CH 5 - Microbiology

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The common parameters used in autoclaving are __________

121 degrees C at 15 psi for 15 min

Biosafety levels are specific combinations of work practices, safety equipment, and facilities required to work with microorganisms. These precautionary guidelines are established by the _______

CDC

Biosafety levels are specific combinations of work practices, safety equipment, and facilities required to work with microorganisms. These precautionary guidelines are established by the ________

CDC

True or False: Methods used to control microbial growth are not important in microbiology labs since they routinely work with many types of microorganisms anyway

False

True or False: There is a standard antimicrobial procedure available from the CDC that can be used for all different microorganisms under any condition

False

Consider the use of low temperature storage for the preservation of food. Which of the following are accurate statements?

Psychrotrophic and some psychrophilic microorganisms can grow at refrigeration temperatures Refrigeration inhibits the growth of many pathogens and spoilage microorganisms by slowing or stopping critical enzyme reactions

True or False: Although endospores of certain thermophiles can survive the commercial canning process, these are rarely a concern

True

In addition to destroying C. botulinum endospores, commercial canning also destroys _____.

all other organisms that grow under normal storage conditions

In addition to destroying C. botulinum endospores, commercial canning also destroys _________

all other organisms that grow under normal storage conditions

A sterile object is free of ________

all viable microorganisms and viruses

______ are chemicals used to decrease the number of microbes on living tissues, whereas _________ are used to destroy microbes on inanimate (non living) objects

antiseptics disinfectants or germicides

It is often difficult to choose which germicide to use because often the most effective options _________

are not the safest

Germicide chemicals __________

are often poorly understood with regards to mechanisms of action usually react irreversibly with proteins, DNA, cytoplasmic membranes or viral envelopes

The precautionary guidelines established by the CDC for laboratories working with microorganisms are known as ________________ or BSLs and range from BSL-1 to BSL-4

biosafety levels

The precautionary guidelines established by the CDC for laboratories working with microorganisms are known as _________________ or BSLs and range from BSL-1 to BSL-4

biosafety levels

Adding sorbic, propionic, and benzoic acid to foods affects ______ of microbes.

cell membrane function

Which of the following are effects of ionizing radiation on food products?

changes in flavor of some foods killing of bacterial pathogens

Choosing the correct antimicrobial procedure depends on many factors including _________

composition of item environmental conditions type and number of microbes

A surgical scalpel is rated as a _______ instrument because it penetrates skin and mucous membranes and therefore must be sterile

critical

A surgical scalpel is rated as a ________ instrument because it penetrates skin and mucous membranes and therefore must be sterile

critical

Treating a surface by washing or using disinfectants in order to reduce the number of pathogens on that surface to a safe level is called

decontamination

Adding large amounts of salt and sugar to foods _____.

dehydrates microbes and prevents their growth

Which of the following are often referred to as germicides?

disinfectants

Potentially harmful chemicals referred to as ________ by products (DBPs) form when chlorine and similar substances react with chemicals in the water

disinfection

Potentially harmful chemicals referred to as __________ by products (DBPs) form when chlorine and similar substances react with chemicals in the water

disinfection

The process of ______ involves the use of antimicrobial chemicals on a surface. As opposed to sterilization, this process leaves some viable microorganisms

disinfection

The process that eliminates most or all pathogens on or in a material is __________

disinfection

To achieve equivalent microbial killing, moist heat requires ____________ exposure times and higher temperatures than _____ heat

dry moist

Cases of salmonellosis have been traced to dried eggs. This demonstrates that ________

drying is not a reliable way to kill all microbes

The most highly resistant microbial structure is the bacterial _____.

