Food Preservation Hurdle Technology Quiz
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Questions and Answers

Which of the following is NOT a physical hurdle for preserving food?

  • Salt (correct)
  • Aseptic packaging
  • Blanching
  • Freezing

    • Microorganisms can easily 'jump over' all the hurdles present in food products.

    False

    What is the primary purpose of preservative factors in food?

    To prevent microorganisms from multiplying and to keep them inactive or kill them.

    ___________ is a measure of the energy status of the water in a system.

    <p>Water activity</p> Signup and view all the answers

    What is the primary purpose of hurdle technology in food preservation?

    <p>To combine various preservation factors for effective results</p> Signup and view all the answers

    Match the following types of hurdles with their examples:

    <p>Physical hurdles = Blanching, freezing, aseptic packaging Physico-chemical hurdles = Salt, sugar, pH Microbially-derived hurdles = Competitive flora, starter cultures Pressure hurdles = Ultrasonication, high pressures</p> Signup and view all the answers

    Hurdle technology is ineffective when using low concentrations of multiple preservatives.

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

    Name one common hurdle used in food preservation.

    <p>Temperature, pH, water activity (Aw), or Eh (redox potential)</p> Signup and view all the answers

    Which of the following is considered a microbially-derived hurdle?

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

    Water activity is dependent on the amount of moisture content in a food sample.

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

    The ability of microorganisms to maintain a stable internal environment is known as _____

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

    Name an example of a physical hurdle used to preserve foods.

    <p>Blanching, freezing, or aseptic packaging.</p> Signup and view all the answers

    Match the following hurdles with their definitions:

    <p>Temperature = Heat treatment to inhibit microbial growth pH = Level of acidity or alkalinity affecting microbial survival Water Activity (Aw) = Amount of moisture available for microbial growth Redox Potential (Eh) = Measure of the electron transfer potential in foods</p> Signup and view all the answers

    What is a synergistic effect in the context of hurdle technology?

    <p>The enhancement of preservation effectiveness through combined methods</p> Signup and view all the answers

    Homeostatic mechanisms help microorganisms thrive in adverse conditions.

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

    What is metabolic exhaustion and how does it relate to hurdle technology?

    <p>Metabolic exhaustion refers to the depletion of energy in microorganisms due to stress reactions, and it's key for hurdle technology's effectiveness.</p> Signup and view all the answers

    Which of the following is NOT a physico-chemical hurdle in food preservation?

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

    Spices and herbs are considered physical hurdles in food preservation.

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

    What is one example of a food preserved using hurdle technology that utilizes high acidity?

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

    The preservation of salami type fermented sausage primarily involves the use of ______, nitrate, Eh, pH, and Aw.

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

    Match the food with its respective hurdle technology used for preservation:

    <p>Salami = Salt, nitrate, Eh, pH, Aw Smoked products = Heat, reduced Aw, salt Jam = Heat, high acidity, high sugar Pickles = Salt, acetic acid, heat</p> Signup and view all the answers

    What factor is NOT considered when selecting a combination of hurdles for food preservation?

    <p>Consumer preferences</p> Signup and view all the answers

    Lactic acid is a microbially derived hurdle in food preservation.

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

    Name one method that combines thermal processing with an antimicrobial agent in food preservation.

    <p>Blanching with sodium benzoate</p> Signup and view all the answers

    Which combination of methods is used to enhance the shelf life of minimally processed fruits and vegetables?

    <p>Chilling + disinfection + MAP</p> Signup and view all the answers

    Blanching is used at temperatures of 35°C for peaches to achieve a shelf life of 3 months.

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

    What is the purpose of using high pressure processing in hurdle technology?

    <p>To enhance food preservation by inactivating microorganisms and enzymes.</p> Signup and view all the answers

    The natural antimicrobial compound derived from garlic is called ______.

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

    Match the fruits with their combined methods for preservation:

    <p>Peach = Blanching (steam, 2 min) at 35°C Mango = Blanching (80°C, 10 min) Papaya = Blanching (steam, 3 min) at 35°C Pineapple = Blanching (steam, 2 min) at 27°C</p> Signup and view all the answers

    Which method is combined with preservatives to enhance the preservation of tropical fruits?

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

    The shelf life of whole sliced pineapple at 27°C is 8 months.

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

    List one benefit of using MAP in food preservation.

    <p>Reduces oxygen levels to slow down spoilage and extend shelf life.</p> Signup and view all the answers

    To prevent postharvest decay in strawberries, UV light is combined with ______ treatment.

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

    What is the pH of papaya that is blanched for 3 minutes?

