Roller conveyer system for the reduction of pesticides using non-thermal gas plasma - A potential food safety control measure?

We previously described a novel roller conveyer plasma device, which generates gas plasma via atmospheric pressure dielectric barrier discharge, to disinfect vegetables in situ during the sorting process. Here, we tested this system to verify whether or not such treatment was also effective in pesticide reduction. Competitive enzyme-linked immunosorbent assay showed the pesticide malathion, present at levels typically observed on treated crops, was efficiently degraded to less than one tenth of the original level within 1 min. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) confirmed the decrease in the level of pesticide cocktail PL-14-2 and FA-2, including organophosphorus pesticides and other classes of pesticides, after plasma treatment. A cholinesterase inhibitory activity assay was used as an index to measure the activity of PL-14-2 and FA-2, which showed that the gas plasma treatment reduced the biological activity of the pesticides. In addition to its proven biocidal effects, our findings demonstrate the potential of this non-thermal plasma system as a food safety control measure ensuring reduction of pesticide residues in foodstuffs.