Module 4

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.

gt 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 Polici
es Management Economics
OUTPUT Final product
Cool
Store
INPUTS - Raw foods - Ingredients - Chemicals -
Packing materials - Water
Receive
Cook
Store
Prep
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

gt Contributing factors
7
Categories of Contributing Factors
?
Contamination Survival Proliferation

gt 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

gt Contributing factors
9
Common Contributing Factors by Causative Agent
and Food

• Situational Keys A-F (starting on page 80)

gt Contributing factors
10
Generalizations
Causative agent Common contributing factors
Spore formers and preformed toxins Cooling, reheating, hot holding, bare- hand contact, room temperature storage, cold holding
Viral infections Ill food worker, bare-hand contact, inadequate handwashing, contaminated raw products, contaminated surfaces
Bacterial infections Ill food worker, bare-hand contact, inadequate handwashing, contaminated raw product, cross-contamination, inadequate cooking
Parasitic infections Contaminated raw products, source, water, cross-contamination, inadequate cooking
gt Contributing factors
11
Class Question
?

• Are the following likely to be contributing
• factors for the outbreaks described?

Contributing factor
Yes
Bare-hand contact of lettuce in an out- break of
shigellosis linked to a salad bar
No
Refrigerator at 47? in an outbreak of hepatitis A
virus linked to a restaurant
Yes
Refrigerator at 47? in an outbreak of
Staphylococcal intoxication linked to potato salad
No
Cat in the kitchen of a restaurant prior to an
outbreak of norovirus
gt 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

gt 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

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

gt Envt 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

gt Envt 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

gt Envt 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

gt Envt 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

gt Envt health assessment
21
Summary
HACCP/Facility Plan Review Regulatory Inspection Envt Health Assessment
When undertaken Before a food safety problem occurs Regularly scheduled
Time focus Future Today
Focus of effort Areas where food safety problems could occur Ongoing processes focusing on common problems
Who initiates Food establishment Regulatory agency
In response to specific problem
Past
Food safety problems related to implicated food
during outbreak period
Outbreak inves-tigation team
gt Envt health assessment
22
Environmental Health Assessment

• Objectives
• Reconstruct past events, focusing on implicated
  food(s)
• Identify contributing factors
• Identify environmental antecedents
• Develop effective interventions

gt Envt 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

gt Envt 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)

gt Envt 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

gt Envt 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

gt Envt health assessment
27
Example Food Flow through Facility
gt Envt 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

gt Envt 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 _________________________
_______________________
  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   WORKERS NAME   WORKERS HEALTH   OTHER INFO
                Y N     Ill Well  
  Y N   Ill Well
gt Envt health assessment
30
Example Flow Diagram
Wooden cutting board cleaned with soapy cloth
Celery and red pepper from grocery store
Celery stored under thawing chicken
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
Cubed potatoes marinated in French dressing
Potatoes cooled and cubed
Potatoes boiled in water until tender
5 lbs. potatoes washed and peeled
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
Paprika sprinkled on top
Potato salad placed in resealable container
(cylindrical 8 in. x 14 in.)
Chopped parsley stirred into mixture
Potatoes cooled and parsley washed and chopped
finely
Brand Z Paprika from grocery store
Served directly from container onto customers
plate with ice cream scoop
Fresh parsley from grocery store
gt Envt 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)

gt Envt 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

gt Envt 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)

gt Envt 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 (contd)
?

• 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
Group Exercise (contd)
?

• 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?

• 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
Group Exercise (contd)
?

• 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

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 (contd)
?

• Question 4 Draw a flow diagram for preparing
  the chicken.

39
Group Exercise (contd)

• 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

gt Envt 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

gt Traceback investigation
43
Results of Traceback Investigations
?
CASES
POINT OF SERVICE ESTABLISHMENTS
DISBUTORS/ IMPORTERS
PRODUCERS/ PROCESSORS
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
gt 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

gt 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

gt 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
gt Traceback investigation
47
Example
Grocery Store B
Cases
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
Grocery Store C
Cases
Domestic Producer F
Processor A
Cases
Deli A
gt 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

gt 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.

51
Quick Quiz

• 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.
• True
• False

52
Quick Quiz

• To prepare for an environmental health
  assessment, the investigator might consult which
  of the following?
• Team epidemiologist
• Laboratory staff
• Regulatory inspector for facility
• All of the above

53
Quick Quiz

• All of the following activities might be
  performed during an environmental health
  assessment of the implicated facility in an
  outbreak EXCEPT
• Interview of the manager of the implicated
  facility
• Walk through of the facility
• Collection of information from ill food workers
• Observation of all food preparation processes
  undertaken at the facility

54
Quick Quiz

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