Module 4 – Environmental Health Investigation

1. Foodborne Disease Outbreak Investigation Team Training: Module 4 – Environmental Health Investigation

2. Module Learning Objectives At the end of this module, you will be able to • Discuss how contributing factors are related to the causative agent, suspect food, and food processing method. • Compare an environmental health assessment with a HAACP plan review, facility plan review, and regulatory inspection. • List types of activities included in an environmental health assessment. • Describe the likely role of local jurisdictions in a traceback investigation. > Learning objectives

3. Food System Primary producers Retailers Distributors Manufacturers Point of service establishments

4. Food Establishments as Dynamic Systems Serve Hold Assemble Reheat Package Underlying Factors Foods and their properties Food workers Equipment Processes Policies Management Economics OUTPUT: Final product Cool Store INPUTS: - Raw foods - Ingredients - Chemicals - Packing materials - Water Cook Receive Prep Store

5. Contributing Factors

6. Contributing Factors • Factors that increase the risk of foodborne illnesses and repeatedly contribute to outbreaks • Identification (and correction) of these factors facilitates prevention and control of foodborne diseases • Three major categories • Contamination • Survival • Proliferation > Contributing factors

7.  Natural toxin Added poisonous substance Toxic container Contaminated food eaten raw or lightly cooked Unsafe sources Cross-contamination Infected food worker Unclean equipment Poor storage practices Improper cooking or heat processing Improper reheating Inadequate acidification Insufficient thawing followed by insufficient cooking Improper refrigeration Preparation too far in advance of serving Prolonged cold storage Improper hot-holding Insufficient acidification Insufficiently low water activity Inadequate thawing of frozen foods Anaerobic packaging Inadequate fermentation Categories of Contributing Factors > Contributing factors

8. Contributing Factors • Presence alone may not be sufficient to cause illness • A relationship exists between contributing factors, food vehicle, causative agent, and processing methods > Contributing factors

9. Common Contributing Factors by Causative Agent and Food Situational Keys A-F (starting on page 80) > Contributing factors

10. Generalizations > Contributing factors

11.  Class Question Are the following likely to be contributing factors for the outbreaks described? Contributing factor Bare-hand contact of lettuce in an out- break of shigellosis linked to a salad bar Refrigerator at 47 in an outbreak of hepatitis A virus linked to a restaurant Refrigerator at 47 in an outbreak of Staphylococcal intoxication linked to potato salad Cat in the kitchen of a restaurant prior to an outbreak of norovirus > Contributing factors

12. Environmental Antecedents • The root cause or circumstances that set the stage for contributing factors to occur • Include economic constraints, inadequate worker education, management decisions, social and cultural beliefs • Must be addressed to eliminate contributing factors > Contributing factors

13.  Example • Salmonellosis outbreak linked to potato salad • Contributing factor: Potato salad contaminated because placed under thawing chicken in refrigerator • Environmental antecedents: Economic issues led to hiring more part-time workers who were less experienced, inadequate food worker education, inadequate oversight and supervision > Contributing factors

14. “When you have a foodborne outbreak, more than one thing went wrong.” Dr. Frank Bryan > Contributing factors

15. Environmental Health Assessment

16. Environmental Health Assessment • A systematic, detailed, science-based evaluation • Focuses on factors that contributed to an outbreak • Different from a • Hazard Analysis and Critical Control Point (HACCP) risk assessment review • Facility plan review • Food establishment regulatory inspection > Env’t health assessment

17. HACCP Risk Assessment Review Preemptive solutions to potential food safety problems in the future Undertaken before a problem occurs Focus Foods produced by establishment and related procedures Identification of potential food safety problems Control measures to mitigate potential problems Initiated by establishment > Env’t health assessment

18. Facility Plan Review Preemptive solutions to potential food safety problems in the future Undertaken before a problem occurs Focus Proposed structural plans and equipment at establishment Relation to intended procedures Functionality, durability, ease of cleaning Initiated by establishment > Env’t health assessment

19. Food Establishment Regulatory Inspection • Addresses food safety problems occurring today • Routinely scheduled inspections • Focus • Ongoing processes and procedures • Leading causes of foodborne illness (risk-based approach) • Initiated by regulatory authority > Env’t health assessment

20. Environmental Health Assessment • Addresses food safety issues that occurred in the past • Occurs in response to a food safety problem • Focuses on (and reconstructs) past events related to • Implicated food(s) • Prepared/served during outbreak period • Outbreak investigation team initiates, guided by epidemiologic and laboratory information > Env’t health assessment

