FDA/NSTA Web Seminar: Food Safety and Nutrition

1. LIVE INTERACTIVE LEARNING @ YOUR DESKTOP FDA/NSTA Web Seminar: Food Safety and Nutrition Thursday, April 26, 2007 7:00 p.m. to 8:00 p.m. Eastern time

2. Foodborne Illness Outbreak Investigation Surveillance and Epidemiology“Be the Detective” Patrick McCarthy, PhD, MPH Food & Drug Administration U.S. Dept of Health and Human Services

3. USDA Food Safety and Inspection Service • Responsible for ensuring safety of meat, poultry, and some egg products

4. US Food & Drug Administration • Responsible for ensuring safety of all other food products

5. Estimates of foodborne illness and death based on surveillance data • 325,000 hospitalizations each year • 5,000 deaths each year • 14 million illnesses due to known pathogens • 62 million illnesses due to unknown pathogens Paul Mead-CDC-1999

6. Factors Pushing the Numbers Up • Globalization of the food supply • Perceived healthiness of raw fruits and vegetables • Increase in susceptible population • Eating out more • International travel D Swerdlow, S Altekruse 1998

7. Which agency regulates these products: Type a “U” for USDA, or an “F” for FDA

8. Why do we do surveillance? • Identify emerging problems and stimulate actions to address them • Take prompt control actions • Identify and interpret trends in foodborne disease • Determine the consequences of foodborne illness • Evaluate intervention programs • Set goals, priorities, policies, training, etc. for food safety

9. How is foodborne illness recognized? • From patients or someone close to patients • Report from MD, RN, laboratory, etc. • Review of national surveillance data • Salmonella Outbreak Detection Algorithm (SODA) • PulseNet • FoodNet • Rarely: local newspaper or television news report

10. Percentage of Foodborne Illness Attributable to Known Pathogens Mead et al., 1999

11. Identify what you think is the best reason to have a foodborne illness surveillance program?

12. Foodborne Outbreaks - FDA products only

13. Why investigate outbreaks? • Identify and eliminate sources of exposure • Develop strategies to prevent future outbreaks • Describe new diseases • Learn more about existing diseases • Evaluate existing prevention strategies

14. Why does it take so long?

15. Determining Burden of Disease Reported to health department Culture-confirmed case Lab tests for organism Specimen obtained Person seeks care Person becomes ill Population exposures

16. Did you ever have a foodborne illness? Yes () No (X)

17. If you answered yes to the previous poll question, did you report the illness to the health department? Yes () No (X)

18. Multiplication Factors For Salmonella and other pathogens that cause non-bloody diarrhea the degree of underreporting has been estimated at about 38 fold. For EC0157H7 and Shigella which cause bloody diarrhea - underreporting has been estimated at about 20 fold. P Mead – CDC 1999

19. Burden of Illness

21. Cohort study: relative risk total 28 11 • At start of cohort study you know everyone’s exposure status • total exposed = 28; total unexposed = 11 • go forward in time and determine risk of getting ill • risk if exposed = 24 / 28 = 0.857 • risk if not exposed = 2 / 11 = 0.182 • Relative Risk = 0.85 / 0.18 = 4.71

22. http://www-unix.oit.umass.edu/~exsc597j/Epi2000/ENGLISH/HELP/statist.htmhttp://www-unix.oit.umass.edu/~exsc597j/Epi2000/ENGLISH/HELP/statist.htm

23. Take Home Message • In cohort studies the relative risk (RR) compares rate of illness in the exposed group to rate of illness in the unexposed group. • In case-control studies the odds ratio (OR) is the odds in favor of exposure among cases compared to the odds in favor of exposure among the controls. • if RR or OR = 1, or the 95 % CI includes 1 then the result is not considered statistically significant • If RR or OR is less than 1 may mean food item is "protective“

24. Review: What pathogen is associated with the most foodborne illness ?

25. Traceback • Track food items back to their source (product type, lot #, delivery time, etc.)

26. Traceback - protocol • Traceback protocol includes • extensive record reviews • extensive interviews • records / information collected includes shipments, inventories, transportation, etc. • data analyses

27. Traceback - case study Details: • AZ; 19-ill; church group, restaurant, July 5th • NV; 12-ill; friends, restaurant, July 8th • CA; 14-ill; party, restaurant supplied food, July 9th • lab reports all cases have identical PFGE pattern • case-control study is conducted • spinach is implicated • traceback is initiated to determine source of the spinach

28. No common restaurant so distributors can be eliminated as a possible contamination source. Farm B supplies both distributors and is suspected contamination source. Restaurant A Phoenix, AZ Farm A Nogales, AZ Spinach Distributor A Denver, CO Restaurant B San Diego, CA Farm B Salinas, CA Spinach Distributor B Salinas, CA Restaurant C Las Vegas, NV Farm C Tucson, AZ Scenario - common farm

30. Product Contamination • 4 important sources • soil • water • farm workers • domestic and feral animals

31. Outbreak of Escherichia coli O157 Infections Associated with Fresh Spinach August-September 2006 • Early epi information • 3 possible processors in California • dozens of possible ranches • Possible ongoing exposures so FDA advises consumers not to consume bagged spinach • Actions taken by other countries based on early information.

32. Question:Type your answers on the chat window • Can you identify potential sources of produce contamination in addition to these: • soil • water • farm workers • domestic and feral animals

33. E. Coli O157:H7 and Spinach Sept. 14th; FDA notified of multi-state investigation possibly linked to bagged spinach - possible ongoing exposures - early epi could not identify a firm or lot code Sept. 14th; California Food Emergency Response Team dispatched to three firms Sept. 14th; phone calls between CDHS, FDA, and implicated firms begin Sept. 15th; firm X initiated a voluntary recall

34. Number Of Cases by Date of Illness OnsetUnited States, August-September, 2006 August 15, 2006 Lot -227 production date August September Date of initial symptom onset All data is preliminary

35. Baby Spinach Harvesting

36. Results: • E.coli O157:H7 found on 4 ranches • 9 isolates, from 1 ranch were PFGE indistinguishable from outbreak strain (1 stream, 1 pig feces, 7 cow feces) • ranch is primarily a beef cattle operation • a stream on the property - ideal habitat for wildlife – feral pigs, etc. • well is shallow and sits in a slight depression in the field.

37. Produce Outbreaks some lessons learned • Leafy vegetables have elevated levels of bacteria due to large surface area • Bacteria tends to adhere and accumulate in structures and at cut surfaces - once internalized, pathogens are difficult to remove • Pathogen survival varies greatly • Negative lab result ≠ absence of pathogen

39. Elluminate logo http://www.elluminate.com

40. NLC screenshot http://learningcenter.nsta.org

41. National Science Teachers Association Gerry Wheeler, Executive Director Frank Owens, Associate Executive Director Conferences and Programs Al Byers, Assistant Executive Director e-Learning NSTA Web Seminars Flavio Mendez, Program Manager Jeff Layman, Technical Coordinator Susan Hurstcalderone, Volunteer Chat Moderator LIVE INTERACTIVE LEARNING @ YOUR DESKTOP