Risk Assessment, the AFSS
Model and Introduction to
Exposure Scoring Barry Hooberman, MPH, Ph.D.
Center for Veterinary Medicine/FDA AFSS Public Meeting
May 22, 2007 |  |
Slide 2 Overview - Risk Recap
- Approach
- Hazard Characterization
- Exposure
- Relative Risk Ranking
|  |
Slide 3 The Purpose of the AFSS - To develop and implement a comprehensive, risk-based,
preventive animal feed safety system that minimizes, reduces or eliminates the risks to animal and human health that
can arise from animal feed
|  |
Slide 4 Why a Risk-Based Approach? - Risk assessment is a logical process for collecting, organizing and analyzing information to inform a risk decision (“science-based decision making”).
- Risk assessment approach is also a forecasting process for the prevention of illnesses/adverse health risks.
- Eases the interactions between decision makers, stakeholders, and the public
|  |
Slide 5 What is Risk Ranking? - Risk assessments provide the “facts” for risk analysis.
Risk Risk Risk Risk Risk Assessement Risk Risk Risk
|  |
Slide 6 Risk Ranking - The risk management decisions about which risks to manage first are value-laden decisions.
Risk Values Risk Risk Risk Management Risk Risk Costs Risk |  |
Slide 7 How Will Ranked Risks Be Used? - Decide how risks from contaminants can best be prevented or controlled:
- Do limits for higher-risk contaminants need to be identified? If yes, which contaminants?
- Do analytical methods for higher-risk contaminants need to be developed?
- What process changes can feed manufacturers make to reduce risks from contaminants?
- What surveillance/sampling programs are needed to ensure compliance with contaminant limits?
- For internal use only
|  |
Slide 8 Risk Assessment Poses Four Simple Questions: - What can go wrong?
- Hazard Identification
- What are the consequences?
- Consequence Assessment
- How can it happen?
- Exposure Assessment
- What is the likelihood it would go wrong?
- Risk Estimation
|  |
Slide 9 Roadmap | Contaminants | Cont. A | Cont. B | Cont. C |
|---|
| Feed Ingredients | Ingredient 1 | Ingredient 2 | Ingredient 3 |
|---|
Manufacturing
Processes | | Mill: Mix, Heat, etc. | |
|---|
| | | Finished Feed | |
|---|
| | | Animals | |
|---|
| Population(s) | | Humans | |
|---|
|  |
Slide 10 Exposure Assessment - Source - Identify source of each hazard entering the feed process.
- Feed ingredients will be linked to each hazard they may contain, resulting in a set of Ingredient:Hazard pairs for each ingredient, such as Corn:Aflatoxin and Clay:Dioxin.
- Initial level of a hazard in a feed ingredient or feed will depend on:
- Environmental conditions
- Human activities
- Source and type of contaminant
- Source and type of feed ingredient
|  |
Slide 11 Exposure Assessment - Ei - Initial Exposure Score
- For each pair, a quantitative or semi-quantitative
- Exposure Score will be calculated or estimated. (Exposure is the amount of the hazard in the feed ingredient.)
- Score based on:
- Measured data (when available)
- Salmonella contamination data
- Expert opinion
|  |
Slide 12 Exposure Assessment - MF - Manufacturing Process(es) Modifying Factors
- Feed manufacturing process(es) will either increase, decrease or not affect the level of a particular hazard in the ingredient and feed
- Manufacturing processes include transportation, storage, steps in feed manufacturing, and on-farm processes
|  |
Slide 13 Exposure Assessment - Ef - Final Exposure Score
- Initial Exposure Score will be modified based on manufacturing processes used in the production of the specific feed ingredient.
- For example, a process may involve sufficient heat to eliminate the possible exposure to a bacterial hazard.
|  |
Slide 14 Roadmap | Contaminants | Cont. A | Cont. B | Cont. C |
|---|
| Feed Ingredients | Ingredient 1 | Ingredient 2 | Ingredient 3 |
|---|
| Manufacturing Processes | | Mill. Mix, Heat, etc. | |
|---|
| | | Finished Feed | |
|---|
| | | Animals | |
|---|
| Populations | | Humans | |
|---|
|  |
Slide 15 Source Materials A = Mycotoxins
B = Agricultural chemicals
C = Microbial pathogens
D = Metals
E = Drug residues
F = TSEs | Plant Origin | Animal Origin | Mineral Origin | Microbial Origin | Misc. Origin |
|---|
| Grains A, B, D | Mammalian protein meals B, C, D, E, F | P, Ca, Na
D
| Yeast & single cell protein C, D | Human food waste A, C | Oilseeds
A, B, D | Poultry meals
B, C, D, E | Trace element premixes D | | Animal manure B, C, D | Molasses
B, D | Aquatic Animal Meals B, C, D | Non-nutritive adsorbentsD | | | Roots & tubers
A, B, D | Fat & Oils B | | | | Forages
A, B, C, D | | | | | Roughages
A, B, C | Fats & oils
B | | | |
|  |
Slide 16 Limitations - DATA!
- Primarily an issue in exposure
- Limited measured data for many hazards
- Strong reliance on expert opinion (not that there is anything wrong with that!)
|  |
Slide 17 Data?!? - Why build a risk model when we know there are data constraints?
- To organize existing data and maximize its use
- To identify the types of data that are needed
- To facilitate the acquisition of that data by demonstrating how it will be used
- Should relevant data not be available to allow the drawing of conclusions with sufficient certainty, what is usefullness of the model?
- Inform decision-makers about what can be said and what cannot be said with reasonable certainty
- Identify data gaps
Inform the Center about the state of regulation for animal feeds - Demonstrate ways in which the Center may implement a risk-based approach
- Inform stakeholders that FDA is willing to adopt new tools and techniques to ensure that the food supply is safe
|  |
Slide 18 Goals for Today - Concepts
- Hazard Ranking vs. Risk Ranking
- The difference is exposur
- Types of data available to CVM
- Chemical contaminants
- Microbial contaminants
- How data can be assembled to estimate exposure
|  |
Slide 19 Exposure to Contaminants in Feeds
and Feed Ingredients – Factors - Levels in raw and processed feed ingredients
– Karen Ekelman - Level changes during processing of feed ingredients
– Linda Benjamin - Levels in finished feeds
– Phares Okelo - Level changes during storage, transportation and feeding
– Phares Okelo - Amount consumed by swine
– Barry Hooberman - Amount consumed by humans
– Barry Hooberman
|  |
