FACTORS DETERMINING THE EFFICACY OF A PULSED LIGHT TREATMENT

The application of pulsed light (PL) to foods has gained increasing interest, from both the research world and food processing industry, as a potential non-thermal alternative to chemical and thermal methods to decontaminate foods and food contact surfaces, with minimal losses of nutrients and flavour. In PL application, the challenge consists in ensuring that all microorganisms receive the same energy dose. Thus, all factors which can have influence on the distribution and the level of energy dose within the treatment chamber as well as on the surface of solid or within liquid substrate exposed to the light treatment, are critical to the outcome of the process. This chapter aims to provide an overview of all possible parameters that may influence the effectiveness of PL treatment. The role played by the main process and design parameters, product properties and microbial factors and their interactions on the inactivation mechanism and efficacy of PL is critically analyzed and discussed. The temperature increase of the irradiated products, which is one the most limiting factors of PL for practical applications, but also the crucial role that moderate temperature coupled with PL treatment can play on the microbial inactivation are also addressed. Finally, the chapter emphasizes the need for standardizing the measurement of energy dose and experimental protocols used by the different research groups in order to allow cross comparison of different data, and suggests some engineering solutions to improve the uniformity of PL treatment