Aqueous Chlorine Dioxide Treatment Research Articles

Effectiveness of Aqueous Chlorine Dioxide in Minimizing Food Safety Risk Associated with Salmonella, E. coli O157:H7, and Listeria monocytogenes on Sweet Potatoes.

Sodium hypochlorite (NaOCl) is a commonly used sanitizer in the produce industry despite its limited effectiveness against contaminated human pathogens in fresh produce. Aqueous chlorine dioxide (ClO2) is an alternative sanitizer offering a greater oxidizing potency with greater efficacy in reducing a large number of microorganisms. We investigated the effect of aqueous chlorine dioxide treatment against human pathogens, Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes seeded on sweet potatoes. Sweet potatoes were spot inoculated (4.2 to 5.7 log CFU/cm2) with multi-strain cocktails of Salmonella spp., E. coli O157:H7, and L. monocytogenes and treated for 10–30 min with 5 ppm aqueous ClO2 or water. Aqueous ClO2 treatment was significantly (p < 0.05) effective in reducing Salmonella with a reduction of 2.14 log CFU/cm2 within 20 min compared to 1.44 log CFU/cm2 for water treatment. Similar results were observed for L. monocytogenes with a 1.98 log CFU/cm2 reduction compared to 0.49 log CFU/cm2 reduction observed after 30 min treatment with aqueous ClO2 the water respectively. The maximum reduction in E. coli O157: H7 reached 2.1 Log CFU/cm2 after 20 min of treatment with aqueous ClO2. The level of the pathogens in ClO2 wash solutions, after the treatment, was below the detectable limit. While in the water wash solutions, the pathogens’ populations ranged from 3.47 to 4.63 log CFU/mL. Our study indicates that aqueous ClO2 is highly effective in controlling cross-contamination during postharvest washing of sweet potatoes.

Combined effects of aqueous chlorine dioxide and ultrasonic treatments on shelf-life and nutritional quality of bok choy (Brassica chinensis)

The combined effects of aqueous chlorine dioxide (ClO2) and ultrasonic treatment on the shelf-life, some nutrients and bioactive compounds of bok choy were investigated. Minimally processed bok choy was treated in 50 ppm aqueous ClO2 solution subjected to 80 kHz frequency ultrasound at 0, 120, 150, 180, and 210 W for 10 min. Aqueous ClO2 plus ultrasound treatments significantly (p < 0.05) reduced total bacterial counts by up to 2.8 log CFU/g and Pseudomonas spp. by up to 2.5 log CFU/g, respectively, on day 0, and inhibited their growth on bok choy throughout the 12 d storage period at 4 °C. Among the treatments studied, aqueous ClO2 plus 180 W-ultrasound treatment demonstrated maximum reduction of microbial loads and minimum impact on visual quality (L*, a*, and b* values), chlorophyll degradation, membrane permeability, ascorbic acid and total phenolic contents. In addition, the combined treatment significantly (p < 0.05) inhibited the activities of polyphenol oxidase and polyphenol peroxidase and increased the activity of phenylalanine ammonia lyase as compared with controls. These results indicated that aqueous ClO2 plus ultrasonic treatments is an effective approach for maintaining some nutrients and bioactive compounds, as well as extending the shelf-life of fresh bok choy.

Synergistic effects of combined X-ray and aqueous chlorine dioxide treatments against Salmonella Typhimurium biofilm on quail egg shells

The current study investigated the synergistic effect of combined X-ray irradiation (0.5, 1.0, 1.5, and 2.0 kGy) and aqueous chlorine dioxide (ClO2) treatment (10, 20, 30, and 50 ppm) on Salmonella enterica serovar Typhimurium biofilms on the surfaces of quail egg shells. The synergistic effect was not dependent on the X-ray irradiation dose or ClO2 concentration. The synergistic reductions of biofilms after X-ray/ClO2 treatment on the egg shells were −0.1–1.1 log CFU/egg. The largest reduction was 1.1 log CFU/cm2 after a 2.0 kGy X-ray and a 20 ppm ClO2 treatment. No significant change (P > 0.05) was observed in the Hunter colors (L*, a*, and b*) and shear force (shell thickness) of the egg shell surfaces after single or combined treatments. Similarly, no significant changes (P > 0.05) were observed in the same parameters on the egg shell surfaces when a combination treatment of minimum X-ray doses/ClO2 concentrations and a combination treatment of maximum X-ray doses/ClO2 concentrations were applied separately. The results indicated that the combination treatment of 2.0 kGy X-ray/20 ppm ClO2 could be used in the egg production, processing, and distribution processes to enhance food safety without causing changes to the egg shell surface color and shell thickness.

