Analysis of Elements and Effects of Common Disinfectants in Common Salad Vegetables

In this research, firstly, the effect of some cleaners or disinfectants (including washing with water, ozone (O3, 0.5ppm), benzalkonium chloride (BAC, 120ppm), the combination of two treatments (O3 + BAC)) on the population of two pathogens plant was evaluated, secondly 14 elements (Ca (calcium), magnesium (magnesium), As (arsenic), Al (aluminum), mercury (mercury), Se (selenium), cadmium (cadmium), K (potassium), Iron (Fe), nickel (Ni), zinc (Zn), sodium (Na), manganese (Mn) and lead (Pb)) were evaluated in romaine lettuce and Brassica oleracea, thirdly, the sensory evaluation of the mentioned vegetables with different treatments was investigated during seven days. The results showed the maximum and minimum mean of essential elements were Ca (5334 ± 178 mg/kg in Brassica oleracea) and Se (0.0021 ± 0.0001 mg/kg in Romaine lettuce), respectively. The maximum and minimum mean of toxic elements were Pb (6.26 ± 0.12 µg/kg in Brassica oleracea) and Hg (lower than LOD in Brassica oleracea), respectively. Also, the combined treatment (O3 + BAC) showed the best result, so that the lowest aerobic bacteria population (3.15-3.86 in Brassica oleracea and 3.25-4.17 log CFU/g in Romaine lettuce), yeast and mold (1.58-2.06 in Brassica oleracea and 1.65-2.29 log CFU/g in Romaine lettuce), E. coli (ND-1.23 in Brassica oleracea and ND-1.76 log CFU/g in Romaine lettuce) and S. Typhimurium (ND-1.35 in Brassica oleracea and 1.06-1.73 log CFU/g in Romaine lettuce) on all days was related to this treatment. Also, the sensory evaluation results showed that the combined treatment (O3 + BAC) obtained the best scores compared to other treatments and control. The results showed that water and combined treatment of aqueous O3 and BAC can have a good health effect on Brassica oleracea and Romaine lettuce.

Application of chitosan-ZnO nanoparticle edible coating to wild-simulated Korean ginseng root

Chitosan-ZnO nanoparticle (ZnONP) edible coating was applied to extend shelf life of wild-simulated Korean ginseng root (WsKG). In antimicrobial testing of various coating solutions (0.01, 0.02, 0.03% ZnONP), Bacillus cereus (Gram-positive) and Escherichia coli (Gram-negative) were most inhibited by the 0.03% chitosan-ZnONP solution. The 0.03% chitosan-ZnONP solution was finally used for edible coating of WsKG. In SEM analysis, the coat of chitosan and ZnONP was well-formed on the surface of WsKG. In isothermal storage tests (temperature: 5–20 °C, RH: 95%), microbial limit (4.70 log CFU/g) of total aerobic bacteria for non-coated and coated WsKG were reached at 3.9 and 6.3 weeks at 5 °C, 1.9 and 4.3 weeks at 10 °C, and 1.3 and 2.0 weeks at 20 °C, respectively. Mold occurred in the non-coated sample at 4 weeks at 5 °C, but not in the coated sample during 6 weeks. Chitosan-ZnONP edible coating was very effective in preserving WsKG.