Vincent J. Radke, MPH, RS, CP-FS, DAAS, CPHSanitarian

Centers for Disease Control and Prevention

Sixth International Conference on Food Safety

Dubai, 2011

Understanding Foodborne Disease Outbreaks Using Environmental

Assessments: The Importance of Antecedents to Contributing Factors

National Center for Environmental Health

Environmental Health Services Branch

Definitions Environmental Assessment

The component of an outbreak investigation that fully describes how the environment contributed to the introduction and or transmission of agents that cause illness. Environment is everything external to the host, including air, food, water, animals, plants, climate, etc as well as people, social and built environments. All aspects of the external environment can be listed as variables that, in relation to transmission, are neutral, conducive or protective. From this description contributing factors and environmental antecedents to an outbreak can be determined.

NOT an inspection

Definitions Contributing Factors

The factors likely to be conducive to the contamination and survival of the etiologic agent or suspected agent and/or to its growth or proliferation.

• Contamination Factors (C1-15)o Toxic substance part of the tissue , Contaminated raw product, Cross-

contamination of ingredients , Bare-hand contact by a food handler/worker/preparer who is suspected to be infectious

• Proliferation Factors (P1-12)o Improper cold holding due to malfunctioning refrigeration equipment,

Improper hot holding due to improper procedure or protocol, Prolonged cold storage

• Survival Factors (S1-4)o Insufficient time and/or temperature during cooking/heat processing ,

Insufficient time and/or temperature during reheating

Definitions

Environmental Antecedents Root causes Supporting factor(s) to the contamination, survival or

increase of biological or chemical agents in food They may be related to

• People• Equipment• Process• Food • Economics• Behavior• Other circumstances

EXAMPLE

What caused the outbreak? Campylobacter Jejuni (CJ) in the “cooked” chicken (EPI, LAB, ENV Assessment)

Why was CJ in the “cooked" chicken? Insufficient temperature during cooking to kill CJ (Contributing Factor)

Why was there insufficient temperature during the cooking process to kill CJ? The cook did not know the temperature (Environmental Antecedent)

Environmental Assessments

Describes how the environment contributes to the introduction and or transmission of agents that cause illness

Objectives of the assessment• Identify contributing factors• Identify environmental antecedents• Generate recommendations for informed

interventions

Relationship of Environmental Antecedents to Contributing Factors

No sick leave Afraid of reporting No policy No supervision Lack of knowledge Hands not washed

No gloves used

PEOPLE Lack of hand wash sinks Location of hand wash sinks Lack of supplies for hand wash sinks No supervision Not enough water available Not enough gloves available EQUIPMENT

Handling after kill step

No kill step

Multiple steps involving process

PROCESS Minimum wage

Equipment costs

Glove costs

ECONOMICS

FOOD

Outbreak

Contamination at preparation step

ContributingFactor A

Bare-hand contact by a food handler/worker/preparer who is suspected

to be infectious

ContributingFactor X

Routine Regulatory Inspections

Past Present Future

Physical Facility Plan Review

HACCP Plan Development

Foodborne Illness Outbreak Environmental Assessment

Environmental Antecedents

Medium(food, water,Wastewater,Air, etc.)

Environmental Health AssessmentEquipment People

Process

Economics

Protective System

preventionunsuccessful

Noillness

prevention

successful

AdverseHealth Outcomes

IncreasingSeverity of illness

Outbreak

Exposure

Using Environmental Assessments to Investigate

Disease Outbreaks

Contributing Factors

Epidemiology

Lab(Identify and/orconfirmAgent)

EHS-Net

Environmental Health Specialist Network

Pronounced “S – Net”

www.cdc.gov/nceh/ehs/EHSNet/default.htm

StudyIntroduction

Foodborne outbreaks investigations represent one aspect of the overall foodborne disease surveillance system

Environmental assessments of investigations provide food safety programs with better understanding of contributing factors and environmental assessments

While contributing factors are sometimes captured these factors are not framed in the context within which they occurred

Environmental antecedents help provide a meaningful context for contributing factors

Purpose

The purpose of this study was to identity contributing factors to foodborne illness outbreaks in food service establishments (restaurants, delis, schools, etc) and to describe the characteristics, policies, and practices (possible environmental antecedents) of these establishments via environmental assessments

Methods

The study was conducted by the Environmental Health Specialists Network (EHS-Net). EHS-Net is a collaborative project of CDC, USFDA, USDA and nine states ( CA, CT, GA, IA, MN, NY, OR, RI, TN)

Descriptive study to collect information on contributing factors and antecedents (food handling policies and practices)

Data collection based on interview with a kitchen manager, observations in the kitchen, development of a food flow of the suspected or identified vehicle, and sometimes re-enactment of the food handling practices used for the vehicle

Methods (Cont.)

Descriptive analysis of the data set included univarate frequencies and cross-tabulations for selected variables

Future analysis to include test for association using chi-square and t-test, we may use regression modeling to examine any multivariate relationships and to control for confounding

Results 154 environmental assessments conducted

( June, 2006 to September , 2007) Of those outbreaks with an identified

etiology (102) 33 (30%) were bacterial and 69 (63%) viral

84% were identified as complex; 13% were cook serve; 3 % were prep serve

Spanish was the primary language of 58% of the food workers but only 41% of the mangers could speak Spanish

Results(Cont.)

95% of establishments had floor cleaning policies (37% of these were written BUT fewer had policies for cleaning food contact surfaces (food slicers 72%). In these establishments 33% had a written policy for cleaning food slicers.

More managers received paid sick leave (66%) than workers (40%)

Establishments physical characteristics potentially related to safe food handling practices such as hand sinks availability revealed the majority of establishments had hand washing sinks in the restroom (96%)

Results(Cont.)

Also a majority of establishments had hand washing sinks available in the work areas (94%). Hands free operated hand washing sinks were rare, found in only 4% of employee restrooms and 3% of work areas

Conclusions

The environmental assessment in a foodborne outbreak investigation is critical to understanding contributing factors and potential antecedents to foodborne illness, yet information regarding potential antecedents is rarely captured.

While current foodborne outbreak surveillance data may identify working while ill or poor handwashing practices as factors contributing to outbreaks information on why these circumstances may have existed is not collected or reported.

Conclusions(Cont.)

A systematic collection, analysis, interpretation, and dissemination of environmental data from foodborne disease outbreak investigations can support the overall foodborne disease surveillance system in a country, strengthening the ability of food control authorities at all levels of government to formulate food safety action and assess the effectiveness of these actions.

Vince Radke

vradke@cdc.gov

www.cdc.gov

For more information please contact Centers for Disease Control and Prevention1600 Clifton Road NE, Atlanta, GA 30333Telephone, 1-800-CDC-INFO (232-4636)/TTY: 1-888-232-6348E-mail: cdcinfo@cdc.gov Web: www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

Thank you

Questions

National Center for Environmental Health

Environmental Health Services Branch