Aqueous chlorine dioxide treatment of horticultural produce: Effects on microbial safety and produce quality–A review

ABSTRACTMicrobial load on fresh fruit and vegetables causes decay and losses after harvest and may lead to foodborne illness in case of contamination with human pathogens on raw consumed produces. Washing with tap water only marginally reduces microorganisms attached to produce surfaces. Chlorine is widely used for decontamination on fresh horticultural produces. However, due to harmful by-products and the questionable efficacy it has become increasingly challenged. During the last 20 years, the interest to study ClO2 treatments as an alternative sanitation agent for industrially prepared fresh produce has largely increased. For a wide range of commodities, the application of gaseous ClO2 has meanwhile been investigated. In addition, since several years, the interest in aqueous ClO2 treatments has further risen because of the better manageability in postharvest processing lines compared to gaseous application. This article critically evaluated the effects of postharvest application of aqueous ClO2, either alone or in combination with other treatments, on microbial loads for various horticultural produces. In laboratory investigations, application of aqueous ClO2 at concentrations between 3 and 100 ppm effectively reduced counts of natural or inoculated microorganisms (bacteria, yeasts, and mold) in the range of 1 and 5 log. However, various effects of ClO2 treatments on produce quality have been described. These mainly comprise implication on sensory and visual attributes. In this context, there is increasing focus on the potential impacts of aqueous ClO2 on relevant nutritional components of produces such as organic acids or phenolic substances.

Combined Treatment on the Inactivation of Naturally Existing Bacteria and Escherichia coli O157:H7 Inoculated on Fresh-Cut Kale.

An aqueous chlorine dioxide (ClO₂) treatment combined with highly activated calcium oxide (CaO) and mild heat was tested for inactivating naturally existing bacteria and Escherichia coli O157:H7 inoculated on fresh-cut kale. Kale samples were treated with different concentrations of ClO₂ (10, 30, and 50 ppm), CaO (0.01%, 0.05%, 0.1%, and 0.2%), and mild heat (25°C, 45°C, 55°C, and 65°C) as well with combinations of 30 or 50 ppm ClO₂ and 0.2% CaO at 55°C for 3 min. An increasing concentration of ClO₂ and CaO significantly reduced the microbialpopulation compared with the control. In addition, mild heating at 55°C elicited greater microbial reduction than the other temperatures. A combined treatment of 50 ppm ClO₂ and 0.2% CaO at 55°C reduced the population of naturally existing bacteria on kale by 3.10 logcolony forming units (CFU)/g, and the counts of E. coli O157:H7 were below the detection limit (1 log CFU/g). In addition, no significant differences in the Hunter color values were evident in any treatment during storage. Therefore, a combined treatment of ClO₂ and active CaO at 55°C can be an effective sanitizing method to improve the microbiological safety of fresh-cut kale without affecting its quality.

DEVELOPMENT OF A PRESERVATION TECHNIQUE FOR STRAWBERRY FRUIT (FRAGARIA × ANANASSA DUCH.) BY USING AQUEOUS CHLORINE DIOXIDE

Effects of aqueous chlorine dioxide (ClO2) treatment on preserving strawberry fruit (Fragaria × ananassa Duch.) were investigated. A stabilized ClO2 powder was dissolved in water to prepare the ClO2 solution. Strawberry fruit were then rinsed with ClO2 solutions at different concentrations (20, 40, 60, and 80 mg/L) for different times (5, 10, and 15 min) at 22±2℃ and 70±5% RH. Following ClO2 treatments, strawberries were stored at 4℃ for 9 days. ClO2 could markedly delay changes in firmness, slow down weight loss, and decay, and maintain sensory quality of strawberry fruit. ClO2 was also effective in retention of ascorbic acid, reducing sugar, and titratable acid. ClO2 concentration and treatment time were two significant factors (P

Quality Changes of Cherry Tomato by Aqueous Chlorine Dioxide Treatment during Storage

To improve the shelf-life of cherry tomato, samples were treated with aqueous chlorine dioxide () at 30 ppm for 0~30 minutes and the weight loss rate as well as the changes in physico-chemical and sensory properties of treated samples were investigated. Weight change in the control and in the samples with aqueous treatment were decreased slightly, and there were no difference during the storage period. There were no differences in soluble solid content among the treatments and during the storage period. There were no differences in the firmness of samples among the treatments but the firmness of the aqueous treated samples were decreased slower than that of the control samples. No significant changes in lightness, redness and yellowness of the controls and the samples by aqueous treatment were observed during 4 weeks storage period. The sensory parameters including taste, flavor, color, texture and overall acceptance at the initial period did not differ among the treatments. The scores for taste, texture and overall acceptance of the control were decreased faster than those of the aqueous treated samples when 3 weeks reached.

