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Safety & Health

Risk Assessment, the AFSS Model and Introduction to Exposure Scoring

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 

Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 1

Slide 2 

Overview

  • Risk Recap
  • Approach
  • Hazard Characterization
  • Exposure
  • Relative Risk Ranking
  • Today’s Topics
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 2

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 
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 3

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 
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 4

Slide 5

What is Risk Ranking?

  • Risk assessments provide the “facts” for risk analysis. 

        Risk  Risk                                                Risk

Risk           Risk Assessement         Risk

  Risk                                                    Risk

Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 5

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

Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 6

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
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 7

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
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 8

Slide 9

Roadmap

 

ContaminantsCont. A Cont. B Cont. C 
Feed IngredientsIngredient 1Ingredient 2 Ingredient 3 
Manufacturing
Processes
 Mill: Mix, Heat, etc.  
  Finished Feed  
  Animals  
Population(s) Humans 
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 9

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  
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 10

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
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 11

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
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 12

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.
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 13

Slide 14

Roadmap

ContaminantsCont. ACont. BCont. C
Feed IngredientsIngredient 1Ingredient 2Ingredient 3
Manufacturing Processes Mill. Mix, Heat, etc. 
  Finished Feed 
  Animals 
Populations Humans 
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 14

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, FP, Ca, Na
D
 
Yeast & single cell protein C, DHuman 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, DNon-nutritive adsorbentsD  
Roots & tubers
A, B, D 
Fat & Oils B   
Forages
A, B, C, D 
    
Roughages
A, B, C 
Fats & oils
B
   
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 15

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!)
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 16

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
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 17

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 
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 18

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
Risk Assessment, the AFSS Model and Introduction to Exposure Scoring - Slide 19