endospore

A retort is an industrial sized autoclave that ensures that __________ are destroyed

endospores of Clostridium botulinum

True or False: Choosing which germicide to use is not that complicated since we only consider how effective it is against the target microbes

false

True or False: There is a standard antimicrobial procedure available from the CDC that can be used for all different microorganisms under any condition

false

True or False: There is no risk of food poisoning with dried food since drying kills all microorganisms associated with the food

false

True or false: ionizing radiation is not an effective method of controlling microbes in food products

false

True or false: microwaves always cook foods and kill microbes effectively

false

_______ is a physical means used for destroying or removing microorganisms

filtration

__________ is a physical means used for destroying or removing microorganisms

filtration

A common dry heat sterilization method used in the microbiology laboratory is:

flaming the inoculating loop

_______ are chemicals used to destroy most pathogens on or in inanimate objects

germicides

It is important to minimize the number of pathogens in health-care settings due to the risk of ________ associated infections (HAIs)

health-care, hospital, or healthcare

It is important to minimize the number of pathogens in health-care settings due to the risk of ________ associated infections (HAIs)

healthcare

Although generally less reliable than heat, germicidal chemicals are especially useful for treating _________

heat sensitive items large surfaces

Autoclaves can be used for flash sterilization of surgical instruments in the operating room. In this case, autoclaving occurs at a _________ temperature for a _________ time

higher shorter

Autoclaves can be used for flash sterilization of surgical instruments in the operating room. In this case, autoclaving occurs at a _____________ temperature for a _________ time

higher shorter

Salting and drying decrease the availability of water in food, resulting in an environment that is ______ relative to microbes, thereby preventing their growth.

hypertonic

________ is the destruction of microbes by subjecting them to extremes of dry heat, reducing them to ashes

incineration

__________ is the destruction of microbes by subjecting them to extremes of dry heat, reducing them to ashes

incineration

What are the effects of increasing the pressure of water in an autoclave?

increases the temperature at which steam forms increases the boiling point of water

What type of radiation has enough energy to remove electrons from atoms, thereby destroying DNA and damaging cytoplasmic membranes?

ionizing

________ provides an alternative to heat for sterilization and disinfection, but the process damages some types of plastics

irradiation

___________ provides an alternative to heat for sterilization and disinfection, but the process damages some types of plastics

irradiation

Adding preservatives such as benzoic acid to food is important because ______.

it inhibits growth of many bacteria and mold

What is the major disadvantage of using dry heat instead moist heat to kill microbes?

longer time requirement

A solution of sodium hypochlorite is more effective against bacteria at ___________ pH

low

A solution of sodium is most effective against bacteria at __________ pH

low

Freeze drying or ________ is used to preserve coffee, milk, meats and vegetables

lypophilization

The process of preserving foods by rapid freezing followed by drying in a vacuum is called __________

lypophilization

Soap generally does not destroy most microbes, but it aids in their _____.

mechanical removal

Washing hands with plain soap and water works by _______ removing microbes

mechanically

Paper-thin membrane filters called ____ contain pore sizes so small they will trap microbes from liquids as they pass through

microfilters

A concentrated culture of cells will take _____ time to kill than a dilute culture of the same organism.

more

Household bleach applied at 55C is ________ effective in killing bacteria than if it were applied at 50

more

A _______ instrument is one that should only come into contact with intact skin

non critical

A _________ instrument is one that should only come into contact with intact skin

non critical instrument

Many germicides lose their effectiveness in the presence of

organic matter

A brief heat treatment that reduces the number of spoilage of organisms and destroys pathogens is called __________

pasteurization

A brief heat treatment used to make foods and beverages safe for consumption is ________

pasteurization

Brief heat treatment that reduces the number of spoilage organisms and destroys disease-causing microbes

pasteurization

Which of the following is a brief heat treatment used to prevent spoilage of wine without changing its flavor?

pasteurization

Water treatment facilities work to ensure that drinking water is devoid of __________

pathogenic microbes

Water treatment facilities work to ensure that drinking water is devoid of ____________

pathogenic microbes

Minimizing the numbers of microbes in hospital settings and other health-care facilities is important because _____. (3)

pathogens are more likely to be found in health-care facilities hospitalized patients are often more susceptible to infection of the danger of acquiring a health-care associated infection

Minimizing the numbers of microbes in hospital settings and other health-care facilities is important because _________

pathogens are more likely to be found in health-care facilities hospitalized patients are often more susceptible to infection of the danger of acquiring a health-care associated infection

A high-solute environment damages microbial cells by causing _____.

