Effect of sequential presoaking and chlorine dioxide treatment on the inactivation of pathogenic Escherichia coli and Salmonella spp. on sprout seeds

Abstract

This study was conducted to evaluate the effect of sequential presoaking and chlorine dioxide (ClO2) on the reduction of pathogenic Escherichia coli and Salmonella spp. in alfalfa. When unsoaked and presoaked alfalfa were exposed to 200 ppm ClO2 for 15 min, the population of E. coli and Salmonella spp. on presoaked seeds reduced more than those on unsoaked seeds by 2.07 and 1.43 log CFU g−1 (p < 0.05), respectively. To determine the optimal concentration and treatment time to reduce pathogenic E. coli and Salmonella spp. in alfalfa seeds immersed in water for 5 h, presoaked seeds were exposed to four different concentrations of ClO2 (50, 100, 150, and 200 ppm) for 15, 30, 45, and 60 min. The most effective condition to eliminate E. coli and Salmonella spp. from alfalfa seeds was sequential immersion in water for 5 h and 200 ppm ClO2 treatment for 1 h. After the optimal condition was applied to eight kinds of sprout seeds, the pathogens were completely inactivated in all seeds, except radish seeds. Growth of pathogenic E. coli and Salmonella spp. during sprouting after ClO2 treatment of alfalfa seeds was also completely inactivated. However, the germination rate of seeds did not significantly decrease after ClO2 treatment. In addition, ClO2 residues were not present in any sprout during 3 days of cultivation. These results demonstrated that sequential presoaking and 200 ppm ClO2 treatment is the optimal seed disinfection treatment to prevent foodborne diseases associated with sprout consumption.

Industrial Hemp (Cannabis sativa L.) Varieties and Seed Pre-Treatments Affect Seed Germination and Early Growth of Seedlings

“…However, no significant differences were observed in GP between barley seeds treated with 500 mg•L −1 of ClO 2 and the control. In addition, the germination of lucerne seeds and other sprouts pre-soaked with 200 mg•L −1 of ClO 2 did not significantly differ from untreated seeds [23].…”

“…Chlorine dioxide (ClO 2 ), a chlorine-based disinfectant, is known for its fungicidal, bactericidal and viricidal properties and is effective in decontaminating seeds and sprouts from a wide range of microorganisms and human pathogens [22][23][24]. However, the effect of ClO 2 on seed germination and seedling growth of industrial hemp has not been studied so far but has recently been explored in other crops, including vegetables [23], cucurbits [24] and barley [26].…”

“…Seed germination and early seedling growth depend on several factors, including varieties with different seed sizes [10][11][12], seed sources [13][14][15] and seed origins [16,17]. They also respond differently to pre-treatments with chemicals, such as plant growth regulators [18][19][20], seed disinfectants [21][22][23][24][25][26][27][28] and cold temperatures [29][30][31][32][33].…”