Campylobacter and Salmonella in poultry based meat ... · Workshop FAVV “Risk assessment in the...

Opportunities and limitations of Quantitative Risk Assessment: Campylobacter and Salmonella in poultry based meat preparations / eggs

Mieke Uyttendaele1 & Koen Grijspeerdt21Laboratory of Food Microbiology and Food Preservation, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium2Department of Animal Product Quality, Agricultural Research Centre, Ministry of the Flemish Community, Melle, Belgium

Workshop FAVV “Risk assessment in the food chain” 20/10/2006

FOOD2KNOWInterfacultary Centre of Excellence for

Food science, nutrition and health

www.food2know.be

• groups 35 laboratories and research units

• supported by some 540 researchers and technicians

• distributed over 5 faculties of the Ghent University


Contents

Microbiological Risk Assessment as a tool for food safety/ FSO /PO

Ex. QRA for Campylobacter in poultry based meat preparations

Ex. QRA for Salmonella in eggs

Opportunities/limitations of QRA


On the demand of the competent national authorities/ initiative (inter)national organisations:Quantitative risk assessments:

For specific microbiological hazard in the food supply to estimate the impact of aparticular hazard on public health

With the intention outputs will be used in the development of food safety measures at the (inter)national level

Microbiological Risk Assessment as a tool for food safety


Microbiological Risk Assessments (FAO/WHO JEMRA)Risk assesments- Salmonella spp. in broilers/eggs- Listeria monocytogenes in ready-to-eat foods. - Vibrio parahaemolyticus in oysters and fish, Vibriovulnificus in oysters, Vibrio cholerae in shrimp- Campylobacter jejuni in poultry. - Enterobacter sakazakii in powdered food formulae

MRA can be developed on many levels of detail, depending upon the complexity of the issue, the urgency for obtaining the risk estimate and the data available


FAO/WHO, Kiel, 2002

Food safety issue identification

Risk profile

Interim food safety assessment

Limited assessment


FAO/WHO, Kiel, 2002

Limited assessment

Conduct MRA


Food Safety objective (FSO)Performance objective (PO)FSO - The maximum frequency and/or concentration of a hazard in a food at the time of consumption that provides or contributes to the ALOP (CAC 2004)e.g. L. monocytogenes in RTE food shall not exceed 3.5 log CFU/serving size of food when eaten

PO – the maximum frequency and/or concentration of a hazard in a food at a specified step in the food chain before the time of consumption that provides/ contributes to an FSO or ALOP (CAC 2004)e.g. Salmonellae and EHEC shall not exceed 1 CFU/10 l when fruit juice is packaged for distribution

Max

imum

ac

cept

able

leve

l


Microbiological Risk Assessment vs Food Safety Management systems

Gorris, Food control 2005


to support the development of risk-based microbiological criteria in Belgium

Report of the Belgian Health Council (N°7947 in 2005) on the demand of Federal Public Service Health, Food Chain Safety and Environment Taking into account data of Campylobacter spp. in poultry based meat preparations from the FAVV Surveillance testing program

Quantitative risk assessment of Campylobacter spp. in poultry based meat preparations as one of the factors to support the development of risk-based microbiological criteria in Belgium(Uyttendaele et al. 2006 Int. J. Food Microbiology 111,149-163)

QRA for Campylobacter in poultry based meat preparations


Limited food safety assessments: = readily accessible information, realistic scenarios, modules from previously constructed MRA

retail to table approach

To analyse, in a relative manner, the reduction of the risk of campylobacteriosis associated with a decrease in the Campylobacter contamination level by definition of various “maximum acceptable level” for these types of food products (poultry based meat preparations) relating to the current situation

QRA for Campylobacter in poultry based meat preparations

RetailNatural logarithm of concentration of Campylobacter in raw chicken meat

products (Crcmp)

Consumer handling

Undercooking

Prevalence of undercooking (Pu)Proportion of cells in protected area

(Propprot)

Cross contamination

Prevalence of cross contamination (Pcross)

Log10 of the proportion of transferred cells from meat to surface and from

surface to meat (Ptms & Ptsm)Number of cells in outside layer (No)

Consumption

Infection and illnessDose response or Infective dose (Ninf)

Probability of illness given infection (Pill I i)

