1. Food Safety Microbiology - February, 2005 1 of 27 Quantitative Risk Assessment Don Schaffner, Ph.D. Rutgers, The State University of NJ

2. Food Safety Microbiology - February, 2005 2 of 27 Overview -How does risk analysis relate to risk assessment? -How is risk assessment applied to food microbiology? -A very simple example of a quantitative risk assessment -Web links and more information

3. Food Safety Microbiology - February, 2005 3 of 27 Risk Analysis Components -(Quantitative) Risk Assessment How big is the risk, what factors control the risk? Scientific process -Risk Communication How can we talk about the risk with affected individuals? Social and psychological process -Risk Management What can we do about the risk? Political process

4. Food Safety Microbiology - February, 2005 4 of 27 Cartoon

5. Food Safety Microbiology - February, 2005 5 of 27 Step in Risk Assessment -Hazard Identification What microbe, food(s) and people are involved? -Exposure Analysis What is the chance of exposure? How many cells? -Dose-Response Analysis What is the human health effect of the exposure? -Risk Characterization Complete picture of the assessed risk

6. Food Safety Microbiology - February, 2005 6 of 27 Hazard Identification -Epidemiological data linking Foods Pathogens Human illness -Special considerations Disease complications Acute vs. chronic disease Specific sensitive consumer populations Characteristics of the organism Organisms mode of action

7. Food Safety Microbiology - February, 2005 7 of 27 Exposure Analysis -Estimate likelihood of consumption likely number (dose) of the pathogen -If “quantitative” assessment Modeling Simulation

8. Food Safety Microbiology - February, 2005 8 of 27 Exposure - Simple Example -Initial number of organisms follows a Poisson distribution -Growth rate is normally distributed -Product composition and storage temperature are fixed -The product becomes unsafe when it contains 100,000 organisms/gram

9. Food Safety Microbiology - February, 2005 9 of 27 Initial number - Poisson

10. Food Safety Microbiology - February, 2005 10 of 27 Growth rate is normal

11. Food Safety Microbiology - February, 2005 11 of 27 Simulation Results

12. Food Safety Microbiology - February, 2005 12 of 27 Dose-Response Analysis Translates exposure analysis output in to a measure of human health If “quantitative” Use dose-response curve Estimate probability of infection and illness from dose

13. Food Safety Microbiology - February, 2005 13 of 27 Dose response curve Cassin et al. Quantitative risk assessment for Escherichia coli O157:H7 in ground beef hamburgers. Int.J.Food Micro. 41 (1):21-44, 1998.

14. Food Safety Microbiology - February, 2005 14 of 27 Dose-Response factors -Statistical model(s) to analyze or quantify dose- response relationships Threshold vs. non-threshold models -Dose response data Human Animal Outbreak or intervention data

15. Food Safety Microbiology - February, 2005 15 of 27 Dose-Response factors -Source and preparation of challenge material or inoculum -Organism type and strain Virulence factors or other measures of pathogenicity -Characteristics of the exposed population Age, immune status, etc.

16. Food Safety Microbiology - February, 2005 16 of 27 Risk Characterization -Final task in risk assessment -Combines the information from Hazard identification Exposure analysis Dose-response analysis -Produces a complete picture of the assessed risk

17. Food Safety Microbiology - February, 2005 17 of 27 A good risk assessment… -Is… Transparent Iterative -Includes… Variability and uncertainty Management input into problem formulation

18. Food Safety Microbiology - February, 2005 18 of 27 A hot-air balloon floats overhead… RM: I’m lost, can you tell me where I am? RA: Sure, you are 30 feet off the ground RM: Aha, you must be a risk assessor RA: Why yes, how did you know? RM: Because what you told me was technically correct, but of absolutely no use.

19. Food Safety Microbiology - February, 2005 19 of 27 A hot-air balloon floats overhead… RA: Aha, you must be a risk manager? RM: Why yes, how do you know? RA: That’s easy, you don’t know where you are, what you want or where you are going… and you are in the same position now as you were before you asked for my help, but now it’s my fault!

20. Food Safety Microbiology - February, 2005 20 of 27 Importance of risk assessment -Teaching Students can see “what if...” -Research Pinpointing uncertainties or knowledge gaps -Industry Optimizing safety while retaining quality -Government Designing regulations for the greatest benefit

21. Food Safety Microbiology - February, 2005 21 of 27 For more information -Annotated bibliography on Food Safety Risk Assessment, Management and Communication http://www.nal.usda.gov/fnic/foodborne/risk.ht mhttp://www.nal.usda.gov/fnic/foodborne/risk.ht m -Food Safety Risk Analysis Clearinghouse http://www.foodriskclearinghouse.umd.edu/wel come.htmhttp://www.foodriskclearinghouse.umd.edu/wel come.htm

22. Food Safety Microbiology - February, 2005 22 of 27 For more information -Revised Framework for Microbial Risk Assessment – ILSI http://www.ilsi.org/file/mrabook.pdf -WHO/FAO microbial risk analysis page http://www.who.int/fsf/mbriskassess/in dex.htmhttp://www.who.int/fsf/mbriskassess/in dex.htm

23. Food Safety Microbiology - February, 2005 23 of 27 Software -USDA Pathogen Modeling http://www.arserrc.gov -@risk http://www.palisade.com/ -Crystal ball http://www.decisioneering.com/ -Analytica http://www.lumina.com

24. Food Safety Microbiology - February, 2005 24 of 27 Books -T. A. McMeekin, et al. Predictive microbiology: Theory and application, Somerset, England:Research Studies Press Ltd., 1993. -C.H. Haas, et al. Quantitative microbial risk assessment, Ny, NY: John Wiley & Sons, 1999. -D. Vose. Risk Analysis: A Quantitative Guide, Chichester:John Wiley & Sons, 2000.

25. Food Safety Microbiology - February, 2005 25 of 27 Published risk assessments -S. enteritidis in eggs http://www.fsis.usda.gov/OPHS/risk/index.htm -Listeria in RTE foods http://www.foodsafety.gov/~dms/lmrisk.html -Fluoroquinolone Resistant Campylobacter in Chicken http://www.fda.gov/cvm/antimicrobial/Risk_ass es.htmhttp://www.fda.gov/cvm/antimicrobial/Risk_ass es.htm

26. Food Safety Microbiology - February, 2005 26 of 27 Published risk assessments -Vibrio in shellfish http://www.cfsan.fda.gov/~dms/vprisk.html -E.coli O157:H7 in ground beef http://www.fsis.usda.gov/OPHS/ecolrisk/home. htmhttp://www.fsis.usda.gov/OPHS/ecolrisk/home. htm -Campylobacter in chicken http://www.who.int/fsf/mbriskassess/studycou rse/annac/index.htmlhttp://www.who.int/fsf/mbriskassess/studycou rse/annac/index.html

27. Food Safety Microbiology - February, 2005 27 of 27 Cartoon