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The data supply chain for tracing Salmonella in pork production
International Journal of Food Microbiology 145 (2011) S66–S67
Contents lists available at ScienceDirect
International Journal of Food Microbiology j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i j f o o d m i c r o
Short Communication
The data supply chain for tracing Salmonella in pork production
Biotracing is a concept, linked to risk assessment and to outbreak investigations, that can be considered independently from particular hazards and particular food chains (Matt et al., unpublished results). The generic features of the biotracing concept have been applied for different pathogens and chains within the Biotracer project and this section will present specific developments with respect to Salmonella in the pork chain. Although the incidence of human salmonellosis has decreased in the EU, Salmonella continues to be one of the most important foodborne pathogens. As a recent example, there was an outbreak of S. Typhimurium in Scandinavian countries, where multiple findings of the outbreak strain in pork and pigs led to the identification of various pork products as the source (Bruun et al., 2009). Pig meat as cause for human salmonellosis has been investigated over a nine-year period for the Dutch population. The year by year estimate between 2001 and 2009 varies from 21.5% to 27.5% (Valkenburgh et al., 2007; van Pelt et al., 2009). Data on the occurrence of Salmonella in fresh pig meat at different stages of the pork processing line from 2006 to 2008 indicate that, in general, the proportion of Salmonella positive samples at slaughterhouses ranged from 0% to 23.8% (Anonymous, 2010). Control measures in primary production have decreased human disease incidence (Anonymous, 2010). EU-wide control of Salmonella, however, requires long-term policies and programmes including risk assessment, implementation of control measures, surveillance and monitoring. The European Food and Safety Authority (EFSA) provides scientific advice for the Community's legislation and policies in EU food safety policy. With respect to the control of Salmonella, EFSA initiated: − A continuous baseline survey for Salmonella in slaughter pigs (latest analysis stems from 2009, The EFSA Journal, 2009). − Legislation on Salmonella and food-borne disease which resulted in Regulation (EC) No 2160/2003 of the European Parliament and of The Council on the control of Salmonella and other specified foodborne zoonotic agents (available online: www.efsa.europa.eu). − An opinion of the Scientific Panel on Biological Hazards on risk assessment and mitigation options of Salmonella in pig production (The EFSA Journal, 2006). − An opinion on Quantitative Microbial Risk Assessment (QMRA), which will be published in the near future. This opinion has an appendix on QMRA with respect to Salmonella in pork as a collaboration project between the Veterinary Laboratories Agency (VLA) in the UK, The Dutch governmental institute for public health and the environment (RIVM) and the National Food Institute of the Technical University of Denmark (Food-DTU). − An opinion on Salmonella incidence estimates in the EU, which will also be published in the near future. 0168-1605/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.ijfoodmicro.2010.12.014
In the meantime, Salmonella is still a major cause of foodborne illness in humans. The periodic outbreaks of salmonellosis caused by pork clearly demonstrate the need for improved tracking and tracing of Salmonella spp. in the pork production chain. In addition, control of Salmonella spp. is still a challenge to the pig industry because: − Pigs are an important reservoir of Salmonella spp. − Shedding of Salmonella in pigs is often intermittent. − Salmonella-free pigs may be cross-contaminated or re-infected after transportation to the slaughterhouse or during the slaughter process. − Decontamination of the slaughter equipment is not a trivial process. − Culture-based diagnostic methods, which are currently used for detection, do not provide the rapidity, which is necessary for timely intervention strategies. − The behaviour of Salmonella through the pork production chain is far from understood. Smid et al. (in press) developed a practical framework to contribute to improved tracing methods. This work evolved from specific hypotheses concerned with tracing Salmonella within a slaughterhouse, being: 1. Concentrations change during the day due to cross-contamination and 2. The slaughter equipment can serve as an independent reservoir where Salmonella may persist in small nooks. This type of dynamic model (also referred to as domain model (Matt et al., unpublished results)) can, however, only be used in practice if the parameter values that form the core of the domain model are estimated from biologically relevant data. Minimal requirements for biotracing with respect to a public health risk are: 1. Prevalence, concentration and typing data at relevant steps in the chain 2. Sensitivity, specificity of analytical methods 3. Detection limits This section highlights several developments concerned with improved data collection of Salmonella in the pork chain. It involves several studies dealing with different aspects of the behaviour of Salmonella, i.e. dynamics of Salmonella in the pork supply chain (Pin et al.); methods for improved quantification of cork borer/swab samples taken from pig carcasses (Krämer et al. and Löfström et al.); and developments in micro-array analysis as a diagnostic tool for genomic variation (Grønlund et al. and Aarts et al.). The integration of this type of data with domain
Short Communication
models will form the basis for an operational biotracing system for Salmonella in pork production. References Anonymous, 2006. Risk assessment and mitigation options of Salmonella in pig production. EFSA Journal 341, 1–131. Anonymous, 2009. Analysis of the baseline survey on the prevalence of Salmonella in holdings with breeding pigs in the EU, 2008, Part A: Salmonella prevalence estimates. EFSA Journal 7 (12) (93 pp., doi:10.2903.1377). Anonymous, 2010. The Community Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and food-borne outbreaks in the European Union in 2008. EFSA Journal 2010, 1496. Bruun, T., Sorensen, G., Forshell, L.P., Jensen, T., Nygard, K., Kapperud, G., Lindstedt, B.A., Berglund, T., Wingstrand, A., Petersen, R.F., Müller, L., Kjelso, C., Ivarsson, S., Hjertqvist, M., Löfdahl, S., Ethelberg, S., 2009. An outbreak of Salmonella Typhimurium infections in Denmark, Norway and Sweden, 2008. Eurosurveillance 14 (10) pii=19147. Matt, M., Andersson, G., Barker, G.C., Binter, C., Gomez, N., Maffre, A., Sanaa, M., Smid, J.H., Straver, J., Tenehaus, F., Pielaat, A., (Unpublished results). A general concept for tracing microbiological contaminations in food chains.
