|Institution:||University of Birmingham|
|Keywords:||QD Chemistry; TP Chemical technology|
|Full text PDF:||http://etheses.bham.ac.uk/6701/|
Thermal processing is the most widely used and well established preservation method used in the food industry for ensuring food safety and extending the shelf life of food products. Besides from the food product, the package needs also to be decontaminated to achieve the required safety goals. This research is concerned with surface pasteurisation treatments in food packages by the method of inversion, primarily for hot-filled food products. Starch solutions and tomato soup, used as model fluids in the current work, were hot-filled in glass jars, were sealed and then inverted for thirty seconds at a filling temperature of 80 °C for achieving a target process equivalent of 5 min at 70 °C; the inversion step was used as a thermal treatment of the headspace and the lid. The inverted jars showed significantly higher process values for the headspace and the lid with the filling temperature being the most important parameter. The effectiveness of the inversion step during hot-fill treatments was quantified by the use of two monitoring techniques, the traditional temperature sensors and the alternative, enzymic based (Bacillus amyloliquefaciens α-amylase) Time Temperature Integrators (TTIs). TTIs are small devices with kinetics similar to the microorganisms, whose level of degradation is measured at the end of the thermal process. The enzyme activity obtained is integrated and the temperature history can be quantified. TTIs were tested for their reliability and accuracy under isothermal and non-isothermal conditions, and were then used for validating the hot-fill process.