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Risk-based Sampling Perspective from Different EU and Non-EU Member States
Risk Based Sampling | May 2016 1
Jenny Scott: Senior Advisor to the Director of the Office of Food Safety at FDA’s Center for Food Safety and Applied Nutrition.
Akos Jozwiak: Vice-director at the Hungarian National Food Chain Safety Office
Annemarie Pielaat: Senior researcher at the Dutch Institute for Public Health and the Environment (RIVM)
The presenters ● Akos Jozwiak:
– Head of the coordination working group on planning of sampling plans, supervising different sampling programs from soil and plant protection to plant and animal health, feed and food domains.
– Presentation: theoretical background of the planning process at central authority level with practical and organizational examples, problems identified and solutions provided recently.
● Jenny Scott:
– Technical lead of the team that developed the new Preventive Controls for Human Food rule, with a risk-based approach to control of food hazards.
– Presentation: risk-based microbial sampling by industry as part of a food safety system. FDA’s approach to its risk-based sampling including data use. (prepared in conjunction with Dr. Yuhuan Chen (RA at FDA).
● Annemarie Pielaat:
– Project manager for different research projects in food safety RA.
– Presentation: Development of a risk based sampling program for the Netherlands Food and Consumer Product Safety Authority (NVWA)
Risk Based Sampling | May 2016 2
Risk Based Sampling
A public health perspective from The Netherlands
Annemarie Pielaat
Jurgen Chardon, Lucas Wijnands, Ellen Delfgou, Angelina Kuijpers, Aarieke de Jong, Eric Evers
Risk Based Sampling | May 2016
Introduction
● Netherlands Food and Consumer Product Safety Authority (NVWA)
● Monitoring program occurrence microorganisms on food products
● Insight in public health risk caused by foodborne pathogens
Risk Based Sampling | May 2016 4
Optimization of program through risk based sampling
Approach
● Optimization of monitoring foodborne pathogens for public health risk estimates
● Input variables:
– Prevalence, concentration microorganisms
– Consumption figures food products & food handling by consumers
– Disease burden
– Sampling costs
● Definition of Risk based sampling
*DALY: Disability Adjusted Life Year (Havelaar et. al, 2012) is a consistent, quantitative measure to compare the disease burden of different foodborne pathogens
Risk Based Sampling | May 2016 5
Distribute the NVWA sampling capacity over retail products proportional to their contribution to the DALY’s*
Methodology
Risk Based Sampling | May 2016 6
Distribute the NVWA sampling capacity over retail products proportional to their contribution to the DALY’s
Optimizing criterion: (C * D) / B(A) expressed as costs per DALY
A. Exposure assessment Pathogen prevalence and concentration at time of purchase, food preparation and amount consumed
B. Attribution to DALY’s Distribute DALY’s on pathogen-product group over products proportional to exposure
C. Sampling Initial prevalence to assess the number of samples needed for each product
D. Costs Personnel and analysis costs
Case studies
Initial pathogen product combinations of interest to NVWA
● Salmonella on pork meat
● Campylobacter on pork meat and on poultry meat
● Toxoplasma on pork meat
● Shiga toxin-producing Escherichia coli (STEC) O157 on beef
Risk Based Sampling | May 2016 7
Exposure Assessment
● Based on swift QMRA tool with deterministic calculations (Chardon and Evers, 2016)
● Changes in numbers of micro-organisms on food products
Retail Storage Preparation Exposure
Risk Based Sampling | May 2016 8
Chardon and Evers
Risk Based Sampling | May 2016 9
Using fit-for-purpose models from sQMRA • Time / temp dynamics • D/z inactivation models • …
P re - retail processing
F ood product
- Consumption data
- prev/conc pathogens
-reduction due to
smoking/salting/drying/cooking/heating
Consumer storage
- fractions
room/fridge/freezer
- storage times
- growth/inactivation
Cross cont - amination
- CC fractions
- CC transfer rate
Heating - Raw consumed products
- Heating Model
- fraction meat balls / raw / medium / done
- D/z inactivation data
- heating time and temp
Exposure No. contaminated portions at consumption and total no. of micro-organisms ingested (pop.n year-1)
Attribute DALY’s to Exposure
Risk Based Sampling | May 2016 10
Food product Exposure* DALYs
Pork, chops, rib 1.6E+03 6.1E+01
Ham, raw 1.1E-01 4.3E-03
Bacon, smoked 1.9E-02 3.7E-03
Sausage, BBQ 1.8E+02 6.9E+00
… … …
*No. contaminated portions at consumption and total number of micro-organisms ingested (pop.n year-1 )
Sampling
Risk Based Sampling | May 2016 11
● NVWA does not monitor DALYs but prevalences for pathogen-product combinations
Mean pathogen prevalences (%) in the Netherlands in retail 2010-2013.
