Introduction of Hazards: Preparation, Consumption, and the Chain of Transmission

1. Introduction of Hazards: Preparation, Consumption, and the Chain of Transmission Pathogen Reduction Dialogue Panel 1 May 6, 2002 Georgetown University Conference Center Robert V Tauxe, M.D., M.P.H. Foodborne and Diarrheal Diseases Branch, DBMD, NCID Centers for Disease Control and Prevention, Atlanta, GA

2. Public health burden of foodborne disease • Each year an estimated 76 million cases • 1 in four Americans gets a foodborne illness each year • 1 in 1000 Americans is hospitalized each year • $6.5 billion in medical and other costs • Prevention depends on efforts from farm to table to reduce contamination of food

3. Foodborne diseases • Infection with a variety of different pathogens • Illness may occur in large focal outbreaks • Most illness is “sporadic”: either individual cases or part of unrecognized dispersed outbreaks • Reservoir: locus of sustained transmission and persistence • Some have a human reservoir: Shigella, hepatitis A, Norwalk virus • Some have an animal reservoir: Salmonella, Campylobacter, E. coli O157:H7, Listeria, Vibrio, Yersinia, Toxoplasma • Often transmitted by several different pathways • Specific foods, water, direct contact with animals, direct contact with humans

4. Bacterial: Bacillus cereus Brucella Campylobacter* Clostridium botulinum Clostridium perfringens E. coli O157:H7* E. coli, non-O157 STEC* E. coli, other diarrheagenic* Listeria monocytogenes* Salmonella Typhi Salmonella non-typhoidal Shigella Staphylococcus Streptococcus Vibrio cholerae, toxigenic* Bacterial, continued: Vibrio vulnificus* Vibrio, other* Yersinia enterocolitica* Parasitic: Cryptosporidium* Cyclospora* Giardia* Toxoplasma* Trichinella Viral: Norwalk-like viruses* Rotavirus* Astrovirus* Hepatitis A Major identified foodborne pathogens, United States – circa 2002 Prions* * Recognized as foodborne in last 30 years

5. Bacterial: Bacillus cereus Brucella Campylobacter* Clostridium botulinum Clostridium perfringens E. coli O157:H7* E. coli, non-O157 STEC* E. coli, other diarrheagenic* Listeria monocytogenes* Salmonella Typhi Salmonella non-typhoidal Shigella Staphylococcus Streptococcus Vibrio cholerae, toxigenic* Bacterial, continued: Vibrio vulnificus* Vibrio, other* Yersinia enterocolitica* Parasitic: Cryptosporidium* Cyclospora* Giardia* Toxoplasma* Trichinella Viral: Norwalk-like viruses* Rotavirus* Astrovirus* Hepatitis A Major identified foodborne pathogens, United States – circa 2002 Prions* * Recognized as foodborne in last 30 years (Zoonotic reservoir)

6. The new foodborne zoonoses • The infected food animal looks healthy • Sustained or repeated infections in animals • Contaminated food looks normal • Pathogen survives standard processing and preparation • Missed by current inspection strategies • Spreads silently around the globe • Requires new control strategies • More to be discovered

7. The chain of production from farm to table: A generic scenario Farm, Feedlot, Fishing site Production Slaughter Plant, Cannery, Packer, Food Factory Processing Final Kitchen: commercial, institutional or domestic Final preparation and cooking

8. The chain of production from farm to table: A generic scenario Farm, Feedlot, Fishing site Production Slaughter Plant, Cannery, Packer, Food Factory Processing Final Kitchen: commercial, institutional or domestic Final preparation and cooking

9. What happens in kitchens? • 1993-1997: Among 2,751 foodborne outbreaks reported to CDC, 43% in restaurants/delis/etc • Contributing kitchen factors noted 73% - poor holding temperatures 38% - poor personal hygiene 21% - inadequate cooking • 1980-1995: New York State: 1806 outbreaks: • 32% - contaminated ingredients • 24% - consumption of raw/lightly heated • 23% - food from unapproved source • 23% - ill food handler

10. Outbreaks are multi-factorial events • Problems in food handling are often reported in foodborne outbreak investigations • Probably frequent in kitchens where an outbreak has not occurred • Training focused on better food handling important, so is handwashing • Reducing the arrival of the pathogens into kitchen is also important

11. Introduction of pathogens into food during final preparation: what are the sources? • Foods arrive contaminated (particularly raw foods of animal origin) • Food handler infected with the pathogen • Other environmental sources

12. When contaminated raw foods of animal origin arrive in the kitchen, • Handling may further amplify risk • Easily cross-contaminate other foods via hands, utensils, surfaces • A direct risk if undercooked (FoodNet 2000 survey) • Raw oysters - 2.5% in preceding month • Pink ground beef - 26% • Runny egg dish - 27% • 3% use a thermometer for burgers

13. When an ill food handler arrives in the kitchen, • They work, because they have no paid sick leave • They may be shedding the organism in feces or vomit • Lapses in personal hygiene can contaminate food • Particularly for pathogens with human reservoir: • Norwalk-like viruses, Shigella, hepatitis A • Occasionally for pathogens with animal reservoirs: • Salmonella, E. coli O157, Campylobacter

