOILAGE
 discontamination-treatment to reduce pathogens to level considered safe
 degerming-mechanism used to decrease number of microbes in an area (particularly the skin)
 sanitized

- implies a substantially reduced microbial population

-not a specific level of control

 preservation- process used to delay spoilage of perishable items
 preservation often includes the addition of _______ ingredients- growth inhibiting
 bactericidal- agents that KILL vegetative cells, but not endospores
 bacteriostatic- agents that prevent of retard the multiplication of bacteria but do NOT kill the cell
 2 disinfectants that kill endospores

1. sterilants- chemical that sterilizes something

2. sporocides- kill spores

 How can you control bacterial growth in daily life?- WASH with soaps and detergents
 nosocomical infection- a disease acquired in the hospital
 instruments in hospitals are ___ to aviod introducing infection to deep tissues- sterilized
 ___ __ and ___ ___ are techniques used in labs to eliminate unwanted organisms.- aseptic technique and sterile media
 How is contamination of the environment controlled in the lab?- contaminated material is treated for disposal
 Food ____ is enhanced through prevention of microbial growth and contamination.- quality
 __ treatment is most common mechanism when controlling bacterial growth on food.- heat treatment
 ___ is generally used to disinfect water.- chlorine
 Selection of antimicrobial removal procedure depends on what 5 factors? most critical?

1. type of microbe*******most critical

2. extent of contamination

3. environment

4. risk of infection

5. composition of infected item

 most resistant bacteria? 
 3 factors affecting killing of microorganisms

1. time if application of agent

2. concentrations of agent

3. conditions (temp, nature of material (porus/nonporus), and presence of extraneous materials

 porours/nonporous materials are more difficult to kill.- porous
 large population of organims means what in terms of killing them- going to take much longer
 Explain "D value"

- unit given to the commercial effectiveness of antimicrobial procedure

-time required to kill 99% of population

 Environmental conditions like (3), strongly influence effectiveness of antimicrobial p.- pH, temp,and presence of organic materials
 Chemicals are most effective at killing microbials at ___ temps and ____ pH.- high temps and lower pH
 Effectiveness of antimicrobial agent can be hampered by the presence of?- organic materials
 critical items 2 examples.

- come in contact with body tissues

 

- needles and scalpels

 semicritical instruments 1 example

- contanct mucous membranes but do NOT penetrate body tissues

 

-endoscope

 

 non-critical instruments 1 example

- contact with unbroken skin only

-show little risk of transmission

 

-stethoscope

 ___ ___ is most useful for microbial control.- heat treatment
 Heat can be used to ___ or ____. Methods include? (2)

-sterilze or disintect

 

 

1. moist heat

2. dry heat

 moist heat detroys through what? methods include? (3)

- irreversible coagulation of proteins

"denatures proteins"

 

1. boiling

2. pasteurization

3. pressurized steam

 

 boiling destroys ___ and ___ but not _____. Not effective method of ____.

- does destroy most microorganims and viruses

-does NOT destroy endospores

-sterilization

 Pasteurization was developed by __ ___ as a means to avoid spoilage of ____.

- Louis Pasteur

- wine

 Pasteurization does not ___ but does do what? Used to increase what?

- NOT sterilize but does significantly reduce organisms

- increase shelf life of food

 Most pasteurization uses the ____ method but some use the ___ method.

- HTST =high temp short time

- UHT =ultra high temp

 ____ is used to sterilize using pressurized steam. Preffered method of _____.

- autoclave

-sterilization

 ___ heat is not as effective as ___ heat.

- dry

-moist*** better

 Sterilization when using dry heat requires ___ times and ___ temps.

- longer times and higher temps

 

 Example of dry heat sterilization- incineration burns carcasses and destroys medical wastes
 Example of dry heat sterilization used in lab- flaming lab inoculation loop incinerates organism = sterile loop
 Other methods of bacterial control other than heat. (3)

- filtration

-irradiation

-high pressure treatment

 ___ filtration is used to remove microbes from fluids and air.- membrane filtration
 Explain HEPA

- high efficiency particulate air filter removes nearly all microbes from air

 

 

 In electromagnetic radiation the range of the wavelenght is called the ___ ____.- electromagnetic spectrum
 In electromagnetic radiation ___ wavelenght and ____ frequency= more energy.

- shorter wavelenght and high frequency

 

 ____ radiation is able to strip electrons from atoms via (3)...

- ionizing

 

1. gamma rays

2. x-rays

3. electron accelerators

 Ionizing radiation does what? (3)

1. strips electrons from atons

2. causes damage to DNA and plasma membrane

3. used to sterilize heat resistant materials

 What method is used to sterilze heat resistant materials like disposble medical supplies?- ionizing radiation
 What type of radiation causes damage to DNA producing thymine dimers?

- ultraviolet radiation

------>non-ionizing

 ultraviolet radiation

- a nonionizing type of radiation that is used to destroy microbes in air, drinking water, and surface

-causes thymine dimers

 high pressure processing (3)

1. used in pasteurization of commercial foods

2. doesn't use high temps, rather high pressure

3. destroys all microbes by denaturing proteins and altering cell membrane permeability

 What is a disadvantage of using UV radiation?- it has poor penetrating power
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