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Together with a number of water supply companies in the Netherlands I have implemented the approach of Water Safety Plans and supported the performance of evaluations of the Water Safety Plans of these companies. Together with colleagues from KWR Watercycle Research Institute and water supply companies I have edited the Hygiene Code Drinking-Water for Storage, Transport and Distribution (2002) and for Groundwater sources infrastructure (2007). Also, together with colleagues of KWR and water supply companies I have built a quantitative model of the probability of detection of contamination during distribution of drinking-water as well as a quantitative model for the probability of infection of consumers of drinking-water based on the detection of fecal contaminations (also see other Publications).
Currently I develop, together with colleagues from NIZO food research and the food industry, Quantitative Microbial Risk Assessments of food chains, from 'Farm to Fork' (see Publications).
Risk analysis consists of three parts:
- Risk assessment: systematic and objective, scientific evaluation of data.
- Risk management: weighing of policy alternatives, considering risk assessment and other factors and when needed (enforce) control of the risk, including legislation.
- Risk communication: exchange of information between all concerned.
Risk assessment consists of four steps:
In this case the four steps for a risk assessment for the safety of drinking-water or food:
- Identification of the hazard: whar microbial, chemical or fysical contaminant?
- Characterisation and identification of the hazard: what are the effects and specifications of the hazard?
- Exposure assessment: what is the exposure of consumers?
- Risk charachterisation: the conclusion regarding the risk (probability x effect) to public health (when the regulator is performing the risk assessment). A company or association of companies also may perform a risk assessment and in these cases the risk assessment usually is aimed at assessing the probability of non-compliance with legal quality levels and company quality targets.
As soon the risk manager (regulator, manager of company) accepts the level of risk and uncertainty in the risk assessment, the risk assessment is finished. When the level of uncertainty is too high, further research is needed to improve the assessment of the level of uncertain variables. When the level of risk is too high (and uncertainty is acceptable), control measures in production and distribution can be taken. These measures can consist of changing the level as well as the variability of the variables most contributing to the risk. These variables are idenfied in a sensitivity analysis.
In the food industry, Hazard Analysis Critical Control Points (HACCP) has been used for decades to assess the risk of deviating product quality. Since 1998 a comparable system, the so-called Water Safety Plan (WSP), is used by an increasing number of water supply companies, Since 2004 the World Health Organisation has guidelines available and since a manual.
Quantitative risk assessment
It is not always possible to semi-quantitatively assess the probabilities and effects of conditions and incidents in the production and distribution chain with enough certainty. Critical parts of a HACCP and WSP therefore always need to be investigated by quantitative research. Examples are pasteurisation and water treatment efficacy, as well as recontamination, temperatures and conditions in the supply chain. It is possible, increasingly necessary and increasingly customary to describe the events occuring in the production and distribution chain in a quantitative model. By including the variability (of reality) and uncertainty (of knowing reality) in the available knowledge and data in a quantitative model, the variables most contributing to the risk can be identified objectively, using sensitivity analysis. When there is much uncertainty of the values of a variable to which the output of the model is sensitive, extra knowledge and data are required. The advantage of a modeling approach is the objective prioritization for the next research step. The techniques most widely used are Monte Carlo analysis and Fault Tree Analysis (a Boolean form of Monte Carlo analysis, see Process reliability).
An important procedure for assessment of risks for food and drinking-water is Quantitative Microbial Risk Assessment (QMRA).
You can find more information about QMRA in a specific product leaflet.
Publications and presentations
2011
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Van Lieverloo, J.H.M., M. de Roode, M. Fox, M.H. Zwietering and Wells-Bennik, M.H.J. (2011). Multivariate regression model of thermal inactivation of Listeria monocytogenes in liquid food products. Presentation at the 7th International Conference Predictive Modelling of Food Quality and Safety, Dublin, Ireland, 12-15 September 2011.
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Van Lieverloo, J.H.M., Smit, H.J.P. en Welling, M. (2011) Evaluatie Waterveiligheidsplan microbiologie van PWN drinkwaterproductiebedrijf Andijk (PSA) Van het IJsselmeer tot en met de watermeter. Rapport Viaeterna 2011.01, PWN, Velserbroek.
2010 Top of page
- Van Lieverloo, J.H.M., Smit, H.J.P., De Haas, S.A., Wielinga, M. en Hoogenboezem, W. (2010) Evaluatie Waterveiligheidsplan microbiologie van PWN drinkwaterproductiebedrijven Wim Mensink (PSM) en Bergen (PSB) Van infiltratie tot en met de watermeter. Rapport Viaeterna 2010.02, PWN, Velserbroek, 87 p.