21. Summary In response to specific problem Past Food safety problems related to implicated food during outbreak period Outbreak inves-tigation team > Env’t health assessment

22. Environmental Health Assessment Objectives: • Reconstruct past events, focusing on implicated food(s) • Identify contributing factors • Identify environmental antecedents • Develop effective interventions > Env’t health assessment

23. Preparation for Assessment • Examine available outbreak information • Causative agent • Onset of illness among cases • Likely exposure dates/meals/foods • Collect food establishment information • Existing regulatory records • Menus, recipes, product formulations • Connection to chain of food establishments • Review information on causative agent • Reservoirs and previously identified vehicles • Modes of transmission • Likely contributing factors > Env’t health assessment

24.  Site Visit Focus on implicated food and time period of outbreak • Manager interview • Facility walk through • Observation of operations • Collection of samples (food and environment) • Worker interviews • Collection of records (and other documents) > Env’t health assessment

25. 1. Manager Interview • Work to gain cooperation in investigation • Assess management knowledge and attitude toward food safety • Collect information about food workers who prepared the implicated food • Review standard operating procedures > Env’t health assessment

26. 2. Facility Walk Through • Get sense of general layout of facility and floor design • Walk through movement of implicated food through facility • Identify opportunities for occurrence of relevant contributing factors > Env’t health assessment

27. Example Food Flow through Facility > Env’t health assessment

28. 3. Observation of Operations • Focus on implicated food and associated processes • Attempt to reconstruct how food was prepared during period of interest • Take measurements • Record observations on food preparation worksheet • Draw flow diagram > Env’t health assessment

29. Example Food Preparation Worksheet FOOD PREPARATION REVIEW WORKSHEET Complaint Number: Establishment Name: _________________________________________________ Address: Phone Number:___________________ Date & Time of Suspect Meal: / : am pm mo day yr Date & Time Food Preparation: / : am pm mo day yr Person Interviewed: Name Position Review: Observing Preparation Interviewing person who made food __Other (specify) Suspect Food: ________________________________________________ > Env’t health assessment

30. Example Flow Diagram Wooden cutting board cleaned with soapy cloth Celery stored under thawing chicken Celery and red pepper from grocery store Washed and chopped 50 lbs. bag of potatoes from Farmer B Eggs in trays of 32 from Farmer B, stored in walk-in refrigerator Eggs boiled for 10 min. Eggs sliced Potatoes, celery, red pepper, and eggs mixed gently with wood spoon 5 lbs. potatoes washed and peeled Potatoes boiled in water until tender Potatoes cooled and cubed Cubed potatoes marinated in French dressing Knife used to cut other items cleaned with soapy water at end of day Same wooden spoon used to get mayonnaise and all mixing 4 cups of mayon-naise added and stirred into mixture with wooden spoon Stored in walk-in refrigerator at 4C (39 F) for up to 2 days Potato salad placed in resealable container (cylindrical 8 in. x 14 in.) Paprika sprinkled on top Chopped parsley stirred into mixture Potatoes cooled and parsley washed and chopped finely Brand Z Paprika from grocery store Served directly from container onto customer’s plate with ice cream scoop Fresh parsley from grocery store > Env’t health assessment

31. 4. Collection of Samples • Collect food, water, and environmental samples based on suspicions about outbreak source • Consult with laboratory on collection, storage, and transportation procedures • Collect as soon as possible and note condition (may store for testing at later time) > Env’t health assessment

32. 5. Worker Interviews • Interview in private • Reconstruct preparation of implicated food during period of interest • Note unusual circumstances during period of interest and inconsistencies in the story • Collect information about food worker hygiene and recent illnesses > Env’t health assessment

33. 6. Collection of Records Collect and review • Records that identify source of food or ingredients (e.g., receipts and invoices) • Worker logs or time cards • Monitoring logs (e.g., temperatures in walk-in refrigerators) > Env’t health assessment

34. Group Exercise Divide into groups by table. Study the information provided on an outbreak of salmonellosis linked to a restaurant at the end of the module. Walk through the environmental health assessment of the restaurant, answering the questions. Do you see any contributing factors likely to be related to the outbreak? Be prepared to share your thoughts with the class. Time: 15 minutes

35.  Group Exercise (cont’d) An outbreak of gastrointestinal illness is linked to a local restaurant. Seven unrelated restaurant patrons are sick with abdominal pain, nausea, vomiting, and diarrhea. Onset of illness among cases was January 22-24. Two ill patrons had stool specimens positive for Salmonella. Question 1: You are responsible for undertaking the environmental health assessment. How would you prepare for the investigation?

