The need for continuous training in food factories

The dissemination in food factories of the organisms I have referred to earlier, represent significant and interesting issues of public health concern. Yet there seem to be difficulties in incorporating material in education-training-information programmes explaining merely the most simple and basic facts about the risk involved in food being contaminated in food factories. Such educational programmes are essential components in the overall scheme of foodborne disease control, yet they often represent the weakest links in the control chain. There has been a decline in the emphasis on food hygiene in some programmes at the level of institutions of higher education, and a de-emphasis on food hygiene has occurred over the past few decades in schools of veterinary medicine in some parts of the world. This committee has taken active steps to improve this situation by convening a professorial consultation on post-graduate teaching in advanced food microbiology, Copenhagen 1989 (Park, 1990). The public, as well as politicians, focus for the time being on chemical contamination of foods, possible presence of residues, thereby ignoring the fact that statistically it is not the residues that cause deaths which count, but, without a shadow of doubt, the foodborne pathogens. This fact emphasizes the need for intensive training in preventive hygienic measures. Since representatives of the food industry are participating in the Symposium, I would like to balance the problems by saying: we all share a responsibility in securing education in food hygiene in food factories.(ABSTRACT TRUNCATED AT 250 WORDS)     

Thermal modelling of the multi-stage heating system with variable boundary conditions in the wafer based precision glass moulding process

In the precision glass moulding process, the heat transfer and the resulting transient temperature distributions of the molten glass are of great importance because they significantly affect the productivity as well as the thermally induced residual stresses in the final product. Thermal modelling of the heating system in the glass moulding process considering detailed heating mechanisms therefore plays an important part in optimizing the heating system and the subsequent pressing stage in the lens manufacturing process.The current paper deals with three-dimensional transient thermal modelling of the multi-stage heating system in a wafer based glass moulding process. In order to investigate the importance of the radiation from the interior and surface of the glass, a simple finite volume code is developed to model one dimensional radiation–conduction heat transfer in the glass wafer for an extreme case with very high temperature difference considering temperature dependant thermal conductivity and heat capacity. Afterwards, by using three-dimensional FEM modelling along with a predefined experimental test, the equivalent glass–mould interface contact resistance is determined for two different pressures. Finally, the three-dimensional modelling of the multi-stage heating system in the wafer based glass moulding process is simulated with the FEM software ABAQUS for a particular industrial application for mobile phone camera lenses to obtain the temperature distribution in the glass wafer. In the numerical modelling, the interface boundary conditions for each heating stage are changed according to the determining heat transfer mechanism(s). Numerical results are compared with experimental data to show the validity of the numerical modelling. The obtained results show that the right thermal modelling is highly dependent on the proper choice of thermal boundary conditions in different stages according to the real physical phenomena behind the process.     

Inhibition of surface bound carbonate stabilization of tetragonal zirconia

Water is known to initiate a tetragonal to monoclinic phase transformation in zirconia particles. Carbonates on the zirconia surface react with water molecules and hence reduce the transformation rate. This study investigates the possibility of inhibition of the reaction between surface carbonates and water in order to increase the transformation rate in the zirconia crystals. It was found possible to limit the reaction by reacting the surface carbonates with alcohols, a thiol and a primary amide prior to reaction with water. It was also concluded that di- and trialcohols are able to stabilize the tetragonal phase, probably as a result of induced lattice strain.     

A comparison of methods for linear prediction of apple flavour from gas chromatographic measurements

A comparative study of linear methods for prediction of sensory profiles from gas chromatography (GC) measurements was performed. The data used came from an experiment on the effect of storing apples at various oxygen concentrations. Partial least-squares regression and continuum regression showed the best performance, measured by a two-step cross-validation principle. The traditional prediction error sum of squares (PRESS) overestimated the predictive ability of a multiple linear regression approach. The quality of the predictions of sensory properties from GC analyses was measured in terms of a ‘panel size equivalent’. Thus, the predictions obtained in the present study were as accurate as predictions from an assessor panel consisting of 4–9 assessors, depending on the sensory property in question.