Development of an Optimized Delivery Method of Surface Irradiation Using an Electron Beam

Abstract

Food safety has long been a nationwide concern. In 2011 alone, 731 outbreaks of foodborne illness were documented in the United States. These outbreaks resulted in over 13,000 illnesses, almost 900 people hospitalized and 45 deaths. The FDA has approved food irradiation as one method to combat foodborne illness.

This research aims to develop a method, using electron scattering, to reduce the maximum to minimum dose ratio over the surface of a cantaloupe while also maintaining the electron penetration depth sufficient to provide an adequate dose throughout the rind. This research utilized a set of Monte Carlo N-Particle eXtended (MCNPX) decks to calculate the dose received by a cantaloupe passing under a 10 MeV electron beam. The decks also included metallic reflectors, to scatter the electron beam, to achieve a more uniform surface dose distribution. Dose distributions as a function of surface position and depth were obtained, and a surface dose map and dose depth curves were generated for each reflector plate model.

It was shown that the surface dose ratio can be reduced from 83505 to 2.176 with the use of metallic reflectors. Additionally, the scattered electrons have sufficient energy to provide adequate dose throughout the rind to combat bacteria internalization without delivering a dose that might damage the texture of the interior of the cantaloupe. This technique could be easily extended to irradiate the surface of other medium-sized objects.