Sterilization Techniques and Contamination Control
24 Questions
0 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

Which of the following is true about UV radiation as a sterilization technique?

  • It penetrates materials deeply.
  • It can effectively penetrate fluids.
  • It is the simplest form of radiation used. (correct)
  • It requires special training to operate.

    • Gamma radiation is safer to work with compared to other radiation sterilization techniques.

    False

    What is the purpose of filter sterilization techniques?

    To remove microbes from heat-sensitive media or substrates.

    ___ filtration involves the removal of microbes based on size.

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

    Match the sterilization technique with its description:

    <p>UV Radiation = Effective for airborne microbes Gamma Radiation = Better penetration but riskier Depth Filtration = Traps particles in a tortuous path Electron Beam = Uses high-energy particles to sterilize</p> Signup and view all the answers

    What is one advantage of filter sterilization?

    <p>Allows for high throughput</p> Signup and view all the answers

    Membrane filtration can separate microorganisms of the same size.

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

    What materials can depth filtration remove effectively?

    <p>Particles from the mobile phase.</p> Signup and view all the answers

    What is the primary purpose of sterilization?

    <p>Complete destruction of all viable organisms</p> Signup and view all the answers

    Fermentation can be improved by introducing foreign microbes.

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

    Name one way to avoid contamination during fermentation.

    <p>Use a pure inoculum.</p> Signup and view all the answers

    Moist heat sterilization is commonly performed using an ________.

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

    Match the sterilization techniques with their characteristics:

    <p>Moist Heat = 121 degrees Celsius for 15-20 mins Dry Heat = 160 degrees Celsius for 2 hours Chemical Sterilization = Use of chemicals to kill microbes Radiation = Using high energy rays to sterilize items</p> Signup and view all the answers

    What is a primary drawback of using moist heat for sterilization?

    <p>Destruction of heat-sensitive components</p> Signup and view all the answers

    Filtration is a method used to sterilize liquids that are heat sensitive.

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

    What temperature and duration are required for dry heat sterilization?

    <p>160 degrees Celsius for 2 hours or 170 degrees Celsius for 1 hour.</p> Signup and view all the answers

    What is a primary advantage of depth filtration?

    <p>Cheaper than membrane filtration</p> Signup and view all the answers

    Membrane filters can achieve 100% efficiency in removing all particulates.

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

    What is the typical hydraulic loading range for depth filters?

    <p>1 - 10 gpm</p> Signup and view all the answers

    The process of cleaning a depth filter by reversing the flow of fluid through it is known as __________.

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

    Match the following types of membrane filtration with their descriptions:

    <p>Microfiltration = Removes larger particles and some microorganisms Ultrafiltration = Removes macromolecules and viruses Nanofiltration = Removes divalent ions and small organic molecules Reverse Osmosis = Removes ions and small molecules, producing high purity water</p> Signup and view all the answers

    Which of the following statements is true regarding prefiltration?

    <p>It involves using depth filters before final filtration.</p> Signup and view all the answers

    Microporous membranes are placed at the beginning of a filtration system.

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

    What is the goal of using membrane filters before the chromatography step in bioprocessing?

    <p>To ensure the absence of particulates.</p> Signup and view all the answers

    Study Notes

    Sterilization Techniques

    • Sterilization is the complete elimination of all viable organisms using heat, radiation, chemicals, or physical removal.

    Fermentation Contamination

    • Contamination by foreign microbes in fermentation results in reduced productivity, possible contamination of final desired bioproduct , and degradation of the desired product.

    • Recovery procedures may also be hindered, and extraction of the desired bioproduct can become difficult.

    Avoiding Contamination

    • Contamination can be prevented by using pure inoculums, sterilizing all materials in contact with the medium and fermenter, and maintaining aseptic conditions throughout the process.

