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76 Cards in this Set
- Front
- Back
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Approaches to control-- What is sterilization? |
complete absence of all microbes including endospores |
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What is disinfection? |
reduce the level of pathogenic organisms but some will survive |
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Are disinfectants used on inanimate objects or living tissues? |
inanimate objects |
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Approaches to control-- Are antiseptics used on inanimate objects or living tissues? |
living tissues
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What is pasteurization and where is it mainly used? |
--mainly used on foods |
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Approaches to control-- What is preservation? |
process of delaying spoilage of foods and other perishable products |
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Selection of an antimicrobial is complicated-- The choice depends on numerous factors: |
--environmental conditions --risk of infection --composition of the infected item |
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Why is heat treatment useful for microbial control? |
it is reliable, safe, relatively fast, inexpensive, and non-toxic |
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Using heat to destroy microorganisms and viruses-- What are the methods of heat treatment? |
moist heat and dry heat |
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What does moist heat do? |
irreversibly denatures proteins |
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Using heat to destroy microorganisms and viruses-- Boiling is a type of moist heat. What does boiling do? |
destroys most microorganisms and viruses |
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Using heat to destroy microorganisms and viruses-- Boiling is a type of moist heat. What does boiling not do? |
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Pasteurization is a type of moist heat. What is pasteurization? |
it destroys pathogens, spoilage organisms |
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What are the 2 types of pasteurization? |
--ultra-high-temperature (UHT) |
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What is high-temperature-short time (HTST) pasteurization used for? |
most products |
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What is ultra-high temperature (UHT) pasteurization used for? |
shelf-stable boxed juice and milk; known as "ultra-pasteurization" |
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Using heat to destroy microorganisms and viruses-- Sterilization using pressurized steam is a type of moist heat. What is the name of the machine used to sterilize using pressurized steam? |
autoclave
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Using heat to destroy microorganisms and viruses-- Autoclave sterilization is typically... |
121 degrees C and 15 psi in 15 minutes; longer for larger volumes |
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Using heat to destroy microorganisms and viruses-- How are prions though the be destroyed in an autoclave? |
at 132 degrees C for 1 hour |
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Commercial canning process-- What size autoclave does it use? |
industrial-sized |
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Commercial canning process-- What is it designed to destroy? |
Clostrdium Botulinum endospores |
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Commercial canning process-- What will happen if the canning process is not done right? |
we will create an oxygen free environment |
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Why is it critical for the canning process to be done right? |
if not done right, endospores can germinate in canned foods |
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Commercial canning process-- When the canning process is not done right, cells grow in low-acid anaerobic condition and produce what? |
botulinum toxin |
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Commercial canning process-- What is botulinum toxin? |
a neurotoxin |
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Is canned food commercially sterile? |
yes |
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Commercial canning process-- Is it possible for the endospores of some thermophiles to survive? |
Yes. They are not in our range of temperature (typically non-disease forming)
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Botulism-- How soon do signs and symptoms begin? |
12-36 hours after eating toxin-contaminated food |
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Botulism-- General symptoms? |
--dry mouth --blurred or double vision |
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Botulism-- Abdominal symptoms? |
--nausea --vomiting --diarrhea --constipation |
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There is progressive paralysis. How does that happen? |
Involves all voluntary muscles. Then to the involuntary muscles. |
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What kind of disease is it? |
Nervous system disease even though it is consumed. |
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What is the causative agent? |
Clostridium botulinum |
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Is Clostridium botulinum aerobic or anaerobic? |
strictly anaerobic |
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Botulism-- Is Clostridium botulinum gram-positive or negative? |
gram-positive |
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Botulism-- Is Clostridium botulinum a spore forming bacillus? |
yes |
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Botulism-- What does Clostridium botulinum produce? |
a neurotoxin |
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Botulism pathogenesis-- What releases the toxin? |
vegetative cells |
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Botulism pathogenesis-- What makes you ill? |
the toxin
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How does the toxin work? |
--passes through the stomach --is absorbed in the small intestine --can circulate in the blood stream --then attaches to receptors on muscle cells and impede muscle contraction stomach-->small intestine-->blood stream-->muscle cells |
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How does intestinal Botulism occur? |
when C. botulinum colonizes |
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Who is primarily affected by intestinal botulism? |
infants (known as infant botulism) |
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What does intestinal botulism rarely happen in adults? |
presumably normal microbiota outcompete |
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Should children under the age of 1 eat honey? |
no |
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How are endospores widely distributed? |
in soils, aquatic sediments |
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Botulism epidemiology-- How many cases/year of foodborne botulism are there in the U.S.? |
Fewer than 30 |
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Botulism epidemiology-- Why is infant botulism most common? |
because of honey |
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T or F: Proper sterilizing is preventative |
true |
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What does intravenous antitoxin do? |
only neutralizes toxin in blood |
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Botulism treatment and prevention-- How long does it take for affected nerves to slowly recover? |
can take weeks or months |
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Why is dry heat less effective that moist heat? |
longer times and higher temperatures necessary |
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Using heat to destroy microorganisms and viruses-- What temperature and time is needed for dry heat? |
200 degrees C for 90 minutes |
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Using heat to destroy microorganisms and viruses-- What temperature and time is needed for moist heat? |
121 degrees C for 15 minutes |
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Hot air ovens are a type of dry heat. How do they work? |
--denature proteins |
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Using heat to destroy microorganisms and viruses-- What is the most common method of dry heat sterilization? |
incineration |
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Using heat to destroy microorganisms and viruses-- What does incineration do? |
oxidizes cell to ashes
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Using heat to destroy microorganisms and viruses-- What is incineration used for? |
used to destroy medical waste and animal carcasses |
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Botulism dry heat-- Laboratory inoculation loop is sterilized by? |
flaming |
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Other methods to sterilize microbes-- T or F: Some materials cannot withstand heat treatment. |
true |
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What are other methods? |
--radiation: --ionizing radiation --ultraviolet radiation --microwaves |
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Other methods to sterilize microbes-- What does filtration do? |
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Other methods to sterilize microbes-- Is filtration of fluids used extensively? |
yes |
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Other methods to sterilize microbes-- What is an example of when filtration is used? |
used on certain vaccines or biological media |
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Other methods to sterilize microbes-- What is ionizing radiation? |
sterilization method that can remove electrons from atoms (gamma and x-rays) |
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Other methods to sterilize microbes-- What can ionizing radiation destroy? |
DNA |
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Ionizing radiation reacts with O2 to produce _____. |
ROS (reactive oxygen species) |
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Other methods to sterilize microbes-- What is ionizing radiation used to sterilize? |
--examples: medical equipment/disposable surgical instruments and penicillin type drugs |
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When is ionizing radiation generally used? |
after packing |
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Other methods to sterilize microbes-- What has ionizing radiation been approved for use on? |
foods, although consumer resistance has limited use |
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Does ultraviolet radiation destroy microbes directly or indirectly? |
directly
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What does ultraviolet radiation do to DNA? |
damages it |
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Other methods to sterilize microbes-- What is ultraviolet radiation used for? |
to destroy microbes in air, water, and on surfaces |
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Other methods to sterilize microbes-- Why does ultraviolet radiation have poor penetrating power? |
--cannot kill microbes in solids or turbid liquids. Glass and plastic block. |
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What must ultraviolet radiation be carefully used? |
damaging to skin, eyes
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How can microwaves kill some bacteria? |
because of the heat they produce
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Other methods to sterilize microbes-- Why is using microwaves not sterilization? |
they heat unevenly
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