sodium-hypochlorite and chlorine-dioxide

This review aims to provide relevant, aggregate information about a variety of disinfectants and antiseptics, along with potential utility and limitations. While not exhaustive, this review's goal is to add to the body of literature available on this topic and give interventional providers and practitioners an additional resource to consider when performing procedures.. In the current SARS-CoV2 epidemiological environment, infection control and costs associated with healthcare-associated infections (HAIs) are of paramount importance. Even before the onset of SARS-CoV2, HAIs affected nearly 2million patients a year in the USA and resulted in nearly 90,000 deaths, all of which resulted in a cost to hospitals ranging from US$28 billion to 45 billion. The onset SARS-CoV2, though not spread by an airborne route, has heightened infection control protocols in hospitals and, as such, cast a renewed focus on disinfectants and their utility across different settings and organisms. The aim of this review is to provide a comprehensive overview of disinfectants used in the inpatient setting.

Topics: Chlorine Compounds; Cross Infection; Disinfectants; Ethanol; Formaldehyde; Glutaral; Humans; Hydrogen Peroxide; Iodophors; Oxides; Peracetic Acid; Phenol; Povidone-Iodine; Quaternary Ammonium Compounds; Sodium Hypochlorite; Triazines

The study aimed to compare the antibacterial effect of a novel disinfectant, hyper-pure chlorine dioxide (hClO. The distal root of the extracted lower molars was infected artificially with Enterococcus faecalis. The control group was rinsed with saline, and the test groups were irrigated with either 5% NaOCl or 0.12% hClO. Our results suggest that the functional penetration depth of NaOCl is at least 2-3 times more than published to date. There is no difference in disinfection effectiveness along the dentin tubules between NaOCl and hClO. Hyper-pure ClO

Topics: Anti-Infective Agents; Bacteria; Biofilms; Chlorine Compounds; Dental Pulp Cavity; Dentin; Enterococcus faecalis; Humans; Root Canal Irrigants; Sodium Hypochlorite

A carrier (stainless steel disc as a default carrier) testing method is very needed for use in the actual food-processing fields by following the standard guideline. Here, we aimed to compare the virucidal efficacy of four commercial liquid disinfectants, including sodium hypochlorite (NaOCl), chlorine dioxide (ClO

Topics: Chlorine Compounds; Disinfectants; Ethanol; Hepatitis A virus; Oxides; Peracetic Acid; Sodium Hypochlorite

This study aimed to evaluate an alternative to reduce trihalomethane (THM) formation in brewing water. THM affects the organoleptic properties of water and, consequently, the produced beer. Water treatment based on common chemicals such as alum and free chlorine could potentially form THM. Therefore, we studied the replacement of chemicals used in water treatment: aluminum sulfate by a tannin-based coagulant and sodium hypochlorite by chlorine dioxide. Experimentally, jar tests were conducted, and the role of coagulants and oxidizing agents was evaluated for: the removal of apparent color, turbidity, natural organic matter (NOM) and microorganisms; the formation of trihalomethanes (THM); and the sensory quality of the water. Using tannin-based coagulant with chlorine dioxide was associated with the lowest THM in treated water (1.7 µg/L) and higher satisfaction in the sensory analysis. However, using these chemicals make the water treatment more expensive than the current strategy. Overall, using the tannin-based coagulant and chlorine dioxide treatment is an alternative to produce water with a lower THM concentration, better physical-chemical, and sensory quality. These findings motivate further brewing experiments and a deeper economics evaluation considering the process's sustainability.

Topics: Chlorine; Disinfection; Oxidants; Sodium Hypochlorite; Tannins; Trihalomethanes; Water Pollutants, Chemical; Water Purification

Mango is highly consumed worldwide; nonetheless, its consumption has been related to foodborne outbreaks. This study was performed to evaluate bacterial transference during mango postharvest management and the feasibility of adopting chlorine dioxide as first choice disinfectant in mango packinghouse. Chlorine dioxide (3 and 5 ppm) and sodium hypochlorite (100 and 200 ppm) were evaluated at different turbidity and times against

Topics: Chlorine Compounds; Disinfectants; Food Handling; Food Microbiology; Fruit; Listeria monocytogenes; Mangifera; Oxides; Salmonella; Sodium Hypochlorite

Clam jeotgal, called "jogaejeotgal," is a Korean fermented seafood product with, generally, a high amount of added salt to inhibit the growth of pathogenic microorganisms. This study aimed to evaluate the efficacy of chlorine dioxide (ClO

Topics: Animals; Bivalvia; Chlorine Compounds; Disinfectants; Electrons; Food Irradiation; Food Preservation; Norovirus; Oxides; Republic of Korea; Shellfish; Sodium Hypochlorite; Virus Inactivation

The highly prescribed antidepressant, citalopram, as one of newly emerging pollutants, has been frequently detected in the aquatic environment. Citalopram oxidation was examined during sodium hypochlorite (NaOCl) and chlorine dioxide (ClO

Topics: Chlorine Compounds; Citalopram; Dimethylnitrosamine; Disinfectants; Halogenation; Hydrogen-Ion Concentration; Kinetics; Molecular Structure; Oxidation-Reduction; Oxides; Sodium Hypochlorite; Water

Bacterial biofilms formed on equipment surfaces are potential sources of cross-contamination and can be responsible for the spread of bacteria involved in food spoilage, such as some Enterobacteriaceae family members. In this study, the effect of chlorite-based disinfectants, including sodium hypochlorite (SH), chlorine dioxide (CD), strongly acidic electrolyzed water (StAEW), and neutral electrolyzed water (NEW), on inactivation of mono-biofilms of Enterobacter cloacae, Klebsiella oxytoca, and Citrobacter freundii was evaluated separately. All the strains were enumerated by the viable plate-count method after disinfection for 30 min. A comparison of the surviving cells after disinfection indicated that E. cloacae biofilms were more resistant to disinfectants than the biofilms of the other two strains, and treatment with all the disinfectants improved sanitizing. SH (200 mg/L) was the most effective in the reduction of cell number in the biofilms of all strains. Considering the safety of use and environmental protection, electrolyzed oxidizing water, especially StAEW, was a good suggestion for the inactivation of cells in K. oxytoca or C. freundii biofilms. These results suggest that the cells in biofilm of E. cloacae, K. oxytoca, and C. freundii were highly sensitive to chlorite-based disinfectants and provide insights into the efficacy of disinfectants in killing bacteria.. The Enterobacteriaceae biofilms formed on equipment surfaces, which can cause cross-contamination and food spoilage, are greatly challenging bacterial contaminants of food products. Electrolyzed oxidizing water is a novel, environmentally friendly disinfectant that can effectively treat Enterobacteriaceae biofilms. The results of this study may be used to design effective measures to disinfect biofilms on equipment contact surfaces.

Topics: Bacterial Infections; Biofilms; Chlorides; Chlorine; Chlorine Compounds; Citrobacter freundii; Disinfectants; Disinfection; Electrolysis; Enterobacter cloacae; Equipment and Supplies; Humans; Hydrogen Peroxide; Klebsiella oxytoca; Oxides; Sodium Hypochlorite

To ensure the safety of produce, including blueberries, elimination of potential pathogens is critical. This study evaluated the efficacy of antimicrobial washes when coupled with frozen storage against Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes on wild blueberries. Inoculated blueberries were sprayed with antimicrobial solutions at different concentrations for various contact times (chlorine dioxide -2.5, 5, 10, and 15 ppm for 10 s, 1, 5, and 10 min; chlorine -100, 150, and 200 ppm for 10s, 1, 5, and 10 min; lactic acid 1 and 2% for 5, 10 and 20 min) and following treatment, stored at -12 °C for 1 week. Compared to antimicrobial washing alone, the additional freezing significantly reduced pathogens (P < 0.05). Concentrations of all three antimicrobials combined with freezing reduced L. monocytogenes to undetectable levels (detection limit < 1 log CFU/g). The greatest reduction of E. coli O157:H7 (4.4 log CFU/g) and Salmonella (5.4 log CFU/g) was achieved by 2% lactic acid or 200 ppm Cl

Topics: Anti-Infective Agents; Blueberry Plants; Chlorine; Chlorine Compounds; Colony Count, Microbial; Consumer Product Safety; Disinfectants; Escherichia coli O157; Food Contamination; Food Microbiology; Food Preservation; Food Quality; Food Storage; Freezing; Humans; Lactic Acid; Listeria monocytogenes; Oxides; Salmonella typhimurium; Sodium Hypochlorite; Temperature; Time Factors

Microbial contamination is an unavoidable problem in industrial processes. Sodium hypochlorite (SH) is the most common biocide used for industrial disinfection. However, in view of the current societal concerns on environmental and public health aspects, there is a trend to reduce the use of this biocide as it can lead to the formation of organochlorinated carcinogenic compounds. In this work the efficacy of SH was assessed against Escherichia coli in planktonic and biofilm states and compared with three alternative chlorine-based biocides: neutral electrolyzed oxidizing water (NEOW), chlorine dioxide (CD) and sodium dichloroisocyanurate (NaDCC). The planktonic tests revealed that SH had the fastest antimicrobial action, NaDCC exhibited the highest antimicrobial rate and NEOW caused the highest antimicrobial effects. Additionally, NEOW was the biocide that allowed the highest formation of reactive oxygen species (ROS). In biofilm control, NEOW and CD were the most efficient biocides causing 3.26 and 3.20 log CFU·cm

Topics: Biofilms; Chlorine Compounds; Disinfectants; Equipment Contamination; Escherichia coli; Industrial Microbiology; Microbial Viability; Oxides; Reactive Oxygen Species; Sodium Hypochlorite; Time Factors; Triazines; Water

The Bio-response Operational Testing and Evaluation (BOTE) Project was a cross-government effort designed to operationally test and evaluate a response to a biological incident (release of Bacillus anthracis [Ba] spores, the causative agent for anthrax) from initial public health and law enforcement response through environmental remediation. The BOTE Project was designed to address site remediation after the release of a Ba simulant, Bacillus atrophaeus spp. globigii (Bg), within a facility, drawing upon recent advances in the biological sampling and decontamination areas. A key component of response to a biological contamination incident is the proper management of wastes and residues, which is woven throughout all response activities. Waste is generated throughout the response and includes items like sampling media packaging materials, discarded personal protective equipment, items removed from the facility either prior to or following decontamination, aqueous waste streams, and materials generated through the application of decontamination technologies. The amount of residual contaminating agent will impact the available disposal pathways and waste management costs. Waste management is an integral part of the decontamination process and should be included through "Pre-Incident" response planning. Overall, the pH-adjusted bleach decontamination process generated the most waste from the decontamination efforts, and fumigation with chlorine dioxide generated the least waste. A majority of the solid waste generated during pH-adjusted bleach decontamination was the nonporous surfaces that were removed, bagged, decontaminated ex situ, and treated as waste. The waste during the two fumigation rounds of the BOTE Project was associated mainly with sampling activities. Waste management activities may represent a significant contribution to the overall cost of the response/recovery operation. This paper addresses the waste management activities for the BOTE field test.. Management of waste is a critical element of activities dealing with remediation of buildings and outdoor areas following a biological contamination incident. Waste management must be integrated into the overall remediation process, along with sampling, decontamination, resource management, and other important response elements, rather than being a stand-alone activity. The results presented in this paper will provide decision makers and emergency planners at the federal/state/tribal/local level information that can be used to integrate waste management into an overall systems approach to planning and response activities.

