Chloroxyanion Residue on Seeds and Sprouts after Chlorine Dioxide Sanitation of Alfalfa Seed

Abstract

The effects of a 6-h chlorine dioxide sanitation of alfalfa seed (0, 50, 100, and 200 mg/kg seed) on total coliform bacteria, seed germination, and the presence of chlorate and perchlorate residues in seed rinse, seed soak, and alfalfa sprouts was determined. Chlorate residues in 20,000 mg/L calcium hypochlorite, commonly used to disinfect seed, were quantified. Chlorine dioxide treatment reduced (P < 0.05) total coliforms on seeds with no effect (P > 0.05) on germination. Dose-dependent sodium chlorate residues were present in seed rinse (4.1 to 31.2 μg/g seed) and soak (0.7 to 8.3 μg/g seed) waters, whereas chlorate residues were absent (LOQ 5 ng/g) in sprouts, except for 2 of 5 replicates from the high chlorine dioxide treatment. Copious chlorate residues were present (168 to 1260 mg/L) in freshly prepared 20,000 mg/L calcium hypochlorite solution, and storage at room temperature increased chlorate residues significantly (P < 0.01).

Distribution and Chemical Fate of [36Cl]Chlorine Dioxide Gas on Avocados, Eggs, Onions, and Sweet Potatoes

“…Skin was processed with tomato flesh in tomato studies, but the greatest accumulation of tomato-associated radioactivity (20–29%) was at the stem scar of the tomato, which represented less than 1% of the tomato weight. Surface deposition can also be inferred from studies with chlorine dioxide-treated alfalfa seed in which chlorate residues were rinsed from seed but were not measurable in sprouts generated from treated seed.…”

“…In commercial situations, it is anticipated that low dose, long exposure periods (hours of treatment with low concentrations of ClO 2 rather than minutes of treatment at very high ClO 2 concentrations) would be optimal for preventing the accumulation of chlorate residues during the treating food items with chlorine dioxide gas. Our laboratory has previously conducted unlabeled residue trials using chlorate as a marker tissue with cantaloupe, tomatoes, ready-to-eat meat, and alfalfa seed . No chlorine dioxide-related chlorate residue was present in edible portions of cantaloupe or tomatoes or in edible sprouts of alfalfa seed, but low concentrations of chlorate were measured in tomato rinses, cantaloupe rinds, and alfalfa seed rinses.…”

“…Skin was processed with tomato flesh in tomato studies, 5 but the greatest accumulation of tomato-associated radioactivity (20−29%) was at the stem scar of the tomato, which represented less than 1% of the tomato weight. Surface deposition can also be inferred from studies with chlorine dioxide-treated alfalfa seed 15 in which chlorate residues were rinsed from seed but were not measurable in sprouts generated from treated seed. Data in Table 3 also clearly demonstrate that radioactive residues were either absent or present at low concentrations in the edible fractions of foods that were separated into edible and traditionally inedible fractions.…”

“…Chlorate formation in this study is consistent with the formation of chlorate in on surfaces of cantaloupe and alfalfa seed. 5,15,19 Chlorate residues, if present, were below detection limits in chlorine-dioxide treated salami, 7 however, presumably because the gas was consumed as rapidly as it was produced (very little gas accumulated) and had little to no opportunity to disproportionate. For the current set of food products, all sanitation reactions were protected from laboratory light, which would mitigate the formation of oxidative reactions on food or experimental surfaces.…”

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

“…In addition, the final product of sprouts may be safe because ClO 2 was not detected after sprouting for 3 days. Smith et al [25] revealed that significant quantities of chlorate residues were formed from ClO 2 treatment of seeds, but these residues were removed during the sprouting process. Moreover, chlorate residues that possibly remained on seeds might have been transformed by bacterial action during the sprouting process as chlorate residues are prone to biodegradation in biotic environments conducive to bacterial growth.…”