Author(s):
Antonio, Amilcar L. 
; Santos, Pedro M.P. ; Bento, Albino ; Quintana, Begoña
Date: 2014
Persistent ID: http://hdl.handle.net/10198/9639
Origin: Biblioteca Digital do IPB
Subject(s): Food irradiation; Dosimetry; Absorbed dose; Effective dose
Description
Food products are processed by different technologies in order to increase its safety and shelflife.
Food irradiation is regulated in European Union by the Directive 1999/2/EC, approved by
international organizations of food (FAO – Food and Agriculture Organization) and health (WHO
– World Health Organization) and the demand for post-harvest processed food products without
use of chemicals could be an opportunity to boost irradiation technologies, that are already
currently used for food preservation, namely for ripening delay, insects’ disinfestation or food
decontamination.
Before starting an irradiation process a dosimetric study is always performed to characterize
the absorbed dose taking in account food product characteristics, namely bulk and volumetric
density, in order to guarantee the desired effect, without compromising the main physicochemical
parameters.
The dose inside the food product can only be assessed indirectly or estimated by
computational methods. The effective dose, a concept used more in human radiotherapy, takes in
account the type of radiation and tissue. In food irradiation the effective dose could be estimated
from the absorbed dose, considering the physical characteristics of the product.
The irradiations of food and food phantoms were performed in a Co-60 experimental
chamber, with a total activity of 198 TBq (5.33 kCi) in November 2012 (Precisa 22, Graviner
Manufacturing Company Ltd, U.K.). The dose was estimated for each fruit in three different
positions in the chamber and the values of absorbed dose were obtained by spectrophotometric
methods, using previous calibrated routine Amber Perspex dosimeters (batch V, from Harwell
Company, U.K.).
Using an experimental approach, the estimated absorbed dose for different phantoms are
presented and corrected with the physical characteristics, dimensions, density and radiation mass
attenuation coefficient of the food product to obtain the effective dose, that could be used to
better characterize the irradiation process.