Topics: Air Pollution, Indoor; Biohazard Release; Chlorine Compounds; Decontamination; Disinfectants; Equipment Contamination; Hydrogen Peroxide; Hydrogen-Ion Concentration; Oxides; Refuse Disposal; Sodium Hypochlorite; Spores, Bacterial

Onions are one of the most widely utilized vegetables worldwide, with demand for fresh-cut onions steadily increasing. Due to heightened safety concerns and consumer demand, the implications of sanitizing and packaging on fresh-cut onion safety and quality need to be better understood. The objective of this study was to investigate the effect of produce sanitizers, in-package atmospheres, and their interactions on the growth of Salmonella Typhimurium, mesophilic aerobic bacteria, yeast and mold, and the physico-chemical quality of diced onions to determine the best sanitizer and in-package atmosphere combination for both safety and quality. Diced onions were inoculated or not with S. Typhimurium, sanitized in sodium hypochlorite, peroxyacetic acid, or liquid chlorine dioxide, and then packaged in either polylactic acid bags containing superatmospheric O2, elevated CO2/reduced O2, or air, or in polyethylene terephthalate snap-fit containers. Throughout 14 days of storage at 7 °C, packaged diced onions were assessed for their safety (S. Typhimurium), and quality (mesophilic aerobic bacteria, yeasts and molds, physico-chemical analyses, and descriptive and consumer acceptance sensory panels). While sanitizer affected (P<0.05) fewer parameters (S. Typhimurium, mesophiles, yeasts and molds, headspace CO2, weight loss, and pH), in-package atmosphere had a significant (P<0.05) effect on all parameters evaluated. Two-way interactions between sanitizer and atmosphere that affected S. Typhimurium and pH were identified whereas 3-way interactions (sanitizer, atmosphere and time) were only observed for headspace CO2. Sodium hypochlorite and elevated CO2/reduced O2 was the best sanitizer and in-package atmosphere combination for enhancing the safety and quality of packaged diced onions. In addition, this combination led to diced onions acceptable for purchase after 2 weeks of storage by trained and consumer panels.

Topics: Chlorine Compounds; Colony Count, Microbial; Consumer Product Safety; Disinfectants; Disinfection; Food Handling; Food Microbiology; Food Packaging; Microbial Sensitivity Tests; Onions; Oxides; Peracetic Acid; Safety; Salmonella typhimurium; Sodium Hypochlorite; Vegetables; Yeasts

Noroviruses are the leading cause of foodborne illness, and ready-to-eat foods are frequent vehicles of their transmission. Studies of the disinfection of fruits and vegetables are becoming numerous. It has been shown that strong oxidizing agents are more effective than other chemical disinfectants for inactivating enteric viruses. The aim of this study was to evaluate the efficacy of oxidizing disinfectants (sodium hypochlorite, chloride dioxide and peracetic acid) at inactivating noroviruses on fruits and vegetables, using a norovirus surrogate, namely murine norovirus 3, which replicates in cell culture. Based on plaque assay, solutions of peracetic acid (85 ppm) and chlorine dioxide (20 ppm) reduced the infectivity of the virus in suspension by at least 3 log10 units after 1 min, while sodium hypochlorite at 50 ppm produced a 2-log reduction. On the surface of blueberries, strawberries and lettuce, chlorine dioxide was less effective than peracetic acid and sodium hypochlorite, which reduced viral titers by approximately 4 logs. A surprising increase in the efficacy of sodium hypochlorite on surfaces fouled with artificial feces was noted.

Topics: Animals; Blueberry Plants; Cell Line; Chlorine Compounds; Disinfectants; Disinfection; Foodborne Diseases; Fragaria; Fruit; Lactuca; Mice; Norovirus; Oxidation-Reduction; Oxides; Peracetic Acid; Sodium Hypochlorite; Vegetables; Virus Inactivation

Preoxidation is manipulated to improve performance of algae and soluble manganese (Mn) removal by coagulation-sedimentation for water treatment plants (WTPs) when large amount of soluble Mn presents in algae-laden waters. This study aimed to investigate the effects of preoxidation on the performance of coagulation-sedimentation for the simultaneous removal of algae and soluble Mn, including ionic and complexed Mn. NaOCl, ClO2, and KMnO4 were used to pretreat such algae-laden and Mn containing waters. The variation of algal cell viability, residual cell counts, and concentrations of Mn species prior to and after coagulation-sedimentation step were investigated. Results show that NaOCl dosing was effective in reducing the viability of algae, but precipitated little Mn. ClO2 dosing had a strongest ability to lower algae viability and oxidize ionic and complexed soluble Mn, where KMnO4 dosing oxidized ionic and complexed Mn instead of reducing the viability of cells. Preoxidation by NaOCl only improved the algae removal by sedimentation, whereas most of soluble Mn still remained. On the other hand, ClO2 preoxidation substantially improved the performance of coagulation-sedimentation for simultaneous removal of algae and soluble Mn. Furthermore, KMnO4 preoxidation did improve the removal of algae by sedimentation, but left significant residual Mn in the supernatant. Images from FlowCAM showed changes in aspect ratio (AR) and transparency of algae-Mn flocs during oxidation-assisted coagulation, and indicates that an effective oxidation can improve the removal of most compact algae-Mn flocs by sedimentation. It suggests that an effective preoxidation for reducing algal cell viability and the concentration of soluble Mn is a crucial step for upgrading the performance of coagulation-sedimentation.

Topics: Cell Survival; Chlorine Compounds; Eukaryota; Eutrophication; Manganese; Oxidation-Reduction; Oxides; Potassium Permanganate; Sodium Hypochlorite; Water Purification

The ability of Clostridium difficile to form highly resilient spores which can survive in the environment for prolonged periods causes major contamination problems. Antimicrobial 405 nm light is being developed for environmental decontamination within hospitals, however further information relating to its sporicidal efficacy is required. This study aims to establish the efficacy of 405 nm light for inactivation of C. difficile vegetative cells and spores, and to establish whether spore susceptibility can be enhanced by the combined use of 405 nm light with low concentration chlorinated disinfectants. Vegetative cells and spore suspensions were exposed to increasing doses of 405 nm light (at 70-225 mW/cm(2)) to establish sensitivity. A 99.9% reduction in vegetative cell population was demonstrated with a dose of 252 J/cm(2), however spores demonstrated higher resilience, with a 10-fold increase in required dose. Exposures were repeated with spores suspended in the hospital disinfectants sodium hypochlorite, Actichlor and Tristel at non-lethal concentrations (0.1%, 0.001% and 0.0001%, respectively). Enhanced sporicidal activity was achieved when spores were exposed to 405 nm light in the presence of the disinfectants, with a 99.9% reduction achieved following exposure to 33% less light dose than required when exposed to 405 nm light alone. In conclusion, C. difficile vegetative cells and spores can be successfully inactivated using 405 nm light, the sporicidal efficacy can be significantly enhanced when exposed in the presence of low concentration chlorinated disinfectants. Further research may lead to the potential use of 405 nm light decontamination in combination with selected hospital disinfectants to enhance C. difficile cleaning and infection control procedures.

Topics: Chlorine Compounds; Clostridioides difficile; Decontamination; Disinfectants; Drug Synergism; Light; Microbial Sensitivity Tests; Oxides; Sodium Hypochlorite; Spores, Bacterial; Triazines

Recent studies show that cationic amine-based water treatment polymers may be important precursors that contribute to formation of the probable human carcinogen N-nitrosodimethylamine (NDMA) during water treatment and disinfection. To better understand how water treatment parameters affect NDMA formation from the polymers, the effects of in situ chloramination, breakpoint chlorination, and pre-oxidation on the NDMA formation from the polymers were investigated. NDMA formation potential (NDMA-FP) as well as dimethylamine (DMA) residual concentration were measured from poly(epichlorohydrin dimethylamine) (polyamine) and poly(diallyldimethylammonium chloride) (polyDADMAC) solutions upon reactions with oxidants including free chlorine, chlorine dioxide, ozone, and monochloramine under different treatment conditions. The results supported that dichloramine (NHCl2) formation was the critical factor affecting NDMA formation from the polymers during in situ chloramination. The highest NDMA formation from the polymers occurred near the breakpoint of chlorination. Polymer chain breakdown and transformation of the released DMA and other intermediates were important factors affecting NDMA formation from the polymers in pre-oxidation followed by post-chloramination. Pre-oxidation generally reduced NDMA-FP of the polymers; however, the treatments involving pre-ozonation increased polyDADMAC's NDMA-FP and DMA release. The strategies for reducing NDMA formation from the polymers may include the avoidance of the conditions favorable to NHCl2 formation and the avoidance of polymer exposure to strong oxidants such as ozone.

Topics: Ammonia; Chloramines; Chlorine Compounds; Dimethylamines; Dimethylnitrosamine; Halogenation; Oxidants; Oxides; Ozone; Polyamines; Polyethylenes; Quaternary Ammonium Compounds; Sodium Hypochlorite; Water Purification

The presence of pathogenic microorganisms in public spa pools poses a serious threat to human health. The problem is particularly acute in herbal spas, in which the herbs and microorganisms may interact and produce undesirable consequences. Accordingly, the present study investigated the effectiveness of a combined disinfectant containing chlorine dioxide and sodium hypochlorite in improving the water quality of a public herbal spa in Taiwan. Water samples were collected from the spa pool and laboratory tests were then performed to measure the variation over time of the microorganism content (total CFU and total coliforms) and residual disinfectant content given a single disinfection mode (SDM) with disinfectant concentrations of 5.2 × 10, 6.29 × 10, 7.4 × 10, and 11.4 × 10(-5) N, respectively. Utilizing the experience gained from the laboratory tests, a further series of on-site investigations was performed using three different disinfection modes, namely SDM, 3DM (once every 3 h disinfection mode), and 2DM (once every 2 h disinfection mode). The laboratory results showed that for all four disinfectant concentrations, the CFU concentration reduced for the first 6 h following SDM treatment, but then increased. Moreover, the ANOVA results showed that the sample treated with the highest disinfectant concentration (11.4 × 10(-5) N) exhibited the lowest rate of increase in the CFU concentration. In addition, the on-site test results showed that 3DM and 2DM treatments with disinfectant concentrations in excess of 9.3 × 10 and 5.5 × 10(-5) N, respectively, provided an effective reduction in the total CFU concentration. In conclusion, the experimental results presented in this study provide a useful source of reference for spa businesses seeking to improve the water quality of their spa pools.

Topics: Chlorine Compounds; Disinfectants; Disinfection; Environmental Monitoring; Oxides; Sodium Hypochlorite; Taiwan; Water Quality

In this study, we evaluated and compared the antibacterial activity of chlorine dioxide (ClO2) and sodium hypochlorite (NaClO) on various multidrug-resistant strains in the presence of bovine serum albumin and sheep erythrocytes to mimic the blood contamination that frequently occurs in the clinical setting. The 3 most important species that cause nosocomial infections, i.e., methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MDRP), and multidrug-resistant Acinetobacter baumannii (MDRA), were evaluated, with three representative strains of each. At a 10-ppm concentration, ClO2 drastically reduced the number of bacteria of all MDRP and MDRA strains, and 2 out of 3 MRSA strains. However, 10 ppm of NaClO did not significantly kill any of the 9 strains tested in 60 seconds (s). In addition, 100 ppm of ClO2 completely killed all MRSA strains, whereas 100 ppm of NaClO failed to significantly lower the number of 2 MRSA strains and 1 MDRA strain. A time-course experiment demonstrated that, within 15 s, 100 ppm of ClO2, but not 100 ppm of NaClO, completely killed all tested strains. Taken together, these data suggest that ClO2 is more effective than NaClO against MRSA, MDRP, and MDRA, and 100 ppm is an effective concentration against these multidrug-resistant strains, which cause fatal nosocomial infections.