36.  Group Exercise (cont’d) The restaurant is known for its burgers but serves a variety of sandwiches and salads. Based on patient interviews, ill persons ate at the restaurant on January 20. All but one ate chicken salad; three ill persons had only chicken salad. Question 2: What type of activities will you under-take at the facility?

37.  Group Exercise (cont’d) Question 3: Given the causative agent (Salmonella), implicated food (chicken salad), and setting (food service establishment), what contributory factors will you be looking for? The manager tells you two employees (Willard and Anita) usually make the salad. Making the chicken salad is a 2-day process. You interview the employees to reconstruct how the salad was made.

38.  Group Exercise (cont’d) Question 4: Draw a flow diagram for preparing the chicken.

39. Group Exercise (cont’d) Question 5: These photos were taken as you ob-served the salad being made. Do any concern you? 1 2 3 4 5 6

40. Develop Effective Interventions • Immediate control measures • Hold • Seize • Cease/desist • License sanctions • Menu limitation • Embargo • Closure • Worker exclusion or restrictions • Recalls • Long term strategies to prevent recurrence • HACCP plan • Risk control plans • Training • Menu/supplier/recipe modifications > Env’t health assessment

41. Traceback Investigation

42. Traceback Investigations • Process used to determine the production and distribution chain of an implicated food • Purpose: • Identify product so that it can be removed from further consumption • Determine likely origin of food safety problem • Strengthen epidemiologic associations between food and illness • Formal regulatory traceback vs. informational traceback > Traceback investigation

43.  Domestic Producer B Domestic Producer C Importer X Foreign Producer A Results of Traceback Investigations CASES POINT OF SERVICE ESTABLISHMENTS DISBUTORS/ IMPORTERS PRODUCERS/ PROCESSORS Domestic Producer A Grocery Store A Domestic Producer A Case #1 Distributor A Restaurant A Domestic Producer B Distributor B Distributor D Distributor D Case #2-4, 6, 8 Cafeteria X Domestic Producer C Importer X Case #5, 7, 13-17 Restaurant B Case #7, 9-12 Deli A Foreign Producer A Distributor C > Traceback investigation

44. Role of Local Health Departments • Undertake scientifically sound investigations to • Implicate specific food item • Rule out end user contamination • Interview cases for product details and where they purchased the food (e.g., receipts) • Collect paperwork (e.g., receipts, invoices, shipping documents) from retail food establishments > Traceback investigation

45. Traceforward Investigations Once source of outbreak identified: • Process used to trace distribution of all implicated lots of food from the original source (not just foods eaten by known cases) • Purpose • Support recall efforts • Support further case-finding • Test hypothesis about source > Traceback investigation

46.  Example Domestic Producer A Grocery Store A Case #1 Distributor A Restaurant A Domestic Producer B Case #2 Distributor B Distributor C Case #3-6 Cafeteria X Domestic Producer C Domestic Producer C Case #8-17 Restaurant B Importer X Foreign Producer A > Traceback investigation

47. Example Cases Grocery Store B Grocery Store A Domestic Producer D Domestic Producer E Case #1 Distributor A Restaurant A Case #2 Distributor B Distributor C Case #3-6 Cafeteria X Domestic Producer C Case #8-17 Restaurant B Distributor E Cases Grocery Store C Domestic Producer F Processor A Cases Deli A > Traceforward investigation

48. Salmonella Typhimurium and Peanut Butter • Cluster of S. Typhimurium detected by PulseNet • Studies implicate peanut butter sold to institutions and peanut butter crackers • Outbreak traced to one plant • Initial recall of specific lots of peanut butter expanded to include all peanuts and peanut products from implicated plant • FDA performs traceforward • Ultimately 3,900 products recalled from several hundred companies > Traceforward investigation

49. Quick Quiz

50. Quick Quiz • Which of the following statements is true about contributing factors. • An outbreak will occur if a contributing factor is present. • The three major categories of contributing factors are contamination, survival (lack of inactivation), and proliferation. • Contributing factors in an outbreak depend on the causative agent but not the food vehicle or processing method. • Correction of the contributing factor will correct the food safety problem and prevent it from occurring again.