S67
Smid, J.H., Swart, A.N., Havelaar, A.H., Pielaat, A., (in press). A practical framework for the construction of a biotracing model: application to Salmonella in the pork slaughter chain. Risk Analysis. Valkenburgh, S., van Oosterom, R., Stenvers, O., Aalten, M., Braks, M., Schimmer, B., van de Giessen, A., van Pelt, W., Langelaar, M.F.M., 2007. Zoonoses and zoonotic agents in humans, food, animals and feed in the Netherlands 2003–2006. RIVM-report no:330152001. ISBN: 978-90-6960-184-7. van Pelt, W., Braks, M.A.H., Schimmer, B., Stenvers, O.F.J., Langelaar, M.F.M., 2009. Staat van zoönosen. 2007-2008. RIVM-report no:330131001/2009.
A. Pielaat RIVM/LZO, Antonie van Leeuwenhoeklaan 9, 3720BA Bilthoven, Netherlands Tel.: +31 30 274 3711. E-mail address: [email protected]
Contents lists available at ScienceDirect
International Journal of Food Microbiology j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i j f o o d m i c r o
Short Communication
The data supply chain for tracing Salmonella in pork production
Biotracing is a concept, linked to risk assessment and to outbreak investigations, that can be considered independently from particular hazards and particular food chains (Matt et al., unpublished results). The generic features of the biotracing concept have been applied for different pathogens and chains within the Biotracer project and this section will present specific developments with respect to Salmonella in the pork chain. Although the incidence of human salmonellosis has decreased in the EU, Salmonella continues to be one of the most important foodborne pathogens. As a recent example, there was an outbreak of S. Typhimurium in Scandinavian countries, where multiple findings of the outbreak strain in pork and pigs led to the identification of various pork products as the source (Bruun et al., 2009). Pig meat as cause for human salmonellosis has been investigated over a nine-year period for the Dutch population. The year by year estimate between 2001 and 2009 varies from 21.5% to 27.5% (Valkenburgh et al., 2007; van Pelt et al., 2009). Data on the occurrence of Salmonella in fresh pig meat at different stages of the pork processing line from 2006 to 2008 indicate that, in general, the proportion of Salmonella positive samples at slaughterhouses ranged from 0% to 23.8% (Anonymous, 2010). Control measures in primary production have decreased human disease incidence (Anonymous, 2010). EU-wide control of Salmonella, however, requires long-term policies and programmes including risk assessment, implementation of control measures, surveillance and monitoring. The European Food and Safety Authority (EFSA) provides scientific advice for the Community's legislation and policies in EU food safety policy. With respect to the control of Salmonella, EFSA initiated: − A continuous baseline survey for Salmonella in slaughter pigs (latest analysis stems from 2009, The EFSA Journal, 2009). − Legislation on Salmonella and food-borne disease which resulted in Regulation (EC) No 2160/2003 of the European Parliament and of The Council on the control of Salmonella and other specified foodborne zoonotic agents (available online: www.efsa.europa.eu). − An opinion of the Scientific Panel on Biological Hazards on risk assessment and mitigation options of Salmonella in pig production (The EFSA Journal, 2006). − An opinion on Quantitative Microbial Risk Assessment (QMRA), which will be published in the near future. This opinion has an appendix on QMRA with respect to Salmonella in pork as a collaboration project between the Veterinary Laboratories Agency (VLA) in the UK, The Dutch governmental institute for public health and the environment (RIVM) and the National Food Institute of the Technical University of Denmark (Food-DTU). − An opinion on Salmonella incidence estimates in the EU, which will also be published in the near future. 0168-1605/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.ijfoodmicro.2010.12.014