Topics: Acinetobacter baumannii; Animals; Cattle; Chlorine Compounds; Disinfectants; Drug Resistance, Multiple, Bacterial; Erythrocytes; Methicillin-Resistant Staphylococcus aureus; Microbial Viability; Oxides; Pseudomonas aeruginosa; Serum Albumin, Bovine; Sheep; Sodium Hypochlorite

The synergistic effects of sequential treatments with chlorine dioxide (ClO2) and drying in killing Salmonella enterica on the surface of chicken eggshells were investigated. Initial experiments were focused on comparing lethalities of sodium hypochlorite (NaOCl) and ClO2. Eggs surface-inoculated with S. enterica in chicken feces as a carrier were immersed in water, NaOCl (50 or 200 μg/mL), or ClO2 (50 or 200 μg/mL) for 1 or 5 min. For 1-min treatments, lethal activities of sanitizers were not significantly different (P>0.05). However, after treatment with ClO2 for 5 min, reductions of S. enterica were significantly greater (P≤0.05) than reductions after treatment with water or NaOCl. The effect of treatment of eggs with ClO2 or NaOCl, followed by drying at 43% relative humidity and 25 °C for 24 and 48 h, were determined. Populations of S. enterica decreased during drying, regardless of the type of sanitizer treatment. ClO2 treatment, compared to water or NaOCl treatments, resulted in additional reductions of ca. >1.3 log CFU/egg during drying. This indicates that sequential treatments with ClO2 and drying induced synergistic lethal effects against S. enterica on the surface of eggshells. These observations will be useful when selecting a sanitizer to control S. enterica on the surface of eggshells and designing an effective egg sanitization system exploiting the synergistic lethal effects of sanitizer and drying.

Topics: Chlorine Compounds; Colony Count, Microbial; Desiccation; Disinfectants; Food Microbiology; Microbial Viability; Oxides; Salmonella enterica; Sodium Hypochlorite

Decontamination of bacterial endospores such as Bacillus anthracis has traditionally required the use of harsh or caustic chemicals. The aim of this study was to evaluate the efficacy of a chlorine dioxide decontaminant in killing Bacillus anthracis spores in solution and on a human skin simulant (porcine cadaver skin), compared to that of commonly used sodium hypochlorite or soapy water decontamination procedures. In addition, the relative toxicities of these decontaminants were compared in human skin keratinocyte primary cultures. The chlorine dioxide decontaminant was similarly effective to sodium hypochlorite in reducing spore numbers of Bacillus anthracis Ames in liquid suspension after a 10 minute exposure. After five minutes, the chlorine dioxide product was significantly more efficacious. Decontamination of isolated swine skin contaminated with Bacillus anthracis Sterne with the chlorine dioxide product resulted in no viable spores sampled. The toxicity of the chlorine dioxide decontaminant was up to two orders of magnitude less than that of sodium hypochlorite in human skin keratinocyte cultures. In summary, the chlorine dioxide based decontaminant efficiently killed Bacillus anthracis spores in liquid suspension, as well as on isolated swine skin, and was less toxic than sodium hypochlorite in cultures of human skin keratinocytes.

Topics: Animals; Bacillus anthracis; Cell Survival; Cells, Cultured; Chlorine Compounds; Disinfectants; Humans; Keratinocytes; Oxides; Skin; Sodium Hypochlorite; Spores, Bacterial; Swine; Time Factors

The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1:13.8% chlorine dioxide, Group 2:17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth.

Topics: Chlorine Compounds; Dental Pulp Cavity; Dentin; Edetic Acid; Hardness; Humans; Incisor; Maleates; Materials Testing; Microscopy, Atomic Force; Oxides; Root Canal Irrigants; Sodium Chloride; Sodium Hypochlorite; Time Factors

The aim of this study was to evaluate the effect of chlorine dioxide and various other more common irrigation solutions on the microhardness and surface roughness of root canal dentin. Fifty human maxillary central incisors were sectioned longitudinally and treated for 1 minute with 5 ml of the following aqueous solutions (v/v%): Group 1: 13.8% chlorine dioxide, Group 2: 17% ethylene diamine tetraacetic acid (EDTA). Group 3: 7% maleic acid, Group 4: 2.5% sodium hypochlorite (5 ml/min), Group 5: Saline (control). Specimens were subjected to microhardness and surface roughness testing. Chlorine dioxide and sodium hypochlorite reduced the microhardness more than other test agents. The highest surface roughness was produced with maleic acid. Chlorine dioxide should be used cautiously during chemomechanical preparation of the root canal system in order to prevent untoward damage to the teeth.

Topics: Chlorine Compounds; Dental Pulp Cavity; Dentin; Edetic Acid; Hardness; Humans; Maleates; Materials Testing; Microscopy, Atomic Force; Oxides; Root Canal Irrigants; Sodium Chloride; Sodium Hypochlorite; Tooth Apex

The porcine gastric mucin binding magnetic bead (PGM-MB) assay was used to evaluate the ability of chlorine, chlorine dioxide, peroxyacetic acid, hydrogen peroxide, and trisodium phosphate to inactivate human norovirus within 10% stool filtrate. One-minute free chlorine treatments at concentrations of 33 and 189 ppm reduced virus binding in the PGM-MB assay by 1.48 and 4.14 log₁₀, respectively, suggesting that chlorine is an efficient sanitizer for inactivation of human norovirus (HuNoV). Five minute treatments with 5% trisodium phosphate (pH~12) reduced HuNoV binding by 1.6 log₁₀, suggesting that TSP, or some other high pH buffer, could be used to treat food and food contact surfaces to reduce HuNoV. One minute treatments with 350 ppm chlorine dioxide dissolved in water did not reduce PGM-MB binding, suggesting that the sanitizer may not be suitable for HuNoV inactivation in liquid form. However a 60-min treatment with 350 ppm chlorine dioxide did reduce human norovirus by 2.8 log₁₀, indicating that chlorine dioxide had some, albeit limited, activity against HuNoV. Results also suggest that peroxyacetic acid has limited effectiveness against human norovirus, since 1-min treatments with up to 195 ppm reduced human norovirus binding by <1 log₁₀. Hydrogen peroxide (4%) treatment of up to 60 min resulted in minimal binding reduction (~0.1 log₁₀) suggesting that H₂O₂ is not a good liquid sanitizer for HuNoV. Overall this study suggests that HuNoV is remarkably resistant to several commonly used disinfectants and advocates for the use of chlorine (sodium hypochlorite) as a HuNoV disinfectant wherever possible.

Topics: Caliciviridae Infections; Chlorine; Chlorine Compounds; Disinfectants; Humans; Hydrogen Peroxide; Norovirus; Oxides; Peracetic Acid; Phosphates; Sodium Hypochlorite; Time; Virus Inactivation

Previously we found that the high purity chlorine-dioxide(ClO2) has a very potent disinfectant efficacy on oral pathogenic microorganisms and as a root canal irrigant it is able to eliminate the experimental Enterococcus faecalis(E. faecalis) infection from the root canal system. This study examines whether the presence of dentin powder influences the antibacterial efficacy of ClO 2.. In an in vitro dentin powder model the following irrigants were tested against planktonic E. faecalis: 2% chlorhexidine (CHX), 2.5% sodium hypochlorite (NaOCl), 0.12%ClO2 (Solumium) and one local root canal medicament: saturated Ca(OH)2. Survival of bacteria exposed to agents without and with human dentin powder or preincubated with dentin powder was investigated. The effect of the dentin powder on ClO2 concentration was investigated by titrations.. Without dentin powder ClO 2 killed all E. faecalis and delivered the best result already after 1 minute; however, after longer contact time with dentin the difference between the disinfectants disappeared. The presence of dentin powder decreased the concentration of ClO 2 and attenuated the antibacterial efficiency of ClO2 and Ca(OH)2, but did not decrease of CHX and NaOCl.Preincubation with dentin powder caused significant loss of antibacterial activity of all investigated agents, ClO2 and Ca(OH)2 having the highest reduction.. As the presence of dentin powder had a negative effect on the efficacy of disinfectants, the importance of elimination of dentin scrapings and smear layer from the root canal system during endodontic treatments is highly recommended. ClO 2 can be effective for a final rinse.

Topics: Calcium Hydroxide; Chlorhexidine; Chlorine Compounds; Culture Media; Dentin; Enterococcus faecalis; Humans; Oxides; Plankton; Powders; Root Canal Irrigants; Sodium Hypochlorite; Time Factors

We investigated the efficacy of sequential treatments of aqueous chlorine and chlorine dioxide and drying in killing Escherichia coli O157:H7 in biofilms formed on stainless steel, glass, plastic, and wooden surfaces. Cells attached to and formed a biofilm on wooden surfaces at significantly (P ≤ 0.05) higher levels compared with other surface types. The lethal activities of sodium hypochlorite (NaOCl) and aqueous chlorine dioxide (ClO₂) against E. coli O157:H7 in a biofilm on various food-contact surfaces were compared. Chlorine dioxide generally showed greater lethal activity than NaOCl against E. coli O157:H7 in a biofilm on the same type of surface. The resistance of E. coli O157:H7 to both sanitizers increased in the order of wood>plastic>glass>stainless steel. The synergistic lethal effects of sequential ClO₂ and drying treatments on E. coli O157:H7 in a biofilm on wooden surfaces were evaluated. When wooden surfaces harboring E. coli O157:H7 biofilm were treated with ClO₂ (200 μg/ml, 10 min), rinsed with water, and subsequently dried at 43% relative humidity and 22 °C, the number of E. coli O157:H7 on the surface decreased by an additional 6.4 CFU/coupon within 6 h of drying. However, when the wooden surface was treated with water or NaOCl and dried under the same conditions, the pathogen decreased by only 0.4 or 1.0 log CFU/coupon, respectively, after 12 h of drying. This indicates that ClO₂ treatment of food-contact surfaces results in residual lethality to E. coli O157:H7 during the drying process. These observations will be useful when selecting an appropriate type of food-contact surfaces, determining a proper sanitizer for decontamination, and designing an effective sanitization program to eliminate E. coli O157:H7 on food-contact surfaces in food processing, distribution, and preparation environments.

Topics: Anti-Infective Agents; Biofilms; Chlorine Compounds; Colony Count, Microbial; Desiccation; Escherichia coli; Escherichia coli O157; Food Handling; Food Microbiology; Glass; Microbial Viability; Oxides; Plastics; Sodium Hypochlorite; Stainless Steel; Water; Wood

Few standardized methods of cleaning and disinfecting equipment in zebrafish facilities have been published, even though the effectiveness of these procedures is vital to preventing the transmission of pathogenic organisms. Four chemical disinfectants and rinsing with municipal tap water were evaluated for their ability to disinfect nets used to capture zebrafish. The disinfectants included benzalkonium chloride+methylene blue, sodium hypochlorite, chlorine dioxide, and potassium peroxymonosulfate+sodium chloride for a soak time of 5 or 30 min. Disinfection effectiveness was evaluated by using an ATP-based system that measured the reduction in absolute number and percentage of relative light units. In addition, nets were cultured aerobically on blood and MacConkey agar plates to determine the number of bacteria remaining after disinfection procedures. Soaking nets in sodium hypochlorite for 30 min and in potassium peroxymonosulfate+sodium chloride for 5 or 30 min were effective means of disinfection, according to at least 90% reduction in the number of relative light units and no bacterial growth after cleaning. These results will aid facility managers, veterinarians and investigators in selecting net cleaning and disinfection protocols.