Reduction of nitrite levels in fresh lettuces with aqueous chlorine dioxide treatment

SummaryLeafy vegetables are the major source of nitrite intake in the human diet, and technological processing to control the nitrite levels is necessary to the harvested vegetables destined for consumption. In this work, the effect of aqueous chlorine dioxide (ClO2) treatment on the nitrite levels in fresh lettuces during storage was studied. The results showed the appropriate aqueous ClO2 solutions treatment (30 and 45 mg L−1, 10 min) could reduce the nitrite levels or retard the peak occurrence in fresh lettuces during storage. The reduction of nitrite levels in fresh lettuces with appropriate ClO2 treatment can be attributed to two aspects including the inactivation of nitrate reductase directly and the reduction of the bacterial populations. This study will provide a useful method to reduce the nitrite levels in fresh lettuces destined for short storage followed by consumption.

Effects of aqueous chlorine dioxide treatment and cold storage on microbial growth and quality of blueberries

The effects of postharvest washing treatment and cold storage on the quality of blueberries were examined. The blueberries were treated with water or 100 ppm aqueous chlorine dioxide (ClO2) and stored at 4 or 20°C for 12 days. The aqueous ClO2 treatment reduced the initial populations of total aerobic bacteria and yeast and mold in the blueberries by 1.4–1.5 and 0.8–0.9 log CFU/g, respectively, compared with the control. Total anthocyanin content indicated that the blueberries stored at 4°C maintained their total anthocyanin content better than those stored at 20°C. Regardless of washing treatment, the blueberries stored at 4°C exhibited lower decay and weight loss than those stored at 20°C. These results suggest that a postharvest treatment of aqueous ClO2 and cold storage can be useful for maintaining the quality of blueberries during storage.

전기분해수 및 이산화염소수 처리에 따른 배추의 미생물 제어 효과

본 연구에서는 일반적인 염소소독법을 대체하기 위하여 살균소독수로의 유효성을 가진 강산성 및 약알칼리 전기분해수와 이산화염소수를 배추 세척에 적용하였다. 배추 표면에 <TEX>$E.$</TEX> <TEX>$coli$</TEX>, <TEX>$B.$</TEX> <TEX>$cereus$</TEX>, <TEX>$Sal.$</TEX> Typhimurium, 및 <TEX>$S.$</TEX> <TEX>$aureus$</TEX>를 인위적으로 오염시킨 후 각각의 살균소독수를 100 ppm의 농도로 하여 침지 시간을 달리하면서 미생물 제어효과를 비교하였다. 전체적으로 줄기 부분보다 잎 부분에서 세척 효과가 더 크게 나타났으며 네 가지 병원성 미생물에 대한 세척효과는 이산화염소수가 가장 큰 것으로 나타났다. 수도수 처리 시 10분이 경과하여도 1 log CFU/g 이하의 낮은 감소 효과가 나타났으며, 살균소독수에 3분 침지 하였을 때 최소 감소효과는 약알칼리 전기분해수에서 1.3 log CFU/g였으며, 최대 감소효과는 이산화염소수에서 4.7 log CFU/g의 수준으로 수도수 세척에 비해 살균소독수의 미생물 감소효과가 크게 나타났다. 또한 5분과 10분 처리구에서 유의성은 있었으나 그 차이가 크지 않아 배추의 미생물학적 위험을 감소시키기 위해서는 5분정도 침지 시키는 방법이 효과적일 것으로 생각된다. 차아염소산 나트륨수와 비교 시 산성 및 약알칼리 전기분해수의 미생물 감소효과는 유사하거나 최대 2.7 log CFU/g 정도(LAlEW, B. cereus, 10분)의 차이를 나타냈고, 이산화염소수는 3.2 log CFU/g (<TEX>$Sal.$</TEX> Typhimurium, 10분) 수준의 차이를 나타내어 본 연구에서 사용된 살균소독수가 염소소독 대체재로서 가능성이 있는 것으로 사료된다. 또한 이산화염소수는 병원성 미생물을 제어하는 데는 우수한 것으로 평가되었으나 배추의 품질 저하가 야기되어 배추 적용에는 부적합한 것으로 판단된다. This study evaluated the efficacy of strong acidic electrolyzed water (SAcEW), low alkaline electrolyzed water (LAlEW) and aqueous chlorine dioxide (ACD) for reducing pathogenic bacteria(<TEX>$Escherichia$</TEX> <TEX>$coli$</TEX>, <TEX>$Bacillus$</TEX> <TEX>$cereus$</TEX>, <TEX>$Salmonella$</TEX> Typhimurium, <TEX>$Stapylococcus$</TEX> <TEX>$aureus$</TEX>) on Chinese cabbage. Artificially inoculated Chinese cabbage was immersed for 1, 5 and 10 min with TW, NaClO, EW and ACD. Generally, leaves showed more effective reduction than stems. Regarding the inhibitory effect, ACD treatment showed the highest effects rather than other treatments. When Chinese cabbage was immersed for 3 min in sterilized water, it was reduced to a minimum of 1.33 log CFU/g at LAlEW and a maximum of 4.70 log CFU/g at ACD. Compared to NaClO, ACD and LAlEW which showed a reduction of 3.2 log CFU/g (<TEX>$Sal.$</TEX> Typhimurium) and 2.7 log CFU/g(<TEX>$B.$</TEX> <TEX>$cereus$</TEX>), respectively. Furthermore, the others had similar inhibitory effects compared to NaClO.

