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57 Cards in this Set

  • Front
  • Back
Agents that kill microbes or inhibit their growth are known as ________.
Antimicrobial agents
The removal or destruction of all forms of microbial live ,including endospores, is called ________.
The technique used to kill Clostridium botulinum and it's spores but is not a complete sterilization is called ______.
Commercial sterilization
What is sanitization?
The reduction of micobes that are present to safe levels.
What is the term given to a technique of controling microbes that actually kills the microbes?
Microbicidal agent
What is the practical use of Commercial sterilization?
A method used to process canned foods.
What are the three different approaches to controling microbial growth?
1)Killing microbes, 2)Preventing microbial growth, 3)Physical removal of microbes
What is the effect of microbistatic agent?
As long as the agent is present the growth of the microbe is halted-they inhibit microbial growth.
Antisepsis is the destruction of vegetative pathogens where?
On skin and other living tissues.
Destruction of vegetative pathogens present but does not kill spores is known as ______.
What is the term given to the complete absence of microbes from an area?
The removal of microbes from an area (such as skin or table)
A strong, harsh chemical agent used to destroy vegetative pathogens on nonliving surgaces is known as a _______.
What is an Antiseptic?
A chemical agent that is used to kill vegetative pathogens on living tissue, it is less harsh than a disinfectant.
Breifly list three reasons for controlling microbial growth.
1)prevent food spoilage, 2)prevention of desease by microbes, 3)prevention of microbial contamination and undesirable alteration of materials.
Of the folowing which is the most resistant to anti microbial agents: Naked virus, endospores, prions.
Of the folowing which is the most resistant to anti microbial agents: vegetative protozoa, enveloped viruses, mycobacteria.
Of the folowing which is the most resistant to antimicrobial agents: Gram-positive bacteria, Enveloped viruses, Fungi.
What is the most resistent pathogen?
What is the least resistant pathogen.
Enveloped viruses.
Why do we wash and scrub our hands even we use soap?
It reduces the concentration of microbes present therefore reducing the concentration of of antimicrobial agent needed.
Why is it better to use hot water when using a chemical agent?
Heat generally increases the activity of a chemical agent.
What are five factors effecting the use of microbial chemical agents?
1)type of pathogen 2)number of microbes present 3)concentration of chemical agent 4)Time of exposure 5)environmental conditions
What is the ideal concentration of a chemical agent and why?
Lowest effect concentration because it is the most cost effective and the least toxic.
List some environmental conditions that effect the activity of chemical agents?
pH, temperature, organic molecules(mucus, fecal matter, blood)
How does decreasing pH effect the activity of a chemical agent?
Acidity generally increases activity of chemical agents.
How is time of expsoure related to activity of chemical agents?
time os exposure is inversely related to the concentration of the chemical agent and directly related to the number of microbes present.
Are cold temperatures microbicidal or microbistatic?
Microbistatic-cold temperature don't kill the microbes they just halt their growth.
Desiccation is microbicidal. True or False?
False-desiccation only halts growth.
What are the three targets by which chemical agents affect microbes?
1)cell membranes 2)proteins 3)nucleic acids(DNA)
What are the targets of phycisal factors that affect microbial growth?
1)cell membranes 2)proteins 3)nucleic acids(DNA)
What effect does exposing microbes to steam heat have and is it microbistatic or microbicidal?
Steam heat causes cellular components to coaggulate and it is microbicidal.
Is dry heat microbicidal or microbistatic and how does exposure to it affect microbe?
Dry heat bakes or oxidizes(burns or incinerates)cell components and it is microbicidal.
A disinfecting process uing high temperatures to kill all pathogens present in foods is known as _________.
What are the different types of pasteurization?
1)classic method of pasteurization 2)high temp short time 3)ultra high temp
Describe the classic method of pasteurization?
Exposure substance to 63C for 30 mins
Explain the difference between the Classic method of pasteurization and the HTST method.
The HTST method has higher temperatures and shorter times and is considered equivelent methods if they kill all the microbes present.
Does steam or dry heat kill quicker and how?
Steam heat kills quicker by penetrating the cellular components and coaggulating then or clumping them together.
What are equivalent treatments?
methodes of changing temperature and varyinge exposure times to acquire the same results as the classic method of pasteurization.
What do we call the minimum time required to kill microbes present in a suspension or liquid at a given temperature?
Thermal death time
What is the decimal reduction time?
the time required to kill 90% of the bacteria present at a given temperature.
What do we use to kill microbes by producing high-energy free radicals which react with DNA and other components killing microbes?
Ionizing radiation
What is a practical use for the killing of microbes by exposing them to ionizing radiation?
Cold sterilization
Killing microbes in foods by the use of ionizing radiation is called _______.
cold sterilization
What are the two types of filters used to remove microbes and what are the mediums they work on?
HEPA filters-removes microbes from the air and Membrane filters-that remove microbes from fluids.
What does HEPA stand for?
High-Efficiency Particulate Air
What is the best way to sterilize a heat sensitive fluid
By using a membrane filter.
Describe the process of lyophilization.
Freeze drying of microbial cultures in a vaccum (water is removed by sublimation)
What is a common way of storing microbes by using both cold temperatures and dessication.
What is the term given to the removal of water and it is ti microbicaidal or microbistic?
Dessication-and its microbistatic
What are the typical conditions of an autoclave?
15 psi. steam pressure at 121C for 15 minutes.
How does high pressure effect microbial growth.
It kills them by altering and denaturing their proteins
List the six methods of physical control of microbial growth?
1)heat 2)cold 3)filtration 4)high pressure 5)desiccation 6)radiation
What are the typical conditions for sterilization with dry heat and what is it used for?
170C for 2hrs.-used to sterilize glassware.
What kind of sterilization do we use to sterilize our inocculation loops in lab?
Dry heat-incineration-oxidizing of cellular components.
What is the term given to the physical removal of microbes?
What type of fluids are best suited for filtration rather that pasteurization?
vitamins and antibacterial fluids that will be destroyed by heat