Topics: Animals; Aquaculture; Chlorine Compounds; Disinfectants; Disinfection; Oxides; Sodium Hypochlorite; Zebrafish

The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard microbiological challenges were developed by surface-associating typed Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis spores, or a clinical methicillin-resistant S. aureus (MRSA) strain on stainless steel, polypropylene, or fabric. All test coupons were subjected to 20-min biocidal aerosols of chlorine-matched (100 ppm) sodium hypochlorite, chlorine dioxide, or ECAS within a standard aerosolization chamber using a commercial humidifier under defined conditions. Biocidal treatment type and material surface had a significant effect on the number of microorganisms recovered from various material surfaces following treatment exposure. Under the conditions of the assay, the order of antimicrobial efficacy of biocidal aerosol treatment was as follows: ECAS > chlorine dioxide > sodium hypochlorite. For all biocides, greater antimicrobial reductions were seen when treating stainless steel and fabric than when treating plastic-associated microorganisms. The experimental fogging system and assay protocol designed within this study were shown capable of differentiating the comparative efficacies of multiple chlorine-matched biocidal aerosols against a spectrum of target organisms on a range of test surface materials and would be appropriate for testing other biocidal aerosol treatments or material surfaces.

Topics: Aerosols; Bacillus subtilis; Biological Assay; Chlorine Compounds; Colony Count, Microbial; Disinfectants; Electrochemical Techniques; Humidity; Methicillin-Resistant Staphylococcus aureus; Microbial Viability; Oxides; Polypropylenes; Pseudomonas aeruginosa; Sodium Hypochlorite; Solutions; Spores, Bacterial; Stainless Steel

We investigated the effectiveness of chlorine dioxide (ClO2) solution in comparison to sodium hypochlorite (NaOCl) and chlorhexidine gluconate (CHX) in the elimination of intracanal Enterococcus faecalis biofilm. Extracted human teeth were inoculated with E. faecalis. After preparation the canals were irrigated with ClO2, NaOCl, CHX or physiologic saline for control. Two and five days later bacterial samples were collected and streaked onto Columbia agar. CFU/mL were counted. The canal walls were investigated by scanning electron microscopy (SEM). The gas phase was investigated in an upside down Petri dish where E. faecalis was inoculated onto blood agar. The irrigants were placed on absorbent paper into the cover. Bacteria were detectable in the control group, but not in any of the irrigants groups. There was a massive reinfection 2 or 5 days after irrigation in the control group. The lowest reinfection was found after the ClO2 treatment. These findings were confirmed by SEM images. We observed an antibacterial effect of ClO2 and NaOCl gas phases on E. faecalis growth, but not of CHX. ClO2 eliminates intracanal biofilm and keeps canal nearly free from bacteria. We suggest the use of high purity ClO2 as a root canal irrigant in clinical practice.

Topics: Biofilms; Chlorine Compounds; Dental Disinfectants; Dental Pulp Cavity; Enterococcus faecalis; Humans; Oxides; Sodium Hypochlorite

This study examines the antibacterial properties of sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX), Listerine®, and high purity chlorine dioxide (Solumium, ClO2) on selected common oral pathogen microorganisms and on dental biofilm in vitro. Antimicrobial activity of oral antiseptics was compared to the gold standard phenol. We investigated Streptococcus mutans, Lactobacillus acidophilus, Enterococcus faecalis, Veillonella alcalescens, Eikenella corrodens, Actinobacillus actinomycetemcomitans and Candida albicans as some important representatives of the oral pathogens. Furthermore, we collected dental plaque from the upper first molars of healthy young students. Massive biofilm was formed in vitro and its reduction was measured after treating it with mouthrinses: CHX, Listerine® or hyper pure ClO2. Their biofilm disrupting effect was measured after dissolving the crystal violet stain from biofilm by photometer. The results have showed that hyper pure ClO2 solution is more effective than other currently used disinfectants in case of aerobic bacteria and Candida yeast. In case of anaerobes its efficiency is similar to CHX solution. The biofilm dissolving effect of hyper pure ClO2 is significantly stronger compared to CHX and Listerine® after 5 min treatment. In conclusion, hyper pure ClO2 has a potent disinfectant efficacy on oral pathogenic microorganisms and a powerful biofilm dissolving effect compared to the current antiseptics, therefore high purity ClO2 may be a new promising preventive and therapeutic adjuvant in home oral care and in dental or oral surgery practice.

Topics: Adolescent; Anti-Infective Agents, Local; Biofilms; Candida albicans; Chlorhexidine; Chlorine Compounds; Dental Disinfectants; Dental Plaque; Drug Combinations; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Mouthwashes; Oxides; Phenol; Salicylates; Sodium Hypochlorite; Students; Terpenes; Young Adult

Lettuce is a leafy vegetable widely used in industry for minimally processed products, in which the step of sanitization is the crucial moment for ensuring a safe food for consumption. Chlorinated compounds, mainly sodium hypochlorite, are the most used in Brazil, but the formation of trihalomethanes from this sanitizer is a drawback. Then, the search for alternative methods to sodium hypochlorite has been emerging as a matter of great interest. The suitability of chlorine dioxide (60 mg L(-1)/10 min), peracetic acid (100 mg L(-1)/15 min) and ozonated water (1.2 mg L(-1)/1 min) as alternative sanitizers to sodium hypochlorite (150 mg L(-1) free chlorine/15 min) were evaluated. Minimally processed lettuce washed with tap water for 1 min was used as a control. Microbiological analyses were performed in triplicate, before and after sanitization, and at 3, 6, 9 and 12 days of storage at 2 ± 1 °C with the product packaged on LDPE bags of 60 μm. It was evaluated total coliforms, Escherichia coli, Salmonella spp., psicrotrophic and mesophilic bacteria, yeasts and molds. All samples of minimally processed lettuce showed absence of E. coli and Salmonella spp. The treatments of chlorine dioxide, peracetic acid and ozonated water promoted reduction of 2.5, 1.1 and 0.7 log cycle, respectively, on count of microbial load of minimally processed product and can be used as substitutes for sodium hypochlorite. These alternative compounds promoted a shelf-life of six days to minimally processed lettuce, while the shelf-life with sodium hypochlorite was 12 days.

Topics: Bacterial Load; Brazil; Chlorine Compounds; Disinfectants; Disinfection; Enterobacteriaceae; Escherichia coli; Food Storage; Lactuca; Oxides; Ozone; Peracetic Acid; Salmonella; Sodium Hypochlorite; Temperature; Time Factors

Epidemiological studies have shown an association between consumption of disinfected drinking water and adverse health outcomes. The chemicals used to disinfect water react with occurring organic matter and anthropogenic contaminants in the source water, resulting in the formation of disinfection by-products (DBPs). The observations that some DBPs are carcinogenic in animal models have raised public concern over the possible adverse health effects for humans. Here, the modulation of liver cytochrome P450-linked monooxygenases (MFO) and the genotoxic effects in erythrocytes of Cyprinus carpio fish exposed in situ to surface drinking water in the presence of disinfectants, such as sodium hypochlorite (NaClO), chlorine dioxide (ClO(2)) and peracetic acid (PAA), were investigated in winter and summer. A complex induction/suppression pattern of CYP-associated MFOs in winter was observed for all disinfectants. For example, a 3.4- to 15-fold increase was recorded of the CYP2B1/2-linked dealkylation of penthoxyresorufin with NaClO (10 days) and PAA (20 days). In contrast, ClO(2) generated the most notable inactivation, the CYP2E1-supported hydroxylation of p-nitrophenol being decreased up to 71% after 10 days' treatment. In summer, the degree of modulation was modest, with the exception of CYP3A1/2 and CYP1A1 supported MFOs (62% loss after 20 days PAA). The micronucleus (MN) induction in fish circulating erythrocytes was also analysed as an endpoint of genotoxic potential in the same fish population. Significant increases of MN induction were detected at the latest sampling time on fish exposed to surface water treated with chlorinate-disinfectants, both in winter (NaClO) and summer (NaClO and ClO(2)), while no effect was observed in fish exposed to PAA-treated water. These results show that water disinfection may be responsible for harmful outcomes in terms of MFO perturbation and DNA damage; if extrapolated to humans, they ultimately offer a possible rationale for the increased urinary cancer risk recorded in regular drinking water consumers.

Topics: Animals; Carps; Chlorine Compounds; Comet Assay; Cytochrome P-450 Enzyme System; Disinfectants; DNA Damage; Drinking Water; Environmental Monitoring; Models, Animal; Nitrophenols; Oxides; Peracetic Acid; Seasons; Sodium Hypochlorite; Water Pollutants, Chemical

Efficacy of sanitizers in an overhead spray and brush roller system was examined for reducing Salmonella on unwaxed, mature green tomatoes. Surface inoculated tomatoes were treated in the overhead spray system for 5, 15, 30, and 60 s. A sodium hypochlorite (NaOCl) study tested NaOCl (25, 50, and 100 mg/L) against a water control. A sanitizer study examined NaOCl (100 mg/L), chlorine dioxide (ClO₂; 5 mg/L), peroxyacetic acid (PAA; 80 mg/L), and water. The overhead spray system was also compared to a scale-model flume. All NaOCl concentrations were significantly more effective at removing Salmonella than water and achieved at least a 3-log₁₀ CFU/mL reduction at different treatment times (P < 0.05). NaOCl (100 mg/L) achieved a 4 ± 1.8 log₁₀ CFU/mL reduction at 15 s. In the sanitizer study, NaOCl, ClO₂, and PAA achieved at least a 3-log₁₀ CFU/mL reduction at 15 s and between 3.9 and 5.5 log₁₀ CFU/mL reductions at 30 to 60 s. NaOCl (100 mg/L) in the overhead spray system significantly reduced more Salmonella than in the flume at 15 to 60 s. NaOCl flume treatment only reached a 1.3 ± 1.1 log₁₀ CFU/mL reduction at 15 s. Results of this study demonstrate the ability of sanitizers in the laboratory model overhead spray system to reduce Salmonella on tomato surfaces. An overhead spray system could be implemented instead of flumes to achieve higher pathogen reduction with less water and sanitizer use, thereby lowering packing costs.. The use of a non-recirculating, overhead spray brush roller system could offer a cost effective and efficacious way of washing tomatoes. The use large communal dump tanks in tomato processing has been suspected as a source of contamination in the tomato processing process. If effective, the brush roller system could augment or possible replace currently used dump tanks.

Topics: Bacterial Adhesion; Chlorine Compounds; Colony Count, Microbial; Cost Savings; Disinfectants; Food Preservation; Fruit; Osmolar Concentration; Oxides; Peracetic Acid; Salmonella; Salmonella Food Poisoning; Sodium Hypochlorite; Solanum lycopersicum; Species Specificity; Surface Properties; Time Factors

The objective of this study was to evaluate the efficacy of individual sanitizing agents (sodium hypochlorite, SH; peracetic acid, PA; chlorine dioxide, CD) and the combination of CD and PA on reducing the total aerobic bacteria, coliforms as well as their effects on ascorbic acid (Vc), chlorophyll, and a* value of Chinese chives. All sanitizing treatments significantly (P < 0.05) reduced microorganisms compared to the control. After treatment with single SH, PA, and CD, the reduction of the total aerobic bacteria on Chinese chives was <1.0 log CFU/g (where colony-forming units is CFU), approximately 1.68 to 2.22 log CFU/g, and approximately 0.99 to 2.85 log CFU/g, respectively. The greatest reduction of total aerobic bacteria achieved by the combination of 40 ppm CD, 150 ppm PA for 8 min, was 2.45 log CFU/g. This treatment had a slight discoloration effect as indicated by a* value and chlorophyll content; and is therefore the optimal combination for reducing microorganisms on Chinese chives.. Fresh-cut vegetables are known to be susceptible to contamination; and subsequent growth of microorganisms result in quality concerns. Chinese chive leaves are hollow, cylindrical, and are more inclined to accumulate microbes. Currently, there is limited information on the decontamination of Chinese chives. This research focused on the evaluation of sanitation options for fresh-cut Chinese chives; and the information obtained should be applicable and useful in other fresh-cut vegetables.

