In situ quantification of chlorine dioxide gas consumption by fresh produce using UV-visible spectroscopy

摘要

The objective of this research was to quantify the chlorine dioxide (ClO_2) gas, a potent sanitizing agent, absorbed by fresh produce in real time during treatment. The information generated allows for understanding how critical variables such as quantity of absorbed ClO_2 gas and rate of ClO_2 gas consumption relate to other performance metrics without requiring post-processing of the produce. Therefore, a new in situ approach to measure the total absorption of ClO_2 gas by fresh produce requiring minimal sample preparation was developed using a system equipped with a UV-vis spectrophotometer. The system can simulate ClO_2 gas treatment at constant and varying concentrations within a package and/or chamber. Strawberries were selected as model fresh produce to assess the system and to evaluate the impact of concentration and time of exposure on total ClO_2 gas consumption. It was found that strawberries consume ClO_2 gas rapidly and that longer exposure times (17 and 84 min) for continuous exposure resulted in around 45% ClO_2 absorption whereas shorter exposure times (7 min) consumed less than 20% of the injected ClO_2 because the latter did not reach steady state ClO_2 consumption prior to completion.