Browsing by Author "Oliveira, Jorge C"
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- A critical survey of predictive mathematical models for migration from packagingPublication . Poças, Maria F.; Oliveira, Jorge C; Oliveira, Fernanda A. R.; Hogg, TimThe migration of chemicals from food contact materials into foods is an important issue in food safety.The assessment of materials compliance with regulations includes migration monitoring for many monomers and additives. However,it is recognized that predictive mathematical modelling can be used in many cases, to avoid or to reduce the effort on migration experiments. This article reviews the approaches followed to apply mathematical models to migration, particularly the models used, the approaches to estimate model parameters, and the systems used to experimentally validate the models. Conclusions on the issues requiring further research are drawn.
- Modelling temperature variability in batch retorts and its impact on lethality distributionPublication . Varga, Szabolcs; Oliveira, Jorge C; Smout, Chantal; Hendrickx, Mark E.Experimental time±temperature distributions from two di erent industrial scale retort systems were statistically analysed. The retort temperature was modelled as the sum of a trend value and a residual, with the trend temperatures being simple functions of time. The residuals were modelled using time-series. The resulting impact on the lethality distribution was assessed by calculating the F-value distribution in the centre of cans simulated via a conduction-heating ®nite element model for 180 simulated temperature histories. Comparing the distributions obtained with those calculated using the actual experimental temperature histories validated the applicability of this approach. The results indicated that the experimental and the modelled average lethalities were statistically similar at 95% con®dence. The standard deviation was also similar for the F-value up to the end of holding but larger for the modelled distribution when considering the whole cycle, which was attributed to a correlation between the heating and cooling parameters that was not considered in the model.