Microbial Control Methods
74 Questions
7 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Cooking utensils are often __ when used in restaurants.

sanitized

Dry heat is more effective at killing microbes than moist heat.

False

Which of the following is NOT a physical agent used to control microbes?

  • filtration
  • boiling water
  • ethylene oxide (correct)
  • pasteurization
  • radiation

    • 100% Ethanol solutions are more effective antimicrobial agents than are 70% solutions.

    <p>False</p> Signup and view all the answers

    Alcohol sterilizes skin.

    <p>True</p> Signup and view all the answers

    Nonionizing radiation such as __ kills bacteria by __.

    <p>UV: including mutations in DNA</p> Signup and view all the answers

    Household bleach is used as a common disinfectant because it has __.

    <p>hypochlorite</p> Signup and view all the answers

    Placing objects in boiling water __ them.

    <p>disinfects</p> Signup and view all the answers

    Which of the following has the HIGHEST resistance to killing?

    <p>bacterial endospores</p> Signup and view all the answers

    A chemiclave sterilizes objects by exposing them to __ gases.

    <p>formaldehyde</p> Signup and view all the answers

    An autoclave sterilizes objects by using __.

    <p>steam under pressure</p> Signup and view all the answers

    Chemical surfactants kill microbes by __.

    <p>disrupting membranes</p> Signup and view all the answers

    A viricidal agent will __.

    <p>kill viruses</p> Signup and view all the answers

    Treatment with cold __ microbial growth.

    <p>slows</p> Signup and view all the answers

    If you had a nonautoclave safe object that you needed to use as a surgical implant, how would you clean it for use? (Select all that apply)

    <p>antisepsis</p> Signup and view all the answers

    What are the advantages of antisepsis? (Select all that apply)

    <p>compatibility</p> Signup and view all the answers

    What are the advantages of vaporized hydrogen peroxide sterilization? (Select all that apply)

    <p>less toxic than ETO</p> Signup and view all the answers

    What are the advantages of plasma sterilization? (Select all that apply)

    <p>various materials</p> Signup and view all the answers

    Which of the following are characteristics of moist heat? (Select all that apply)

    <p>physical</p> Signup and view all the answers

    Which of the following are characteristics of ethylene oxide? (Select all that apply)

    <p>chemiclave</p> Signup and view all the answers

    Which of the following are characteristics of pasteurization? (Select all that apply)

    <p>denatures proteins</p> Signup and view all the answers

    Which of the following are characteristics of halogenation? (Select all that apply)

    <p>disrupts S bonds</p> Signup and view all the answers

    Which of the following are characteristics of filtration? (Select all that apply)

    <p>isolating or separating organisms</p> Signup and view all the answers

    Which of the following are characteristics of ionizing radiation? (Select all that apply)

    <p>breaks DNA</p> Signup and view all the answers

    Which of the following are characteristics of surfactants? (Select all that apply)

    <p>cell membrane</p> Signup and view all the answers

    Which of the following are characteristics of hydrogen peroxide? (Select all that apply)

    <p>chemical</p> Signup and view all the answers

    Which of the following are characteristics of quaternary ammonia compounds? (Select all that apply)

    <p>chemical</p> Signup and view all the answers

    Which of the following are characteristics of heavy metals? (Select all that apply)

    <p>thimerosal</p> Signup and view all the answers

    Which of the following are characteristics of Aldehydes? (Select all that apply)

    <p>cidex</p> Signup and view all the answers

    Which of the following are characteristics of sanitizing? (Select all that apply)

    <p>pathogens</p> Signup and view all the answers

    Which of the following are characteristics of cold temperatures? (Select all that apply)

    <p>refrigeration</p> Signup and view all the answers

    Which of the following are characteristics of phenolics? (Select all that apply)

    <p>protein denaturant</p> Signup and view all the answers

    Unwanted organisms in a culture are called __.

