- Reports - Articles - Presentations - Posters -Abstracts

This page shows all results of the CARMA project, that are available in English. Summaries of reports and scientific papers are presented, with links to full text when available. Results of the CARMA project are regularly presented at international meetings. This page also shows these presentations.

	Havelaar AH, CARMA: A multidisciplinary project to inform the risk management of campylobacteriosis, Swedish Seminar on Possibilities fo Campylobacter Risk Management, Stockholm, October 2004
	Havelaar AH, Risk Assessment of Foodborne pathogens,5th World Congress on Foodborne Infections and Intoxications, Berlin, June 5-11, 2004
	Havelaar AH. CARMA: Campylobacter Risk Management and Assessment. 3e Nationaal Congres Voedselveiligheid. Euroforum, 25 september 2002, Rotterdam.
	CARMA approach

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	Nauta M et al.,Risk assessment of Campylobacter in the broiler meat production chain,XVII European Symposium on the Quality of Poultry Meat, XI European Symposium on the Qualtiy of Eggs and Egg Products, Doorwerth, NL, May 22-25, 2005
	Havelaar AH et al., The effect of logistic slaughter and/or germicidal treatment on Campylobacter contamination of broiler meat - a model based approach, 5th World Congress on Foodborne Infections and Intoxications, Berlin, June 5-11, 2004
	Poppe KJ, Bogaardt MJ, Havelaar AH. The economics of Campylobacter: an example of multidisciplinary research in food safety. Presented at: Exploring Diversity in the European Agri-Food System. 10th EAAE congress, Zaragoza Spain, August 28-31, 2002
	Havelaar AH. CARMA: een multidisciplinaire aanpak van campylobacteriose. Symposium 'Veilig Voedsel in de Keten'. Stichting EFFI, Wageningen, 30 mei 2002 (samenvatting van bovengenoemde poster).
	Ritz-Breacud M,Nauta MJ, Teunis PFM, Federighi M, Havelaar AH. Modelling of Campylobacter survival on frozen chicken meat. Presented at: Predictive modelling in foods, Quimper, France, June 15-19, 2003
	CHRO2003: 12th International Workshop on Campylobacter, Helicobacter, & Related Organisms, Aarhus, 6-9 September 2003
	Estimation of the relative importance of Campylobacter transmission routes based on exposure assessment, Eric Evers, Ine van der Fels-Klerx, Arie Havelaar, Maarten Nauta, Jack Schijven
	Statistical modelling of Campylobacter transmission within broiler farms in The Netherlands, Statistical modelling of Campylobacter transmission, Egil Fischer , Wilma Jacobs-Reitsma , Jaap Wagenaar , Arie Havelaar , Mart C.M. De Jong
	CARMA:a multidisciplinary approach to controlling campylobacteriosis, Arie Havelaar, Marc-Jeroen Bogaard, Roger Cooke, Eric Evers, Ine van der Fels-Klerx, Louis Goossens, Wilma Jacobs-Reitsma, Mart de Jong, Marie-Josee Mangen Sido Mylius, Maarten Nauta, Wilfrid van Pelt, Jack Schijven, Henk Stegeman, Jaap Wagenaar, Ardine de Wit, Henk van der Zee
	Campylobacteriosis in the Netherlands, Estimating the cost-of-illness and the disease burden, Mangen, M.-J.J., de Wit. G.A. and Havelaar, A.H.
	CARMA:Modelling cross-contamination of Campylobacter in the consumer phase, Sido Mylius, Maarten Nauta, Arie Havelaar
	A chicken processing model for quantitative microbiological risk assessment of Campylobacter, Maarten Nauta, Ine van der Fels-Klerx, Roger Cooke, Louis Goossens and Arie Havelaar

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	Havelaar AH, Risk Assessment of Foodborne pathogens,5th World Congress on Foodborne Infections and Intoxications, Berlin, June 5-11, 2004

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Havelaar AH (red). Campylobacteriose in Nederland. Risico's en interventiemogelijkheden. Rijksinstituut voor Volksgezondheid en Milieu, Bilthoven, 2002, Rapport nummer 250911001.

Summary:Campylobacteriosis in the Netherlands: risks and intervention possibilities Campylobacter infections pose an important public health problem for the Nether-lands.

