Interagency Retail Listeria monocytogenes

Risk Assessment

Background, Scope, and Purpose

Janell Kause

Food Safety and Inspection Service

June 23, 2009

What is risk assessment?

• Risk assessment is the scientifically based process of estimating the likelihood (probability) of exposure to a hazard and the resulting pubic health impact from this exposure.

• It is used to facilitate the application of science to policy.

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3

Risk Assessment

• Evaluate data and information

• Estimate exposure and risk

Risk Analysis

Risk Management

• Weigh and select policy options

• Education/Outreach

Risk Communication

• Exchange information

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• Scientific basis for food safety

decisions

integrates data and information

systematically address food safety issues

focus resources to improve food safety

• Predicts public health benefits of

changes in policies, practices, or

interventions

Why use risk assessment?

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• FDA-FSIS Quantitative Risk Assessment for Listeria

monocytogenes in Ready-to-Eat Foods (2003)

• FSIS Listeria Risk Assessment for Deli Meats (2003)

• Risk-based Listeria monocytogenes Verification

(2004)

• FSIS Comparative Risk Assessment for Listeria

monocytogenes in Ready-to-Eat Meat and Poultry

Products (2009)

Past Listeria monocytogenes Risk Assessments

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• 2003 FDA/FSIS Listeria monocytogenes Risk

Assessment• Estimated the relative risks of serious illness and

death associated with the consumption of 23 types of ready-to-eat foods

• Retail-to-table probabilistic risk assessment• Developed through close collaboration between

USDA/FSIS and DHHS/FDA

Which foods pose the greatest risk of listeriosis?

Source: http://www.foodsafety.gov/~dms/lmr2-toc.html

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Predicted Cases of Listeriosis per Serving–Total Population

-16

-15

-14

-13

-12

-11

-10

-9

-8

-7

-6

DM

FN

R P

UM

SS

CR

HF

D

SU

C

PM

FS

C FR

PF

RS F

DF

S

SS

C

SR

C V

DS IC PC

CD

HC

To

tal

Cas

es L

iste

rio

sis

per

Ser

vin

g (

log

sca

le)

Deli meats Frankfurters (not-reheated) Deli salads

Frankfurters (heated)

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Predicted Cases of Listeriosis per Annum–Total Population

-5.00

-4.00

-3.00

-2.00

-1.00

0.00

1.00

2.00

3.00

4.00

To

tal C

ases L

iste

rio

sis

per

An

nu

m (

log

scale

)

DM

PM

HF

D

FN

R

SU

C P

CR

UM

SS F

FR V

DF

S

FS

C

SS

C

SR

C

DS

RS

PF IC PC

CD

HC

Deli meats Frankfurters (not-reheated)

Deli saladsFrankfurters (heated)

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2003 FSIS Listeria risk assessment• Plant-to-table probabilistic risk assessment

Built in a few months by adding a module to the prior Listeria monocytogenes risk assessment developed by FDA and FSIS

• Evaluated the number of illnesses prevented and lives saved annually based on the adoption of various interventions during manufacturing

Conta

min

atio

nE

vent

Time and Duration

Fre

quency

Number of Lspp Organisms

Food ContactSurface

RTE Productbefore post-processing

transfe

rco

efficient

Conce

ntr

atio

nof Lm

Concentration ofListeria Spp

L spp Testing& Sanitation

on FoodContactSurface

Positive? ApplyCorrective action

Listeria Reservoir(niches, harborage sites, drains, …)

ContaminationEvent

transport to retail:EGR, packaging

Distribution atretail for FDA/FSIS model

Post-processingcontrols

RTE Productafter post-processing

RTE producttesting Positive?

Dispose

Source: http://www.fsis.usda.gov/PDF/Lm_Deli_Risk_Assess_Final_2003.pdf

Which processing interventions effectively control Listeria

monocytogenes?