Pathogen / food animal
combination
Fresh
meat
Meat
product Source
STEC beef&veal 1,31 3,88 A
STEC mutton/lamb 6,69 3,44 A
Salmonella pork 0,97 1,29 A
Campylobacter pork 0,37 0,16B A
Toxoplasma pork 0,90C 0,90C Zomer et al. (2014)
Campylobacter chicken 27,38 11,60 Zomer et al. (2014)
A: data from the NVWA. B: no measurements available, calculated using ratio for chicken
(0,37*11,6/27,38); C: based on serological prevalence in slaughter house.
Sampling ● Link Sampling with
Prevalence
● How many samples are needed to estimate prevalence within defined uncertainty
● Basic principle:
Numbers based on
one positive sample
Number of samples with number of positives
Uncertainty about prevalence estimate slowly
Risk Based Sampling | May 2016 12
PATH.-PRODUCT RETAIL PRODUCT NO PORTIONS DALYs PREVALENCE
Campy-pork Pork, spare rib (SH 786) 2,5E+06 0,0 0,37%
Campy-pork Pork, fricandeau 1,1E+07 0,0 0,37%
Campy-pork Pork, silverside 5,7E+07 0,1 0,37%
Campy-pork "rotterdammertje" 7,5E+05 0,1 0,16%
Campy-pork Salami 2,3E+08 29,7 0,16%
Campy-pork "Worst, met" 5,9E+07 8,1 0,16%
Campy-poultry Chicken n.s. 5,0E+07 15,3 27,38%
Campy-poultry Chicken, wing 2,7E+07 16,2 27,38%
Campy-poultry Chicken, leg 4,6E+07 46,4 27,38%
Salm-pork Dried sausages n.s. 4,8E+07 5,3 1,29%
Salm-pork Cervelaat 2,7E+08 13,2 1,29%
Salm-pork "rotterdammertje" 7,5E+05 0,1 1,29%
STEC-beef Salami 2,3E+08 0,9 3,88%
STEC-beef Roasted meat, cold n.s. 1,3E+07 0,0 3,88%
STEC-beef Filet americain 3,2E+08 12,8 3,88%
Toxopl-pork "Worst, paling" 4,8E+07 0,0 0,90%
Toxopl-pork Dried sausages n.s. 4,8E+07 76,4 0,90%
Toxopl-pork Cervelaat 2,7E+08 185,0 0,90%
Toxopl-pork "Worst, chorizo" 2,0E+07 28,3 0,90%
… … … … …
Exposure
Sampling
Risk Based Sampling | May 2016 13
PATH.-PRODUCT RETAIL PRODUCT NO PORTIONS DALYs PREVALENCE
Campy-pork Pork, spare rib (SH 786) 2,5E+06 0,0 0,37%
Campy-pork Pork, fricandeau 1,1E+07 0,0 0,37%
Campy-pork Pork, silverside 5,7E+07 0,1 0,37%
Campy-pork "rotterdammertje" 7,5E+05 0,1 0,16%
Campy-pork Salami 2,3E+08 29,7 0,16%
Campy-pork "Worst, met" 5,9E+07 8,1 0,16%
Campy-poultry Chicken n.s. 5,0E+07 15,3 27,38%
Campy-poultry Chicken, wing 2,7E+07 16,2 27,38%
Campy-poultry Chicken, leg 4,6E+07 46,4 27,38%
Salm-pork Dried sausages n.s. 4,8E+07 5,3 1,29%
Salm-pork Cervelaat 2,7E+08 13,2 1,29%
Salm-pork "rotterdammertje" 7,5E+05 0,1 1,29%
STEC-beef Salami 2,3E+08 0,9 3,88%
STEC-beef Roasted meat, cold n.s. 1,3E+07 0,0 3,88%
STEC-beef Filet americain 3,2E+08 12,8 3,88%