Approximately 100,000 cases of gastroenteritis occur annually as well as 60 cases of Guillain-Barré syndrome and several thousands of cases of reactive arthritis. The associated costs are expected to exceed 100 million euro per year. Animals, including farm animals, wild animals and pets, are the most important reservoirs of Campylobacter. Food products and the environment including the residential environment undergo continuous contamination from these reservoirs. The relative importance of different reservoirs and exposure pathways in the epidemiology of human campylobacteriosis is unknown. Many studies have indicated chicken meat to be an important carrier of infection, while other risk factors are the consumption of pork and beef or raw milk, direct contact with animals, foreign travel and contaminated surface water. Drinking water is not an important source of infection in the Netherlands. Improved hygienic measures have led to a reduced prevalence of Campylobacter in broiler flocks. However, in 2000, 35% of all flocks were still contaminated and a sizeable decrease is not expected in the short term. Additional measures at later stages in the food chain are necessary, including canalisation of contaminated flocks (logistic slaughtering), decontamination of poultry meat and consumer education. There is little information on the quality of imported poultry products. Effective prevention of campylobacteriosis in humans will require more knowledge than currently available and research needs are identified. The complex epidemiology of campylobacteriosis and the limited available knowledge make reliable predictions of the expected results of interventions difficult and call for prudence when defining policy objectives. Effective intervention will require a carefully balanced set of measures. A risk assessment model of the contamination chains is recommended to structurally integrate the available knowledge, so that the effects of interventions and the accompanying uncertainty can be quantified. Integration of these models with economic models and policy analyses will provide an optimal basis for risk management decisions.

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Maarten Nauta, Ine van der Fels-Klerx, Arie Havelaar, A Poultry Processing Model for Quantitative Microbiological Risk Assessment,, submitted for publication

A mechanistic poultry processing model for a quantitative microbiological risk assessment (QMRA) of campylobacter is presented, which can also be applied to other QMRA's involving poultry processing. The same basic model is applied in each consecutive stage of industrial processing. It describes the effects of inactivation and removal of the bacteria, and the dynamics of cross-contamination in terms of the transfer of campylobacter from the intestines to the carcass surface or the environment, from the carcass to the environment, and from the environment to the carcass. From the model it can be derived that, in general, the effect of inactivation and removal is dominant for those carcasses with high initial bacterial loads, and cross-contamination is dominant for those with low initial levels. In other QMRA poultry processing models, the input-output relationship between the levels of contamination on the carcasses is usually assumed to be linear on a logarithmic scale. This mechanistic model shows that this may not be realistic. As non-linear behavior may affect the predicted effects of risk mitigations, this finding is relevant for risk management. Good knowledge of the variability of bacterial loads on poultry entering the process is important. The common practice in microbiology to only present geometric means of bacterial counts is insufficient: arithmetic means are more suitable to describe the effect of cross-contamination. The effects of logistic slaughter (scheduled processing) as a risk mitigation strategy are predicted to be small. Some additional complications in applying microbiological data obtained in processing plants are discussed. In a next study the model will be applied in QMRA of campylobacter in the Netherlands.

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Van der Fels-Klerx, H.J., Cooke, R.M., Nauta, M.J., Goossens, L.H.J., Havelaar, A.H., A structured expert judgment study for a model of Cmaplyobacter contamination during broiler chicken processing, submitted.

A structured expert judgement study was organized to obtain input data for a microbial risk assessment model describing the transmission of Campylobacter during broiler chicken processing in the Netherlands. More specially, the expert study was aimed at quantifying the uncertainty on input parameters of this model and focused on the contamination of broiler chicken carcasses with Campylobacter during processing. Following the protocol for structured expert judgement studies, expert assessments were elicited individually by means of subjective probability distribution functions. The Classical model was used to aggregate the individual experts' distributions in order to obtain a single combined distribution per variable. Three different weighting schemes were applied, including equal weighting and performance based weighting with and without optimalization of the combined distributions. The individual experts' weights were based on their performance on the seed variables. Results of the various weighting scheme

s are presented in terms of performance, robustness, and combined distributions of the seed variables and some of the query variables. All three weighting schemes had adequate performance, with the optimized combined distributions significantly outperforming the equal weight and the non-optimized combined distributions. Hence, this weighting scheme, having adequate robustness, was chosen for further processing of the results.

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