Topics: Bacteria, Aerobic; Chive; Chlorine Compounds; Colony Count, Microbial; Decontamination; Disinfectants; Evaluation Studies as Topic; Food Contamination; Food Handling; Food Microbiology; Oxides; Peracetic Acid; Sodium Hypochlorite

A sensitive and rapid method to evaluate toxic and genotoxic properties of drinking water supplied from Lake Trasimeno (Umbria, Central Italy) was worked out analysing bile in Cyprinus carpio exposed for 20 d to lake water treated with 3 different disinfectants, sodium hypochlorite (NaClO), chlorine dioxide (ClO(2)) and peracetic acid (PAA). Fish were sacrificed at 0, 10 and 20 d in order to investigate the time course of these endpoints. An aliquot of bile samples was fractionated by adsorption on C(18) silica cartridges and the genotoxic potential of whole bile and of bile fractions was evaluated by the single-cell microgel-electrophoresis (comet) assay on human colonic adenocarcinoma cells (Caco-2). Bile (both whole and fractionated) from specimens exposed to the three disinfectants always showed a genotoxic activity as compared to the control group. The results of this study provide evidence that all three disinfectants cause an increase in bile genotoxicity of chronically exposed fish.

Topics: Animals; Bile; Biomarkers; Caco-2 Cells; Carps; Chlorine Compounds; Disinfectants; Humans; Mutagenicity Tests; Mutagens; Oxides; Peracetic Acid; Sodium Hypochlorite; Water Pollutants, Chemical

Nitrosamines are a class of emerging disinfection by-products (DBPs), which are mainly formed when water is treated by chloramination. Nitrosamines are highly carcinogenic and are hence a major concern for drinking water supplies. Although dissolved organic nitrogen (DON) compounds such as dimethylamine (DMA) have been recognized as important precursors of nitrosamines, many of them have not been identified, especially those used in consumer products. In this study, nine representative nitrogenous organic compounds with different DON characteristics and structures were selected to react with free chlorine, chlorine dioxide and monochloramine, respectively, for their DBP formation characteristics (nitrosamines, trihalomethanes (THMs) and haloacetic acids (HAAs)). It was found that in addition to DMA, benzyldimethyltetradecylamine (benzalkonium chloride, BKC) and 3-(N,N-dimethyloctyl-ammonio)propanesulfonate (3-N,N-DAPSIS) inner salt were potent precursors for carbonated DBPs (C-DBPs) and nitrogenated DBPs (N-DBPs). The DBP formation potential (DBPFP) tests showed that 1 mM of BKC formed more than 2 × 10(5) ng/L of N-nitrosodimethylamine (NDMA) when treated with monochloramine and high levels of C-DBPs (2713 ± 145 μg/L of THMs and 356 ± 5 μg/L of HAAs) when treated with chlorine. 3-N,N-DAPSIS was a less potent DBP precursor: 1 mM of 3-N,N-DAPSIS generated 1155 ± 7 ng/L of NDMA, 1351 ± 66 μg/L of THMs and 188 ± 1 μg/L of HAAs. DMA, 3-N,N-DAPSIS and BKC were examined for their DBPFPs at various pH and temperatures to determine the impact of pH and reaction temperature on DBP yields and their formation mechanisms. The results showed that DBP yields apparently increased with rising temperature. However, no consistent correlations were observed between DBPs yields and pH. Bromide shifted the DBP species into brominated DBPs, and this phenomenon was more apparent when BKC was treated with chloramine.

Topics: Bromides; Carbon; Chloramines; Chlorine Compounds; Disinfection; Hydrogen-Ion Concentration; Nitrogen; Nitrogen Compounds; Organic Chemicals; Oxides; Sodium Hypochlorite; Solubility; Temperature

Routine surface decontamination is an essential hospital and laboratory procedure, but the list of effective, noncorrosive disinfectants that kill spores is limited. We investigated the sporicidal potential of an aqueous chlorine dioxide solution and encountered some unanticipated problems. Quantitative bacteriological culture methods were used to determine the log(10) reduction of Bacillus anthracis (Sterne strain) spores following 3min exposure to various concentrations of aqueous chlorine dioxide solutions at room temperature in sealed tubes, as well as spraying onto plastic and stainless steel surfaces in a biological safety cabinet. Serial 10-fold dilutions of the treated spores were then plated on 5% sheep blood agar plates, and the survivor colonies were enumerated. Disinfection of spore suspensions with aqueous chlorine dioxide solution in sealed microfuge tubes was highly effective, reducing the viable spore counts by 8log(10) in only 3min. By contrast, the process of spraying or spreading the disinfectant onto surfaces resulted in only a 1log(10) kill because the chlorine dioxide gas was rapidly vaporised from the solutions. Full potency of the sprayed aqueous chlorine dioxide solution was restored by preparing the chlorine dioxide solution in 5% bleach (0.3% sodium hypochlorite). The volatility of chlorine dioxide can cause treatment failures that constitute a serious hazard for unsuspecting users. Supplementation of the chlorine dioxide solution with 5% bleach (0.3% sodium hypochlorite) restored full potency and increased stability for one week.

Topics: Bacillus anthracis; Chlorine Compounds; Colony Count, Microbial; Disinfectants; Oxides; Sodium Hypochlorite; Spores, Bacterial; Time Factors

The organic tissue dissolution properties of irrigating solutions are important for the success of endodontic treatment. Chlorine dioxide (ClO2) has been recently proposed as an irrigation solution in endodontics. The organic tissue dissolution property of sodium hypochlorite (NaOCl) is well-known and extensively investigated, but apparently no data have been published on tissue-dissolving properties of ClO2. The aim of this in vitro study was to compare organic tissue dissolution capacity of NaOCl and ClO2. In this study, 5.25% NaOCl, 13.8% ClO2, and, as a control, isotonic saline solutions (0.9% NaCl) were used. Thirty bovine pulp specimens were previously weighed and immersed for 20 minutes in each test solution (changing the solution every 2 minutes). The pulp specimens were then blotted dry and weighed again. The percentage of weight loss was calculated and statistically analyzed by using one-way analysis of variance and post hoc Tukey honestly significant difference tests. Saline solution did not dissolve the organic tissue. Both 5.25% NaOCl and 13.8% ClO2 dissolved the tissue pieces more effectively than saline control (P < .05). No statistically significant difference was found between the tissue-dissolving properties of 5.25% NaOCl and those of 13.8% ClO2 (P > .05). Within the limitations of this in vitro study, it was concluded that ClO2 and NaOCl are equally efficient for dissolving organic tissue.

Topics: Animals; Cattle; Chlorine Compounds; Debridement; Dental Disinfectants; Dental Pulp; Oxides; Root Canal Irrigants; Root Canal Preparation; Smear Layer; Sodium Hypochlorite; Solubility

Chlorine dioxide (ClO(2)) has been postulated as an alternative to sodium hypochlorite (NaClO) for fresh-cut produce sanitization to avoid risks associated with chlorination by-products. Experiments were performed to determine the prevention of cross-contamination of fresh-cut lettuce by Escherichia coli using chlorine dioxide (3 mg/L) or sodium hypochlorite (100 mg/L) as sanitation agents. The efficacy of these sanitation solutions was evaluated simulating as much as possible the conditions of a fresh-cut processing line. Thus, to evaluate the potential risk of cross-contamination during pre-washing, inoculated fresh-cut lettuce was pre-washed and after that non-inoculated lettuce was then pre-washed in the same water. After this pre-washing, non-inoculated lettuce was cross-contaminated, changing from 0 to 3.4 log units of E. coli cells. During washing with sanitizers, none of the tested sanitation agents significantly reduced E. coli counts in both inoculated and cross-contaminated lettuce. These results suggest that when cross-contamination occurs, even if the event is recent, subsequent sanitation steps are inefficient for inactivating E. coli cells on the vegetable tissue. However, chlorine dioxide and sodium hypochlorite solutions were able to inactivate most E. coli cells that passed from inoculated product to wash water. Therefore, they might be able to avoid cross-contamination between clean and contaminated product during the washing step. Scanning electron microscopy micrographs indicated that bacterial cells were mainly located in clusters or tissue stomata where they might be protected, which explains the low efficacy of sodium hypochlorite and chlorine dioxide solutions observed in this study.

Topics: Chlorine Compounds; Disinfectants; Escherichia coli; Food Contamination; Food Handling; Food Microbiology; Lactuca; Oxides; Sodium Hypochlorite

We evaluated the antiviral activity of a chlorine dioxide gas solution (CD) and sodium hypochlorite (SH) against feline calicivirus, human influenza virus, measles virus, canine distemper virus, human herpesvirus, human adenovirus, canine adenovirus and canine parvovirus. CD at concentrations ranging from 1 to 100 ppm produced potent antiviral activity, inactivating >or= 99.9% of the viruses with a 15 sec treatment for sensitization. The antiviral activity of CD was approximately 10 times higher than that of SH.

Topics: Adenoviruses, Canine; Adenoviruses, Human; Antiviral Agents; Calicivirus, Feline; Chlorine Compounds; Distemper Virus, Canine; Herpesvirus 1, Human; Measles virus; Orthomyxoviridae; Oxides; Parvovirus, Canine; Sodium Hypochlorite

We used a mixture of surrogates (Acinetobacter baumannii, Mycobacterium terrae, hepatitis A virus, and spores of Geobacillus stearothermophilus) for bioagents in a standardized approach to test environmental surface disinfectants. Each carrier containing 10 microl of mixture received 50 microl of a test chemical or saline at 22 +/- 2 degrees C. Disinfectant efficacy criteria were > or = 6 log(10) reduction for the bacteria and the spores and > or = 3 log(10) reduction for the virus. Peracetic acid (1,000 ppm) was effective in 5 min against the two bacteria and the spores but not against the virus. Chlorine dioxide (CD; 500 and 1,000 ppm) and domestic bleach (DB; 2,500, 3,500, and 5,000 ppm) were effective in 5 min, except for sporicidal activity, which needed 20 min of contact with either 1,000 ppm of CD or the two higher concentrations of DB.

Topics: Acinetobacter baumannii; Chlorine Compounds; Disinfectants; Disinfection; Environmental Microbiology; Geobacillus stearothermophilus; Hepatitis A virus; Microbial Viability; Nontuberculous Mycobacteria; Oxides; Peracetic Acid; Sodium Hypochlorite; Spores, Bacterial; Temperature; Time Factors

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.

Topics: Biofilms; Chlorine Compounds; Disinfectants; Listeria monocytogenes; Microbial Viability; Oxides; Phase Transition; Sodium Hypochlorite

The purpose of this study was to determine bactericidal efficacy of 0.04% stabilized chlorine dioxide, 3% sodium hypochlorite, 2% chlorhexidine gluconate, and sterile distilled water in a polymicrobial biofilm model.. Roots of 35 permanent bovine incisors had pulps extirpated, and their apical size and root length were standardized. Teeth were coated with mucin, inoculated with standardized suspensions of Streptococcus sanguinis, Actinomyces viscosus, Fusobacterium nucleatum, Peptostreptococcus micros, and Prevotella nigrescens and incubated anaerobically. Teeth were randomly divided into four groups and rinsed for 3 minutes with 15 mL of irrigant. Biofilms were harvested and spiral-plated on selective media. Numbers of bacteria in the harvested biofilms was determined via the standard spiral-plating methodology. Treatment groups were evaluated using the nonparametric Kruskal-Wallis procedure. Pair-wise comparisons among the four groups and five organisms were made using the Wilcoxon-Mann-Whitney procedure. Adjustments for multiple comparisons were made using the Holm method with p < 0.05.. Results provide strong evidence of a significant difference in levels of bactericidal activity associated with the type of irrigant for all five bacterial species tested. Levels of bactericidal activity were significantly higher for the NaOCl group than for the stabilized chlorine dioxide (ClO₂) group for S. sanguinis, A. viscosus, and P. nigrescens. Results for F. nucleatum and P. micros were not significant after the adjustment for multiple comparisons.. The triple-inoculation bovine tooth model system is a robust, consistent, and reproducible model system to study polymicrobial biofilms. It should be used with the knowledge expansion of biofilm structure and function as well as the development of antimicrobial protocols.