    <p>contaminants</p> Signup and view all the answers

    Which of the following are examples of contaminants? (Select all that apply)

    <p>poison air</p> Signup and view all the answers

    What are the three methods used in decontamination protocols? (Select all that apply)

    <p>disinfection</p> Signup and view all the answers

    What is the difference between physical and chemical methods of microbial control?

    <p>Physical methods use physical forces to control microbes, such as heat, radiation, or pressure, whereas chemical methods use chemical reactions.</p> Signup and view all the answers

    Are all contaminants equally susceptible to physical and chemical means of decontamination?

    <p>False</p> Signup and view all the answers

    How do sterilization and disinfection differ?

    <p>A sterile object has no living cells, spores, or viruses, while a disinfected object may still have a small number of these.</p> Signup and view all the answers

    Can something be almost sterile?

    <p>False</p> Signup and view all the answers

    What is the difference between a -cidal agent and a -static agent?

    <p>-cidal agents kill microorganisms, while -static agents only inhibit their growth and reproduction.</p> Signup and view all the answers

    If you take bacteriostatic antibiotics for an infection, what will happen when you stop taking the antibiotic?

    <p>Stopping bacteriostatic antibiotics too soon can allow the infection to reoccur and may contribute to antibiotic resistance.</p> Signup and view all the answers

    Disinfectants are used on __ surfaces.

    <p>inanimate</p> Signup and view all the answers

    Antiseptics are used on __.

    <p>body</p> Signup and view all the answers

    Which of the following are examples of disinfectants? (Select all that apply)

    <p>bleach</p> Signup and view all the answers

    Which of the following are examples of antiseptics? (Select all that apply)

    <p>antibacterial soap</p> Signup and view all the answers

    Your bathroom in a public restroom may say "sanitized for your protection". Is sanitization the same as sterilization?

    <p>False</p> Signup and view all the answers

    When is a microbe considered dead?

    <p>When it has permanently lost its ability to reproduce under ideal conditions.</p> Signup and view all the answers

    How do the number of organisms and their state of growth (spores vs. vegetative cells) affect microbial death rate?

    <p>A larger population takes longer to completely eliminate due to the logarithmic nature of microbial death, with spores generally being much more resistant, leading to a slower death rate compared to vegetative cells.</p> Signup and view all the answers

    How does a chemical agent's concentration affect microbial death rate?

    <p>Higher concentrations generally lead to a faster rate of microbial killing.</p> Signup and view all the answers

    What are the four major cellular targets for antimicrobial agents? (Select all that apply)

    <p>protein synthesis (ribosomes)</p> Signup and view all the answers

    Name one agent that targets bacterial cell walls.

    <p>penicillin</p> Signup and view all the answers

    How do surfactants work?

    <p>Surfactants interfere with and break up the cell membrane components such as lipids and proteins.</p> Signup and view all the answers

    How may proteins be denatured?

    <p>Proteins can be denatured by heat, chemicals, or pH extremes. This process disrupts the 2nd,  3rd and 4th structure of proteins, causing them to lose their function. The loss of structure and function can lead to the death of the cell.</p> Signup and view all the answers

    How does heat affect microbial cells?

    <p>Heat denatures their proteins and disrupts their cell membranes, which can lead to cell death at high temperatures.</p> Signup and view all the answers

    Moist heat is more effective than __ heat.

    <p>dry</p> Signup and view all the answers

    If organism A has a TDT of 15 minutes and organism B has a TDT of 35 minutes, using the same temperature, which organism is most resistant to heat?

    <p>organism B</p> Signup and view all the answers

    Why is pressure added to the stream present in an autoclave?

    <p>Pressure in an autoclave serves to increase the temperature and efficiency of sterilization, prevent evaporation, and enable the process to occur faster and more effectively.</p> Signup and view all the answers

    What is tyndallization?

    <p>Tyndallization is a method of sterilization that involves intermittent boiling with periods of cooling to destroy both vegetative cells and endospores over multiple cycles.</p> Signup and view all the answers

    Does boiling water sterilize the water?

