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• Efficient production of bioprocessed food

  • Objective is to stimulate growth and increase the viability of desirable microorganisms
• Objective for spoilage and pathogenic microorganisms


  • Minimize their numbers or completely eliminate them from food
• Objective to prevent food contamination and spread of disease

  To ensure the good health of people eating the food
• Objective to prevent food contamination and spread of disease

  To protect the health of the food handler
• Methods to control microorganisms in foods

  1. Controlling access of the microorganisms in foods

  2. Physically removing the microorganisms present in foods

  3. Preventing or reducing the growth of microorganisms and germination of spores present in foods

  4. Killing microbial cells and spores present in foods
• Control or Preservation Methods

  • Control of Access (Cleaning and Sanitation)
  • Control by Physical Removal
  • Control by Heat
  • Control by Low Temperature
  • Control by Reduced Aw
  • Control by Low pH and Organic Acids
  • Control by Modified Atmosphere (or Reducing O-R Potential)
  • Control by Antimicrobial Preservatives
  • Control by Irradiation
  • Control by Novel Processing Technologies
  • Control by Combination of Methods (Hurdle Concept)
• Control of Access (Cleaning and Sanitation)

  1. Cleaning

  2. Sanitation
• Sanitizers approved for use in food processing plants

  • Chlorine-based sanitizers
  • Iodophores
  • Quaternary ammonium compounds
  • H2O2
• Control by Physical Removal

  1. Centrifuge

  2. Filtration

  3. Trimming

  4. Washing
• Control by Heat


  1. The main objective is to destroy vegetative cells and spores of microorganisms, especially pathogenic and spoilage causing ones

  2. Low-heat processing or pasteurization

  3. High-heat processed foods
• Low-heat processing or pasteurization


  1. The temperature used is below 100°C to destroy all the vegetative cells of the pathogens

  2. Two methods used: Low temperature long time (LTLT) and High temperature short time (HTST)
• High-heat processed foods


  Heating foods at or above 100°C for a desired period of time based on product characteristics and specific microorganisms to be destroyed
• Control by Low Temperature


  1. Main objective is to prevent or reduce growth of microorganisms and reduce or prevent catalytic activity of microbial enzymes and spore germination

  2. Methods used: Ice chilling, Refrigeration, Freezing
• Control by Reduced Aw


  1. Main objectives are to prevent or reduce the growth of microorganisms and toxin production by toxigenic molds and bacteria

  2. Methods used: Natural dehydration, Mechanical drying, Smoking
• Control by Low pH and Organic Acids

  1. Main objective is to reduce the pH of the food to control microbial growth

  2. Acids used: Acetic acid, Propionic acid, Lactic acid, Citric acid, Sorbic acid, Benzoic acid
• Control by Modified Atmosphere

  1. Growth of aerobes is reduced, but anaerobic and facultative anaerobic bacteria can grow unless other techniques are used

  2. Methods used: Vacuum packaging
• Control by Modified Atmosphere

  The growth of aerobes is reduced, but under these conditions anaerobic and facultative anaerobic bacteria can grow unless other techniques are used to control their growth
• Methods for control by Modified Atmosphere

  • Vacuum packaging
  • Gas flushing
• Gases used in gas flushing

  • Mixed of CO2 and N2 with some O2 for packaging red meats
• Control by Antimicrobial Preservatives


  Antimicrobial chemicals are used in food in relatively small doses either to kill undesirable microorganisms or to prevent their growth
• Antimicrobial chemicals


  • Differ greatly in the ability to act against different microorganisms
  • Some are narrow spectrum, some are broad spectrum
  • Some act against G+ or G- bacteria spores or viruses
• Designations for chemicals capable of killing microorganisms

  • Germicides
  • Fungicides
  • Bactericides
  • Sporicides
  • Viricides
• Designations for chemicals that inhibit or retard microbial growth

  • Fungistatic
  • Bacteriostatic
• Chemical terms


  Bactericidal, fungicidal, and microbicidal all mean that the chemical will kill bacteria, fungi, and microorganisms respectively
• Control by Irradiation


  Food irradiation is a form of food processing that can extend shelf life and reduce spoilage
• Control by Novel Processing Technologies


  Novel food processing technologies arose as a result of consumer’s desire for safe, tasty, fresh and mild processed food products with long shelf life and maintained quality
• Thermal Technologies


  • Microwave
  • Radio Frequency
  • Ohmic Heating
  • Direct Steam Injection
• Microwave heating


  A multiphysics phenomenon involving electromagnetic waves and heat transfer
• Radio Frequency heating


  Heat is generated within the product due to molecular friction resulting from oscillating molecules and ions caused by the applied alternating electric field
• Ohmic Heating


  Also known as direct Joule heating, used in the food industry to rapidly increase the temperature for cooking or sterilization purposes
• Direct Steam Injection


  A heating technique that injects steam directly into process liquids, creating precise temperature control and thorough mixing
• Non-Thermal Technologies


  • High Pressure Processing (HPP)
  • Pulsed Electric Field (PEF)
  • Ultrasound
• High Pressure Processing (HPP)


  A non-thermal food and beverage preservation method that guarantees food safety and achieves an increased shelf life while maintaining organoleptic and nutritional attributes
• Pulsed Electric Field (PEF)


  A food pasteurization method that uses short bursts of high voltage electric fields on foods to achieve desired microbial inactivation or modification of food structure
• Ultrasound


  A green novel technology known for its role in environmental sustainability
• Eurization method


  Uses short bursts of high voltage electric fields on foods to achieve desired microbial inactivation or modification of food structure
• Ultrasound


  • Known as a green novel technology due to its role in environmental sustainability
  • Commonly used in several fields such as medicine or in the automobile industry, but still scarce in the food industry
• Irradiation


  Food enters a chamber where it is exposed to a specific amount of radiation to kill germs or prevent them from multiplying
• Light-based technology


  • Nonthermal technology used for inactivation of microorganisms in food processing, utilizing the germicidal effect of light based on variable wavelength against bacteria, viruses, and fungi
• Cold Plasma


  • A novel nonthermal food processing technology that uses energetic, reactive gases to inactivate contaminating microbes on meats, poultry, fruits, and vegetables