Topics: Actinomyces viscosus; Animals; Anti-Infective Agents, Local; Bacterial Load; Bacteriological Techniques; Biofilms; Cattle; Chlorhexidine; Chlorine Compounds; Dental Disinfectants; Dental Pulp Cavity; Fusobacterium nucleatum; Incisor; Materials Testing; Microbial Viability; Microscopy, Electron, Scanning; Oxides; Peptostreptococcus; Prevotella nigrescens; Random Allocation; Root Canal Irrigants; Sodium Hypochlorite; Streptococcus; Time Factors; Water

This study evaluated the inactivation of Bacillus anthracis Vollum spores dried on a nonporous surface using a superabsorbent polymer (SAP) gel containing commercially available liquid decontaminants.. The first phase determining the availability of the liquid decontaminant within the SAP showed that the SAP gel containing pH-adjusted sodium hypochlorite (NaOCl) inhibited B. anthracis growth while the water control SAP gel had no affect on growth. For testing surface decontamination, B. anthracis spores were dried onto steel coupons painted with chemical agent resistant coating and exposed to SAP containing either pH-adjusted NaOCl, chlorine dioxide (ClO(2)) or hydrogen peroxide/peracetic acid (H(2)O(2)/PA) for 5 and 30 min. At contact times of both 5 and 30 min, all of the SAP gels containing pH-adjusted NaOCl, ClO(2) or H(2)O(2)/PA inactivated B. anthracis spores at levels ranging from 2.2 to > or =7.6 log reductions.. Incorporation of three commercially available decontaminant technologies into a SAP gel promotes inactivation of B. anthracis spores without observable physical damage to the test surface.. This work provides preliminary data for the feasibility of using SAP in inactivating B. anthracis spores on a nonporous surface, supporting the potential use of SAP in surface decontamination.

Topics: Bacillus anthracis; Chlorine Compounds; Decontamination; Disinfectants; Gels; Hydrogen Peroxide; Microbial Viability; Oxides; Polymers; Sodium Hypochlorite; Spores, Bacterial

A study was conducted to determine the effects of three commercially available disinfectants on the reduction of Alicyclobacillus acidoterrestris spores in single-strength apple juice applied to stainless steel surfaces. Apple juice was inoculated with A. acidoterrestris spores, spread onto the surface of stainless steel chips (SSC), dried to obtain spore concentrations of approximately 10(4) CFU/cm2, and treated with disinfectants at temperatures ranging from 40 to 90 degrees C. The concentrations of disinfectants were 200, 500, 1,000, and 2,000 ppm of total chlorine for Clorox (CL) (sodium hypochlorite); 50, 100, and 200 ppm of total chlorine for Carnebon 200 (stabilized chlorine dioxide); and 1,500, 2,000, and 2,600 ppm for Vortexx (VOR) (hydrogen peroxide, peroxyacetic acid, and octanoic acid). For all temperatures tested, VOR at 2,600 ppm (90 degrees C) and CL at 2,000 ppm (90 degrees C) were the most inhibitory against A. acidoterrestris spores, resulting in 2.55- and 2.32-log CFU/cm2 reductions, respectively, after 2 min. All disinfectants and conditions tested resulted in the inactivation of A. acidoterrestris spores, with a maximum reduction of > 2 log CFU/cm2. Results from this study indicate that A. acidoterrestris spores, in single-strength apple juice, may be effectively reduced on stainless steel surface by VOR and CL, which may have practical applications in the juice industry.

Topics: Beverages; Chlorine Compounds; Colony Count, Microbial; Disinfectants; Dose-Response Relationship, Drug; Food Microbiology; Food Preservation; Gram-Positive Endospore-Forming Rods; Hydrogen Peroxide; Malus; Oxides; Peracetic Acid; Sodium Hypochlorite; Spores, Bacterial; Stainless Steel; Temperature

Besides the traditionally used sodium hypochlorite (20 and 200 mg L(-1)), alternative sanitizers such as peroxyacetic acid (80 and 250 mg L(-1)) and neutral electrolyzed oxidizing water (4.5 and 30 mg L(-1) free chlorine) as well as chlorine dioxide gas (1.54 mg L(-1)) were evaluated for their efficiency in reducing the microbial load of fresh-cut iceberg lettuce. An additional rinsing step with tap water and cooling of the sanitizing solutions, which are obvious for the fresh-cut industry, were not performed within the current study. The high doses of sodium hypochlorite and peroxyacetic acid tested within this study do not conform to the normally used concentrations within the fresh-cut industry. Neutral electrolyzed oxidizing water (30 mg L(-1)), peroxyacetic acid (250 mg L(-1)), and gaseous chlorine dioxide significantly reduced the total aerobic plate count of cut lettuce in comparison with water wash treatments alone. None of the treatments significantly affected the sensory quality of the lettuce, although small color changes were observed after colorimetric measurements. From a nutritional point of view water rinsing significantly decreased the vitamin C (maximum 35%) and phenol (maximum 17%) contents, but did not affect the carotenoid and α-tocopherol contents. Additional effects caused by adding a sanitizer to the wash water were not observed for vitamin C and phenols. Conversely, washing with 250 mg L(-1) peroxyacetic acid reduced the β-carotene content by about 30%, whereas using 200 mg L(-1) sodium hypochlorite reduced both the lactucaxanthin and the lutein contents by about 60%. Use of gaseous chlorine dioxide also had an impact on the lutein content (-18%). Furthermore, the α-tocopherol content was reduced by 19.7 and 15.4% when the two concentrations of neutral electrolyzed oxidizing water were used, respectively. These data represent the situation on day 0. In a next phase, shelf-life studies considering microbial and sensory quality and nutrient content should be conducted.

Topics: Carotenoids; Chlorine Compounds; Decontamination; Disinfectants; Food Handling; Humans; Lactuca; Nutritive Value; Oxidation-Reduction; Oxides; Peracetic Acid; Sensation; Sodium Hypochlorite; Water

Several decontamination agents including water, sodium hypochlorite, peroxyacetic acid, neutral electrolyzed oxidizing water, and chlorine dioxide gas were tested for their effectiveness to reduce the natural microflora on grated carrots. Microbial reductions of the total aerobic count obtained after the different treatments varied between 0.11 and 3.29 log colony-forming units (cfu)/g. Whether or not a decontamination step induced significant changes in the sensory attributes of grated carrots is highly dependent on the type and concentration of disinfectant. To maintain the nutritional value, the influence of the decontamination agents on carotenoid content, alpha-tocopherol content, total phenols, and antioxidant capacity was studied. Besides the part of the nutrients that was leached away from the cutting areas by water, the nutrient losses caused by adding sanitizers were rather limited. Compared with the untreated carrots alpha-tocopherol content was, however, significantly reduced when 250 ppm of peroxyacetic acid (-80%) or 200 ppm of sodium hypochlorite (-59%) was used. Additional losses in carotenoid content were caused by contact with chlorine dioxide gas (-9%). On the condition of an optimized decontamination process toward time and concentration, the microbial quality of fresh-cut carrots could be improved without negatively influencing their sensory quality and nutrient content.

Topics: alpha-Tocopherol; Carotenoids; Chlorine Compounds; Daucus carota; Decontamination; Food Handling; Nutritive Value; Oxides; Peracetic Acid; Sensation; Sodium Hypochlorite

To compare the effects of disinfection of chlorine dioxide (ClO2), sodium hypochlorite(NaClO) and their combination (ClO + NaClO) on simulative water samples.. The simulative water samples containing 5.0 x 10(4) - 5.0 x 10(5) cfu/100ml Escherichia coli were prepared in laboratory and disinfected by different doses of chlorine dioxide, sodium hypochlorite and their combination for 60, 60, 30 + 60 min respectively. The kill ratio for Escherichia coli, and the residual chlorine dioxide, and the product of chlorite ion (ClO2-) and total residual chlorine were detected and compared by the membrane filter(MF) technique and electrometric titration.. The minimum effective dosage (MED) for disinfect of simulative water samples were 0.4 mg/L of chlorine dioxide, 0.5 mg/L of sodium hypochlorite, and the 0.1 mg/L + 0.3 mg/L or 0.2 mg/L + 0.2 mg/L of their combination. By comparision with disinfection of ClO2 and NaClO alone, the residual chlorine dioxide increased 13.43% - 166.67% in simulative water sample under disinfection by the combination of ClO2 + NaClO, While chlorite ion decreased 13.11% - 19.97% and total residual chlorine increased 9.34% - 40.15%.. The combination of chlorine dioxide and sodium hypochlorite for disinfection of drinking water could achieve better effect of disinfection and decrease disinfection by-products as well.

Topics: Chlorine Compounds; Disinfectants; Dose-Response Relationship, Drug; Drug Synergism; Escherichia coli; Oxides; Sodium Hypochlorite; Water Microbiology; Water Purification

The effects of chlorine dioxide (ClO2), sodium hypochlorite (NaOCl), and hydrogen peroxide (H2O2) on cell death and the cell cycle of human gingival fibroblast (HGF) cells were examined.. The inhibition of HGF cell growth was evaluated using a Cell Counting Kit-8. The cell cycle was assessed with propidium iodide-stained cells (distribution of cells in G0/G1, S, and G2/M phases) using flow cytometry. The patterns of cell death (necrosis and apoptosis) were analyzed using flow cytometry with annexin V-FITC/PI staining.. The lethal doses for 50% of the cells (LD50) of ClO2, NaOCl, and H2O2 were 0.16, 0.79, and 0.11 mM, respectively. All three dental disinfectants induced G0/G1 cell cycle arrest. H2O2 induced apoptosis at concentrations of 0.05 and 0.1 mM, while NaOCl and ClO2 did not induce significant apoptosis at any concentration examined.. These results suggest that ClO2 is sufficient for use as a dental disinfectant compared with H2O2 or NaOCl.

Topics: Apoptosis; Cell Count; Cell Cycle; Cell Death; Cell Division; Cells, Cultured; Chlorine Compounds; Fibroblasts; G1 Phase; G2 Phase; Gingiva; Humans; Hydrogen Peroxide; Lethal Dose 50; Materials Testing; Necrosis; Oxidants; Oxides; Resting Phase, Cell Cycle; Root Canal Irrigants; S Phase; Sodium Hypochlorite

The spores of six strains of Bacillus anthracis (four virulent and two avirulent) were compared with those of four other types of spore-forming bacteria for their resistance to four liquid chemical sporicides (sodium hypochlorite at 5,000 ppm available chlorine, 70,000 ppm accelerated H2O2, 1,000 ppm chlorine dioxide, and 3,000 ppm peracetic acid). All test bacteria were grown in a 1:10 dilution of Columbia broth (with manganese) incubated at 37 degrees C for 72 h. The spore suspensions, heat treated at 80 degrees C for 10 min to rid them of any viable vegetative cells, contained 1 x 10(8) to 3 x 10(8) CFU/ml. The second tier of the quantitative carrier test (QCT-2), a standard of ASTM International, was used to assess for sporicidal activity, with disks (1 cm in diameter) of brushed and magnetized stainless steel as spore carriers. Each carrier, with 10 microl (> or = 10(6) CFU) of the test spore suspension in a soil load, was dried and then overlaid with 50 microl of the sporicide being evaluated. The contact time at room temperature ranged from 5 to 20 min, and the arbitrarily set criterion for acceptable sporicidal activity was a reduction of > or = 10(6) in viable spore count. Each test was repeated at least three times. In the final analysis, the spores of Bacillus licheniformis (ATCC 14580(T)) and Bacillus subtilis (ATCC 6051(T)) proved to be generally more resistant than the spores of the strains of B. anthracis tested. The use of one or both of the safe and easy-to-handle surrogates identified here should help in developing safer and more-effective sporicides and also in evaluating the field effectiveness of existing and newer formulations in the decontamination of objects and surfaces suspected of B. anthracis contamination.