    Sterilization Techniques Used in Experiments

    • Common sterilization techniques are:
      • Moist heat (steam): Autoclaving at 121°C for 15-20 minutes is a common method for sterilizing liquids and other heat-resistant materials.
      • Dry heat: Heating at 160°C for 2 hours (or 170°C for 1 hour) is used for glassware, metals and other heat-resistant materials.
      • Chemicals:** Various chemicals are used for sterilization, such as formaldehyde, phenolics (Lysol), and hypochlorite (bleach).
      • Radiation: UV and gamma radiation are used to sterilize surfaces and materials. X-rays and electron beams are also employed.
      • Filter sterilization: Used when heat is not suitable because it does not destroy the product, involves filtering out microorganisms/contaminants using filters.

    Moist Heat Sterilization (Steam)

    • Autoclaving is the most reliable and economical approach for liquid sterilization

    • Autoclaving generally uses steam at a high temperature (121°C) for a specified duration (15-20 minutes) to eliminate all living cells.

    • Moist heat sterilization, in particular autoclaving, is beneficial for sterilizing liquids because it's easy, dependable, and cost-efficient.

    • Drawbacks: Heat-sensitive components like vitamins, amino acids, and growth factors (e.g., EGF, NGF) might be damaged by this process.

    Dry Heat Sterilization

    • A method for sterilization that employs elevated temperatures without water; it's useful for materials sensitive to moisture
    • A common application of this method is the sterilization of glassware and other lab equipment.

    Chemical Sterilization

    • Disinfectants like formaldehyde, phenolics (Lysol), hypochlorite (bleach), mercuric chloride, and ethanol are widely used in laboratory settings to sterilize equipment and surfaces.

    Radiation Sterilization

    • UV, X-rays, gamma radiation and electron beams are used for sterilizing certain lab equipment and materials.

    Sterilization Using Filtration

    • Filtration methods can be used to remove microbes from heat-sensitive liquids/solutions by passing the material through a filtration apparatus with a filter membrane with varying pore sizes.

    • Using filters to separate microorganisms and suspended particles from liquids

    • Two types are commonly used:

      • Depth filtration: Used as pre-filters to remove large particles.
      • Membrane filtration: used for heat-sensitive products, microorganisms are trapped in the membrane.

    Membrane Filters

    • Types of membrane filters include depth and membrane/surface filters
    • Membrane filters with small pore sizes remove microorganisms more effectively.

    Considerations in Filter Sterilization

    • Specific conditions for filtration:* Filtration is best suited for heat-sensitive biological materials; pore size considerations are needed for efficiency.

    Additional Filter Sterilization Techniques

    • Different filter types are used, each with different pore sizes for separating various particles.

    • The throughput (amount passing through) increases if the same pore size filters are used.

    • Different pore sizes allow for separation of different microorganisms.

    Types of Membrane Filtration

    • Different types of membrane filtrations (MF) exist, each with a specific purpose: -Microfiltration (MF): For removing larger particles. -Ultrafiltration (UF): Separates particles based on molecular weight. -Nanofiltration (NF): Used to separate molecules with specific size, and charge. -Reverse Osmosis (RO): Used to remove small molecules.

    Microfiltration

    • Used when there is a need to remove particles of size 0.1-10µm
    • Microfiltration is the process of separating smaller microbes from heat-sensitive fermentation media.

    Ultrafiltration

    • Smaller pore sizes to separate components based on molecular weights are used in ultra-filtration
    • It's used for fractionating components, and its success is based on correct pore size specifications.

    Nanofiltration

    • It is a sterilisation method where components are separated based on pore sizes ranging from 0.1 to 10 nanometers.
    • It works best with materials that are heat-sensitive.

    Reverse Osmosis

    • Reverse osmosis is a method of filtering water to remove dissolved salts and other impurities.

    • In this process, hydrostatic pressure is used to push water through a membrane that selectively allows water molecules to pass while retaining dissolved solids.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Bioprocess Tech Notes PDF

    Description

    This quiz covers sterilization methods and the control of contamination in fermentation processes. It highlights the importance of eliminating viable organisms and the procedures to maintain aseptic conditions. Understand the techniques and their applications in laboratory experiments.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser