Chlorine Dioxide Treatment Research Articles

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.

Combined effects of aqueous chlorine dioxide and ultrasonic treatments on postharvest storage quality of plum fruit ( Prunus salicina L.)

The individual and combined effects of aqueous chlorine dioxide (40 mg L −1 ClO 2 for 10 min) and ultrasonic (100 W ultrasound for 10 min) treatments on postharvest storage quality of plum fruit ( Prunus salicina L.) were investigated. Two combination modes of these two treatments, treatment with ClO 2 solution accompanied by simultaneous ultrasonic waves (one-step mode) and applying them sequentially (two-step mode) were adopted. The effect of combined treatments on maintaining contents of total flavonoids, ascorbic acid, reducing sugars, and titratable acids were similar but were more beneficial than the individual treatments and the untreated control. The one-step mode was more effective in reducing the initial microflora and retaining sensory qualities of plum fruit than the two-step mode, and fruit shelf-life could be extended to 60 d compared to 35 d for the control. Moreover, there were no detectable chemical residues in the treated samples with the one-step mode. These results demonstrated that the combined treatments of ClO 2 and ultrasound could be a promising approach to maintain postharvest storage quality of plum fruit without significant risks to consumers.

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.

Combined effects of chlorine dioxide, drying, and dry heat treatments in inactivating microorganisms on radish seeds

We determined the combined effectiveness of ClO 2 (200 and 500 μg/ml, 5 min), air drying [25 °C, 40% relative humidity (RH), 2 h], and mild dry heat (55 °C, 23% RH, up to 48 h) treatments in killing total aerobic bacteria (TAB), Escherichia coli O157:H7, and molds and yeasts (MY) on radish seeds. A 5.1-log reduction in the number of TAB was achieved on radish seeds treated with 200 or 500 μg/ml ClO 2 followed by air drying for 2 h and dry heat treatment for 48 h or 24 h, respectively. When radish seeds were treated with 200 and 500 μg/ml ClO 2, air dried, and heat treated for 12 h and 6 h, respectively, the initial population of E. coli O157:H7 (5.6 log CFU/g) on seeds was reduced to an undetectable level (<0.8 log CFU/g). However, the pathogen was detected in 5-day-old sprouts. The reduction of MY (1.2–1.0 log CFU/g) on radish seeds under similar experimental conditions was not changed significantly during subsequent heat treatment up to 48 h. Results show that treating radish seeds with 500 μg/ml ClO 2, followed by air dried at 25 °C for 2 h and heat treatment at 55 °C for 36 h achieved a >5-log CFU/g reduction of TAB and E. coli O157:H7. These observations will be useful when developing effective strategies and practices to enhance the microbiological safety of radish sprouts.

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.

Synergistic effect of chlorine dioxide and drying treatments for inactivating Escherichia coli O157:H7 on radish seeds.

Studies were done to determine whether calcium hypochlorite (Ca(OCl)(2)) and chlorine dioxide (ClO(2)) treatment followed by drying had a synergistic killing effect on microorganisms on radish seeds intended for sprout production. Uninoculated radish seeds and seeds inoculated with Escherichia coli O157:H7 were treated with water, Ca(OCl)(2) (free chlorine concentrations of 50 or 200 microg/ml), or ClO(2) (50 or 200 microg/ml) for 5 min and subsequently dried at 25 degrees C for up to 24 h. Populations of total aerobic bacteria (TAB), molds and yeasts (MY), and E. coli O157:H7 on the seeds treated with Ca(OCl)(2) were not significantly different (P = 0.05) than populations on seeds treated with ClO(2) at the same concentrations. However, populations of microorganisms on seeds treated with ClO(2) decreased more rapidly during drying. Treatment with ClO(2) (200 microg/ml) followed by drying caused reductions in TAB, MY, and E. coli O157:H7 of 3.1, 2.0, and 3.8 log CFU/g, respectively. When seeds were treated with water, Ca(OCl)(2) (50 or 200 microg/ml), and ClO(2) (50 microg/ml) and subsequently dried, reductions in TAB, MY, and E. coli O157:H7 were 0.2 to 2.0, 0.4 to 2.0, and 1.4 to 2.2 log CFU/g, respectively. Results indicate that inactivation of E. coli O157:H7 on radish seeds is greater after treatment with ClO(2) followed by drying than after treatment with Ca(OCl)(2) followed by drying, thus providing a synergistic treatment combination for reducing the safety risk associated with sprouts produced from these seeds.

Comparison of inactivation of Listeria monocytogenes within a biofilm matrix using chlorine dioxide gas, aqueous chlorine dioxide and sodium hypochlorite treatments

The present research compared the effect of chlorine dioxide (CD) gas, aqueous CD and aqueous sodium hypochlorite (SHC) treatments on the inactivation of a five strain mixture of Listeria monocytogenes – containing biofilms. Four day old biofilms were developed on a stainless steel (SS 304) coupon by using a mixture of five cultures of L. monocytogenes (Scott A, N1-227, 103M, 82 and 311) using a 100% relative humidity (RH) dessicator for incubation at room temperature (22 ± 2 °C). After biofilm development, coupons were rinsed and dried for 2 h and treated with 0.3 mg/l CD gas at 75% RH, 7 mg/l of aqueous CD and 50 mg/l SHC. Initial log 10 population of biofilm cells before CD gas, aqueous CD and SHC treatment was 4.80, 5.09 and 4.95 log 10 CFU/cm 2. The Weibull model was used to fit non-linear survivor curves. Treatments and time points of 0.3 mg/l CD gas and 7 mg/l aq. CD solution were significantly different ( p < 0.05). A 10 min treatment of 0.3 mg/l CD gas, 7 mg/l of aq. CD, and 50 mg/l SHC resulted in reductions of 3.21, 3.74 and 3.09 log 10 CFU/cm 2, respectively. At 10 min, all treatments were not statistically different ( p > 0.05). Low levels of CD (0.3 mg/l CD gas and 7 mg/l aq. CD solution) for 10 min resulted in similar log reductions compared to 50 mg/l SHC.

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.

Retention of Vibrio parahaemolyticus in oyster tissues after chlorine dioxide treatment

Vibrio parahaemolyticus is an important food-borne bacterium that is closely related to food poisoning from consumption of raw or lightly-cooked oysters. Therefore, intensive efforts must be taken to depurate the contaminated oysters. Chlorine dioxide (ClO 2) is considered to be a safe and effective disinfectant and is routinely applied for treatment of drinking water and seafood. However, the retention of V. parahaemolyticus in oyster tissues has not yet been explored after using ClO 2 as a disinfectant. To address this lack of information, oysters ( Crassostrea gigas) were artificially contaminated with V. parahaemolyticus (ATCC 17802). Individual oysters, the gills and the digestive glands were analyzed by spreading supernatants from homogenized tissues onto thiosulfate–citrate–bile–salt sucrose agar and polymerase chain reaction assays on the resulting bacterial colonies. V. parahaemolyticus that bioaccumulated in different oyster tissues could be disinfected completely after 6 h of treatment with 20 mg/L of ClO 2. Thus, ClO 2 appears to be a candidate disinfectant for V. parahaemolyticus depuration in oysters. The digestive glands appear to be a promising target tissue for detection of bacterial pathogens in oysters, using either conventional methods or molecular assays. The shelf life of oysters was extended to at least 12 days following 6 h of ClO 2 treatment at 4 °C.

