Quantifying and mapping the spatial distribution of fluence inside a pulsed light treatment chamber and various liquid substrates

A numerical approach for predicting volumetric inactivation of food borne microorganisms in liquid substrates by pulsed light treatment

“…For BPB, TSB, and apple juice, the°Brix values were 0.5, 3.25, and 11.25°Brix, respectively, and the pH values were 6.8, 7.4, and 4.0, respectively (Hsu and Moraru, 2011). The substrates, including their spectral irradiance profiles, are described in detail in the paper by Hsu and Moraru (2011).…”

“…A pyroelectric head (Ophir Optronics, MA) with a Nova II display (Ophir Optronics Inc.; Wilmington, MA) was used to measure the fluence inside the PL chamber and for each substrate, using the methodology described by Hsu and Moraru (2011). Fluence is the dose of total radiant energy that reaches the substrate, and is expressed in J/cm 2 .…”

“…Previous work done by Hsu and Moraru focused on generating maps of the spatial distribution of both fluence and UV fluence within an empty PL chamber and three liquid substrates. In that study it was found that the spatial distribution of fluence varied greatly not only with distance from the lamp, but also spatial location relative to the focal point of the lamp (Hsu and Moraru, 2011). As a result of the non-uniform distribution of fluence, it can be expected that the microbial inactivation achieved throughout the substrate will also be non-uniform.…”

“…The distribution of light energy may vary throughout a substrate, depending on the optical properties of the substrate and spatial location of the substrate relative to the light source (Hsu and Moraru, 2011). Thus, the potential for non-uniform treatment of the substrate must be addressed before commercial applications of PL are developed.…”

Inactivation of Bacillus subtilis spores by combined pulsed light and thermal treatments

“…However, its application for liquid food treatment is limited by their composition, opacity or turbidity, which determines the exposure of microorganisms to the incident light (Artíguez et al, 2012;Hsu and Moraru, 2011) and, therefore, treatment effectiveness. The effectiveness of PL for inactivating microorganisms in complex food substrates could be improved by combination with other emerging technologies or milder conventional preservation methods.…”