food borne risk assessment

1. MICROBIOLOGICAL RISK
ASSESSMENT ON FOOD
BORNE PATHOGENS
Prepared by
Dr.Hariharan.R
PhD Scholar
Dept. of VPH
CVAS, KVASU
Pookode

2. Health
Health
“ The absence of diseases”
“ A state of complete physical, mental, and social well-being and not
merely the absence of disease or infirmity” - WHO

3. Food borne disease (FBD)
Food borne disease (FBD)
is any illness resulting from the food spoilage of contaminated food,
pathogens (Bacteria, viruses, or parasites) that contaminate food, as
well as chemical, physical or natural toxins/particals.

4. Food borne disease (FBD)
• Demonstrated that almost 1 in 10 people fall ill every year from
eating contaminated food
• Children less than 5 years of age are at highest risk
• Cosiderable regional difference on specific FBD burden
• FBD are of a similar burden in order of magnitude as the “big three”
infectious diseases (HIV, TB, Malaria)

5. Risk analysis
Risk analysis is a process comprising:
• Risk assessment – the scientific evaluation of known or potential adverse
health effects;
• Risk management – evaluating, selecting and implementing policy
alternatives; and
• Risk communication – exchange of information amongst all interested
parties.

6. Risk assessment
• Risk assessment for microbiological hazards in foods is defined by the
Codex Alimentarius Commission (CAC) as a scientifically based process
consisting of four components:
• Hazard identification
• Exposure assessment
• Hazard characterization
• and Risk characterization.

7. Standards setting Organisations

8. Hazard identification
• Hazard identification is predominantly a qualitative process intended
to identify microorganisms or microbial toxins of concern in food or
water. It can include information on the hazard of concern as well as
relevant related data, such as clinical and surveillance data.

9. Exposure assessment
• Exposure assessment should provide an estimate, with associated
uncertainty, of the occurrence and level of the pathogen in a specified
portion of food at the time of consumption, or in a specified volume of
water using a production-to consumption approach.

10. Hazard characterization
• Hazard characterization provides a description of the adverse health
effects that may result from ingestion of a microorganism. When data
are available, the hazard characterization should present quantitative
information in terms of a dose response relationship and the
probability of adverse outcomes.

11. Risk characterization
• Risk characterization is the integration of the three previous steps to
obtain a risk estimate (i.e. an estimate of the likelihood and severity of
the adverse health effects that would occur in a given population, with
associated uncertainties).

12. Risk Analysis – CODEX framework

14. Risk characterization
Hazard
identification
Exposure
assessment
Hazard
characterization
Risk
characterization

15. Risk characterization (qualitative risk assessment)

16. Risk Management
• Process of deciding and implementing mitigation methods for the
appropriate level of safety.
• NOTE - there is usually no “0” risk.
Food security
Food safety

17. ELEMENTS OF RISK MANAGEMENT
• A. Risk evaluation
• B. Risk management option assessment
• C. Implementation of management decision
• D. Monitoring and review

18. Risk evaluation
 Identification of a food safety problem.
 Establishment of a risk profile.
 Ranking of the hazard for risk assessment and risk management priority.
 Establishment of risk assessment policy for conduct of risk assessment.
 Commissioning of risk assessment.
 Consideration of risk assessment result.

19. Risk management option assessment
Identification of available management options.
 Selection of preferred management option, including consideration
of an appropriate safety standard.
 Final management decision.

20. Monitoring and review
• Assessment of effectiveness of measures taken.
• Review risk management and/or assessment as necessary.