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50

100

150

200

4-2-

18-

4-2

10-1

0-10

16-8

-4

32-1

6-8

40-2

0-10

60-6

0-60

PP-95%

PP-99%

Growth

Inhib

itor (

GI)

PP-95%

& G

I

Scenario

Nu

mb

er o

f an

nu

al li

ves

save

d a

mo

ng

eld

erly

: M

edia

n p

red

icti

on

Sampling Effectiveness Process Control Effectiveness

*Proposed mandatory testing:

4 tests/line/month

2 tests/line/month

1 test/line/month

* Proposed testing for Listeria monocytogenes (66 FR 12589; 2001)post-lethality interventions;

antimicrobial agent/processes

Comparing Listeria monocytogenes Processing

Controls

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Interim Final Rule (9 CFR 430)

Alternative 1: Use of post-lethality treatment AND antimicrobial agent/process (growth inhibitor)

Alternative 2: Use of post-lethality treatment OR antimicrobial agent/process (growth inhibitor)

Alternative 3: Use of sanitation procedures only

Alternative

Sampling PP GI PP&GI

Fra

ctio

n o

f R

TE

Del

i M

eat

Pro

du

ctio

n

0.0

0.2

0.4

0.6

0.8Pre regulationCurrent

Result: Industry Adoption of more Effective Interventions

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Reduction of Listeria monocytogenes in Deli Meats From Manufacturer

Why a plateau in listeriosis?

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• Compare the risk of listeriosis from prepackaged vs. retail-sliced deli meat

• Analysis using 2003 FDA/FSIS Listeria monocytogenes Risk Assessment NFPA Data (Gombas, 2003), AMI consumer behavior data (2003) NAFSS Data (Draughon, 2006), RTI consumer behavior data (2006)

FSIS Comparative Listeria monocytogenes Risk Assessment (2009)

Source: http://www.fsis.usda.gov/PDF/Comparative_RA_Lm_Report.pdf

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• Statistical difference in prevalence by slicing source– Prepackaged prevalence: 0.2%– Retail-sliced prevalence: 1.4%

• Retail-sliced product has higher concentrations of Lm than prepackaged product

-3 -2 -1 0 1 2 3

0.98

50.

990

0.99

51.

000

log10(Lm concentration, MPN/g)C

umul

ativ

e F

ract

ion

retail slicedprepackaged

Listeria monocytogenes contamination in prepackaged versus retail-sliced deli meats

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Listeria monocytogenes prevalence in retail-sliced vs. prepackaged deli meat by state

Source: National Food Processors Association (Gombas, 2003); National Alliance for Food Safety and Security (USDA/ARS Funded; Lead: Ann Draughon, 2006)

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Consumer Storage Times

• Consumers tend to use retail-sliced product more quickly than prepackaged.

• This limits the amount of growth of Listeria monocytogenes in retail-sliced product prior to consumption.

0 10 20 30 40 50 60

0.0

00

.02

0.0

40

.06

0.0

80

.10

Storage time (d)

Re

lativ

e F

req

ue

ncy

Retail-slicedPrepackaged

Data: RTI International, www.FoodRisk.org

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Results of the 2009 Comparative Listeria monocytogenes Risk Assessment: Attributable Listeriosis Cases and Deaths

Category  Public HealthImpact

Retail-slicedDeli Meat

Pre-packaged Deli Meat

Total Illnesses/

Deaths

With Growth Inhibitor

Deaths 26.5 10.5 37.1

Illnesses 146 58 205

Without Growth Inhibitor

Deaths 140.3 23.6 163.9

Illnesses 773 130 904

Total

Deaths166.9 34.1 201.0

Illnesses 920 189 1108

Note: Approximately 83% of listeriosis cases and deaths attributed to deli meats are associated with those sliced at retail.

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Why would retail-sliced products be more contaminated than prepackaged ones?

• Major hypothesis: additional contamination– More than one kind of product manipulated at a given

time or place• Meat, Poultry, Vegetables, Seafood, …

– More than one process at a given time and place• Slicing, Cutting, Mixing, …

• Additional consideration: potential growth of Listeria monocytogenes (e.g. storage time and temperature abuse)

Objective

• Ascertain the impact on public health of current practices and potential interventions that reduce or prevent Listeria monocytogenes contamination in ready-to-eat food sliced, prepared and/or packaged in retail facilities

Risk Management Questions

• “What is the exposure to Listeria monocytogenes from consuming ready-to-foods prepared in retail facilities?”

• “What are the key processes that increase ready-to-foods contamination at retails?”

• “How much is the relative risk per serving reduced according to specific risk management options?”

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New: Interagency Retail Listeria monocytogenes Risk Assessment

• Interagency collaboration: USDA/FSIS and DHHS/FDA

• New approach: retail cross-contamination model

• Develop data specifically for the risk assessment model

• Involve scientists from academia: VA Tech, University of Maryland, and Cornell University

• Stakeholder participation early in the process

Thank you