title: Development of predictive modelling approaches for surface temperature and associated microbiological inactivation during hot dry air decontamination.
abstract: This research deals with the development of predictive modelling approaches in the field of heat transfer and microbial inactivation. Upon making some backstage microbiological considerations, surface temperature predictions during hot dry air decontaminations are incorporated in a microbial inactivation model, in order to describe inactivation kinetics under realistic (time-varying) temperature conditions. In the present study, the following parts are presented. (i) First, a one-dimensional heat transfer model is developed taking into account exchanges by convection, radiation and evaporation. The model is subsequently validated on a laboratory setup and on a test rig, assuming no water activity changes. This test rig is developed for studying-at a later stage-surface pasteurisation treatment on food products with the use of hot dry air. (ii) Isothermal inactivation data of Escherichia coli K12 MG1655 have been collected and inactivation parameters are accurately estimated by using a primary and a secondary model in a global modelling approach. (iii) Microbiological considerations such as microbial growth effects during come-up times, initial temperature of inactivation, and heat resistance effects, based on experimental observations and on literature studies, are formulated in order to evaluate possible microbial effects arising under the dynamic temperature conditions modelled in step (i). (iv) Microbial inactivation simulations with the incorporation of surface temperature predictions are presented. (v) Finally, the level of the microbial decontamination in an example based on the design of an industrial installation is presented, outlining the importance of the combination of surface temperature and microbial inactivation modelling approaches.
authors.affiliation: BioTeC-Bioprocess Technology and Control, Department of Chemical Engineering, Katholieke Universiteit Leuven, W. de Croylaan 46, B-3001 Leuven, Belgium.
authors.forename: V P
authors.initials: VP
authors.lastname: Valdramidis
authors.forename: N
authors.initials: N
authors.lastname: Belaubre
authors.forename: R
authors.initials: R
authors.lastname: Zuniga
authors.forename: A M
authors.initials: AM
authors.lastname: Foster
authors.forename: M
authors.initials: M
authors.lastname: Havet
authors.forename: A H
authors.initials: AH
authors.lastname: Geeraerd
authors.forename: M J
authors.initials: MJ
authors.lastname: Swain
authors.forename: K
authors.initials: K
authors.lastname: Bernaerts
authors.forename: J F
authors.initials: JF
authors.lastname: Van Impe
authors.forename: A
authors.initials: A
authors.lastname: Kondjoyan
mesh_terms: D004926:Escherichia coli / Q000254:growth & development*; D005506:Food Contamination / Q000032:analysis* / Q000517:prevention & control; D005516:Food Microbiology; D007700:Kinetics; D008954:Models, Biological; D008962:Models, Theoretical; D011237:Predictive Value of Tests; D013696:Temperature