    <p>False</p> Signup and view all the answers

    Does pasteurization sterilize milk?

    <p>False</p> Signup and view all the answers

    What does pasteurization of milk do?

    <p>Pasteurization kills harmful bacteria in milk, making it safe to drink and increasing its shelf life.</p> Signup and view all the answers

    Why is cold not used to kill microbes?

    <p>Cold temperatures primarily only slow down or inhibit their growth, not outright destroy them.</p> Signup and view all the answers

    Why does radiation limit microbe growth?

    <p>Radiation can damage the DNA of microorganisms, disrupting their ability to replicate and causing cell death.</p> Signup and view all the answers

    What is ionizing radiation?

    <p>Ionizing radiation is a type of high-energy radiation that has enough power to remove electrons from atoms within a cell, creating ions and potentially causing significant damage to DNA, leading to cell death.</p> Signup and view all the answers

    How is the usefulness of nonionizing radiation limited?

    <p>The usefulness of nonionizing radiation is limited by its penetration power, resistance of certain microorganisms, dose requirements, safety concerns, and environmental interference.</p> Signup and view all the answers

    When is filtration an effective method to remove contaminants?

    <p>Filtration is effective when removing contaminants that are large, suspended, or when a high level of purity is required.</p> Signup and view all the answers

    How do aqueous solutions differ from tinctures?

    <p>Aqueous solutions are water-based, while tinctures are alcohol-based.</p> Signup and view all the answers

    Describe several characteristics that the ideal chemical antimicrobial agent would have.

    <p>The ideal chemical antimicrobial agent would have broad-spectrum activity against a variety of microbes while maintaining selective toxicity towards pathogens, high potency at low concentrations, rapid action, stability in different environments, minimal resistance development potential, low toxicity to host tissues, good solubility in body fluids, reasonable cost, and a manageable half-life allowing for appropriate dosing intervals.</p> Signup and view all the answers

    How does bleach work as a disinfectant?

    <p>Bleach works as a disinfectant by denaturing proteins in microorganisms, which kills bacteria, viruses, and fungi.</p> Signup and view all the answers

    How does alcohol kill bacteria?

    <p>Alcohol kills bacteria through a process called denaturation, which breaks down the proteins in the structure of germs.</p> Signup and view all the answers

    What is the cellular target of detergents?

    <p>The cellular target of detergents is the cell membrane.</p> Signup and view all the answers

    What are the cellular targets of heavy metals?

    <p>Heavy metals can target various cellular components, including proteins, DNA, cell membranes, mitochondria, and enzymes.</p> Signup and view all the answers

    Glutaraldehyde is used to sterilize contaminated areas--how does it kill microbes?

    <p>Glutaraldehyde kills microbes by cross-linking proteins and nucleic acids, disrupting cell membranes, and preventing the microbe from replicating, making it a powerful and broad-spectrum sterilizing agent.</p> Signup and view all the answers

    Ethylene oxide is a sterilant. Why is it not used on human tissues?

    <p>Ethylene oxide is a known human carcinogen, meaning it can directly cause cancer in humans, due to its ability to damage DNA.</p> Signup and view all the answers

    Study Notes

    Microbial Control Methods

    • Sanitization: Reduces microorganisms to safe public health levels. Often used on cooking utensils.

    • Dry Heat vs. Moist Heat: Dry heat is not more effective at killing microbes than moist heat.

    • Physical Agents: Ethylene oxide is not a physical method to control microbes. Physical methods include heat, radiation, and filtration.

    • Alcohol Effectiveness: 70% ethanol solutions are more effective antimicrobial agents than 100%.

    • Alcohol's Role: Alcohol can sterilize skin.

    • UV Radiation: Nonionizing radiation like UV light kills microbes by causing mutations in DNA.

    • Bleach as Disinfectant: Household bleach's disinfecting power comes from its hypochlorite content.