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Van Lieverloo, J.H.M., Smit, H.J.P. en Hoogenboezem, W. (2010) Het Waterveiligheidsplan van PWN Waterbedrijf Noord-Holland. Methode voor beoordeling van microbiële risico’s. Rapport Viaeterna 2010.01. PWN, Velserbroek, 27 p.
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Van Lieverloo, J.H.M., Meeuwisse, J., Wagendorp, A., Fox, M.B. and Wells-Bennik, M.H.J. (2009). Estimating undetectably low post-pasteurization recontamination levels of milk with pathogens using surrogate microbial variables. Proceedings 6th International Conference of Predictive Modelling in Foods, Washington, USA, 8-12 September
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Van Lieverloo, J.H.M., Willig, C.P., A., Fox, M.B. and Wells-Bennik, M.H.J. (2009). Estimating the probability of undetected failure of pasteurization process control using Fault Tree Analysis. Proceedings 6th International Conference of Predictive Modelling in Foods, Washington, USA, 8-12 September
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- Wemmenhove, E. Van Lieverloo, J.H.M., Van Valenberg, H.J.F., Zwietering, M.H., Van Hooijdonk, H.C.M. and Wells-Bennik, M.H.J. (2009). Quantification of inhibition of Listeria monocytogenes by organic acids and pH relevant to semi-hard Dutch cheese. Proceedings 6th International Conference of Predictive Modelling in Foods, Washington, USA, 8-12 September (presented by J.H.M. van Lieverloo
- Van Lieverloo, J.H.M., Bakker, P.C.M., Brouwer, H., Boogaard, J.H., Hoogenboezem, W., Smit, H.J.P., Weeteling, K. en Welling, M.A.G. (2009) Evaluatie Waterveiligheidsplan microbiologie van PWN drinkwaterproductielocaties Laarderhoogt en Huizen. Viaeterna 2009.01, PWN, Velserbroek, 48 p.
- Van Lieverloo, J.H.M., Boogaard, J.H., Koning, R., Siebrand, M., Smit, H.J.P., Visser, M., De Vos, E., Welling, M.A.G., Wielinga, M. en Hoogenboezem, W. (2009) Evaluatie Waterveiligheidsplan microbiologie PWN waterwinstation Prinses Juliana. Viaeterna 2009.02, PWN, Velserbroek, 36 p.
- Van Lieverloo, J.H.M., Admiraal, G., Boogaard, J.H., Schaap, P., Siebrand, M., Smit, H.J.P., De Vos, E., De Wit, S., Zwart, J., Wielinga, M. en Hoogenboezem, W. (2009) Evaluatie Waterveiligheidsplan microbiologie PWN productiebedrijf Jan Lagrand (PSHK en PSHV). Viaeterna 2009.03, PWN, Velserbroek, 29 p.
· Van Lieverloo, J.H.M., Wübbels G.H. and Willig C.P. (2008) Quantitative Risk Assessment and Fault Tree Analysis to quantify the balance of reliability, availability and costs of water treatment facilities. IWA – Waternetwork Conference on Industrial Water Treatment Systems, Amsterdam 1-3 October. To be pubished in Journal of Water Supply Research & Technology - AQUA.
· Van Lieverloo, J.H.M., Mesman, G.A.M., Bakker, G.L., Baggelaar, P.K., Hamed, A. and Medema, G.J. (2007). ‘Probability of detecting and quantifying faecal contamination of drinking water by periodically sampling for E. coli; a simulation model study. Water Research 41, 4299-4308.
Link
· Hambsch, B., Böckle, K and Van Lieverloo, J.H.M. (2007) Incidence of faecal contamination in chlorinated and non-chlorinated systems of neighbouring European countries. Journal of Water and Health 5, Supplement 1, 119-130.
Link
· Van Lieverloo, J.H.M. et al. (2007). Evolving from high through low uncertainty risk assessments using kinetic, stochastic and fault tree modelling. Presentation at the 5th International Conference of Predictive Modelling in Foods, Athens, Greece, 16-19 September
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· Van Lieverloo, J.H.M., Blokker, M., Hambsch, B., Loret, J.-F., Soyeux, E. and Medema, G.J. ‘Contamination during distribution’ in Medema, G.J. et al. (2006) ‘Quantifying risks of faecal contamination of drinking water’. (www.microrisk.com)
· Van Lieverloo, J.H.M., Bosklopper, K., Dekker, J., Worm, I. en Kroesbergen, J. (2005). Water Safety Plans. Voorstel voor beleid en implementatie. KWR 05.025 voor DZH, PWN en WLB. Kiwa Water Research, Nieuwegein, 40 p.