Toxopl-pork "Worst, paling" 4,8E+07 0,0 0,90%
Toxopl-pork Dried sausages n.s. 4,8E+07 76,4 0,90%
Toxopl-pork Cervelaat 2,7E+08 185,0 0,90%
Toxopl-pork "Worst, chorizo" 2,0E+07 28,3 0,90%
… … … … …
SAMPLES
540
540
540
1250
1250
1250
6
6
6
153
153
153
50
50
50
220
220
220
220
…
k n d
1 1250 0,16%
1 540 0,37%
1 220 0,90%
1 205 0,97%
1 153 1,29%
1 151 1,31%
1 56 3,45%
1 50 3,85%
1 28 6,67%
1 16 11,11%
1 6 25,00%
Costs ● NVWA budget: e.g. €225,000.-
● Catch maximum number of DALYs for minimum budget
● Optimization criterium:
● Sort on Costs per DALY (min max)
Risk Based Sampling | May 2016 14
What is the best sampling strategy from a public health perspective within this budget?
Pathogen/ Product
Source Costs*
Campylobacter
Fresh meat Pork 17,-
Fresh meat Poultry 50,-
Meat product Pork 15,-
Meat product Poultry 30,-
STEC
Fresh meat Beef/Veal 25,-
Meat product Beef/Veal 37,-
Fresh meat Mutton/Lamb 52,-
Meat product Mutton/Lamb 35,-
Salmonella
Fresh meat Pork 20,-
Meat product Pork 21,-
Toxoplasma
Fresh meat Pork 100,-
* € Per sample, incl admin #Samples • Costs DALYs
Results
Top 26
pathogen-product combinations
for sample analysis
maximised for DALYs as measure for
public health risk
Risk Based Sampling | May 2016 15
TOP ID foodnum pathogen/matrix VCP-product DALY's Prevalentie
Aantal
monsters
Totale
kosten
Kosten/
DALY
Cumulatieve
kosten
Cumulatieve
aantal
monsters
1 149 0863 1. Campy-kip Kip filet 579,28 27,38% 6 € 505 8,72E-01 € 505,0 6
2 146 0860 1. Campy-kip Kip poot 46,41 27,38% 6 € 505 1,09E+01 € 1.010,1 12
3 147 0861 1. Campy-kip Kip drumstick 41,69 27,38% 6 € 505 1,21E+01 € 1.515,1 18
4 155 0870 1. Campy-kip Kip braadstuk 39,50 27,38% 6 € 505 1,28E+01 € 2.020,1 24
5 151 0865 1. Campy-kip Kip half 21,56 27,38% 6 € 505 2,34E+01 € 2.525,2 30
6 150 0864 1. Campy-kip Kip heel 17,22 27,38% 6 € 505 2,93E+01 € 3.030,2 36
7 145 0859 1. Campy-kip Kip vleugel 16,25 27,38% 6 € 505 3,11E+01 € 3.535,2 42
8 144 0857 1. Campy-kip Kip n.s. 15,26 27,38% 6 € 505 3,31E+01 € 4.040,3 48
9 148 0862 1. Campy-kip Kip borst met bot 13,34 27,38% 6 € 505 3,79E+01 € 4.545,3 54
10 157 2667 1. Campy-kip Kip reepjes 11,54 27,38% 6 € 505 4,37E+01 € 5.050,3 60
11 156 0871 1. Campy-kip Kip karbonade 8,57 27,38% 6 € 505 5,89E+01 € 5.555,3 66
12 154 0868 1. Campy-kip Kip TV stick 6,48 27,38% 6 € 505 7,79E+01 € 6.060,4 72
13 500 0970 2.Toxopl-varken Salami 374,59 0,90% 220 € 30.283 8,08E+01 € 36.343,4 292