Effect of aqueous chlorine dioxide and UV-C treatment on the microbial reduction and color of cherry tomatoes

The effect of aqueous chlorine dioxide (ClO2) combined with UV-C irradiation on the postharvest quality of cherry tomatoes were examined. Cherry tomatoes were inoculated with Salmonella enterica serotype Typhimurium and Escherichia coli O157:H7, and then treated with 10 mg L−1 ClO2, 5 kJ m−2 UV-C, and a combination of ClO2/UV-C treatment. The populations of S. Typhimurium and E. coli O157:H7 in cherry tomatoes were reduced by 2.53 and 2.26 log CFU/g after treatment with aqueous ClO2, respectively. Treatment with UV-C irradiation also reduced the populations of S. Typhimurium and E. coli O157:H7 by 2.58 and 2.65 log CFU/g, respectively, compared to the control. However, the combined treatment of ClO2/UV-C irradiation completely eliminated the inoculated bacteria during storage. Color measurement indicated that Hunter L, a, and b values were not significantly different among the treatments during storage. Therefore, these results suggest that the combined aqueous ClO2 and UV-C treatment could be useful in improving microbial safety of cherry tomatoes during storage without impairing the quality.

Reduction of Escherichia coli O157:H7 on radish seeds by sequential application of aqueous chlorine dioxide and dry-heat treatment

To assess the effectiveness of sequential treatments of radish seeds with aqueous chlorine dioxide (ClO(2) ) and dry heat in reducing the number of Escherichia coli O157:H7. Radish seeds containing E. coli O157:H7 at 5.5 log CFU g(-1) were treated with 500 μg ml(-1) ClO(2) for 5 min and subsequently heated at 60 °C and 23% relative humidity for up to 48 h. Escherichia coli O157:H7 decreased by more than 4.8 log CFU g(-1) after 12 h dry-heat treatment. The pathogen was inactivated after 48 h dry-heat treatment, but the germination rate of treated seeds was substantially reduced from 91.2 ± 5.0% to 68.7 ± 12.3%. Escherichia coli O157:H7 on radish seeds can be effectively reduced by sequential treatments with ClO(2) and dry heat. To eliminate E. coli O157:H7 on radish seeds without decreasing the germination rate, partial drying of seeds at ambient temperature before dry-heat treatment should be investigated, and conditions for drying and dry-heat treatment should be optimized. This study showed that sequential treatment with ClO(2) and dry-heat was effective in inactivating large numbers of E. coli O157:H7 on radish seeds. These findings will be useful when developing sanitizing strategies for seeds without compromising germination rates.