Number of Campylobacter in a raw chicken meat product of

100g (Nrcmp)

Prevalence of Campylobacter in raw chicken meat products (Prcmp)

Number of Campylobacter in a cooked chicken meat product

due to undercooking (Ncu)

Number of Campylobacter in a cooked chicken meat product due to

cross contamination (Ncc)

Probability of Campylobacter in a cooked chicken meat product

due to undercooking (Pcu)

Probability of Campylobacter in a cooked chicken meat product

due to cross contamination (Pcc)

Number of Campylobacter that are consumed (Ncons)

Probability of exposure to Campylobacter (Pcons)

Probability of infection (PI) or ratio of ingested dose and infective dose (RI)

Probability of ilness (Pill) or ratio of ingested dose and infective dose, when illness can ocur (Rill)

Prevalence (% contaminated)

Number of Campylobacter

Transport and preservation at retail & home (time/temperature)

Preparation(cross contamination)Heat treatment(undercooking)

Consumption

Dose – Response

Probability of illness


QRA for Campylobacter in poultry based meat preparations: input distribution

Lack of quantitative data (enumeration) !

< 1 cfu/25g67%

1-2500 cfu/25g24%

> 2500 cfu/25g9%

0

0 ,2

0 ,4

0 ,6

0 ,8

1

-30 -20 -10 0 10 20

C rc mp ( ln C F U / g )

Scenario analysis based on the current situation but limiting (<1%) Campylobacter positive samples at > 1000/g

at > 100/g at > 10/g ......


Different outputs:exposure, probability of infection and probability of illness using different formats to define the dose-response).

Limited data on infective dose Campylobacter !

QRA for Campylobacter in poultry based meat preparations: dose response

06.75E-07 (sit 1:3525)1.63E-03 (sit 1:1.2x1010)7 (<1% with > 1/10g)

06.33E-06 (sit 1:376)1.23E-02 (sit 1:1.6x109)6 (<1% with > 1/g)

05.50E-05 (sit 1:43)3.26E-01 (sit 1:6.2x107)5 (<1% with > 10/g)

0.0003 (sit 1 : 118)2.42E-04 (sit 1:10)1.98E+01 (sit 1:1.0x106)4 (<1% with > 100/g)

0.0016 (sit 1:22)6.72E-04 (sit 1:4)1.77E+03 (sit 1:11390)3 (<1% with > 1000/g)

0.0089 (sit 1:4)1.38E-03 (sit 1:2)1.83E+05 (sit 1:110)2 (<1% with > 10000/g)

1.0155 (sit 1 x 29)4.98E-02 (sit 1x21)1.45E+10 (sit 1x718)**1* (raw)

0.03532.38E-032.02E+07 1*

MeanMean

Approach 3 (% infected)Approach 2 (Probability of infection)

Exposure (cfu per 100g serving)

Situation


Reduction of the Campylobacter contamination level- Eliminate samples with >100/g (<1%)- Restrict samples >10/g (max. 2%)

Decrease probability of infection: 10xRaw consumption

Increase probability of infection: 20 x

Verification risk estimate of current situation: need epidemiological data !

Lack of extended supporting data: the uncertainty of the outcome may be high !

QRA for Campylobacter in poultry based meat preparations: output


QRA for Campylobacter in poultry based meat preparations: scientific needs- (semi-)quantitative data for pathogen in food under consideration- data related to consumer habits, concerning food handling procedures/consumption patterns - prevalence of undercooking, prevalence of cross-contamination- effect of packaging and exact survival of Campylobacter during storage

Limited data sets, surrogate data, assumptions, simplifications increase the uncertainty of the outcome of the QRA


QRA for Salmonella in eggsTo identify effective strategic interventions

- QRA of salmonellosis due to the consumption of shell eggs contaminated with S. Enteritidis in Belgium- Risk model based based on WHO/FAO risk assessment of Salmonella in eggs (2002)(= based on FSIS/USDA (1998) and Health Canada models (2000, unpublished)- exposure assessment adapted to the Belgian situation

Egg Defence QLK5-CT-2001-01606 (2001-2004) ‘Improving Quality and Safety of Hen Eggs in New Production System by Reinforcing the Antimicrobial Natural Defence and by Developing Tools for Grading Eggs’


QRA for Salmonella in eggs: Model structure

Distribution and storage

Preparation and consumptionProduction

Egg products processing

Farm to table approach: number of flocks, flock prevalence, storage in packing station, transport, consumers behaviour, etc.


