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

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

2 2Environmental health investigation Module Learning Objectives At the end of this module, you will be able to 1.Discuss how contributing factors are related to the causative agent, suspect food, and food processing method. 2.Compare an environmental health assessment with a HAACP plan review, facility plan review, and regulatory inspection. 3.List types of activities included in an environmental health assessment. 4.Describe the likely role of local jurisdictions in a traceback investigation. > Learning objectives

3 3Environmental health investigation Food System Primary producers Manufacturers Distributors Retailers Point of service establishments

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

5 5Environmental health investigation Contributing Factors

6 6Environmental health investigation 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 7Environmental health investigation ContaminationSurvivalProliferation 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 Categories of Contributing Factors  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 > Contributing factors

8 8Environmental health investigation 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 9Environmental health investigation Common Contributing Factors by Causative Agent and Food Situational Keys A-F (starting on page 80) > Contributing factors

10 10Environmental health investigation Generalizations Causative agentCommon contributing factors Spore formers and preformed toxins Cooling, reheating, hot holding, bare- hand contact, room temperature storage, cold holding Viral infectionsIll food worker, bare-hand contact, inadequate handwashing, contaminated raw products, contaminated surfaces Bacterial infectionsIll food worker, bare-hand contact, inadequate handwashing, contaminated raw product, cross-contamination, inadequate cooking Parasitic infectionsContaminated raw products, source, water, cross-contamination, inadequate cooking > Contributing factors

11 11Environmental health investigation Class Question Are the following likely to be contributing factors for the outbreaks described?  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 Contributing factor

12 12Environmental health investigation 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 13Environmental health investigation 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 14Environmental health investigation “When you have a foodborne outbreak, more than one thing went wrong.” Dr. Frank Bryan > Contributing factors

15 15Environmental health investigation Environmental Health Assessment

16 16Environmental health investigation 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 17Environmental health investigation 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 18Environmental health investigation 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 19Environmental health investigation 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 20Environmental health investigation 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 21Environmental health investigation Summary HACCP/Facility Plan Review Regulatory Inspection Env’t Health Assessment When undertaken Before a food safety problem occurs Regularly scheduled Time focusFutureToday Focus of effort Areas where food safety problems could occur Ongoing processes focusing on common problems Who initiates Food establishment Regulatory agency Past In response to specific problem Food safety problems related to implicated food during outbreak period Outbreak inves- tigation team > Env’t health assessment

22 22Environmental health investigation Environmental Health Assessment Objectives: 1.Reconstruct past events, focusing on implicated food(s) 2.Identify contributing factors 3.Identify environmental antecedents 4.Develop effective interventions > Env’t health assessment

23 23Environmental health investigation 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 24Environmental health investigation Site Visit Focus on implicated food and time period of outbreak 1.Manager interview 2.Facility walk through 3.Observation of operations 4.Collection of samples (food and environment) 5.Worker interviews 6.Collection of records (and other documents) > Env’t health assessment 

25 25Environmental health investigation 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 26Environmental health investigation 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 27 Environmental health investigation Example Food Flow through Facility > Env’t health assessment

28 28Environmental health investigation 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 29Environmental health investigation 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: ________________________________________________ DATE PROCESS OBSERVATION AMOUNT OF FOOD TIME OF DAY TEMP OF FOOD EQUIP- MENT USED DEPTH OF CONTAINER OR FOOD THICKNESS HAND CONTACT WITH FOOD WORKER’S NAME WORKER’S HEALTH OTHER INFO YN YN Ill Well YN YN Ill Well > Env’t health assessment

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

31 31Environmental health investigation 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 32Environmental health investigation 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 33Environmental health investigation 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 34Environmental health investigation Group Exercise Divide into groups by table. 1.Study the information provided on an outbreak of salmonellosis linked to a restaurant at the end of the module. 2.Walk through the environmental health assessment of the restaurant, answering the questions. 3.Do you see any contributing factors likely to be related to the outbreak? Time: 15 minutes Be prepared to share your thoughts with the class.

35 35Environmental health investigation 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 36Environmental health investigation 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 37Environmental health investigation 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 38Environmental health investigation Group Exercise (cont’d) Question 4: Draw a flow diagram for preparing the chicken. 

39 39Environmental health investigation Group Exercise (cont’d) Question 5: These photos were taken as you ob- served the salad being made. Do any concern you? 123 456

40 40Environmental health investigation 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 41Environmental health investigation Traceback Investigation

42 42Environmental health investigation 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 43Environmental health investigation Results of Traceback Investigations Case #1 Case #2-4, 6, 8 Case #5, 7, 13-17 Case #7, 9-12 Grocery Store A Restaurant A Cafeteria X Restaurant B Deli A Distributor A Distributor B Distributor C Distributor D Importer X Domestic Producer A Domestic Producer C Domestic Producer B Foreign Producer A  Distributor D Importer X Domestic Producer B Domestic Producer C Foreign Producer A Domestic Producer A > Traceback investigation CASES POINT OF SERVICE ESTABLISHMENTS DISBUTORS/ IMPORTERS PRODUCERS/ PROCESSORS

44 44Environmental health investigation 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 45Environmental health investigation 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 46Environmental health investigation Example Case #1 Case #3-6 Case #8-17 Grocery Store A Restaurant A Cafeteria X Restaurant B Distributor A Distributor BDistributor C Domestic Producer C Importer X Foreign Producer A Domestic Producer A Domestic Producer B Case #2 Domestic Producer C  > Traceback investigation

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

48 48Environmental health investigation 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 49Environmental health investigation Quick Quiz

50 50Environmental health investigation Quick Quiz 1.Which of the following statements is true about contributing factors. A.An outbreak will occur if a contributing factor is present. B.The three major categories of contributing factors are contamination, survival (lack of inactivation), and proliferation. C.Contributing factors in an outbreak depend on the causative agent but not the food vehicle or processing method. D.Correction of the contributing factor will correct the food safety problem and prevent it from occurring again.

51 51Environmental health investigation Quick Quiz 2.An environmental health assessment of a food establishment undertaken during an outbreak investigation is similar to a regulatory inspection except it focuses on the past. A.True B.False

52 52Environmental health investigation Quick Quiz 3.To prepare for an environmental health assessment, the investigator might consult which of the following? A.Team epidemiologist B.Laboratory staff C.Regulatory inspector for facility D.All of the above

53 53Environmental health investigation Quick Quiz 4.All of the following activities might be performed during an environmental health assessment of the implicated facility in an outbreak EXCEPT A.Interview of the manager of the implicated facility B.Walk through of the facility C.Collection of information from ill food workers D.Observation of all food preparation processes undertaken at the facility

54 54Environmental health investigation Quick Quiz 5.Staff from local health departments are likely to be responsible for all of the following activities during a traceback investigation EXCEPT A.Interview of cases for product details B.Determining whether contamination at the food service facility is the source of the outbreak C.Collection of paperwork from the implicated food establishment D.Detailed analysis of receipts and invoices


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