September 18, 2019

Mathematical Modelling - Safety of traditional foods

Traditional foods have delighted us for centuries

  • Part of the regional cultural heritage

  • Important engines for the fragile regional economies

  • Producers’ knowledge
  • Invisible action of beneficial bacteria

Mathematical Modelling - Safety of traditional foods

Protected designation of origin (PDO)

Protected geographical indication (PGI)

Mathematical Modelling - Safety of traditional foods

Threats to traditional foods!
  • Spoilage and pathogenic bacteria are lurking
What can we do to counteract the lurking bacteria?
Barriers that oppose their growth, namely:
  • Low contamination of raw materials

  • Addition of salts (nitrites/nitrates)

  • Low pH, low Aw, smoking, etc.

Mathematical Modelling - Safety of traditional foods

Further valorisation of traditional foods

Ensure their quality and safety
  • Predictive microbiological models (PMM)

  • Environmental conditions (intrinsic and extrinsic)

Dynamic data
  • Validate the PMM

Mathematical Modelling - Safety of traditional foods

Predictive microbiology models
  • Assess traditional foods shelflife
  • Assess traditional foods safety
  • Innovation in traditional foods

Mathematical Modelling - Safety of traditional foods

Computing power and web applications
  • Growth of computing power
  • Development of web applications
    • Predictive microbiology that are globally available
    • Traditional food producers should benefit
      • Scientific and technological advances
      • Inform their decisions on the safety of their products

Mathematical Modelling - Safety of traditional foods

Predictive microbioly models

kinetic growth models
  • Microbial growth assessment over time
  • Microbiological growth
    • Different instrinsic parameters: pH, salt level, etc.
    • Inoculated with the relevant organism or cocktail of organisms
    • Range of temperatures
    • Dynamic temperatures
Growth/no growth or time to growth models
  • Microbial growth is
    not evaluated
  • Growth occurs?

Mathematical Modelling - Safety of traditional foods

Several PMM have been developed
  • Spoilage microorganisms
  • Pathogenic microorganisms
  • Enviromental variables included
    • Storage temperature - fluctuating temperatures
    • pH
    • Salt
    • Water activity
    • Preservatives: nitrite, CO2, lactic and acetic acids
  • PMM needs to be validate for the traditional foods

Mathematical Modelling - Safety of traditional foods

Parameters of interest

  • Spoilage microorganisms
  • Time to reach a specified target level

  • Pathogenic microorganisms
  • Time for growth to start (lag time): Salmonella, C. botulinum
  • Toxins producers microrganisms - critical level is reached: S. aureus and B. cereus
  • Time taken to reach toxins producing levels
  • Shelf life: Listeria monocytogenes, level of 100 cfu/g during storage (EU legislation)

Mathematical Modelling - Safety of traditional foods

Acidified traditional foods

  • PMM are used to predict the time to growth rather than growth curves

  • Data for predictions
  • pH
  • water activity
  • % salt
  • temperature (static or dynamic)
  • acidified foods: level of preservative?

Mathematical Modelling - Safety of traditional foods

Final remarks

  • Research is needed considering the traditional foods
    • Acquire data: along the process maceration/fermentation/maturation
    • Food matrix’s intrinsic properties also vary in time
  • Dynamic predictive microbiology models
    • Intrinsic properties: water activity, pH, lactic acid concentration
    • Manufacture characteristics (i.e., addition of starter cultures, fermentation/maturation time/temperature)
  • Need for interdisciplinar teams
    • Expertise in food microbiology
    • Microbial ecology and physiology (functional cultures, effect of antimicrobial compounds and survival of pathogens)
    • Food technology
    • Food sensory science: maintainance of the organoleptic qualities of the traditional foods
    • predictive microbiology and microbial risk assessment
      • Modelling, simulation and optimisation
      • Informatics - development of the IT tools

Mathematical Modelling - Safety of traditional foods

PRIMA project focused in traditional foods