14. Food may be contaminated by other environmental sources • Food prepared or consumed around animals • Petting zoos, county fairs, “barn dances” • Large E. coli O157 outbreak, U Wisconsin, 2001 34 cases after a breakfast in the stock pavilion • Food prepared with contaminated water • Rodents, insects, and other vermin may cross-contaminate food

15. Prevention strategies for the general public to reduce contamination in the kitchen • Basic food safety education • Avoid risky food practices • Separate handling raw meat and infant care • Purchase foods processed for safety: • Pasteurized milk, juice • Pasteurized shell eggs • Irradiated ground beef • Ask restaurants about their sick leave policies

16. Prevention strategies for food establishments to reduce contamination in the kitchen • Basic food safety training and certification • Paid sick leave policies • Make handwashing easy and frequent • Reduce contact with ready to eat food • Include pathogen reduction standards in purchase contracts

17. For institutional kitchens serving high risk populations, foods processed for safety are available now • Pasteurized shell eggs and liquid eggs to avoid Salmonella Enteritidis infections • Irradiated ground beef to avoid E. coli O157:H7 and Salmonella infections • Frozen chicken and turkey, to reduce risk of Campylobacter infections

18. Food safety education is important but not sufficient to protect public health • Raw foods of animal origin are often contaminated • Serious infections, grave complications • Traditional recipes call for limited cooking • Raw oysters, rare ground beef, soft boiled eggs, hollandaise sauce • Hard to tell when food is thoroughly cooked • Boiled eggs, baked lasagna, “browned” burgers • Raw meat, poultry, eggs in the kitchen is handled by someone also handling other foods • Fresh produce, rinsed and eaten without cooking

19. The chain of production from farm to table: Where contamination can occur Feed, water, manure, wildlife, new stock Production Lairage, water baths, Manure, sanitation, cross contamination Processing Time, temperature, Cross-contamination, Worker health, hygiene Final preparation and cooking

20. Principle sources of pathogens • Pathogens: • Campylobacter • E. coli O157:H7 • Salmonella • Yersinia • Listeria monocytogenes • Norwalk-like viruses • Hepatitis A • Sources: • Poultry, production level • Cattle, production level, • Poultry, cattle, pig, produce, production level • Pigs, production level • Ready to eat meats, processing level • Humans, production and preparation level • Humans, production and preparation level

21. The chain of production from farm to table: Where contamination can occur Fish and shellfish Land Animals Plants Production Processing Final preparation and cooking Fruits, nuts, vegetables Seafoods Meat, poultry, dairy, eggs

22. Shellfish in their beds The chain of production from farm to table: Where contamination can occur with Vibrio parahaemolyticus Fish and shellfish Land Animals Plants Production Processing Final preparation and cooking Fruits, nuts, vegetables Seafoods Meat, poultry, dairy, eggs

23. The chain of production from farm to table: Where contamination can occur with Norwalk like viruses Fish and shellfish Land Animals Plants Production Ill humans Processing Final preparation and cooking Fruits, nuts, vegetables Seafoods Meat, poultry, dairy, eggs

24. The chain of production from farm to table: Where contamination can occur with zoonotic Salmonella Carrier food animals Fish and shellfish Land Animals Plants Production Processing Final preparation and cooking Fruits, nuts, vegetables Seafoods Meat, poultry, dairy, eggs

25. The chain of production from farm to table: Prevention possible at many points On-farm sanitation, safety of animals' food and water biosecurity, and other "Good Agricultural Practices" Production Factory sanitation, quality control HACCP, microbial verification, inspection and other "Good Manufacturing Processes" Processing {Pathogen Killing Step} Pasteurization, retort canning, irradiation Final preparation and cooking Food handler training, handwashing, sick leave, Restaurant inspection, Consumer education

26. Schematic map of food industry Fish & shellfish Land animals Plants Production Transport/ lairage HACCP Processing HACCP Distribution Preparation Meat, poultry, dairy,eggs Fruit, nuts & vegetables Seafood Consumption (and foodborne illness)

27. HACCP monitoring samples (FSIS data). Percent of ground beef samples yielding Salmonella, by size of processing plant, and year Baseline

28. HACCP monitoring samples. Percent of broiler, ground turkey and hog samples yielding Salmonella, by year, large processing plants (FSIS data)

29. Human illness data (CDC-FoodNet). Change in incidence of foodborne infections relative to 1996 Decrease of 15% 25% 31%49%

30. Some future prevention points for foodborne disease (with microbial validation) Fish & shellfish Land animals Plants Production QAP Transport/ lairage HACCP Processing HACCP Distribution Preparation Meat, poultry, dairy,eggs Fruit, nuts & vegetables Seafood Consumption (and foodborne illness)

31. Some future prevention points for foodborne disease (with microbial validation) Fish & shellfish Land animals Plants Production QAP Transport/ lairage HACCP Processing HACCP HACCP Distribution Preparation Meat, poultry, dairy,eggs Fruit, nuts & vegetables Seafood Consumption (and foodborne illness)

32. Summary • Foodborne pathogens enter food chain at multiple points • Pathogen reduction approaches can reduce risk at each step • Microbial monitoring can verify control measures • In the kitchen: • Educating the food preparers is important, so is • Handwashing • Keeping ill workers out of the kitchen, and • Decreasing contamination of food coming into the kitchen • Microbial standards in purchase contracts may help • For high risk populations, using safer food products