Assessment of potential infectivity of human norovirus in the traditional Korean salted clam product "Jogaejeotgal" by floating electrode-dielectric barrier discharge plasma

Abstract

This study investigated the antiviral effects of floating electrode-dielectric barrier discharge (FE-DBD) plasma treatment (1.1 kV, 43 kHz, N2 1.5 m/s, 5-30 min) against human norovirus (HuNoV) GII.4 in Jogaejeotgal Infectivity was assessed using real-time quantitative-PCR (RT-qPCR) following treatment of samples with propidium monoazide (PMA) and sodium lauroyl sarcosinate (Sarkosyl). This study also investigated the effects of FE-DBD plasma treatment on Jogaejeotgal quality (assessed using pH value and Hunter colors). Following inoculation, the average titers of HuNoV GII.4 in Jogaejeotgal significantly (P < 0.05) decreased with increases in the FE-DBD plasma treatment time in both the non-PMA-treated and PMA + Sarkosyl-treated samples; in the nonPMA and PMA + Sarkosyl treated Jogaejeotgal, HuNoV GII.4 titers (log10 copy number/mu L) were to: 3.16 and 2.95 (5 min), 2.90 and 2.48 (10 min), 2.82 and 2.40 (15 min), 2.58 and 2.26 (20 min), 2.48 and 2.06 (25 min), and 2.23 and 1.91 (30 min), respectively. The average titers of HuNoV demonstrated significant (P 0.05) reductions of 0.35 log10 (55.3%) in PMA + Sarkosyl-treated samples compared with the non-PMA treated samples following exposure to 5-30 min of FE-DBD plasma. Reductions of 1-log for HuNoV in PMA + Sarkosyltreated Jogaejeotgal required treatments of FE-DBD of 5-30 min. Using the first order kinetic model (R2 = 0.95), GII.4 decimal reduction time (D-value) resulting from FE-DBD plasma was 23.75 min. The pH and Hunter colors ("L", "a", and "b") were not significantly different (P > 0.05) between the untreated and FE-DBD plasma-treated Jogaejeotgal. Based on these results, the PMA + Sarkosyl/RT-qPCR method could be assessing HuNoV viability following 5-30 min treatment of FE-DBD plasma. Furthermore, may be an optimal treatment for Jogaejeotgal without altering the food quality (color and pH).