이산화염소수 처리에 의한 주요 식중독균의 불활성화에 관한 두 kinetic models의 비교

Inactivation kinetic data of Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus, Salmonella Typhimurium, and Salmonella Enteritidis via treatment with aqueous chlorine dioxide treatment at a specific concentration were evaluated using the first-order kinetic and Weibull models. The Weibull model showed a better fit with the kinetic data than the first-order kinetic model. The survival curves after the aqueous chlorine dioxide treatment showed values(time required to reduce microbial populations by 90%) of 2.49 min for E. coli O157:H7 at 5 ppm, 1.47 min for L. monocytogenes at 5 ppm, 0.94 min for S. aureus at 5 ppm, 0.87 min for S. Typhimurium at 1 ppm, and 0.08 min for S. Enteritidis at 1 ppm, according to the Weibull model.

Effects of aqueous chlorine dioxide treatment on nutritional components and shelf-life of mulberry fruit (Morus alba L.)

Effects of aqueous chlorine dioxide (ClO(2)) treatment on nutritional components and shelf-life of mulberry fruit (Morus alba L.) were investigated. Mulberry fruit were immersed into 20, 60, and 80 mg/l ClO(2) solutions for 5, 10, and 15 min, respectively. Mulberries were then rinsed with potable tap water for 1 min and stored at -1°C for 14 d. ClO(2) treatment was effective in retention of flavonoid, ascorbic acid, reducing sugar, and titratable acid. ClO(2) concentration and treatment time were significant factors affecting ClO(2) treatment. The shelf-life of the samples treated by 60 mg/l ClO(2) for 15 min was extended to 14 d compared to 8 d for the control. No ClO(2), ClO(2)(-), or ClO(3)(-) residues were detected in samples treated by 60 mg/l ClO(2) for 15 min. These results indicated that ClO(2) treatment was a promising approach to preserve mulberry fruit with no significant risks of chemical residues.

Effects of aqueous chlorine dioxide treatment on enzymatic browning and shelf-life of fresh-cut asparagus lettuce ( Lactuca sativa L.)

Effects of aqueous chlorine dioxide (ClO 2) treatment on enzymatic browning and shelf-life of fresh-cut asparagus lettuce ( Lactuca sativa L. var. angustana) were investigated. Fresh-cut asparagus lettuce was treated at different concentrations (10, 40, and 100 mg L −1) for different times (5, 10, and 20 min). Following treatments, lettuce slices were stored at 4 °C for 14 d. The activities of polyphenol oxidase (PPO) and peroxidase (POD) in the lettuce were reduced by ClO 2, and degradation of color was also delayed. Thus ClO 2 concentration and treatment time were two significant factors affecting ClO 2 treatment on enzymatic browning of fresh-cut asparagus lettuce. From the microbiological and sensory quality perspectives, the treatment with 100 mg L −1 ClO 2 for 20 min could prolong the shelf-life to 14 d compared to 4 d for the control. These results indicated that ClO 2 treatment was a promising approach to inhibit enzymatic browning and prolong shelf-life of fresh-cut asparagus lettuce.

The effects of aqueous chlorine dioxide or fumaric acid treatment combined with UV-C on postharvest quality of ‘Maehyang’ strawberries

The combined effect of aqueous chlorine dioxide (ClO 2) or fumaric acid with ultraviolet-C (UV-C) on postharvest quality of “Maehyang” strawberries was examined. The strawberries were treated with distilled water, 50 mg L −1 ClO 2, 0.5% fumaric acid, 5 kJ m −2 UV-C irradiation, and a combination of 50 mg L −1 ClO 2/5 kJ m −2 UV-C and 0.5% fumaric acid/5 kJ m −2 UV-C. The combined treatment of fumaric acid/UV-C reduced the initial populations of total aerobic bacteria and yeast and molds in the strawberries by 2.25 and 2.01 log CFU g −1, respectively. Sensory evaluation results indicated that the combined treatment provided better sensory scores than did the control. These results suggest that postharvest treatments of either ClO 2 or fumaric acid with UV-C can be useful for maintaining the quality of ‘Maehyang’ strawberries.

