Mathematics and Computers in Simulation 65 (2004) 231–243 Sensitivity analysis of microbial growth parameter distributions with respect to data quality and quantity by using Monte Carlo analysis F. Poschet a , K. Bernaerts a , A.H. Geeraerd a , N. Scheerlinck b , B.M. Nicola¨ ı b , J.F. Van Impe a,∗ a Bioprocess Technology and Control (BioTeC), Department of Chemical Engineering, Katholieke Universiteit Leuven, W. de Croylaan 46, B-3001 Leuven, Belgium b Laboratory for Postharvest Technology, Department of Agro-Engineering and -Economics, Katholieke Universiteit Leuven, W. de Croylaan 42, B-3001 Leuven, Belgium Received 28 August 2003; received in revised form 25 November 2003; accepted 12 December 2003 Abstract Nowadays, most of the mathematical models used in predictive microbiology are deterministic, i.e. their model output is only one single value for the microbial load at a certain time instant. For more advanced exploita- tion of predictive microbiology in the context of hazard analysis and critical control points (HACCP) and risk analysis studies, stochastic models should be developed. Such models predict a probability mass function for the microbial load at a certain time instant. An excellent method to deal with stochastic variables is Monte Carlo analysis. In this research, the sensitivity of microbial growth model parameter distributions with respect to data quality and quantity is investigated using Monte Carlo analysis. The proposed approach is illustrated with experimental growth data. There appears to be a linear relation between data quality (expressed by means of the standard deviation of the normal distribution assumed on experimental data) and model parameter un- certainty (expressed by means of the standard deviation of the model parameter distribution). The quantity of data (expressed by means of the number of experimental data points) as well as the positioning of these data in time have a substantial influence on model parameter uncertainty. This has implications for optimal experiment design. © 2004 IMACS. Published by Elsevier B.V. All rights reserved. Keywords: Monte Carlo analysis; Non-linear predictive growth model; Parameter uncertainty; Data quality; Data quantity ∗ Corresponding author. Tel.: +32-16-32-14-66; fax: +32-16-32-29-91. E-mail address: jan.vanimpe@cit.kuleuven.ac.be (J.F. Van Impe). 0378-4754/$30.00 © 2004 IMACS. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.matcom.2003.12.002