Food safety risk assessment lecture microbial risk assessment
Problem of foodborne outbreaks:
- Illness/death
- Recalls
- Investigations and interventions
- Law suits
- Food security
Problem:
- Not prevent totally but reduce
- More and more quantitative objectives
- Intelligent interventions: largest effect
- Combination various knowledge sources
Shared responsibly microbial risks:
- Manufacturer
- Retailer
- Legislator
- Cook
- Consumer
Risk analysis
- Risk assessment → what is the problem and how important is it?
- Risk management → communication to the consumer, retail enc..
- Risk communication → manage the risk, decisions, actions that are required
Risk assessment:
- Hazard identifications = potential danger
- Hazard characterisation = P(N) + severity (dose + severity)
- Exposure assessment = N (initial contamination)
- Risk characterisation = probability and severity including variability and uncertainty
Definitions of hazard and risk (CODEX)
Hazard = A biological, chemical or physical agent in, or condition of food with 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 In food
- Risk = severity + probability
Hazard identification: objective procedure
Survival rules, general rules, cardinal parameters and user expertise
,Hazard identification example
Well defined qualitative rules:
1. Survival rules: if pasteurisation removes vegetative organisms
2. General rules: remove exotic pathogens
3. Cardinal parameters: remove non growers
Warning
- 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 degrees)
Rough hazard identification: Clostridium botulinum Type A
Detailed hazard identification: 33 different microorganisms
Using all 3 types of knowledge rules given that pathogens:
- Are present and survive in end product
- Are likely to cause and cause health problems in practise
- Are able to grow in end product
Bacillus cereus, clostridium Botulinum Type E, D
Exposure assessment
Balances and characteristic numbers:
Out = (in + external cont.) * inactivation/growth
Nout = (Nin + rc)*e(kt)
Nin = initial number of micro organisms
Rc = number of organisms added by contamination
E (kt) = growth or inactivation factor
Hazard characterisation: dose response
Different micro organisms have different dose responses
Shigella dysenteriae = lower dose will can cause a severe effect (faster effective)
S pullorum = higher dose can only cause severe effects (less effective)
,Risk characterisation
Probability/severity 10.000.000 products
Stochastic distributions (variability uncertainty)
- Severity: health (quality years), financial (recall, media) ranking
- Variability: ‘natural variation: reduce by better control
- Uncertainty: lack of knowledge (reduces by more research)
Approaches to improve variability and uncertainty
- Approach 1: Monte Carlo simulation → mathematical technique that predicts possible
outcomes of an uncertain event
- Approach 2: FSO concept (food safety objective)
Growth, initial level and the contamination are combined the Nt (number of organisms total),
put into the dose response relation, this will give the probability of illness, this will give an
indication of the total number of servings that have been consumed and then this will give
the number of consumers that get ill in the population.
The eventually level has the be lower then the set FSO, this norm is set by the government
, Performance objective: the maximum frequency or concentration of a (microbial) hazard in a
food product at a specific step in the food chain (except before consumption). During the
primary product and food industry production step the amount of microbes has to be lower
than the PO (performance objective)
Before consumption → < FSO
Example food chains PO (log cfu/g)
If the product is contaminated before the production there is a certain log production
necessary to get the number to be below the FSO before consumption
Problem of foodborne outbreaks:
- Illness/death
- Recalls
- Investigations and interventions
- Law suits
- Food security
Problem:
- Not prevent totally but reduce
- More and more quantitative objectives
- Intelligent interventions: largest effect
- Combination various knowledge sources
Shared responsibly microbial risks:
- Manufacturer
- Retailer
- Legislator
- Cook
- Consumer
Risk analysis
- Risk assessment → what is the problem and how important is it?
- Risk management → communication to the consumer, retail enc..
- Risk communication → manage the risk, decisions, actions that are required
Risk assessment:
- Hazard identifications = potential danger
- Hazard characterisation = P(N) + severity (dose + severity)
- Exposure assessment = N (initial contamination)
- Risk characterisation = probability and severity including variability and uncertainty
Definitions of hazard and risk (CODEX)
Hazard = A biological, chemical or physical agent in, or condition of food with 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 In food
- Risk = severity + probability
Hazard identification: objective procedure
Survival rules, general rules, cardinal parameters and user expertise
,Hazard identification example
Well defined qualitative rules:
1. Survival rules: if pasteurisation removes vegetative organisms
2. General rules: remove exotic pathogens
3. Cardinal parameters: remove non growers
Warning
- 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 degrees)
Rough hazard identification: Clostridium botulinum Type A
Detailed hazard identification: 33 different microorganisms
Using all 3 types of knowledge rules given that pathogens:
- Are present and survive in end product
- Are likely to cause and cause health problems in practise
- Are able to grow in end product
Bacillus cereus, clostridium Botulinum Type E, D
Exposure assessment
Balances and characteristic numbers:
Out = (in + external cont.) * inactivation/growth
Nout = (Nin + rc)*e(kt)
Nin = initial number of micro organisms
Rc = number of organisms added by contamination
E (kt) = growth or inactivation factor
Hazard characterisation: dose response
Different micro organisms have different dose responses
Shigella dysenteriae = lower dose will can cause a severe effect (faster effective)
S pullorum = higher dose can only cause severe effects (less effective)
,Risk characterisation
Probability/severity 10.000.000 products
Stochastic distributions (variability uncertainty)
- Severity: health (quality years), financial (recall, media) ranking
- Variability: ‘natural variation: reduce by better control
- Uncertainty: lack of knowledge (reduces by more research)
Approaches to improve variability and uncertainty
- Approach 1: Monte Carlo simulation → mathematical technique that predicts possible
outcomes of an uncertain event
- Approach 2: FSO concept (food safety objective)
Growth, initial level and the contamination are combined the Nt (number of organisms total),
put into the dose response relation, this will give the probability of illness, this will give an
indication of the total number of servings that have been consumed and then this will give
the number of consumers that get ill in the population.
The eventually level has the be lower then the set FSO, this norm is set by the government
, Performance objective: the maximum frequency or concentration of a (microbial) hazard in a
food product at a specific step in the food chain (except before consumption). During the
primary product and food industry production step the amount of microbes has to be lower
than the PO (performance objective)
Before consumption → < FSO
Example food chains PO (log cfu/g)
If the product is contaminated before the production there is a certain log production
necessary to get the number to be below the FSO before consumption
