The combined effects of aqueous chlorine dioxide, fumaric acid, and ultraviolet-C with modified atmosphere packaging enriched in CO2 for inactivating preexisting microorganisms and Escherichia coli O157:H7 and Salmonella typhimurium inoculated on buckwheat sprouts

Abstract

The combined effects of a sanitizer mixture, ultraviolet-C (UV-C), and modified atmosphere packaging (MAP) on the quality of non-inoculated and inoculated (Escherichia coli O157:H7 and Salmonella typhimurium) buckwheat sprouts were examined. Buckwheat sprouts were treated with a sanitizer mixture (comprising 100mgL−1 aqueous ClO2 and 0.3% fumaric acid) and 2kJm−2 UV-C, packaged under two different conditions (air and CO2 gas) and storage for 8d at 4°C. The combination of the sanitizer mixture and UV-C treatment reduced the initial counts of preexisting microorganisms in the buckwheat sprouts by 1.9logCFUg−1 and reduced the initial inoculated counts of E. coli O157:H7 and S. typhimurium on buckwheat sprouts by 3.0 and 2.3logCFUg−1, respectively. The preexisting microorganisms and inoculated pathogens in buckwheat sprouts packaged under CO2 gas were significantly reduced during storage following the combined treatment compared to those of the control by above 95%. Differences in Hunter L*, a*, and b* values among the treatments were negligible. The combined sanitizer mixture and UV-C treatment increased the sprout rutin content by 147%, but there was no significant difference in 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity between treatments during storage. Therefore, the combination of sanitizer mixture made from aqueous ClO2 and fumaric acid, UV-C irradiation, and MAP can improve the microbial safety and quality of buckwheat sprouts.