HURDLE TECHNOLOGY

• Hurdle technology


  A preservation approach that involves the use of multiple barriers or hurdles or a combined use of several preservation methods to prevent microbial growth, enzymatic activity, and other deteriorative processes in food products

  
• Also known as


  • Combined method technology
  • Barrier Technology
• Types of hurdles


  • Physical hurdles
  • Chemical hurdles
  • Biological hurdles
• Physical hurdles


  • Temperature control
  • Moisture control
  • Packaging
• Temperature control


  • Blast chilling of cooked meals
  • Controlled atmosphere storage of fruits
  • Freeze-drying of coffee
  • Cryogenic freezing of seafood
  • High-pressure processing (HPP) of packaged juices
• Packaging


  • Vacuum Packaging for Meat Products
  • Modified Atmosphere Packaging (MAP) for Fresh Produce
  • Aseptic Packaging for Liquid Foods
  • Barrier Films for Snack Foods
  • Active Packaging with Oxygen Scavengers

  
• Chemical hurdles


  • pH control
  • Additives
• pH control


  • Acidification
  • Alkalization
  • Pickling
  • Fermentation
  • Buffering
  • pH Adjustment
• Acidification


  • Adding acidic ingredients or using acidulants to lower the pH of the food
• Alkalization


  • Increases the pH using bases (e.g., sodium hydroxide)
• Pickling


  • Submerging foods in a solution of vinegar or brine, which lowers the pH and creates an acidic environment
• Fermentation


  • Encouraging the growth of beneficial bacteria or yeast that produce organic acids, which lower the pH of the food
• Buffering


  • Adding buffering agents to maintain a stable pH level in the food
• pH Adjustment


  • Monitoring and adjusting the pH of the food throughout processing and storage to ensure it remains within the optimal range for microbial control

  
• Additives


  • Preservatives such as sorbic acid, benzoic acid, and sulfites inhibit microbial growth
  • Antioxidants such as vitamin E and BHA (butylated hydroxyanisole) prevent oxidation reactions
• Biological hurdles


  • Biological control agents
• Bacteriophages in Meat Processing


  • Bacteriophages targeting Escherichia coli O157:H7
• Bacteriophages


  Viruses that specifically infect and lyse bacterial cells
• Nisin in Cheese Production


  • Nisin as a natural preservative in cheese
• Nisin


  A natural antimicrobial peptide produced by the bacterium Lactococcus lactis
• Antimicrobial Peptides in Beverage Preservation


  • Antimicrobial peptides derived from natural sources
• Antimicrobial peptides


  Small proteins with antimicrobial properties that can be derived from various natural sources such as plants, animals, and microorganisms
• Applications of hurdle technology in the food sector


  • Fruits and Vegetables
  • Meat Industry
  • Dairy Products
  • Fish Industry

  
• Fruits and Vegetables


  • Modified atmosphere packaging (MAP)
  • Osmotic dehydration
  • Mild heat treatments
• Meat Industry


  • Salting
  • Smoking
  • Curing
• Dairy Products


  • Pasteurization
  • Acidity
  • Fermentation
• Fish Industry


  • Salting
  • Freezing
  • Drying
• Principles of hurdle technology

  • Multiple Barriers
• Multiple Barriers - Pre-cooked Ham


  • High Temperature
  • Modified Atmosphere Packaging (MAP)
  • Nitrates/Nitrites
• Multiple Barriers - Pickled Vegetables


  • Acidity
  • High Salt Content
  • Anaerobic Environment
• Modified Atmosphere Packaging (MAP)


  • Pre-cooked hams are often packaged with reduced oxygen levels, which slows down the growth of remaining spoilage microbes that might survive the initial cooking
• Nitrates/Nitrites


  • Some hams contain nitrates or nitrites which further inhibit the growth of certain bacteria like Clostridium botulinum
• Principles of Hurdle Technology - Multiple Barriers


  1. Acidity: Pickling involves submerging vegetables in a brine or vinegar solution, creating a highly acidic environment that most spoilage microbes struggle to survive in

  2. High Salt Content: The brine used in pickling often contains a high amount of salt, which draws out water from the vegetables and reduces the water activity (Aw) – making less free water available for microbes to grow

  3. Anaerobic Environment: Pickled vegetables are often stored in an airtight container, creating an anaerobic environment (low oxygen) that further restricts the growth of some spoilage microbes
• Principles of Hurdle Technology - Synergistic Effects


  • The combination of hurdles in hurdle technology creates synergistic effects that are more effective than individual hurdles alone
  • Combining pH control with temperature control can have a greater inhibitory effect on microbial growth than either method used alone
• Principles of Hurdle Technology - Synergistic Effects (Yogurt)


  1. Heat Treatment: Milk is first heated to a specific temperature to kill most spoilage bacteria

  2. Live Lactic Acid Bacteria (LAB): Specific strains of LAB cultures are then introduced into the milk. These "good" bacteria ferment the lactose sugar in milk, producing lactic acid

  3. Lactic acid lowers the overall pH of the yogurt, creating an acidic environment that inhibits the growth of remaining spoilage microbes that might have survived the heat treatment

  4. Lactic acid contributes to the tangy flavor of yogurt

  5. Lactic acid causes milk proteins to coagulate, giving yogurt its characteristic thick and creamy texture
• Principles of Hurdle Technology - Sequential Application (Shelf-stable milk)


  1. Pasteurization: The milk is first heated to a specific temperature for a set time to eliminate harmful bacteria

  2. Homogenization: After pasteurization, the milk is forced through a small opening to break down fat globules and prevent creaming

  3. Aseptic Packaging: The homogenized milk is then filled into sterile containers in a sterile environment to minimize re-contamination

  4. High-Pressure Processing (HPP): In some cases, shelf-stable milk might undergo an additional step of high-pressure processing (HPP) where intense pressure is applied to inactivate spoilage enzymes and further extend shelf life
• Principles of Hurdle Technology - Tailored Approach (Fresh-cut fruits)


  1. Washing: Fruits are first washed with chlorinated water to remove surface contaminants

  2. Minimally Processed Cut: Precise cuts on fruits minimize browning caused by enzymatic reactions

  3. Anti-Browning Agent: Fruits might be dipped in a solution with an edible anti-browning agent (like ascorbic acid) to specifically target enzymatic browning

  4. Modified Atmosphere Packaging (MAP): MAP with lower oxygen levels is used to slow down respiration and spoilage
• Principles of Hurdle Technology - Safety Assurance


  • The hurdles employed should effectively inhibit the growth of pathogenic microorganisms while allowing for the proliferation of desirable or harmless microorganisms

  
• Principles of Hurdle Technology - Monitoring and Control


  • Careful monitoring and control of critical parameters such as pH, temperature, water activity, and microbial load throughout the food processing and storage chain

  
• Importance of Hurdle Technology


  • Extended Shelf Life
  • Preservation of Quality
  • Safety Assurance
  • Flexibility and Customization
  • Reduction of Chemical Additives
  • Global Food Supply Chain
  • Minimization of Environmental Impact
  • Compliance with Regulatory Standards