이산화염소수 처리에 의한 잔류농약 분해 효과

본 연구는 이산화염소수 처리가 식품에서의 잔류농약 제거에 효과가 있는지 조사하기 위해서 수행되었다. 10, 50, 100 ppm 이산화염소수로 채소류에 흔히 쓰이는 농약인 chlrpyrifos, diazinon, metalaxyl을 처리하여 GC를 이용하여 농약의 분해율을 측정하였다. 상기 세 가지 농약 성분은 이산화염소수 처리 농도뿐만 아니라 처리시간에 비례하여 분해되었으며 특히 100 ppm 이산화염소수 처리가 가장 효과적이었다. 또한, 인위적으로 농약을 오염시킨 상추를 증류수, 100 ppm 이산화염소수에 각각 침지하여 농약의 제거율을 비교해 보았을 때, 100 ppm 이산화염소수에 10분 동안 침지하였을 때가 가장 효과가 좋았다. 본 연구 결과, 이산화염소수 처리는 신선농산물에서의 잔류농약을 제거하기 위한 세척수로 이용될 수 있을 것으로 판단된다.

Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes on stored iceberg lettuce by aqueous chlorine dioxide treatment.

Inactivation of Escherichia coli O157:H7, Salmonella typhimurium, and Listeria monocytogenes in iceberg lettuce by aqueous chlorine dioxide (ClO(2)) treatment was evaluated. Iceberg lettuce samples were inoculated with approximately 7 log CFU/g of E. coli O157:H7, S. typhimurium, and L. monocytogenes. Iceberg lettuce samples were then treated with 0, 5, 10, or 50 ppm ClO(2) solution and stored at 4 degrees C. Aqueous ClO(2) treatment significantly decreased the populations of pathogenic bacteria on shredded lettuce (P < 0.05). In particular, 50 ppm ClO(2) treatment reduced E. coli O157:H7, S. typhimurium, and L. monocytogenes by 1.44, 1.95, and 1.20 log CFU/g, respectively. The D(10)-values of E. coli O157:H7, S. typhimurium, and L. monocytogenes in shredded lettuce were 11, 26, and 42 ppm, respectively. The effect of aqueous ClO(2) treatment on the growth of pathogenic bacteria during storage was evaluated, and a decrease in the population size of these pathogenic bacteria was observed. Additionally, aqueous ClO(2) treatment did not affect the color of lettuce during storage. These results suggest that aqueous ClO(2) treatment can be used to improve the microbial safety of shredded lettuce during storage.

Effects of aqueous chlorine dioxide treatment on browning of fresh-cut lotus root

Effect of aqueous chlorine dioxide (ClO 2) treatment on browning of fresh-cut lotus root (FLR) was investigated to explore the feasibility to apply ClO 2 for browning inhibition of fresh-cut products. Cut lotus roots were treated in ClO 2 solutions at different concentrations (10, 50 and 100 mg/l) for different time (5, 10 and 15 min), followed by chilled storage for 8–10 days at 4 °C. Color parameters ( L ∗, a ∗ and b ∗), polyphenol oxidase (PPO) activity and overall visual quality (OVQ) were measured at one-day interval during storage. Results showed that higher ClO 2 concentration and longer treatment time can provide better inhibitory effects on the browning of FLR. ClO 2 concentration, treatment time and storage time were three significant factors ( P < 0.05) and some significant interactions were observed. PPO activities were largely inhibited by 100 mg/l ClO 2 treatment for 10 min. The 100 mg/l ClO 2 treatment maintained high OVQ scores during 10-day storage; while 50 mg/l ClO 2 treatment was acceptable for maintaining OVQ during 4-day storage. ClO 2 treatment was demonstrated to be a promising alternative approach to control browning and improve OVQ of FLR.

Inactivation of Agrobacterium tumefaciens Inoculated on Fresh Radix Ginseng by Electron Beam Irradiation and Aqueous Chlorine Dioxide Treatment

Inactivation of Agrobacterium tumefaciens was evaluated on the inoculated fresh Radix Ginseng by electron beam irradiation or aqueous chlorine dioxide () treatment. Two groups of fresh ginsengs were prepared and inoculated with A. tumefaciens. One group was then irradiated at 0, 2, and 4 kGy using an electron beam accelerator, and the other group was treated with 0, 50, and 100 ppm of aqueous . Microbiological data indicated that populations of A. tumefaciens significantly decreased with increasing irradiation dose or aqueous concentration. In particular, A. tumefaciens was eliminated by irradiation at 4 kGy, and 100 ppm treatment reduced the populations of A. tumefaciens by 1.44 log CFU/g. These results suggest that electron beam irradiation or aqueous treatment can be useful in improving the microbial safety of fresh ginsengs during storage.