    <p>4.1</p> Signup and view all the answers

    Study Notes

    Hurdle Technology

    • Hurdle technology is a preservation method combining mild, but reliable preservation factors or techniques.
    • It aims to improve product quality and safety.
    • It uses gentle, but effective preservation methods.
    • Stress factors, known as hurdles, often have a synergistic (enhancing) or additive effect.

    pH Scale and Preservation Examples

    • A pH scale measures acidity or basicity.
    • More acidic foods have a lower pH (1-6).
    • More basic foods have a higher pH (8-14).
    • Examples:
      • 1 M HCl (Battery Acid): Highly acidic
      • Stomach Acid: Acidic
      • Coke/Vinegar: Acidic
      • Rain Water: Neutral
      • Pure Water: Neutral
      • Baking Soda: Slightly basic
      • Ammonia (household cleaner): Basic
      • 1 M NaOH: Highly basic

    Synergistic Effect

    • Effective preservation is achieved using several preservatives at low concentrations.
    • This surpasses the effectiveness of using a single preservative at high concentrations.
    • Microorganisms have multiple targets within the cell – cell membrane, and even DNA.
    • Preservatives affect different targets within the microorganism's cell, preventing it from repairing itself.

    Hurdle Factors

    • Temperature, pH, water activity (Aw), and redox potential (Eh) are common hurdles.
    • There are 50 different hurdles used in food preservation.
    • Other hurdles include ultrahigh-pressure treatment, modified atmosphere packaging (MAP), edible coatings/films, ethanol, and bacteriocins.

    Homeostasis and Hurdles

    • Homeostasis is a microorganism's ability to maintain a stable and uniform internal environment.
    • Microorganisms have mechanisms to resist stress factors such as pH, water activity (Aw), and temperature.
    • Hurdles disrupt homeostatic mechanisms that make growth impossible.
    • Several combined hurdles used simultaneously are more effective for food preservation.

    Microorganism Stress Responses

    • Microorganisms respond to stress through active processes which expend energy.
    • They use mechanisms such as transporting protons across the cell membrane and maintaining high cytoplasmic concentrations to keep their internal environment stable.
    • Disrupting this homeostasis is key to food preservation by the application of hurdles.
    • Effective application of hurdle technology relies upon metabolic exhaustion of the microorganism.

    Principle of Hurdle Technology

    • Preservative factors disrupt microorganism homeostasis.
    • Microorganisms aren't able to adapt effectively to multiple hurdles.
    • Preservative factors prevent microorganisms from multiplying and causing food to spoil.
    • Combinations of different hurdles (temperature, water activity, pH) create significant effects on microbial stability.

    Water Activity (Aw)

    • Water activity (aw) is a measure of the energy status of water in a system (qualitative).
    • It is an intensive property that does not depend on the amount of material—differentiating it from moisture content.
    • Water activity is crucial for microbial stability.

    Intensive and Extensive Properties

    • Intensive properties, like aw and temperature, don't depend on the amount of substance.
    • Extensive properties, like weight and volume, depend on the amount of substance.

    Examples of Foods Preserved by Hurdle Technology

    • Salami-type fermented sausages: Combinations of salt, nitrate, Eh, pH, and aw.
    • Smoked products: Heat, reduced aw, salt, and antimicrobial chemicals.
    • Jam: Heat, high acidity, high sugar content, reduced aw.
    • Pickles: Salt, acetic acid, heat, and chemical preservatives (e.g., benzoate, sorbate).

    Hurdle Technology Applications and Examples

    • Thermal processing (blanching, pasteurization, or canning), combined with antimicrobial agents like sodium benzoate or vanillin.
    • High pressure combined with biopreservative sources.
    • Irradiation with preservatives like organic acids, bacteriocins, or natural antioxidants.
    • Modified atmosphere packaging (MAP) combined with high-pressure processing and irradiation.

    Industrial Applications of Hurdle Technology

    • Minimally processed fruits and vegetables using temperature control, antioxidant solutions, and chlorinated water.
    • Combining chilling, disinfection, and modified atmosphere packaging (MAP).
    • Combining UV light with chemical disinfectants and MAP.
    • Combined use of chlorinated water and UV light for fresh cut fruit and vegetable disinfection.
    • Using UV light in combination with mild heat treatment to inactivate harmful fungi in products like strawberries and sweet cherries.

    Combined Methods for Preserving Tropical Fruits

    • Different combinations of blanching methods, temperature, and preservatives are examined to discover optimal preservation methods.

    Intermediate Moisture Foods

    • Modifications to traditional intermediate-moisture (IMF) foods result in high moisture stable foods.
    • Ease of preparation, storage without refrigeration, and energy efficiency are advantages over conventional preservation methods.
    • Disadvantages: Too high sugar content and potential health hazard from additive use.

    Hurdle Technology Summary

    • Increased moisture content and aw while reducing sugar and salt is a key application to ensure microbial stability during ambient storage.
    • Hurdles such as mild heat, reduced aw, low pH, preservatives, anti-browning agents, and anti-softening agents are used.

    Significance of Hurdle Technology

    • Improved product quality and enhanced safety.
    • Reduced costs in terms of money, energy, and other resources saved due to more effective preservation.
    • Maintenance of stable foods with high sensory and nutritious qualities due to minimal processing.
    • Preserves the integrity of foods, especially fruits.
    • Applicability to both large and small food industries across the manufacture of new products.

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    Related Documents

    Hurdle Technology PDF

    Description

    Test your knowledge on hurdle technology and its role in food preservation. This quiz covers the primary purposes, examples, and mechanisms of various hurdles in food safety. Understand how these factors contribute to keeping food safe from microorganisms.

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