Foodborne Disease Outbreak Investigation Team Training

1. Module 5 – Environmental Health Investigation Foodborne Disease Outbreak Investigation Team Training

2. At the end of this module, you will be able to • Discuss how contributing factors are related to causative agent, suspect food, and food processing method. • Compare environmental health assessment with 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.

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

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

8. Contributing Factors • Presence alone may not be sufficient to cause illness • Relationship between • Contributing factors • Food vehicle • Causative agent • Processing methods

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

10. Generalizations

11.  Question Are the following likely to be contributing factors for the outbreaks described? Contributing factor Yes Bare-hand contact of lettuce in an outbreak of shigellosis linked to a salad bar Refrigerator at 47 in an outbreak of hepatitis A virus linked to a restaurant No Refrigerator at 47 in an outbreak of Staphylo- coccal intoxication linked to potato salad Yes Cat in the kitchen of a restaurant prior to an outbreak of norovirus No

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

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

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

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

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

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

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

20. Environmental Health Assessment • Addresses food safety issues that occurred in the past • Occurs in response to a food safety problem • Focuses on (reconstructs) past events related to • Implicated food(s) • Prepared/served during outbreak period • Initiated by outbreak investigation team, guided by epidemiologic and laboratory information

21. Summary In response to specific problem Past Problems related to implicated food during outbreak period Outbreak inves-tigation team

22. Environmental Health Assessment • Objectives: • Reconstruct past events, focusing on implicated food(s) • Identify contributing factors • Identify environmental antecedents • Develop effective interventions

23. Preparation for Assessment • Examine available outbreak information • Causative agent • Onset of illness • Likely exposure dates/meals/foods • Review information on causative agent • Reservoirs and previously identified vehicles • Modes of transmission • Likely contributing factors • Collect food establishment information • Existing regulatory records • Menus, recipes, product formulations • Connection to chain of food establishments

24.  Site Visit • Focuses 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)

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

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

27. Example Food Flow through Facility

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

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: ________________________________________________

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

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)

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

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)

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

35.  SMALL 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? • Examine available information on the outbreak. • Collect existing information on the facility. • Review basic information on salmonellosis.

36.  SMALL 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 undertake at the facility? • Focus on chicken salad: • Talk with manager • Determine who prepared the chicken salad • Walk through the facility • Observe preparation of chicken salad • Interview worker to reconstruct past events • Determine worker food preparation knowledge • Collect left over chicken salad

37.  SMALL 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? • Cross contamination • Inadequate refrigeration • Improper holding temperatures • Heat process failure • Improper cooling

38.  SMALL GROUP Exercise (cont’d) 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.

39. SMALL GROUP Exercise (cont’d)

40.  SMALL GROUP Exercise (cont’d) Question 4: Draw a flow diagram for preparing the chicken. Wash chicken under running water and trim (70F) Place in tubs and transport to cooking area Remove to packaging area Insert rotisserie spindles Cook Store in walk-in refrigerator in metal pan on the top shelf, covered, labeled, dated • Remove from refrigerator • Debone • Dice Place in walk-in refrigerator single layer/ not covered

41. SMALL GROUP Exercise (cont’d) Question 5: These photos were taken as you observed the salad being made. Do any concern you? 1

42. SMALL GROUP Exercise (cont’d) 2

43. SMALL GROUP Exercise (cont’d) 3

44. SMALL GROUP Exercise (cont’d) 4

45. SMALL GROUP Exercise (cont’d) 5

46. SMALL GROUP Exercise (cont’d) 6

47. 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

48. TracebackInvestigationS

49. 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

50.  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