14 497 0966 2.Toxopl-varken Cervelaat 185,02 0,90% 220 € 30.283 1,64E+02 € 66.626,4 512
15 502 0972 2.Toxopl-varken Worst snij 145,08 0,90% 220 € 30.283 2,09E+02 € 96.909,4 732
16 208 0989 2. Salm-varken Ham coburger 28,92 1,29% 153 € 6.209 2,15E+02 € 103.118,6 885
17 265 0970 2. Salm-varken Salami 26,74 1,29% 153 € 6.209 2,32E+02 € 109.327,9 1038
18 377 1012 2. STEC-rund Filet americain 12,78 3,88% 50 € 3.255 2,55E+02 € 112.583,1 1088
19 501 0971 2.Toxopl-varken Worst met 102,26 0,90% 220 € 30.283 2,96E+02 € 142.866,1 1308
20 496 0965 2.Toxopl-varken Worst gedroogd n.s. 76,41 0,90% 220 € 30.283 3,96E+02 € 173.149,1 1528
21 153 0867 1. Campy-kip Kip soep 1,12 27,38% 6 € 505 4,50E+02 € 173.654,2 1534
22 262 0966 2. Salm-varken Cervelaat 13,21 1,29% 153 € 6.209 4,70E+02 € 179.863,4 1687
23 159 0869 2. Campy-kip Kip rollade 1,85 11,60% 16 € 906 4,89E+02 € 180.769,8 1703
24 443 0989 2.Toxopl-varken Ham coburger 55,56 0,90% 220 € 30.283 5,45E+02 € 211.052,8 1923
25 267 0972 2. Salm-varken Worst snij 10,25 1,29% 153 € 6.209 6,06E+02 € 217.262,0 2076
26 266 0971 2. Salm-varken Worst met 7,30 1,29% 153 € 6.209 8,51E+02 € 223.471,3 2229
Product*
*Net number of samples: 1894
*
Trend analysis
● Minimum no. samples in two consecutive sampling events (n1=n2) to identify a significant difference in prevalence (d1 and d2) with certain probability (power of the test)
H0: d1 = d2
Ha: d1 ≠ d2
● Power: P(reject H0 in favour of Ha when Ha is true) depends on:
– Actual difference between d1 and d2
– Significance level, α and
– Number of samples (n)
Risk Based Sampling | May 2016 16
Trend analysis
Risk Based Sampling | May 2016 17
d1
d2
d2
d2
d2
d1
d1 d1
Conclusion
The Netherlands:
● If €225,000.-
● n ~2000 samples over ~20 different meat products
● Top 12: Campylobacter on different poultry products
– Chicken filet no. 1 product
● Not sufficient for trend analysis in two consecutive years
– Power of the test ≤ 55%
● Consistent iterative implementation of risk based sampling plan
– Monitor pathogen prevalence based on public health risk
– Adapt intervention programs based on public health risk
– Trend analysis
Risk Based Sampling | May 2016 18
Discussion
● Extend for other pathogen-product combinations
– Next important DALY
● Update prevalence estimates
– Use of molecular methods for monitoring? (reduce costs)
● Improve exposure assessment parameter estimates
– Pathogen survival on meat (STEC on beef)
Risk Based Sampling | May 2016 19