The effects of gaseous chlorine dioxide (ClO2) treatment, applied to inactivate Salmonella, on lipid oxidation, volatile compounds, and chlorate levels of dehulled almonds were evaluated during a 3 month accelerated storage at 39 °C. At treatment levels that yielded a 2.91 log reduction of Salmonella, ClO2 promoted lipid oxidation as indicated by increased peroxide values, total acid number, conjugated dienes, and thiobarbituric acid-reactive substances. Furthermore, several chlorine-containing volatile compounds including trichloromethane, 1-chloro-2-propanol, 1,1,1-trichloro-2-propanol, and 1,3-dichloro-2-propanol were identified in ClO2-treated samples. However, all the volatile chlorine-containing compounds decreased during the 3 months of storage. Chlorate (26.4 ± 5.1 μg/g) was found on the ClO2-treated samples. The amounts of non-ethanol alcohols, aldehydes, and carboxylic acids increased following ClO2 treatments. Some volatiles such as 2,3-butanediol that were present in non-treated samples became non-detectable during post-ClO2 treatment storage. Overall, our results demonstrated that gaseous ClO2 treatment promoted lipid oxidation, generation of volatiles of lipid origin, and several chlorine-containing compounds.
Keywords: ClO2; HS-SPME-GC/MS; accelerated storage; chlorate; heat treatment.