21. Safer Pork for Vietnamese consumers
A case study

22. Background - pork in Vietnam
Pork is an important component of the Vietnamese diet
• The most widely consumed meat: 29.1Kg/person/year
• 83% comes from very small or small farms
• 76% of pigs are processed in small slaughtering
• Preference for fresh “warm” pork supplied in traditional markets (>80% of all
pork marketed)
Food safety among the most pressing issues for people in Vietnam, more important than
education or health care
• Food exports relatively well managed but deficits in domestic markets

23. Safety assessments and pathways towards safer
pork
Research questions
Is pork safe in Vietnam?
Methods:
 Quantitative and qualitative
risk assessment
 Assess cost of FBD illness
(hospitalisation)
 Cross-contamination
Salmonella (household)
Research questions
 What are faesable options for safer
Pork?
Methods:
 Food safety (FS) performance of value
chain
 FS interventions (e.g. RCT)
 Risk communication
• Interdisciplinary team
• Risk based approach
• Food safety hazards:
– Biological and chemical

24. Farm to fork concept

25. Methodology
Risk analysis framework
Risk management
Hazard identification
• Lit review, expert opinion
Hazard characterisation
• Dose-response, from literature (clinical
studies)
Exposure assessment
• Prevalence studies, dose-response,
pork intake, gender/age aspects
Risk characterisation
• Magnitude of the risk

26. Hazard identification
• Pork/Food-borne disease
• Parasitic
• Cysticercus cellulosae
• Trichinella spiralis
• Toxoplasma gondii
• Fasciola spp.
• Bacterial
• Bacillus cereus
• Brucella suis
• Campylobacter spp.
• Salmonella spp.
• Staphylococcus aurues
• Streptococcus suis
• Shiga toxin producing E. coli
• Yersinia enterocolitica
• Virus
• Hepatitis E
• Norovirus
Tape worms
Salmonella spp.

27. Results from risk assessment
• Chemical risk assessment: Risk due to chemical hazards is low
(heavy metals, grow promoters and antibiotics) low – overwhelming
majority of meat samples negative tested.

28. Microbial Risk assessment
• Microbial Risk assessment:
• Salmonella contamination started at farm and increased along the
pork chain (farm – slaughter – market) mainly related to poor hygienic
practices 44.7% to 83% of pork across different retail contaminated
with Salmonella
• Risk for pork consumer: 1 – 2 person from 10 (17%) estimated to
suffer Salmonella caused FBD annually
• Miss-perception towards risk – public most concerned on chemical
hazards but major health risk was related to microbiological hazards

29. Potential health impact – FBD Vietnam
• Hospitalization costs of foodborne diarrhoea per treatment episode
and per day: USD 107 and USD 34 respectively
• 94 million people
• Cases of foodborne diseases (FBD) by Salmonella in pork at 17%:
16 million get sick annually
• 40% get hospitalised: 6.4 million
• Cost $ 107 to treat a case (episode):
$ 684 million (0.4% GDP)
• Potential intervention to reduce 20% FBD burden: $ 134 million SAVED

30. SAFE Pork – interventions
Challenges for improving food safety including pork
• Various approaches to improving safety had been tried, largely based on systems used
in developed countries e.g.:
• GAP, traceability, certification, modernising retail etc
• However, safe meat production has not yet take a significant share of the market in
Vietnam (e.g. VietGAHP < 5%)
• The key constraints to uptake include:
• high cost of adoption, lack of benefits from changing behaviour
• To overcome these constraints our focus will be on:
• gradual improvements to the food system in place, rather than introduction of a new
system
• incentive-based, light-touch interventions.

31. Safe PORK - low-cost innovations
Simple, rapid, cheap tests that detect contaminated food
• Could be used directly by retailers or consumer to have direct verification of safety e.g. food
sniffer
Reduce contamination of pork
• Portable ozone machines to plug into water supply
• 2 slaughterhouses identified, Hanoi and Hung Yen
• Avoid floor slaughter
• Training, antimicrobial cutting board, clothes etc.. (retailer)
(tested under lab condition)

32. Pilot intervention
Use of tailored slaughter grid
The improvement in hygiene (using grid versus floor) was
indicated by lower coliform load (p = 0.002) on the carcass
surface compared to the control.
The pilot trial also demonstrated that technical solutions must
go along with behaviour change of butchers and require
incentive

