Podcast
Questions and Answers
Decimal reduction time is the time in minutes in which __________ of the population at a given temperature will be killed.
Decimal reduction time is the time in minutes in which __________ of the population at a given temperature will be killed.
90%
Which of these conditions is likely to interfere with the effectiveness of an antiseptic or disinfectant?
Which of these conditions is likely to interfere with the effectiveness of an antiseptic or disinfectant?
You conclude from these results that __________.
You conclude from these results that __________.
the compound is fungistatic
An antiseptic is used to remove microbes from __________.
An antiseptic is used to remove microbes from __________.
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Which of these is NOT a characteristic of the autoclave?
Which of these is NOT a characteristic of the autoclave?
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A chemical that reduces spoilage in fruit by destroying fungi but does NOT appear to affect other microbes would be called a __________.
A chemical that reduces spoilage in fruit by destroying fungi but does NOT appear to affect other microbes would be called a __________.
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Which of the following correctly describes antisepsis?
Which of the following correctly describes antisepsis?
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Which treatment is most effective against S. enterica?
Which treatment is most effective against S. enterica?
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The DRT for a particular bacterial species at 60°C is 30 minutes. How long would it take at this temperature to remove 99.9% of this bacterial population?
The DRT for a particular bacterial species at 60°C is 30 minutes. How long would it take at this temperature to remove 99.9% of this bacterial population?
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Which of the following is true of an antimicrobial substance with a microbial death rate of 90% after 1 minute?
Which of the following is true of an antimicrobial substance with a microbial death rate of 90% after 1 minute?
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Which of the following are NOT major targets for action of antimicrobials?
Which of the following are NOT major targets for action of antimicrobials?
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Which of the following treatments achieves sterilization?
Which of the following treatments achieves sterilization?
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Operating rooms may receive ventilation from air that has passed through __________ filters to remove microorganisms.
Operating rooms may receive ventilation from air that has passed through __________ filters to remove microorganisms.
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__________ bacteria may survive pasteurization.
__________ bacteria may survive pasteurization.
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The most likely explanation for pasteurized milk spoiling is __________.
The most likely explanation for pasteurized milk spoiling is __________.
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Packages of milk and coffee creamers may be stored without refrigeration if they have been sterilized by __________.
Packages of milk and coffee creamers may be stored without refrigeration if they have been sterilized by __________.
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Which of the following is LEAST likely to be damaged by exposure to gamma radiation?
Which of the following is LEAST likely to be damaged by exposure to gamma radiation?
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Pasteurization was first used by Pasteur to control spoilage of __________.
Pasteurization was first used by Pasteur to control spoilage of __________.
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Sterilization is the __________.
Sterilization is the __________.
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Which of the following types of radiation is the LEAST effective control method against microorganisms?
Which of the following types of radiation is the LEAST effective control method against microorganisms?
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Which type of radiation is LEAST effective in killing microbes?
Which type of radiation is LEAST effective in killing microbes?
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All of the following methods are used for food preservation EXCEPT __________.
All of the following methods are used for food preservation EXCEPT __________.
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Which of the following is an appropriate strategy for preparing and sterilizing a medium for growing fastidious bacteria?
Which of the following is an appropriate strategy for preparing and sterilizing a medium for growing fastidious bacteria?
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How were the creamer products treated to eliminate microbial growth and prevent spoilage?
How were the creamer products treated to eliminate microbial growth and prevent spoilage?
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Which one of the following physical methods of microbial control is bactericidal?
Which one of the following physical methods of microbial control is bactericidal?
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For control of microbial growth on a surface, which of these conditions is LEAST likely to interfere with the effectiveness of an antiseptic or disinfectant?
For control of microbial growth on a surface, which of these conditions is LEAST likely to interfere with the effectiveness of an antiseptic or disinfectant?
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Which term refers to an agent that inhibits bacterial growth?
Which term refers to an agent that inhibits bacterial growth?
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Study Notes
Microbiology Concepts and Definitions
- Decimal Reduction Time (DRT) is the duration required to kill 90% of a microbial population at a specific temperature.
- Antiseptics are agents that remove microbes from living tissue, commonly used on skin prior to injections.
- A fungistatic compound inhibits fungal growth without killing them, as seen in reduced fungal weight on treated apples compared to untreated ones.
- A fungicidal agent destroys fungi, effectively reducing spoilage in fruit without affecting other microorganisms.
Antimicrobial Agents and Effects
- The presence of biofilms significantly decreases the effectiveness of antiseptics and disinfectants.
- Heat treatment at 52°C is the most effective method against Salmonella enterica, with a DRT of 2 minutes.
- Antimicrobial substances often display a 90% death rate; after one minute, 10% of the original microbial population remains.
Sterilization and Pasteurization Techniques
- Autoclaves use high pressure and moist heat for sterilization, not requiring long exposure times.
- Pasteurization traditionally aimed to control spoilage in wine but has broader applications in food safety, like milk preservation.
- Thermoduric bacteria can survive pasteurization processes but face challenges at refrigeration temperatures.
- Ultra-high-temperature (UHT) treatment allows for storage of dairy products without refrigeration by eliminating microbial growth.
Radiation and Microbial Control
- Gamma rays are highly effective, while microwaves are the least effective method of all types of radiation in controlling microbial populations.
- Prions are notably resistant to heat and various radiation treatments compared to other microorganisms like viruses and bacteria.
General Microbial Control Facts
- Direct flaming is not a method typically used for food preservation compared to methods like desiccation and commercial canning.
- Bacteriostatic agents inhibit bacterial growth, while bactericidal agents kill bacteria.
- HEPA filters are used in operating rooms to filter out microorganisms from the air for infection control.
Key Takeaways for Laboratory Practices
- For media requiring heat-labile solutions, prepare and autoclave the medium before adding sensitive ingredients.
- Environmental conditions like warm temperatures do not significantly hinder antiseptic effectiveness compared to high microbial numbers or biofilms.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on key concepts from Microbiology Chapter 7 with these flashcards. Focus on terms like decimal reduction time and factors affecting antiseptic effectiveness. Perfect for reinforcing your understanding of microbial control.
