Microbiological Risk Assessment 1 and 2
Problems:
- Illnesses/ deaths
- Recalls ($ and product) you have to throw away the food, loss of money and product
- Investigations and interventions
- Law suits
- Food security through have food safety hazard, in that period of time food security can
become an issue (the example of
How to tackle these problems:
- Not prevent totally, but reduce
- More and more quantitative objectives
- Intelligent interventions: largest effects
- Combination various knowledge sources
Three dimensions:
- Technology (HPP, preservation etc.)
- Legislation rules (general food law, microbiological bacteria)
- Human behavior (how people handle food at home)
Shared responsibility (to reduce the risk the whole chain as to play a role)
Risk analysis:
1. Risk assessment
- Hazard identification: potential danger (objective procedure)
- Hazard characterization: Dose-response (disease probability/ severity as function of dose)
P(N) + severity
- Exposure assessment: Initial contamination kinetics (N)
- Risk characterization: Probability and severity including variability and uncertainty
(Probability/ severity 50.000.000 products)
2. Risk communication
3. Risk management
Definitions of hazard and risk (CODEX):
- Hazard: A biological, chemical or physical agent in, or condition of, food with the potential to
cause an adverse health effect.
- Risk: A function of the probability of an adverse health effect and the severity of that effect
consequential to a hazard(s) in food. In other words: Risk = Severity x Probability
,Hazard identification: objective procedure
All the pathogens that are relevant in the specific food product
Survival rules, general rules, cardinal parameter and user expertise.
Hazard identification
Well defined qualitative rules:
1. Survival rules: If pasteurization remove vegetative organisms
2. General rules: remove exotic pathogens
3. Cardinal parameters: remove non growers
Warnings:
- Survival rules: warning Salmonella/animal products
- Cardinal parameters: removal on temperature: abuse
Use of knowledge with criticism:
- Structured
- develop in time
Example: cooked potato (T= 7 °C)
- Rough hazard identification: Clostridium botulinum type A
- Detailed hazard identification: 33 different microorganisms
- Using all 3 types of knowledge rules gives pathogens that: are present and survive in end
product, are likely to cause health problems in practice, are able to grow in end product
- Bacillus cereus, Clostridium botulinum type E,F
Exposure assessment
- (Re)contamination kinetic /growth /inactivation /contamination/ process model
- Quantitative microbiology: experiments, characteristic numbers, main aspects
Balances and characteristics numbers:
Balance over each stage
Out = (in + external cont.) * inactivation/growth
Nout = (Nin + rc) ekt
, Biological kinetics (characteristics number = log increase)
Inactivation growth: ΣG/ΣR = log(ekt)
contamination: ΣC=log((Nin+rc)/Nin)
Total growth in each process step: ∆log(N) = ΣG - ΣR + ΣC
Determine important phenomena and ranking
Hazard characterization (dose-response)
- Probability (and severity) of disease: Pill (organism)
- What is the probability that one organism causes illness
Risk characterization:
- Probability/severity 10.000.000 products stochastic
distributions (variability uncertainty)
- Severity: health (Quality years), financial (recall, media):
ranking (comparison P=0. days ill with P=10 -
death)
- Variability: “natural” variation: reduce by better control
- Uncertainty: lack of knowledge: reduce by more research
Different approaches to calculate Pill (risk characterization):
1. Monte Carlo simulation
2. First overall analysis / FSO (Food Safety Objective)
concept
FSO norm set by the government
, Risk assessment
Ho-ΣR+ΣG+SΣC<FSO: forces to put numbers
Structured and transparent, but large uncertainty
- Experimental values, literature, databases
- Methods, models, characteristic numbers
- Intelligent users
Risk management
Weighing policy alternatives in the light of the results of risk assessment, selecting and implementing
appropriate control options.
- Risk evaluation
- Option assessment
- Option implementation
- Monitoring and review
Risk communication
Interactive exchange of information and opinions concerning risks