33. Safe PORK - low-cost innovations
Simple, rapid, cheap tests that detect contaminated food
Could be used directly by retailers or consumer to have direct verification of safety e.g. food
sniffer.
Reduce contamination of pork
• Portable ozone machines to plug into water supply
• 2 slaughterhouses identified, Hanoi and Hung Yen
• Avoid floor slaughter
• Training, antimicrobial cutting board, clothes etc.. (retailer)
(tested under lab condition)
Anti microbial cutting boards

34. Safe PORK - low-cost innovations
• Reduce use of antimicrobial (in collaboration with private sector)
• Replacement of antimicrobials by pro-biotics
• Increasing transparency and traceability in food system
• 24 hour on farm, branding and certification,
done with private sector

35. Safe PORK - low-cost innovations
• Assessment of the potential to use nudges for improved
food safety in the pork value chain in Vietnam
• Risk communication
 Media, risk assessors, value chain
actors – training & materials

36. Safe PORK
Conclusions & next steps
From assessments:
Pork is not safe & the risk is considerable
Modern retail not safer than traditional retail
Microbiological hazards are most important
Pathways towards safer pork:
Techincal innovations require also practice change
Government efforts to improve FS need to include all retail types - the informal
sector has been relatively ignored.
Risk communication messages must be tailored to the audience and use most
trusted channels

37. Overall conclusion
• FBD are a major health concern comparable to three big infectious
diseases
• Risk analysis – important tool to evaluate risk and make evidence
based decisions to mitigate risks in a context with limited resources.
 Focus on the few relevant and not many trivial
• Case study example
• Safer food can be achieved but technical solutions need to be:
• Evidence
• Feasible
• Incentivized
• Cost - beneficial

38. Example of Food chain modelling in
European countries

39. Pathways to be included in risk assessment
of Campylobacter in chickens.
• A quantitative risk assessment on Campylobacter jejuni in whole,
chilled or frozen chicken products in Denmark has been developed.
• To quantify the health risks attributed to Campylobacter contaminated
chickens
• Two models were developed: one describing the transfer and spread of
Campylobacter through a chicken slaughterhouse
• and another dealing with the transfer and spread of Campylobacter
during food handling in private kitchens.
• Uncertainty and variability linked to the model parameters were
included.

40. • In the slaughterhouse part, changes in prevalence and load on
contaminated carcasses throughout the different processing steps were
modelled using a simple linear modelling approach.
• Cross-contamination between negative and positive flocks was
modelled as an overall process assuming an exponential reduction in
the Campylobacter load as function of the number negative broilers
slaughtered after the last positive broiler.

41. • The route of transfer modelled in the consumer part was the cross-
contamination of prepared chicken and salad via unwashed cutting
boards. Consumers were split into those preparing the food and those
ingesting a serving, allowing the inclusion of the variable hygiene
levels of the persons preparing meals.
• With respect to persons ingesting a serving, the size of meal and the
number of people ingesting salad with the chicken was included.

42.  By combining the two models, the effect of different mitigation strategies on the
probability of exposure and illness could be analysed.
 In particular strategies, which reduced the Campylobacter load on chickens, seemed to
have significant impact on the number of human cases.
 Cross-contamination from positive to negative flocks had almost no effect, which may
indicate that logistic slaughter has a minor influence on the risk.
 Finally, the simulations showed that people in the age of 18-29 years had the highest
risk of illness, a result, which is in good agreement with current observations.

43. Modular Process Risk Model (MPRM)
methodology
• The basic processes were: At the slaughterhouse, cross contamination,
inactivation (e.g. by scalding) and removal (e.g. by the scald, washing
and chiller water flow), at the retail level; inactivation (freezing), at
private kitchens; cross contamination, inactivation (e.g. by drying out
or heat treatment) and removal (e.g. by washing utensil and cutting
board).
• Note that growth of Campylobacter was not considered to occur in
any of the processing steps, because Campylobacter do not to grow
at temperatures below 30°C.

44. Example of pathways to be included in
microbial risk assessment of
Campylobacter in chickens.

45. THANK YOU