Fluence and Dose Distribution Modeling of an Ultraviolet Light Disinfection Process for Pathogen Inactivation Efficiency Evaluation

Abstract

This study addresses the need to utilize bench-scale experimental results for ultraviolet (UV) light disinfection on solid food surfaces by proposing a novel framework to evaluate the fluence rate field of arbitrarily placed UV sources to ensure proper disinfection in industrial-scale food processing. Despite extensive research establishing UV fluence values for disinfection of various food types, industrial applications often face challenges due to nonhomogeneous UV distribution. This study introduces a method capable of determining the fluence distribution on solid food and food contact surfaces in both static and moving environments. Additionally, it aids in selecting the appropriate light sources and irradiation times. Our model leverages UV radiation models from different engineering disciplines to determine the UV fluence and dose distribution on the surface of convex objects. This helps to understand and optimize processes for proper decontamination, improved food quality, and a longer shelf life for processed products.

Figure 1

Evaluation process flowchart.

Figure 2

Difference between relative intensity estimations: a) closest value, b) linear interpolation, and c) FFT reconstruction—fluence rate values on a plane facing the LED light source (with 110 mW total radiated power) perpendicularly at 100 mm distance.

Figure 3

Light environment examples with similar layout and radiated power: 20 LPM light source (top) and 250 LED light source (bottom) at 0.1 m height above the base XY plane.

Figure 4

Example of processing 3D models (raw chicken breast (top, photo by PaShok3D from Sketchfab), apple (bottom, photo by mali maeder from Pexels)): a) real object, b) triangulated, quasi-uniform convex hull mesh, and c) evaluated radiation field on the surface of the object.

Figure 5

Example of object motion modeling, using key poses at normalized key timestamps. The object poses are written in a homogeneous transformation matrix form. Interpolated poses for 10 steps are also shown for linearly moving the object and flipping it in the middle of the motion.

Figure 6

General arrangement of an object point P with position vector , local surface normal and a line light source described with the position vector of its center point and direction vector of its center line inside the base coordinate system CSB. gives the relative position of P from the lamp center point. In the lamp-focused approach, equations are described in local (lamp) coordinate system CSL.

Figure 7

Inactivation curves on raw chicken breasts for different pathogens from the example studies using two different types of light sources.

Figure 8

Lamp and apple arrangement in the experiment for dose distribution using RCFs. Blue rectangles on the apple’s surface are the simulated versions of the RCFs used in the reference study.

Figure 9

Arrangement of measuring a twin-tube UV–C light source.

Figure 10

Fluence distribution analysis: Top and bottom view of the radiated object, in the case of the LPM and LED setups (left), histogram of fluence values for fluence uniformity visualization (right).

Figure 11

Bacterial inactivation efficiency of the LPM and LED setups for three different types of bacteria.

Figure 12

Results of the irradiance simulation compared to the measurements in the reference study. The error bars show the standard error.

Figure 13

Dose and fluence distribution evaluation on an apple’s surface based on measurements in the reference study.

Figure 14

Comparison of the measured irradiance values with the LSDE irradiance model.