Food processes, bio-processes and bio-systems are coupled systems that may involve heat, mass and momentum transfer together with kinetic processes. This work illustrates, with a number of examples, how model-based techniquesi.e. simulation, optimization and control-offer the possibility to improve our knowledge about the system at hand and facilitate process design and optimisation even in real time. The contribution is mainly based on the authors experience and illustrates concepts with several examples such as biofilm formation, gluconic acid production, deep-fat frying of potato chips and the thermal processing of packaged foods.

Numerical models based on the two‐dimensional shallow water equations (2D‐SWE) are routinely used in flood risk management and inundation studies. However, most of these models do not adequately account for vertically confined flow conditions that can appear during inundations, due to the presence of hydraulic structures such as bridges, culverts, or underground river reaches. In this article we propose a new mathematical modification of the standard 2D‐SWE, inspired by the two‐component pressure approach for 1D flows, to address the issue of transient vertically confined flows including transitions between free surface and pressurized conditions. A finite volume discretization to solve the proposed system of equations is proposed and analyzed. Various test cases are used to show the numerical stability and accuracy of the discretization, and to validate the proposed formulation. Results show that the proposed method is numerically stable, accurate, mass conservative, and preserves the C‐property. It can also handle subcritical, supercritical, and transcritical flows under free surface or vertically confined conditions.

Listeria monocytogenes is a food-borne pathogen that can persist in food processing plants by forming biofilms on abiotic surfaces. The benefits that bacteria can gain from living in a biofilm, i.e., protection from environmental factors and tolerance to biocides, have been linked to the biofilm structure. Different L. monocytogenes strains build biofilms with diverse structures, and the underlying mechanisms for that diversity are not yet fully known. This work combines quantitative image analysis, cell counts, nutrient uptake data and mathematical modeling to provide a mechanistic insight into the dynamics of the structure of biofilms formed by L. monocytogenes L1A1 (serotype 1/2a) strain. Confocal laser scanning microscopy (CLSM) and quantitative image analysis were used to characterize the structure of L1A1 biofilms throughout time. L1A1 forms flat, thick structures; damaged or dead cells start appearing early in deep layers of the biofilm and rapidly and massively loss biomass after 4 days. We proposed several reaction-diffusion models to explain the system dynamics. Model candidates describe biomass and nutrients evolution including mechanisms of growth and cell spreading, nutrients diffusion and uptake and biofilm decay. Data fitting was used to estimate unknown model parameters and to choose the most appropriate candidate model. Remarkably, standard reaction-diffusion models could not describe the biofilm dynamics. The selected model reveals that biofilm aging and glucose impaired uptake play a critical role in L1A1 L. monocytogenes biofilm life cycle.

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Two-dimensional (2D) hydraulic models solve the Shallow Water Equations (SWE) for the simulation of free surface flows. The necessity of considering in the calculations specific hydraulic structures, such as bridges, gates, weirs, culverts, etc., for representing more realistic flood scenarios, imply the integration in the 2D-SWE of empirical equations that represent the flow through these structures. These empirical equations are usually implemented as internal conditions over a 1D line, modifying the equations with which the flow is calculated in the edges of the mesh elements located at both sides of the line. This approach can be good enough for representing the hydraulic behavior in general. However, this 1D condition over a line, which only affects the element edges, is not a good approximation for simulating the hydrodynamics of pressurized flows, as it is the case of very wide bridges and lids over channelized rivers. New modelling strategies for simulating pressurized flows using the 2D-SWE, the Two-Component Pressure Approach method (TPA) and the Preissmann Slot Method (PSM), have been implemented in Iber. Both approaches were tested in a coverage of a channeled river characterized by several abrupt curvature changes and a contraction/expansion of their wide, and in a bridge located in a river reach that obstructs most of the floodplain. The TPA and PSM methods presented good numerical approaches for simulating pressurized flow for 2D-SWE-based models, fine-tuning the hydraulic behavior, and representing the most critical regions when a pressurized flow is generated in hydraulic structures.