Disinfection of football protective equipment using chlorine dioxide produced by the ICA TriNova system

BackroundCommunity-associated methicillin-resistant Staphylococcus aureus outbreaks have occurred in individuals engaged in athletic activities such as wrestling and football. Potential disease reduction interventions include the reduction or elimination of bacteria on common use items such as equipment. Chlorine dioxide has a long history of use as a disinfectant. The purpose of this investigation was to evaluate the ability of novel portable chlorine dioxide generation devices to eliminate bacteria contamination of helmets and pads used by individuals engaged in football.MethodsIn field studies, the number of bacteria associated with heavily used football helmets and shoulder pads was determined before and after overnight treatment with chlorine dioxide gas. Bacteria were recovered using cotton swabs and plated onto trypticase soy agar plates. In laboratory studies, Staphylococcus aureus was applied directly to pads. The penetration of bacteria into the pads was determined by inoculating agar plates with portions of the pads taken from the different layers of padding. The ability to eliminate bacteria on the pad surface and underlying foam layers after treatment with chlorine dioxide was also determined.ResultsRates of recovery of bacteria after treatment clearly demonstrated that chlorine dioxide significantly (p < 0.001) reduce and eliminated bacteria found on the surface of pads. For example, the soft surface of shoulder pads from a university averaged 2.7 × 103 recoverable bacteria colonies before chlorine dioxide treatment and 1.3 × 102 recoverable colonies after treatment. In addition, the gas was capable of penetrating the mesh surface layer and killing bacteria in the underlying foam pad layers. Here, 7 × 103 to 4.5 × 103 laboratory applied S. aureus colonies were recovered from underlying layers before treatment and 0 colonies were present after treatment. Both naturally occurring bacteria and S. aureus were susceptible to the treatment process.ConclusionResults of this study have shown that chlorine dioxide can easily and safely be used to eliminate bacteria contamination of protective pads used by football players. This could serve to reduce exposure to potential pathogens such as the methicillin-resistant Staphylococcus aureus among this group of individuals.

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.

Combined treatment of fumaric acid with aqueous chlorine dioxide or UV-C irradiation to inactivate Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes inoculated on alfalfa and clover sprouts

Abstract Effect of fumaric acid, chlorine dioxide (ClO2), and UV-C treatment was examined on the inactivation of microorganisms in alfalfa and clover sprouts. Clover sprouts were irradiated with UV-C light (1–10 kJ/m2), and the treatment decreased the population of total aerobic bacteria by 1.03–1.45 log CFU/g. Clover sprouts inoculated with pathogenic bacteria were treated with various concentration of fumaric acid, and 0.5 g/100 ml fumaric acid treatment was the most effective. In addition, the combined treatment of fumaric acid (0.5 g/100 ml)/UV-C (1 kJ/m2) reduced the populations of Escherichia coli O157:H7, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes inoculated on clover sprouts by 3.02, 2.88, and 2.35 log CFU/g. Alfalfa sprouts were treated with ClO2, fumaric acid, and the combination of fumaric acid/ClO2. The combined treatment was the most effective, and it reduced the total aerobic bacteria by 3.18 log CFU/g as well as the initial populations of E. coli O157:H7, S. typhimurium, and L. monocytogenes inoculated on alfalfa sprouts by 4.06, 3.57, and 3.69 log CFU/g. These results suggest that the combined treatment of fumaric acid with UV-C or ClO2 can be useful for improving the microbial safety of alfalfa and clover sprouts.

Effects of Nonthermal Processes on the Inactivation of Microorganisms and Antioxidants in Minimally Processed Vegetables

Effects of several nonthermal disinfection processes, including high pressure carbon dioxide treatment (HCT), gaseous chlorine dioxide treatment (GCT) and pulsed xenon treatment (PXT), on the inactivation of microorganisms and antioxidants in ten cut vegetables (red paprika, green pepper, cucumber, cabbage, lettuce, mizuna, celery, onion, carrot, and bean sprout) were investigated. HCT (6 or 10 MPa, 10 min, 35°C) showed similar inactivation effects on microorganisms using conventional NaOCl treatment (100 ppm, 10 min) by controlling pressure. However, HCT caused a loss of more antioxidants such as vitamin C and phenolic compounds in cut vegetables under severe conditions. In addition, HCT softened the leaf vegetables, cabbage, lettuce, and mizuna. All samples after PXT (500 J, 10 times) had the same antioxidant contents and DPPH radical scavenging activities as the untreated intact samples, suggesting PXT could be a disinfection method that does not influence the antioxidants in cut vegetables. For inactivation of microorganism, PXT decreased the viable cell count by about 10-fold, but not significantly. On the other hand, GCT (10 ppm, 30 min) showed almost the same microorganism inactivation as NaOCl treatment. The loss of vitamin C and phenolic compounds due to GCT were negligible. These results suggest that GCT might be a promising nonthermal disinfection treatment for cut vegetables.

