Experimental Evaluation of a New Thermal Process for Microorganisms Inactivation

A new thermal process for the inactivation of microorganisms in beverages has been studied and is presented in this paper. The treatment, not yet studied in the scientific literature, mainly consists of a thermal shock characterized by temperature increases up to 30°C/s, with final temperatures up to 65°C. This study presents the first experimental results obtained by the application of the new thermal treatment, with different combinations of the process parameters (rate of temperature rise, final temperature and holding time), on separate suspensions of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Listeria innocua and Candida albicans. The required rapid temperature increase has been performed by means of a properly designed test bench. The treatment proved to be effective against all the microorganisms tested, obtaining a load reduction greater than 5 Log units. Compared with the commonly employed thermal treatments for microorganisms inactivation, this new process is characterized by a very interesting combination of a short duration (few seconds) and a low final temperature, which makes it particularly attractive for the application in the beverage industry.