Overview of 3 published risk assessments

1. Overview of 3 published risk assessments Don Schaffner, Ph.D. Rutgers, The State University of NJ Food Safety Risk Assessment - PubH 7100-104

2. Three risk assessments • Salmonella Enteritidis Risk Assessment • Draft Risk Assessment of the Public Health Impact of Escherichia coli O156:H7 in Ground Beef • Quantitative Assessment of Relative Risk to Public Health from Foodborne Listeria monocytogenes Among Selected Categories of Ready-to-Eat Foods Food Safety Risk Assessment - PubH 7100-104

3. Se in eggs • Oldest “full” microbial risk assessment (started 1996, completed in 1998) • Quite complex! • Uses @risk add-in to Microsoft Excel Food Safety Risk Assessment - PubH 7100-104

4. Se in eggs objectives • Model from farm to table the unmitigated risk of foodborne illness due to SE from the consumption of eggs and egg products; • Identify target areas along the farm-to-table continuum for potential risk reduction activities • Compare the public health benefits accruing from the mitigated risk of SE foodborne illness with the implementation of various intervention strategies • Provide information on risk-effectiveness of mitigation to be utilized by the agency for subsequent cost-effectiveness and cost-benefit analysis • Identify data gaps and guide future research and data collection efforts Food Safety Risk Assessment - PubH 7100-104

5. Diagram of Se in eggs QRA Food Safety Risk Assessment - PubH 7100-104

6. Diagrams from production module Food Safety Risk Assessment - PubH 7100-104

7. Diagram (again) Food Safety Risk Assessment - PubH 7100-104

8. Shell Eggs Processing and Distribution Module Food Safety Risk Assessment - PubH 7100-104

9. SE are found in the white The white contains growth inhibitors The yolk membrane keeps SE out of the yolk The yolk membrane degrades with time and temperature Yolk membrane breakdown Food Safety Risk Assessment - PubH 7100-104

10. Unpublished data from Tom Humphreys, UK Data points represent the time for more than 25% of a group of 9-11 eggs to permit SE growth Data used to create model Food Safety Risk Assessment - PubH 7100-104

11. Diagram of Se in eggs QRA Food Safety Risk Assessment - PubH 7100-104

12. Example of LE processing complexity Food Safety Risk Assessment - PubH 7100-104

13. Diagram of Se in eggs QRA Food Safety Risk Assessment - PubH 7100-104

14. Preparation and consumption diagram • Pooling (the process of combining eggs together) influences risk Food Safety Risk Assessment - PubH 7100-104

15. Diagram of Se in eggs QRA Food Safety Risk Assessment - PubH 7100-104

16. Dose response Salmonella species used in feeding trials appear to be less virulent than SE, based on the epidemiologic data. Morales et al. (1996) proposed Shigella dysenteriae as a surrogate for SE Food Safety Risk Assessment - PubH 7100-104

17. E. coli O157:H7 • Initiated in 1998 • http://www.fsis.usda.gov/OPHS/ecolrisk/home.htm • Draft released in 2001 • http://www.fsis.usda.gov/OPPDE/rdad/FRPubs/00-023NReport.pdf • Reviewed by National Academy of Science 2002 • http://books.nap.edu/books/0309086272/html Food Safety Risk Assessment - PubH 7100-104

18. E. coli O157:H7 in ground beef objectives • Goal is to produce a baseline risk assessment that • Reflects current practices along the farm-to-table continuum • Accurately assesses the likelihood of illness and death • The primary use is to assist FSIS in reviewing and refining its risk reduction strategy for E. coli O157:H7 in ground beef • The risk assessment produces scientific support for • Development of regulatory impact assessments to support FSIS rulemaking • Identification of critical control points and critical control limits in HACCP systems for ground beef • Risk-based sampling plans for FSIS inspectors • Identification of food safety research on E. coli O157:H7 in ground beef. Food Safety Risk Assessment - PubH 7100-104

19. E. coli O157:H7 in ground beef diagram Food Safety Risk Assessment - PubH 7100-104

20. The problem of prevalence • How common is the problem in herds? • In a positive herd, how common is the problem? Food Safety Risk Assessment - PubH 7100-104