QRA for Salmonella in eggs: Distribution and storage module

Initial egg temperature (°C)

k – Temperature

k – Temperature

k – Temperature

k – Temperature

k – Temperature

Storage before Transportation

Transportation

Storage before processing

Time

Time

Time

Initial contamination in albumen, small fraction in yolk (3 % on average)

Processing

Transportation to retail/institutions

Time

Time

Inactivation only considered in preparation phase

Storage after processing

Time

k – Temperature

Initial Salmonellacontamination Probability of yolk contamination

Bacterial growth is modelled with a modifiedBaranyi-model

Lag phase is imposed by the membrane breakdown time

Number of Salmonella in egg after processing


QRA for Salmonella in eggs: Some inputs

Messens et al.(2002)Time-temperature institutions

Grijspeerdt et al.(1999)Time-temperature homes

50%Percent eggs to shell egg processor

25%Prevalence of infected flocks

365 Days in Lay

0.72 Eggs/day

24332Average hens/flock

460 Number of flocks


Rel

ativ

e fre

quen

cy

Annual cases

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

Mean=18925.58

0 25000 50000 75000 100000

274274

0 25000 50000 75000 100000

90% 5% > 274 70812

Mean=18925.58

QRA for Salmonella in eggs: Baseline results


QRA for Salmonella in eggs: Baseline results

216881077865650Reactive arthritis

350118390Death

330114591850Hospitalization

3848131868079960Physician visit

677882423197186177700Recovery with no medical care

721222583399768189261Cases

10115924138434167302597811Servings

2756931156124801707099029Positive eggs

95th percentile5th percentileMaximumMeanMinimumOutput

Considerable uncertainties with model input/structureoutput distributions can be very wide


QRA for Salmonella in eggs: Sensitivity analysis

Annual salmonellosis cases

10000 20000 30000 40000 50000

Tmin

(squa

re roo

t mod

el)

Initia

l num

ber o

f bac

teria

b (sq

uare

root m

odel)

Prevale

nce

Time

Yolk m

embra

ne br

eakd

own t

imeTe

mperat

ure

Systematically varying inputs (e.g. base value ± 25%) to have an indication of the most influential inputs


QRA for Salmonella in eggs: Mitigation strategiesLimit temperature to 6°C

751192234Cases from institutions

6685923215961Cases from homes

7189425318307Cases

Institutions



4694514911556Cases

Consumer



5000914511693Cases

Retail



21136525810Cases

Whole chain

95th percentile5th percentileMean

69%

39%

39%

3%


Opportunities/Limitations of risk assessment• Risk assessment is a valuable tool to identify effective strategic interventions to reduce the number of human Salmonella/Campylobacter cases

o often scenario analysis / equivalence of alternative technologieso verification risk estimate: difficult task!

• Define research and data collections needso set priorities for data collection and format/quality of datao concept of QRA / impact of assumptions / uncertainty

• a tool to decide on control measureso “any action and activity that can be used to prevent or eliminate a food safety hazard or to reduce it to an acceptable level” e.g. microbiological criteria


FSO versus Microbiological criteria

Food Control special issue 16 (9), 2005

Sampling plan ~ confidence level

Method ~ degree of uncertainty


Opportunities/Limitations of risk assessment• Need of open and objective communicationbetween risk assessors and risk managers

o QRA should have clear purpose and scopeo Point out uncertainty of outcome and implicationso Communicate the right information in the right format, including an interpretation of mathematical resultso Communication of scientific basis to all interested parties

• Planning and resources allocation is essential:o Lack of good quality data for undertaking QRA o Create modular components, can be adapted by individual countries with different data inputs international context!


Acknowledgements

Multidisciplinary teamM. Uyttendaele, K. Baert, Y. Ghafir, G. Daube, L. De Zutter, L. Herman, K. Dierick , D. Pierard, JJ. Dubois, B. Horion, J. Debevere, F. Devlieghere, K.Grijspeerdt, W. Messens, M. Heyndrickx,...

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