Factors affecting microbial inactivation by Pulsed Light in a continuous flow-through unit for liquid products treatment

Abstract

Pulsed light (PL) could be an effective alternative technology to traditional thermal treatment in order to assure the microbial quality and safety of liquid food products. However, there is no published research about the factors affecting microbial inactivation in a continuous flow-through unit, which must be elucidated in order to successfully apply this novel technology for liquid products treatment at industrial level. The aim of this work was therefore to evaluate the impact of several PL process parameters on microbial inactivation in flow-through treated liquid systems. Reduction in L. innocua culturability increased with the number of light pulses and with the total fluence. Independently of treatment conditions, total fluences of 10 J/cm(2) induced more than 5 Log reductions in L. innocua culturability whereas no important rise in water temperature (< 7 degrees C) was detected. For treatments of identical applied total fluences, L. innocua inactivation was higher at lower liquid thickness (2.15 mm) and faster flow-rate (5 L/min). The level of inactivation was also affected by the voltage input since a higher microbial inactivation was observed in treatments performed at 1000 V than at 3000 V. The results of this study demonstrate the high potential of PL for microbial inactivation in flow-through treated liquid systems. (c) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of 11th International Congress on Engineering and Food (ICEF 11) Executive Committee.