· Van Lieverloo, J.H.M., Medema, G.J. and Van der Kooij, D. (2006). ‘Risk Assessment and Risk Management of Faecal Contaminations in Drinking Water Distributed Without a Disinfectant Residual. Presented at the 2nd IWA Leading Edge Technology Conference, June 1-4, 2004, Prague, Czech Republic. Published in JWRST - AQUA.
Link
· Van Lieverloo, J.H.M., Mesman, G.A.M., Baggelaar, P.K., Hamed, A. en Bakker, G.L. (2004). ‘Detectiekans van fecale verontreinigingen in drinkwaterdistributiesystemen’. BTO 2004.063. Kiwa Water Research, Nieuwegein, 49 p.
· Van Lieverloo, J.H.M., Hoogenboezem, W., Karels, T., De Rijck, Y., Wesselius, P. en Kroesbergen, J. (2004), ‘Waterveiligheidsplan microbiologie drinkwaterproductiebedrijven Wim Mensink en Jan Lagrand. Van voorbehandeld oppervlaktewater tot en met de watermeters’. KWR 04.008 voor PWN. Kiwa Water Research, Nieuwegein, 50 p.
· Van Lieverloo, J.H.M., Boogaard, J., Hoogenboezem, W., Hoekman, H., Karels, T., Lampe, M., De Rijck, Y. en Welling, M. (2004), ‘Waterveiligheidsplan microbiologie drinkwaterproductiebedrijven Andijk en Bergen. Winning, behandeling en distributie’. KWR 04.036 voor PWN. Kiwa Water Research, Nieuwegein, 54 p.
· Wübbels, G.H., Bruins, J.H. en Van Lieverloo, J.H.M. (2004). ’Waterveiligheidsplan drinkwaterproductiebedrijf De Punt. Inventarisatie en beheersing van risico’s bij de productie en opslag van drinkwater’. Waterlaboratorium Noord, Glimmen, 41 p.
· Van Lieverloo, J.H.M., Mesman, G.A.M., Nobel, P.J. en Kroesbergen, J. (2003). ‘Hygiëne tijdens het werk. Hoofdpunten uit de Hygiënecode Drinkwater. Opslag, transport en distributie’. BTO 2003.027. Kiwa Water Research, Nieuwegein, 29 p.
· Van Lieverloo, H.; Mesman, G., Nobel, P., Kroesbergen, J. (2003) Hygiënecode Drinkwater. H2O 36 (19):5.
· Medema G.J. en Van Lieverloo, H. (2003) Waterveiligheidsplannen speerpunt van WHO voor bescherming van drinkwater. H2O 36 (19):6-7.
· Van Lieverloo, J.H.M., Kroesbergen, J., Bakker, G.L. en Hoogenboezem, W. (2003). ‘Systematische beheersing van microbiologische risico’s’. H2O 36 (19), p. 30-33.
· Van Lieverloo, J.H.M., Esveld-Amanatidou, E., Hijnen, W.A.M. en Groennou, J.Th. (2003). ‘Microbiologische verontreiniging van drinkwater tijdens opslag, transport en distributie. BTO 2002.130(c). Kiwa Water Research, Nieuwegein, 191 p.
· Van Lieverloo, J.H.M., Van der Kooij, D. and Hoogenboezem, W. (2002). ‘Invertebrates and Protozoa (Free-living) in Drinking Water Distribution Systems’. In: Bitton, G. (ed.). ‘Encyclopedia of Environmental Microbiology’. John Wiley & Sons, New York, pp. 1718-1733.
· Van Lieverloo, J.H.M., Kroesbergen, J., Hoogenboezem, W., Nobel, P.J., Willemsen-Zwaagstra, J., Nijman, M. en Hoeijmakers, R. (2001). ‘Inventarisatie en beheersing van microbiologische besmettingsrisico’s in drinkwaterproductiebedrijven en – voorzieningsgebieden in ’t Gooi’. KOA 2001.062 voor PWN. Kiwa Water Research, Nieuwegein, 56 p.
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