Impact of SDBD plasma treatment on the safety and quality of fresh cut melon

Cold atmospheric plasma (CAP) is a non-thermal technology which could be applied for food product decontamination (microorganisms, moulds and mycotoxins) and stabilization. The aim of this work was thus to analyse the decontamination effect of plasma treatment with a surface dielectric barrier discharge (SDBD) on fresh cut melon. The treatment was performed under two different chemical regimes, one with a high concentration of ozone (O3) and the other with a high concentration of nitrogen oxides (NO, NO2, NO3, N2O5), obtained varying the power density of the discharge. Exposure to the two plasma regimes was evaluated up to 30 min addressing the reduction of the main spoilage and pathogenic microorganisms. Some qualitative parameters, such as pH, dry matter, colour and the effect on the tissue metabolism (endogenous heat production and respiration rate) were evaluated and compared to the untreated sample. Results showed that plasma exposure allowed to obtain a reduction of microbial loads up to about 1-1.5 log CFU/g but different microorganisms showed different sensitivities. Moreover, the presence of nitrogen oxides proved to be more efficient in microbial decontamination compared to ozone. Quality of the products was only slightly affected but interesting results, that need further investigation, were observed in relation to the tissue metabolic response to plasma highly reactive species. These findings contribute to gain and collect further knowledge for the scale-up of this technology to industrial processing. The present work is part of the project “PRIN 2017 -PLASMAFOOD - Study and optimization of cold atmospheric plasma treatment for food safety and quality improvement” founded by MIUR - Ministero dell’Istruzione dell’Università e della Ricerca.