In the meantime, Salmonella is still a major cause of foodborne illness in humans. The periodic outbreaks of salmonellosis caused by pork clearly demonstrate the need for improved tracking and tracing of Salmonella spp. in the pork production chain. In addition, control of Salmonella spp. is still a challenge to the pig industry because: − Pigs are an important reservoir of Salmonella spp. − Shedding of Salmonella in pigs is often intermittent. − Salmonella-free pigs may be cross-contaminated or re-infected after transportation to the slaughterhouse or during the slaughter process. − Decontamination of the slaughter equipment is not a trivial process. − Culture-based diagnostic methods, which are currently used for detection, do not provide the rapidity, which is necessary for timely intervention strategies. − The behaviour of Salmonella through the pork production chain is far from understood. Smid et al. (in press) developed a practical framework to contribute to improved tracing methods. This work evolved from specific hypotheses concerned with tracing Salmonella within a slaughterhouse, being: 1. Concentrations change during the day due to cross-contamination and 2. The slaughter equipment can serve as an independent reservoir where Salmonella may persist in small nooks. This type of dynamic model (also referred to as domain model (Matt et al., unpublished results)) can, however, only be used in practice if the parameter values that form the core of the domain model are estimated from biologically relevant data. Minimal requirements for biotracing with respect to a public health risk are: 1. Prevalence, concentration and typing data at relevant steps in the chain 2. Sensitivity, specificity of analytical methods 3. Detection limits This section highlights several developments concerned with improved data collection of Salmonella in the pork chain. It involves several studies dealing with different aspects of the behaviour of Salmonella, i.e. dynamics of Salmonella in the pork supply chain (Pin et al.); methods for improved quantification of cork borer/swab samples taken from pig carcasses (Krämer et al. and Löfström et al.); and developments in micro-array analysis as a diagnostic tool for genomic variation (Grønlund et al. and Aarts et al.). The integration of this type of data with domain
Short Communication
models will form the basis for an operational biotracing system for Salmonella in pork production. References Anonymous, 2006. Risk assessment and mitigation options of Salmonella in pig production. EFSA Journal 341, 1–131. Anonymous, 2009. Analysis of the baseline survey on the prevalence of Salmonella in holdings with breeding pigs in the EU, 2008, Part A: Salmonella prevalence estimates. EFSA Journal 7 (12) (93 pp., doi:10.2903.1377). Anonymous, 2010. The Community Summary Report on Trends and Sources of Zoonoses, Zoonotic Agents and food-borne outbreaks in the European Union in 2008. EFSA Journal 2010, 1496. Bruun, T., Sorensen, G., Forshell, L.P., Jensen, T., Nygard, K., Kapperud, G., Lindstedt, B.A., Berglund, T., Wingstrand, A., Petersen, R.F., Müller, L., Kjelso, C., Ivarsson, S., Hjertqvist, M., Löfdahl, S., Ethelberg, S., 2009. An outbreak of Salmonella Typhimurium infections in Denmark, Norway and Sweden, 2008. Eurosurveillance 14 (10) pii=19147. Matt, M., Andersson, G., Barker, G.C., Binter, C., Gomez, N., Maffre, A., Sanaa, M., Smid, J.H., Straver, J., Tenehaus, F., Pielaat, A., (Unpublished results). A general concept for tracing microbiological contaminations in food chains.
S67
Smid, J.H., Swart, A.N., Havelaar, A.H., Pielaat, A., (in press). A practical framework for the construction of a biotracing model: application to Salmonella in the pork slaughter chain. Risk Analysis. Valkenburgh, S., van Oosterom, R., Stenvers, O., Aalten, M., Braks, M., Schimmer, B., van de Giessen, A., van Pelt, W., Langelaar, M.F.M., 2007. Zoonoses and zoonotic agents in humans, food, animals and feed in the Netherlands 2003–2006. RIVM-report no:330152001. ISBN: 978-90-6960-184-7. van Pelt, W., Braks, M.A.H., Schimmer, B., Stenvers, O.F.J., Langelaar, M.F.M., 2009. Staat van zoönosen. 2007-2008. RIVM-report no:330131001/2009.
A. Pielaat RIVM/LZO, Antonie van Leeuwenhoeklaan 9, 3720BA Bilthoven, Netherlands Tel.: +31 30 274 3711. E-mail address: [email protected]