21. Why is season important? Food Safety Risk Assessment - PubH 7100-104

22. E. coli O157:H7 in ground beef diagram Food Safety Risk Assessment - PubH 7100-104

23. Slaughter module Note that contamination may increase, decrease or stay the same Food Safety Risk Assessment - PubH 7100-104

24. E. coli O157:H7 in ground beef diagram Food Safety Risk Assessment - PubH 7100-104

25. Preparation module Food Safety Risk Assessment - PubH 7100-104

26. Change during storage Food Safety Risk Assessment - PubH 7100-104

27. Change during cooking Food Safety Risk Assessment - PubH 7100-104

28. E. coli O157:H7 in ground beef diagram Food Safety Risk Assessment - PubH 7100-104

29. Dealing with dose response Food Safety Risk Assessment - PubH 7100-104

30. Risk characterization (picture) Food Safety Risk Assessment - PubH 7100-104

31. Risk characterization (words) • Most contaminated cooked ground beef servings contain only 1 E. coli O157:H7 organism… and the risk of illness from one E. coli O157:H7 is low. • Few contaminated cooked ground beef servings contain 100,000 E. coli O157:H7 organisms per serving (1.8 × 10-7) but this dose results in the highest risk of illness (1.0 × 10-7) from E. coli O157:H7 in a ground beef serving. • Reducing the number of E. coli O157:H7-contaminated ground beef servings may reduce risk of illness more than reducing the amount of E. coli O157:H7 in contaminated servings. Food Safety Risk Assessment - PubH 7100-104

32. Listeria monocytogenes in RTE foods • The purpose of the assessment is • to examine systematically the available scientific data and information • to estimate the relative risks of serious illness and death associated with consumption of different types of ready-to-eat (RTE) foods • This examination of the current science and the models developed from it are among the tools that food safety regulatory agencies will consider when evaluating the effectiveness of current and future policies, programs, and regulatory practices. • A distinction is made between the mild non-invasive illness (referred to as listerial gastroenteritis) and the severe, sometimes life-threatening, disease (referred to as listeriosis). This risk assessment only considers listeriosis. Food Safety Risk Assessment - PubH 7100-104

33. Listeria monocytogenes in RTE foods • Released plan in 1999 • Released draft in 2001 • Revised in 2003 • Note different FAO/WHO risk assessment ongoing during the same time Food Safety Risk Assessment - PubH 7100-104

34. What does it do? • Provides analyses and models that… • Estimate the potential level of exposure • Three age-based population groups and the total United States population to • Listeria monocytogenes contaminated foods for 23 food categories • Relates this exposure to public health consequences Food Safety Risk Assessment - PubH 7100-104

35. Diagram of QRA Food Safety Risk Assessment - PubH 7100-104

36. Interesting features Assumed detected Lm is just the tip of the iceberg Food Safety Risk Assessment - PubH 7100-104

37. Comparing relative ranks Food Safety Risk Assessment - PubH 7100-104

38. High risk per serving Deli Meats Frankfurters, not reheated Pâté and Meat Spreads Unpasteurized Fluid Milk Smoked Seafood Cooked Ready-to-Eat Crustaceans High risk per year (cases) Deli Meats (1598.7) Pasteurized Fluid Milk (90.8) High Fat and Other Dairy Products (56.4) Frankfurters, not reheated (30.5) Risk Characterization Food Safety Risk Assessment - PubH 7100-104

39. RC table Food Safety Risk Assessment - PubH 7100-104

40. Three very different risk assessments • Salmonella Enteritidis in eggs • Farm-to-fork, many foods • Draft Risk Assessment of the Public Health Impact of Escherichia coli O156:H7 in Ground Beef • Farm-to-fork, single food, still not done! • Quantitative Assessment of Relative Risk to Public Health from Foodborne Listeria monocytogenes Among Selected Categories of Ready-to-Eat Foods • Limited scope (i.e. not farm-to-fork), many (many!) foods Food Safety Risk Assessment - PubH 7100-104