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.

Molecular epidemiology of Legionella pneumophila serogroup 1 isolates following long-term chlorine dioxide treatment in a university hospital water system

This paper describes the results of a five-year monitoring programme applied to the water distribution system of the University Hospital of Pisa (Italy). The purpose of the programme was to evaluate the efficacy of an integrated water safety plan in controlling Legionella spp. colonisation of the potable water system. The impact of the safety plan on the ecology of legionella in the water network was evaluated by studying the genetic variability and the chlorine susceptibility of the strains isolated prior to, and throughout, the application of continuous chlorine dioxide treatment. After 45 months of water hyperchlorination, Legionella spp. were still present but the positive supply points were reduced by 79.4%. The samples exceeding 10(3)cfu/L were reduced by 83.8% and the mean counts showed a decrease of 94.6%. The majority of the isolates belonged to Legionella pneumophila serogroup 1 (overall positivity rate: 161/423; 38%). Molecular typing was performed on 61 isolates (37.9% of the positive samples) selected on spatial and temporal criteria. This revealed the circulation and the persistence in the hospital environment of three prevalent types of L. pneumophila Wadsworth, demonstrating allelic and electrophoretic characteristic profiles and different chlorine susceptibility. Two of these, one predominant and pre-dating the sanitation regimen, and one other isolated after three years of water treatment, were chlorine tolerant. Despite the ineffectiveness of chlorine dioxide in eradicating L. pneumophila, the risk management plan adopted appeared to discourage further cases of nosocomial legionellosis.

Effect of Aqueous Chlorine Dioxide Treatment on the Microbial Growth and Quality of Chicken Legs during Storage

The effect of aqueous chlorine dioxide (ClO₂) treatment on microbial growth and quality of chicken leg during storage was examined. Chicken leg samples were treated with 0, 50, and 100 ppm of ClO₂ solution and stored at 4℃. Aqueous ClO₂ treatment significantly decreased the populations of total aerobic bacteria, yeast and mold, and coliforms in chicken leg. One hundred ppm ClO₂ treatment reduced the initial populations of total aerobic bacteria, yeast and mold, and coliforms by 0.93, 1.15, and 0.94 log CFU/g, respectively. The pH and volatile basic nitrogen values in the chicken leg decreased with increasing aqueous ClO₂ concentration, while concentrations thiobarbituric acid reactive substances (TBARS) increased during storage regardless of aqueous ClO₂ concentration. Sensory evaluation results revealed that the quality of the chicken leg treated with aqueous ClO₂ during storage was better than that of the control. These results indicate that aqueous ClO₂ treatment can be useful for improving the microbial safety of chicken leg during storage.

Inactivation of Listeria monocytogenes and Campylobacter jejuni in Chicken by Aqueous Chlorine Dioxide Treatment

Aqueous chlorine dioxide (ClO₂) treatment was used for the inactivation of Listeria monocytogenes and Campylobacter jejuni in chicken. Chicken breasts and legs were inoculated with 8~9 log CFU/g of Listeria monocytogenes and Campylobacter jejuni, respectively, and then treated with 0, 50, and 100 ppm of ClO₂ solution. Aqueous ClO₂ treatment decreased the populations of the pathogenic bacteria on the chicken samples. One hundred ppm ClO₂ treatment on the chicken breast and leg reduced the populations of Listeria monocytogenes and Campylobacter jejuni by 0.61~1.93 and 0.99~1.21 log CFU/g, respectively. Aqueous ClO₂ treatment affected the microbial growth during storage at 4oC by decreasing the initial microbial populations. These results clearly suggest that aqueous ClO₂ treatment should be useful in improving the microbial safety of chicken during storage and extending the shelf life.