    • Boiling Water: Boiling water disinfects objects.

    • Endospore Resistance: Bacterial endospores have the highest resistance to killing methods compared to other microbial forms.

    • Chemical Sterilization: A chemiclave uses formaldehyde gas for sterilization.

    • Chemical vs. Physical Control: Filtration is a physical method, not a chemical one. Chemical agents directly affect microbial cells, while physical agents often alter the environment to kill or inhibit.

    • Autoclave: An autoclave sterilizes using steam under pressure.

    • Surfactant Mechanism: Chemical surfactants kill by disrupting cell membranes.

    • Viricidal Agents: Viricidal agents kill viruses.

    • Cold Temperatures: Cold temperatures slow microbial growth.

    • Decontamination Protocols: The three methods are sterilization, disinfection, and antisepsis.

    • Sterilization vs. Disinfection: Sterilization eliminates all living microorganisms, whereas disinfection reduces them to safe public health levels.

    • Sterile vs. Almost Sterile: 100% sterility is unattainable, and the concept of 'almost sterile' exists.

    • -Cidal vs. -Static: -Cidal agents kill microbes, while -static agents inhibit their growth.

    • Antibiotic Usage: Stopping bacteriostatic antibiotics too soon can allow the infection to return and potentially lead to antibiotic resistance.

    • Disinfectant vs. Antiseptic: Disinfectants are used on inanimate objects, and antiseptics on living tissue.

    • Types of Microbial Death: A microbe is considered dead when it permanently loses reproductive ability under ideal conditions.

    • Death Rate Factors: Microbial death rate depends on population size, growth state (e.g., spores vs. vegetative cells), and agent concentration.

    • Cellular Targets: Key targets for antimicrobial agents are cell walls, cell membranes, proteins, and nucleic acids.

    • Microbial Death Mechanisms: Various mechanisms exist, from disrupting structures to altering protein or DNA function.

    • Heat's Effect: Heat affects microbial cells through protein denaturation and membrane disruption.

    • Moist vs. Dry Heat: Moist heat is generally more effective than dry heat in microbial killing.

    • TDT (Thermal Death Time): Lower TDT values indicate greater sensitivity to heat.

    • Autoclave Principle: Pressure in autoclaves increases temperature and sterilization efficiency.

    • Tyndallization: A method of sterilization that targets both vegetative cells and endospores in intermittent boiling cycles.

    • Pasteurization: Pasteurization does not sterilize, merely reduces microbial load in foods and liquids.

    • Cold's Effect: Cold slows microbial growth, preventing their cell development but not necessarily their death.

    • Radiation Effects: Ionizing radiation damages DNA, limiting microbial growth through cell destruction or mutations. Nonionizing radiation also limits microbe growth.

    • Filter Effectiveness: Filtration effectively removes pathogens from air or liquids, particularly with large or suspended organisms.

    • Solution Types: Aqueous solutions are water-based, while tinctures are alcohol-based.

    • Ideal Chemical Antimicrobial Agent: Characteristics include broad spectrum, selective toxicity, rapid action, and stability.

    • Bleach Action: Bleach's disinfectant effect is due to protein denaturation.

    • Alcohol Action: Alcohol denatures proteins, killing bacteria.

    • Detergent Target: Detergents act on cell membranes.

    • Heavy Metals: Heavy metals affect proteins, DNA, cell membranes, mitochondria, and enzymes.

    • Glutaraldehyde: Glutaraldehyde crosslinks proteins and nucleic acids to destroy microbes.

    • Ethylene Oxide: Ethylene oxide is a potent sterilant but is a known carcinogen and thus, not used on human tissues.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Test your knowledge on various methods of microbial control including sanitization, heat treatments, and the effectiveness of alcohol. This quiz covers essential concepts such as the role of UV radiation and the resistance of bacterial endospores. Perfect for students in microbiology and public health fields!

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser