Moez SANAA

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Microbial Risk Assessment and Mitigation
Workshop towards a Quantitative HACCP Approach

• Moez SANAA Ewen Todd

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General introduction to risk assessment in food
safety

• Ewen Todd

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Definitions of Risk

• Risk a function of the probability of an adverse
  health effect and the severity of that effect,
  consequential to a hazard(s) in food
• Risk Analysis a process consisting of three
  components risk assessment, risk management and
  risk communication

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Purpose of Risk Analysis Codex Alimentarius

• To identify methods to address food safety more
  effectively
• To introduce appropriate food control measures
• Risk analysis has become the cornerstone in
  developing food control measures by linking
  epidemiological and laboratory findings with
  modeling procedures to estimate risks and their
  mitigation

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Difference Between Risk Analysis and Hazard
Analysis - Codex Alimentarius

• Hazard analysis - addresses hazards within a
  narrow context, such as the potential for the
  hazard to enter a food at a plant/processing
  level. A hazard analysis is usually conducted at
  the plant/process level to establish a HACCP plan
• Risk analysis also deals with hazards, as well
  as the condition of a food however, it does so
  on a broader scale by examining the potential
  impact of a hazard that is introduced into the
  food supply, taking into account exposure from
  other sources

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Risk assessment
Material or situations, physical, chemical, and
or microbial agents

• RA is the qualitative or quantitative
  characterization or estimation of potential
  adverse health effects associated with exposure
  of individuals or populations to hazards

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Purpose of Risk Assessment

• A systematic examination of an issue to help make
  better risk management decisions
• The risk manager should request the assessment to
  respond to specific questions

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Risk Assessment Definitions -Codex Alimentarius
Risk assessment the scientific evaluation of
known or potential adverse effects resulting from
human exposure to foodborne hazards
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Risk Assessment Definitions -Codex Alimentarius

• Hazard identification The identification of
  biological, chemical and physical agents capable
  of causing adverse health effects and which may
  be present in a particular food or group of foods
• Hazard characterization The qualitative and/or
  quantitative evaluation of the nature of the
  adverse health effects associated with
  biological, chemical, and physical agents which
  may be present in food
• For chemical agents, a dose-response assessment
  should be performed
• For biological and physical agents, a
  dose-response assessment should be performed if
  the data are available

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Risk Assessment Definitions -Codex Alimentarius

• Exposure assessment The qualitative and/or
  quantitative evaluation of the likely intake of
  biological, chemical, and physical agents via
  food as well as exposures from other sources if
  relevant
• Risk characterization The qualitative and/or
  quantitative estimation, including attendant
  uncertainties, of the probability of occurrence
  and severity of known or potential adverse health
  effects in a given population based on hazard
  identification, hazard characterization and
  exposure assessment

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Definitions -Codex Alimentarius

• Risk management The process, distinct from risk
  assessment, of weighing policy alternatives, in
  consultation with all interested parties,
  considering risk assessment and other factors
  relevant for the health protection of consumers
  and for the promotion of fair trade practices
  and, if needed, selecting appropriate prevention
  and control options
• Risk communication The interactive exchange of
  information and opinions throughout the risk
  analysis process concerning risks, risk-related
  factors and risk perception, among risk
  assessors, risk managers, consumers, industry,
  the academic community and other interested
  parties, including the explanation of risk
  assessment findings and the basis of risk
  management decisions

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Risk Communication Pointers - Codex Alimentarius

• Know the audience
• Involve the scientific experts
• Establish expertise in communication
• Be a credible source of information
• Share responsibility
• Differentiate between science and value
  judgement
• Assure transparency and put the risk in
  perspective
• Effective communication is an integral component
  of the risk analysis process and is often the
  least well done

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What Risk Analysis Tries to Address

• Risk Communication questions (science plus
  economical, social and ethical values)
• Who are the stakeholders?
• What are we trying to communicate - information
  out or input in?
• What level of technicality should be discussed -
  assessors to managers/managers to other
  managers/managers to the industry and public?
• How much time do we allow for this process?
• What degree of dialog do we allow?
• How much does risk perception of an issue affect
  the communication process?

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Examples if Risk assessment and risk management
questions

• Risk Assessment questions (science)
• What could go wrong?
• How likely is it to happen?
• Who would be affected?
• How severe would the consequences be?
• What populations are affected?
• What can we do that will reduce risk?
• Risk Management questions (science plus policy
  issues)
• What are the most effective and acceptable
  policies to reduce risk to acceptable levels -
  choosing management options which may include
  doing nothing?
• When instituted, how well have these policies
  worked implement an evaluation and review
  process?

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Risk Assessment in Risk-Based Decision-Making

• To support decisions, the objectives of RA are
• Estimate the probability of a given consequence,
  event, or effect
• Understand how and when such consequences may
  occur
• Estimate the impact of the various consequences
  and
• Evaluate the potential outcomes or consequences
  of selected management options
• Risk assessment is a tool to inform risk managers
  and policy makers about risk management

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What is needed?

• Timely, broadly based and
• Well informed, founded on the most reliable data,
  accurate in the interpretation of data, and
• Transparent in the communication of results to
  interested parties.
• With consideration and recognition of
  socio-political context in which activities and
  decisions are undertaken.

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Risk Assessment challenges

• Transparency Characteristics of a process where
  the rationale, the logic of development,
  constraints, assumptions, value judgements,
  decisions, limitations and uncertainties of the
  expressed determination are fully and
  systematically stated, documented, and accessible
  for review
• Many risk assessors offer their peers a draft
  assessment for comment before it is finally given
  to the risk manager or for publication
• Uncertainty Analysis a method to estimate the
  uncertainty associated with model inputs,
  assumptions and structure/form
• Data Variability Assessments also include data
  that are generated with small to large
  variability

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Risk Managers vs. Risk Assessors

• The risk manager determines the need for the
  assessment but leaves the process to the
  scientific assessors
• However, certain interactive elements are
  essential for a systematic risk assessment
  process
• include ranking of hazards in the hazard
  identification step and consideration of possible
  management options

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Limitations of Risk Assessments

• Although a risk assessment must be soundly based
  upon science, the amount of data available are
  often very limited, and may they be conflicting,
  including variability and uncertainty
• Assumptions then may have to be made on the best,
  informed judgements to the assessors
• Good quality quantitative information is
  preferable to qualitative data but there is often
  less of it

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Type of Risk Assessments

• Quantitative Risk Assessment (QRA) a risk
  assessment that provides numerical expressions of
  risk and indication of the attendant
  uncertainties
• Qualitative Risk Assessment a risk assessment
  based on data, which, while forming an inadequate
  basis for numerical risk estimations,
  nonetheless, when conditioned by prior expert
  knowledge and identification of attendant
  uncertainties permits risk ranking or separation
  into descriptive categories of risk

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Microbial Risk Assessment
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Worldwide Perspective on Foodborne Disease

• The World Health Organization believes that
  hundreds of millions of people worldwide suffer
  from diseases caused by contaminated food,
  especially in developing countries
• There is an estimated annual incidence of some
  1.5 billion episodes of diarrhea in children
  under five years of age
• Over two million deaths and many of these
  diarrheal cases are foodborne in origin
• In the U.S. there are 48 million cases and 3000
  deaths annually (Scallan et al., 2011)
• Main agents norovirus, Salmonella, Clostridium
  perfringens, Campylobacter, Staphylococcus aureus

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Microbial Foodborne Pathogens
Pathogen Implicated Foods Disease
Bacillus cereus Rice, vegetables, meat Mild vomiting and diarrhea
Clostridium perfringens Stews, chili, etc. (anaerobic) Mild cramps, diarrhea
Salmonella Eggs, meat, fruit, juices, spices, chocolate, etc. Moderate GI symptoms, reactive arthritis
Campylobacter Chicken, meat Moderate GI symptoms with bloody diarrhea, GBS
E. coli O157H7 STEC/EHEC Ground beef, juices, sprouts, water, etc. Severe colon lining and kidney damage, HUS, death
Listeria monocytogenes RTE foods, e.g., deli meats, smoked fish, soft cheese, etc. Severe GI symptoms, meningitis, death
Clostridium botulinum Improperly canned or bottled food (anaerobic) Severe paralysis and GI symptoms, death
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What Do We Know About Hazards Such as How Does
Escherichia coli O157H7 Cause Illness?
Exposure to E. coli 0157
Recovery
Infection
Hemolytic uremic syndrome 5HUS)
Hemorrhagic colitis (bloody diarrhea)
Squeal (not considered)
Watery diarrhea
Recovery
Death
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Defining Some Dose Response Issues

• What are the characteristics of the
  pathogen/agent that affect its ability to cause
  disease in the host (e.g., infectivity,
  pathogenicity, virulence)?
• What adverse health effects may be associated
  with exposure to the pathogen (from mild and
  self-limiting symptoms, to life-threatening
  conditions)?
• Who is susceptible to infection
  (individual/subpopulation/population)?

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Source Data for Dose Response Assessments

• Data input with pros and cons
• Outbreak data
• Surveillance data
• More micro than chemical data relating to illness
• Volunteer feeding studies (limited and mostly old
  data)
• Animal studies (uncertainty relating to humans)
• In vitro studies
• Expert elicitation

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Dose-response Curves for Morbidity From
Epidemiological Data or Expert Elicitations for
Listeria monocytogenes
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Microbial Risk Assessment general flowchart
Food contamination
Number of bacteria per gr, raw material
Food processing
Food consumption pattern
Number of bacteria per gr at retail level
Transport storage Foodhandling
Describe food handling and amount and frequency
of consumption
Number of bacteria per gr before consumption
Single exposure
Number of ingested bacteria for a consumer
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Exposure Assessment

• Exposure assessment (EA) varies according to the
  food product and region
• Extent of the EA depends on the risk management
  question(s)
• Farm-to-Fork (the whole process)
• Retail-to-consumption (post production)
• Individual food processing/food handling steps
• Combines prevalence and concentration of an agent
  with consumption amounts and frequency
• Pathogen exposure tends to be individual separate
  events, whereas chemical tends to be cumulative
  over time

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Exposure Assessment

• Usually we want frequency and level of an agent
  (typically a pathogen) ingested by consumer but
  difficult to get data at the final stage of a
  food consumed, so we estimate by modeling
• Identify initial and subsequent sources,
  frequency and level of contamination
• Try and model from various environmental knowns
  (pH, aW, time, temperature, etc.) at earlier
  stages what the frequency and level of a pathogen
  will be at consumption

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Mathematical Models

• Models are meant to capture the essential
  elements of a process in a simplistic form
• The intention is not to create a perfect and
  exact duplicate of reality
• Rather to create a tool that will provide insight
  into the system
• Modular approach to describe a complex system
  where there are several steps

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Exposure Assessment Salmonella spp. in Broiler
Chicken (FAO/WHO)
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Risk Characterization

• Provides a model that estimates the probability
  of illness due to the ingestion of a pathogen in
  a food with or without cooking, e.g., Salmonella
  in chicken or E. coli O157H7 in hamburgers
• For most chemicals it is the total exposure not
  one food
• Risk measure is the probability of illness
• 1) by estimating the predicted number of cases
  per 100,000 population based on contaminated
  servings eaten differences reflect different
  exposure pathways
• 2) the total number of cases in population, e.g.,
  USA, France, UAE or elsewhere differences
  reflect different population sizes

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Challenges for the Risk Assessment Process
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Questions on a Science-based Policy

• Dilemma
• If science based policy is the ideal, why go
  beyond the experts who should know best
• However, rarely are polices based purely on
  science
• Fundamental questions
• Should regulations and policy be based on science
  or values or a combination of the two
• Why do some science-based policies not work?

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Consumer Choices

• Is there an increase in todays society allowing
  consumer choices, and if so does it increase the
  risk of spread of pathogens?
• Almonds can be pasteurized with heat, steam or
  propylene oxide to reduce risk of contamination
  but some groups want to stay with the raw almonds
• Bagged spinach or lettuce or neither - is
  irradiation acceptable?
• Raw milk (cheeses) vs. pasteurized milk
  (cheeses)?
• Steak tartar vs. well cooked ground beef?
• Raw or cooked oysters?
• Do we know the risks vs. benefits well enough to
  communicate meaningfully with consumers and other
  stakeholders?
• Danisch and Mudry (2008) reviewed FDAs Vibrio in
  oyster risk assessment and found the analysis too
  complicated and it left out values such as liking
  fresh raw oysters, i.e., partly a communications
  issue

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Is the Risk Analysis Paradigm Still Valid?

• Thus, the classical food risk analysis model
  (risk assessment, risk management, and risk
  communication) may not be addressing consumers
  concerns on challenging food safety issues
• Perception
• EU consumers appear slightly more concerned about
  external risk factors that are beyond their
  control, e.g., less worried about personal
  factors such as food allergies and those linked
  to their own behavior, such as food preparation,
  hygiene and weight gain
• Women tend to be more worried about food safety
  than men
• Over 40 of people either ignore stories about
  food safety or do nothing despite being worried
• So, how does perception affect communication?

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Safe Food EU Funded Project

• "This Integrated Project addresses the issue of
  how consumer confidence in consumer protection
  and risk analysis can be restored and
  strengthened.
• Increased transparency increased credibility?
• Incorporation of societal values to create an
  integrated framework

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SAFE FOODS - a Recent EU Approach to Risk Analysis

• Framing stage would allow interested parties,
  experts and officials to work together to gain an
  initial shared understanding of the issue, the
  objectives of regulatory action, and alternative
  risk management measures
• Scope is expanded to include the assessment of
  health and environmental benefits as well as
  risks, and the explicit consideration of
  economic- and social-impacts of risk management
  action and their distribution.
• Evaluation stage, interested parties, experts,
  and officials may compare and weigh the risks,
  costs, and benefits and their distribution.

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Francis Bacon The Advancement of Learning, 1605

• If a man will begin with certainties he shall
  end in doubts, but if he will be content to begin
  with doubts, he shall end in certainties.
• Bacon identified both observation of nature and
  formal experimentation as necessary to test a
  hypothesis properly
• This concept still holds true today, scientific
  theories are examined from a number of different
  angles and must be reliably repeated before they
  become the accepted wisdom to the day
• Risk assessments are estimates and are never the
  complete truth value for making management
  decisions

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QUESTIONS?