Topics: Bacillus; Bacillus anthracis; Chlorine Compounds; Decontamination; Disinfectants; Hydrogen Peroxide; Oxides; Peracetic Acid; Sodium Hypochlorite; Spores, Bacterial; Stainless Steel

Escherichia coli O157:H7 contaminated spinach has recently caused several outbreaks of human illness in the USA and Canada. However, to date, there has been no study demonstrating an effective way to eliminate E. coli O157:H7 in spinach. Therefore, this study was conducted to investigate the effect of chemical sanitizers alone or in combination with packaging methods such as vacuum and modified atmosphere packaging (MAP) on inactivating E. coli O157:H7 in spinach during storage time. Spinach inoculated with E. coli O157:H7 was packaged in four different methods (air, vacuum, N(2) gas, and CO(2) gas packaging) following treatment with water, 100 ppm chlorine dioxide, or 100 ppm sodium hypochlorite for 5 min at room temperature and stored at 7+/-2 degrees C. Treatment with water did not significantly reduce levels of E. coli O157:H7 in spinach. However, treatment with chlorine dioxide and sodium hypochlorite significantly decreased levels of E. coli O157:H7 by 2.6 and 1.1 log(10)CFU/g, respectively. Levels of E. coli O157:H7 in samples packaged in air following treatments grew during storage time, whereas levels were maintained in samples packaged in other packaging methods (vacuum, N(2) gas, and CO(2) gas packaging). Therefore there were significant differences (about 3-4 log) of E. coli O157:H7 populations between samples packed in air and other packaging methods following treatment with chemical sanitizers after 7 days storage. These results suggest that the combination of treatment with chlorine dioxide and packaging methods such as vacuum and MAP may be useful for improving the microbial safety of spinach against E. coli O157:H7 during storage.

Topics: Carbon Dioxide; Chlorine Compounds; Colony Count, Microbial; Consumer Product Safety; Disinfectants; Escherichia coli O157; Food Microbiology; Food Packaging; Food Preservation; Hydrogen-Ion Concentration; Microbial Viability; Nitrogen; Oxides; Refrigeration; Sodium Hypochlorite; Spinacia oleracea; Vacuum

Epidemiological evidence suggests a link between consumption of chlorinated drinking water and various cancers. Chlorination of water rich in organic chemicals produces carcinogenic organochlorine by-products (OBPs) such as trihalomethanes and haloacetic acids. Since the discovery of the first OBP in the 1970s, there have been several investigations designed to determine the biological effects of single chemicals or small artificial OBP combinations. However, there is still insufficient information regarding the general biological response to these compounds, and further studies are still needed to evaluate their potential genotoxic effects. In the current study, we evaluated the effect of three drinking water disinfectants on the activity of cytochrome P450 (CYP)-linked metabolizing enzymes and on the generation of oxidative stress in the livers of male and female Cyprinus carpio fish (carp). The fish were exposed in situ for up 20 days to surface water obtained from the Trasmene lake in Italy. The water was treated with 1-2 mg/L of either sodium hypochlorite (NaClO) or chlorine dioxide (ClO2) as traditional disinfectants or with a relatively new disinfectant product, peracetic acid (PAA). Micronucleus (MN) frequencies in circulating erythrocytes from the fish were also analysed as a biomarker of genotoxic effect. In the CYP-linked enzyme assays, a significant induction (up to a 57-fold increase in the deethylation of ethoxyresorufin with PAA treatment) and a notable inactivation (up to almost a 90% loss in hydroxylation of p-nitrophenol with all disinfectants, and of testosterone 2beta-hydroxylation with NaClO) was observed in subcellular liver preparations from exposed fish. Using the electron paramagnetic resonance (EPR) spectroscopy radical-probe technique, we also observed that CYP-modulation was associated with the production of reactive oxygen species (ROS). In addition, we found a significant increase in MN frequency in circulating erythrocytes after 10 days of exposure of fish to water treated with ClO2, while a non-significant six-fold increase in MN frequency was observed with NaClO, but not with PAA. Our data suggest that the use of ClO2 and NaClO to disinfect drinking water could generate harmful OBP mixtures that are able to perturb CYP-mediated reactions, generate oxidative stress and induce genetic damage. These data may provide a mechanistic explanation for epidemiological studies linking consumption of chlorinated drinking water to incr

Topics: Animals; Carps; Chlorine Compounds; Cytochrome P-450 Enzyme System; DNA Damage; Electron Spin Resonance Spectroscopy; Liver; Male; Oxidative Stress; Oxides; Sodium Hypochlorite; Water Supply

This study was carried out in order to assess the effects of disinfectant-treatment on antioxidant response of Cyprinus carpio L. Therefore, enzymatic activities of glutathione S-transferases, glyoxalase I, glyoxalase II, glutathione peroxidases, glutathione reductase, catalase and total glutathione content of carp liver, exposed to surface water treated with three disinfectants for potabilization, sodium hypochlorite, chlorine dioxide and peracetic acid were investigated. Specimens of carp were exposed in four experimental tanks supplied with a continuous water flow from Lake Trasimeno (Italy), three of them treated with constant concentration of sodium hypochlorite, chlorine dioxide and peracetic acid, for 10 and 20 days, while the control tank was supplied with untreated lake water. Differences in biochemical parameters were observed in specimens following exposure to these disinfectants and mainly, chlorine compounds induced marked biochemical variations of carp liver, compared to those induced by peracetic acid treatment. Our results showed that antioxidant parameters of Cyprinus carpio could be used as biomarkers of oxidative stress when this species is exposed to disinfectants for water potabilization.

Topics: Animals; Carps; Chlorine Compounds; Disinfectants; Enzymes; Liver; Oxides; Peracetic Acid; Sodium Hypochlorite; Water Supply

The purpose of this study was to develop and evaluate the effectiveness of alternative disinfection techniques at the bench-scale level using wastewater from Ciudad Juarez, Mexico, as model feed. This paper presents findings on the effectiveness of UV radiation, peracetic acid (PAA), chlorine dioxide (ClO2), and hypochlorous acid (HOCl) as disinfectants for advanced primary treatment (APT) plant effluent. Wastewater samples for bench-scale testing were collected from an agua negra ("black water") ditch that is part of the combined sewer system in Ciudad Juarez. Bench-scale simulations of the APT process used in Ciudad Juarez were run using a jar test apparatus and aluminum sulfate [Al2(SO4)3] as the coagulant. Jar test effluent from the bench system was used for disinfection testing. The Mexican discharge quality standard for total coliforms is 10 000/100 mL. Ultraviolet radiation met this standard at a dose of 47.5 mW-s/cm2. Ultraviolet disinfection proved reliable and effective despite the presence of suspended solids, and UV dose effectiveness expressed as a total coliforms survival ratio was best explained by a linear regression model. The ClO2 dose ranged from 10 to 20 mg/L and was only effective under ambient temperature conditions found during the winter months; PAA disinfection never met Mexican standards. Chlorine disinfection was effective at a dose range of 8 to 10 mg/L on samples collected at low temperature conditions. Since the completion of this research, Ciudad Juarez has discontinued the use of chlorine disinfection because of its high cost and ineffectiveness.

Topics: Chlorine Compounds; Disinfectants; Disinfection; Enterobacteriaceae; Escherichia coli; Humans; Mexico; Oxides; Peracetic Acid; Sodium Hypochlorite; Time Factors; Ultraviolet Rays; Water Purification

The use of water flotation tanks during apple packing increases the risk of contamination of apples by spores of Penicillium expansum, which may accumulate in the recirculating water. Routine addition of sanitizers to the water may prevent such contamination. Sodium hypochlorite (NaOCl), chlorine dioxide (ClO2), and electrolyzed oxidizing (EO) water have varied activity against spores of P. expansum, and their effectiveness could be enhanced using surfactants. The objective of this study was to determine the ability of three nonionic surfactants, polyoxyethylene sorbitan monooleate (Tween 80), polyoxyethylene sorbitan monolaurate (Tween 20), and sorbitan monolaurate (Span 20), to enhance the efficacy of NaOCl, ClO2, and EO water against spores of P. expansum in aqueous suspension at various temperatures and pH conditions. The efficacy of NaOCl solutions was enhanced by the addition of surfactants at both pH 6.3 and pH 8 (up to 5 log CFU reduction). EO water and ClO2 were effective against P. expansum spores (up to 5 log CFU and 4 log CFU reduction, respectively), but addition of surfactants was not beneficial. All solutions were less effective at 4 degrees C compared to 24 degrees C irrespective of the presence of surfactants. Nonionic surfactants could potentially be used with NaOCl to improve control of P. expansum in flotation tanks, but the efficacy of such formulations should be validated under apple packing conditions.

Topics: Chlorine Compounds; Colony Count, Microbial; Disinfectants; Drug Synergism; Electrolysis; Food Contamination; Hydrogen-Ion Concentration; Malus; Oxidation-Reduction; Oxides; Penicillium; Polysorbates; Sodium Hypochlorite; Spores, Fungal; Surface-Active Agents; Temperature; Water

In this study, the persistence of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) was observed in feces, urine and water. In addition, the inactivation of SARS-CoV in wastewater with sodium hypochlorite and chlorine dioxide was also studied. In vitro experiments demonstrated that the virus could only persist for 2 days in hospital wastewater, domestic sewage and dechlorinated tap water, while 3 days in feces, 14 days in PBS and 17 days in urine at 20 degrees C. However, at 4 degrees C, the SARS-CoV could persist for 14 days in wastewater and at least 17 days in feces or urine. SARS-CoV is more susceptible to disinfectants than Escherichia coli and f2 phage. Free chlorine was found to inactivate SARS-CoV better than chlorine dioxide. Free residue chlorine over 0.5 mg/L for chlorine or 2.19 mg/L for chlorine dioxide in wastewater ensures complete inactivation of SARS-CoV while it does not inactivate completely E. coli and f2 phage.

Topics: Chlorine; Chlorine Compounds; Disinfectants; Escherichia coli; Feces; Humans; Levivirus; Oxides; Reverse Transcriptase Polymerase Chain Reaction; RNA, Viral; Severe acute respiratory syndrome-related coronavirus; Sewage; Sodium Hypochlorite; Urine; Virus Inactivation; Water Microbiology

The genotoxicity of two widely used drinking water disinfectants, sodium hypochlorite (NaClO) and chlorine dioxide (ClO(2)), and a new disinfectant, peracetic acid (PAA, CH(3)-CO-COOH), was evaluated in three short-term plant tests: (1) induction of anaphase chromosome aberrations in the root cells of Allium cepa, (2) micronucleus induction in the root cells of Vicia faba, and (3) micronucleus induction in Tradescantia pollen cells. The study was carried out in the laboratory by directly exposing the plants to several concentrations of the disinfectants in redistilled water at unadjusted (acid) and adjusted (neutral) pHs. Both 0.1 and 0.2 mg/l NaClO induced chromosome aberrations in the Allium cepa test at acid pH, but concentrations up to 0.5 mg/l of all the disinfectants were negative at neutral pH. Concentrations ranging from 0.1 to 0.5 mg/l NaClO, ClO(2,) and PAA induced micronuclei in Vicia faba at acid pH, while 1-2 mg/l NaClO and ClO(2) and 0.5-2 mg/l PAA gave positive responses at neutral pH. Most of concentrations of ClO(2) produced positive responses in the Tradescantia micronucleus test. In general, the highest levels of genotoxicity were observed under acid conditions; at acid pH, significant effects were induced by low concentrations of ClO(2) and PAA. Since the test concentrations of disinfectants are typical of those encountered in the biocidal treatment of tap water and similar concentrations are consumed daily by a large number of people, the genotoxicity of these compounds may constitute a significant public health concern.