plasmolysis

The act of delaying spoilage is _____.

preservation

process of delaying spoilage of foods and other perishable products

preservation

process of delaying spoilage of perishable products

preservation

Chemicals called __________ are used to prevent the growth of undesirable organisms in foods and beverages

preservatives

Which of the following use moist heat to destroy microbes?

pressurized steam boiling pasteurization

When boiling of pasteurizing a sample, microorganism are destroyed because their __________

proteins are irreversibly denatured

When boiling or pasteurizing a sample, microorganisms are destroyed because their _____.

proteins are irreversibly denatured

Which four of the following microbial groups are the most resistant to chemical control methods?

protozoan cysts and oocysts bacterial endospores Mycobacterium species non-enveloped viruses

Which four of the following microbial groups are the most resistant to chemical control methods?

protozoan cysts and oocysts bacterial endospores Mycobacterium species non-enveloped viruses

Ionizing radiation causes indirect tissue damage by reacting with O2 to produce __________ oxygen _____________ (ROS)

reactive species

What are the main limitations of using UV radiation?

safety of use poor penetration

A process that substantially reduces the number of microbes to meet accepted health standards, but doesn't indicate any specific level of control, is known as _______

sanitation

A process that substantially reduces the number of microbes to meet accepted health standards, but doesn't indicate any specific level of control, is known as _________

sanitation

Endoscopy and endotracheal tubes are considered _____ instruments, since they come into CONTACT with mucous membranes.

semi critical

Medical instruments are classified into three categories according to their risk for transmitting diseases. These are: critical instruments, __________________ and __________________

semi critical instruments noncritical instruments

Endoscopy and endotracheal tubes are considered _____ instruments, since they come into CONTACT with mucous membranes.

semi-critical

Medical instruments are classified into three categories according to their risk for transmitting pathogens. These are: critical instruments, __________ and ________________

semi-critical instruments non-critical instruments

The main effect of low temperature storage is to ______.

slow the activity of microbes

Following treatment to remove all viable microorganisms, including viruses, an object is considered to be ________

sterile

The process of destroying or removing all microbes through physical or chemical processes is _________

sterilization

________ is the removal or destruction of all microorganisms and viruses on or in a product

sterilization

Prior to being used to cultures, media is ________ to ensure that the cultures remain pure

sterilized

Prior to being used to grow cultures, media is _____ to ensure that the cultures remain pure.

sterilized

Which of the following are used as preservatives by creating an environment that will draw water out of cells, dehydrating them?

sugar salt

UV radiation is used extensively to destroy microbes in _________

the air drinking water

Where would it be acceptable to risk using an effective germicide that is somewhat toxic to humans?

the hospital

The effectiveness of germicidal chemicals depends upon ________

the presence of organic matter the concentration used

It is important to destroy all endospores of Clostridium botulinum in commercial canning because ________

the spores can germinate in canned foods and vegetative cells can produce botulinum toxin

it is important to destroy all endospores of Clostridium botulinum in commercial canning because _________

the spores can germinate in canned foods and vegetative cells can produce botulinum toxin

Disinfectants are normally only used on inanimate objects because _________

they are harmful to living tissues

Microwave ovens are not reliable for killing microbes in food because ________

they often heat food unevenly

The number of cells in a culture will most influence the ________ necessary to kill them.

time

True or False: germicides are generally somewhat toxic to humans and the environment

true

Choosing the correct antimicrobial procedure depends on many factors including ________

type and number of microbes composition of item environmental conditions

Choosing the correct antimicrobial procedure depends on many factors including _________

type and number of microbes composition of item environmental conditions

Which of the following are physical ways to remove or destroy microbes?

ultraviolet radiation filtration autoclaving incineration

Germicide chemicals __________

usually react irreversibly with proteins, DNA, cytoplasmic membranes, or viral envelopes are often poorly understood with regards to mechanisms of action

As the pressure in an autoclave increases, the boiling point of _____ also increase, as does the temperature at which _____ forms.

water steam

When would it be a better idea to use a filter rather than an autoclave to sterilize a solution?

when the solution is heat sensitive


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