Risk Assessment, the AFSS
Model and Introduction to
Barry Hooberman, MPH, Ph.D.
Center for Veterinary Medicine/FDA
AFSS Public Meeting
May 22, 2007
- Risk Recap
- Hazard Characterization
- Relative Risk Ranking
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
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
What is Risk Ranking?
- Risk assessments provide the “facts” for risk analysis.
Risk Risk Risk
Risk Risk Assessement Risk
- The risk management decisions about which risks to manage first are value-laden decisions.
Risk Values Risk
Risk Risk Management Risk
Risk Costs Risk
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
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
|Contaminants||Cont. A ||Cont. B ||Cont. C |
|Feed Ingredients||Ingredient 1||Ingredient 2 ||Ingredient 3 |
| ||Mill: Mix, Heat, etc. || |
| || ||Finished Feed || |
| || ||Animals || |
|Population(s)|| ||Humans|| |
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
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
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
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.
|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|| |
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|
|Yeast & single cell protein C, D||Human food waste A, C|
A, B, D
B, C, D, E
|Trace element premixes D|| ||Animal manure B, C, D|
|Aquatic Animal Meals B, C, D||Non-nutritive adsorbentsD|| || |
|Roots & tubers|
A, B, D
|Fat & Oils B|| || || |
A, B, C, D
| || || || |
A, B, C
|Fats & oils|
| || || |
- Primarily an issue in exposure
- Limited measured data for many hazards
- Strong reliance on expert opinion (not that there is anything wrong with that!)
- 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
Goals for Today
- 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
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