An EU-funded research project is underway to develop more accurate models of microbial reductions during surface pasteurisation of foods, which specifically looks at High Temperature Short Time processing (HTST).
The first year of the study, conducted by the UK-based Food Refrigeration and Process Engineering Research Centre has now been completed and has revealed a number of interesting results.
Currently food poisoning by pathogens is still increasing throughout Europe in defiance of general improved hygiene and food control. Over 60 per cent of outbreaks are associated with meat, fresh fruit, and salad vegetables. Contaminating pathogens are mostly located on the surface of foods. Thus, controlling surface pasteurisation is a very important issue and one which the study has been particularly focused on.
The overall objective of the study is to improve food safety by better control in thermal processing, in particular using HTST processing, heating and cooling cycles, but also in slow thermal processing. The study team says that its objective will be reached by the establishment of more accurate models of microbial death in response to the processing.
Major project results obtained after the first year have included the establishment of accurate testing apparatus, the introduction of a "lux-gene" into the test and the creation of heat transfer models.
The team has constructed what it claims is accurate and very flexible apparatus which may heat or cool the food between 5 and 120°C in both wet and dry environments. The temperature cycles are repeatable within more or less 2°C and the accuracy of measuring food surface temperatures is better than 1°C.
The introduction of a "lux-gene" into the test pathogens allows these to glow (bioluminescence) only when alive. Therefore the scientists can quickly measure the effect of thermal cycles as the bioluminescence fades when the treatment is effective.
Meanwhile the creation of heat transfer and microbial death models will be verified against data obtained from the apparatus developed within the project and combined to create a model to predict the effect of temperature changes on the food surfaces to microbial death.
For more information on the project please contact the study group by clicking here.