Topics: Biological Assay; Cell Nucleus; Chlorine Compounds; Disinfectants; Hydrogen-Ion Concentration; Micronucleus Tests; Mutagenicity Tests; Onions; Oxides; Peracetic Acid; Plants; Sodium Hypochlorite; Tradescantia; Vicia faba; Water Purification

Surface water disinfection can lead to the formation of mutagenic/carcinogenic by-products derived from reactions with naturally occurring inorganic compounds. We investigated the feasibility and potential usefulness of an integrated approach to genotoxicity analysis of drinking water. The approach employed the Comet and micronucleus (MN) assays to evaluate the DNA and chromosomal damage produced by water extracts in human blood cells. Surface water samples from Lago Trasimeno (Italy) were collected in different seasons (July 2000, October 2000, February 2001, and June 2001), and samples were disinfected with sodium hypochloride (NaClO), chlorine dioxide (ClO(2)), or peracetic acid (PAA). Extracts of untreated and treated water were incubated with primary human leukocytes. The Comet assay revealed both strong seasonal variations and differences between samples processed by the three disinfection protocols. The three disinfectants increased the genotoxicity of the water collected in July 2000 and October 2000, with PAA producing the greatest amount of DNA damage. Extracts of raw water collected in February 2001 produced so much DNA damage that the relative genotoxic potentials of the three disinfectants could not be evaluated. No increase in MN frequency was detected in any of the samples. The multi-endpoint MN assay indicated, however, that our study samples (especially the sample collected in the February 2001) were cytotoxic. We conclude that this integrated approach to genotoxicity assessment may be useful both for the quality control of raw drinking water and to help compare the potential health risks associated with alternative disinfection processes.

Topics: Chlorine Compounds; Comet Assay; Disinfectants; DNA; Dose-Response Relationship, Drug; Feasibility Studies; Fresh Water; Humans; Leukocytes; Micronucleus Tests; Mutagenicity Tests; Oxides; Peracetic Acid; Seasons; Sodium Hypochlorite; Water Pollutants, Chemical; Water Purification

The purpose of this study was to measure the cytotoxicity of six endodontic irrigants on cultured gingival fibroblasts using the CyQuant assay. Human gingival fibroblasts were grown in Dulbecco's Modified Eagle Medium (DMEM) containing 10% fetal bovine serum at 37 degrees C and 5% CO(2). At confluence, cells were split, plated in 96-well plates and incubated for 24-h to allow attachment. The following irrigants were tested at various concentrations: Sodium hypochlorite (NaOCl); iodine potassium-iodide (IKI); Betadine scrub (BS); calcium hydroxide [Ca(OH)2]; chlorine dioxide (SCD) and DMEM (positive control). Experimental groups were compared by the logarithmic difference between the clinical and LD50 concentrations of a particular irrigant. The results showed that IKI and Ca(OH)2 were significantly less cytotoxic than SCD, NaOCl, and BS. In conclusion, IKI and Ca(OH)2 are well tolerated by human gingival fibroblasts.

Topics: Analysis of Variance; Calcium Hydroxide; Cell Proliferation; Cells, Cultured; Chlorine Compounds; Fibroblasts; Gingiva; Humans; Iodine Compounds; Lethal Dose 50; Oxides; Povidone-Iodine; Root Canal Irrigants; Sodium Hypochlorite

Clostridium difficile is an increasingly common nosocomial pathogen, and its spores are resistant to common environmental surface disinfectants. Many high-level disinfectants (eg, aldehydes) are unsuitable for environmental decontamination because they need several hours of contact to be sporicidal. This study tested the potential of selected oxidative microbicides to inactivate C. difficile spores on hard surfaces in relatively short contact times at room temperature.. The spores of a clinical isolate of C. difficile were tested using disks (1 cm diameter) of brushed stainless steel in a quantitative carrier test. The spores of C. sporogenes and Bacillus subtilis, common surrogates for evaluating sporicides, were included for comparison. The clostridia were grown separately in Columbia broth (CB), and B. subtilis was grown in a 1:10 dilution of CB. Each disk received 10 microL test spores with an added soil load, and the inoculum was dried. One disk each was placed in a glass vial and overlaid with 50 microL test formulation; controls received an equivalent volume of normal saline with 0.1% Tween 80. At the end of the contact time the microbicide was neutralized, the inoculum recovered from the disks by vortexing, the eluates were membrane filtered, and the filters placed on plates of recovery medium. The colony-forming units (CFU) on the plates were recorded after 5 days of incubation. The performance criterion was > or = 6 log(10) (> or = 99.9999%) reduction in the viability titer of the spores. The microbicides tested were domestic bleach with free-chlorine (FC) levels of 1000, 3000, and 5000 mg/L; an accelerated hydrogen peroxide (AHP)-based product with 70,000 mg/L H2O2 (Virox STF); chlorine dioxide (600 mg/L FC); and acidified domestic bleach (5000 mg/L FC).. Acidified bleach and the highest concentration of regular bleach tested could inactivate all the spores in < or = 10 minutes; Virox STF could do the same in < or = 13 minutes. Regular bleach with 3000 mg/L FC required up to 20 minutes to reduce the viability of the all the spores tested to undetectable levels; chlorine dioxide and the lowest concentration of regular bleach tested needed approximately 30 minutes for the same level of activity.. Acidified bleach, Virox STF, and regular bleach (3000-5000 mg/L FC) could inactivate C. difficile spores on hard environmental surfaces in approximately 10 to 15 minutes under ambient conditions. All of these products are strong oxidizers and should be handled with care for protection of staff, but acidified and regular bleach with high levels of FC also release chlorine gas, which can be hazardous if inhaled by staff or patients.

Topics: Chlorine Compounds; Clostridioides difficile; Disinfectants; Dose-Response Relationship, Drug; Environmental Microbiology; Hydrogen Peroxide; Oxides; Sodium Hypochlorite; Spores, Bacterial

The use of chlorinated disinfectants during drinking-water production has been shown to generate halogenated compounds as a result of interactions of humic acids with chlorine. Such chlorinated by-products have been shown to induce genotoxic effects and consumption of chlorinated drinking-water has been correlated with increased risk for cancer induction in human populations. The aim of this work was to test the potential genotoxic effects on circulating erythrocytes of the fish Cyprinus carpio exposed in vivo to well-waters disinfected with sodium hypochlorite (NaClO), chlorine dioxide (ClO2) or peracetic acid (CH3COO2H, PAA), in the absence or presence of standard humic acids (HA). The effects were measured by use of the micronucleus (MN) and the single-cell gel electrophoresis (Comet) assays at different sampling times after a 3-day exposure period. The exposure to chlorine disinfectants without the addition of HA produced a clear toxic effect. Significant cytogenetic damage (i.e. MN induction) was detected in fish populations exposed to both NaClO and ClO2 with humic acids. In the Comet assay, a significant decrease of DNA migration was observed in erythrocytes of specimens after exposure to NaClO-disinfected water without HA. No effects were observed in any other experimental condition.

Topics: Animals; Carps; Chlorine Compounds; Comet Assay; Disinfectants; DNA Damage; Erythrocytes; Humic Substances; Micronucleus Tests; Oxides; Peracetic Acid; Sodium Hypochlorite; Water Purification

Mutagenicity of drinking water is due not only to industrial, agricultural and urban pollution but also to chlorine disinfection by-products. Furthermore, residual disinfection is used to provide a partial safeguard against low level contamination and bacterial re-growth within the distribution system. The aims of this study were to further evaluate the genotoxic potential of the world wide used disinfectants sodium hypochlorite and chlorine dioxide in human leukocytes by the Comet assay and in Saccharomyces cerevisiae strain D7 (mitotic gene conversion, point mutation and mitochondrial DNA mutability, with and without endogenous metabolic activation) and to compare their effects with those of peracetic acid, proposed as an alternative disinfectant. All three disinfectants are weakly genotoxic in human leukocytes (lowest effective dose 0.2 p.p.m. for chlorine dioxide, 0.5 p.p.m. for sodium hypochlorite and peracetic acid). The results in S.cerevisiae show a genotoxic response on the end-points considered with an effect only at doses higher (5- to 10-fold) than the concentration normally used for water disinfection; sodium hypochlorite and peracetic acid are able to induce genotoxic effects without endogenous metabolic activation (in stationary phase cells) whereas chlorine dioxide is effective in growing cells. The Comet assay was more sensitive than the yeast tests, with effective doses in the range normally used for water disinfection processes. The biological effectiveness of the three disinfectants on S.cerevisiae proved to be strictly dependent on cell-specific physiological/biochemical conditions. All the compounds appear to act on the DNA and peracetic acid shows effectiveness similar to sodium hypochlorite and chlorine dioxide.

Topics: Chlorine Compounds; Comet Assay; Mutagens; Oxides; Peracetic Acid; Saccharomyces cerevisiae; Sodium Hypochlorite

The aim of this study was to evaluate the formation of toxic and genotoxic compounds in surface drinking waters treated with two widely used disinfectants, sodium hypochlorite (NaClO) and chlorine dioxide (ClO(2)), and a new disinfectant, peracetic acid (PAA). For this purpose a pilot plant was set up to add these biocides continuously to pre-filtered lake water flowing into three different basins. During three seasonal experiments, short-term in vivo tests (with plant, fish and molluscs) and in vitro tests (with bacteria, yeast and human cells) were carried out to evaluate the formation of genotoxic disinfection by-products (DBPs). Gas chromatography/mass spectrometry (GC/MS) was used to identify DBPs produced during the different treatments, microbiological analyses were performed to test the biocidal activity of the disinfectants, and chemical analyses were carried out to evaluate the quality of the water. The pilot drinking water plant under study was useful in studying the toxicity and genotoxicity of disinfected drinking water with this combined chemical/biotoxicological approach. This paper describes the setting up of the pilot plant and sets out/reports the results of the microbiological and chemical analyses.

Topics: Animals; Bacteria; Cell Culture Techniques; Chlorine Compounds; Disinfectants; Fishes; Humans; Mollusca; Mutagenicity Tests; Oxides; Plants; Risk Assessment; Sodium Hypochlorite; Water Pollutants, Chemical; Water Purification; Yeasts

The aim of this research was to study the influence of classic (sodium hypochlorite and chlorine dioxide) and alternative (peracetic acid [PAA]) disinfectants on the formation of mutagens in surface waters used for human consumption. For this proposal, in vivo genotoxicity tests (Comet and micronucleus assay) were performed in an experimental pilot plant set up near Lake Trasimeno (Central Italy). The effects were detected in different tissues (haemocytes for the Comet assay and gills for the micronucleus test [MN]) of Dreissena polymorpha exposed in experimental basins supplied with lake water with/without the different disinfectants. Specimen collection was performed before disinfectant input for both tests and after the start of disinfection (3 h and 20 days for the Comet assay and 10 and 20 days for micronucleus test, respectively) to assess short- and long- term exposure effects during three sampling campaigns (October 2000, February 2001, and June 2001). Seasonal differences in baseline levels of DNA migration and micronucleus frequency were observed. Raw water quality modulation on disinfection by-product formation was shown. The results of the micronucleus and Comet assays on zebra mussel cells after in situ exposure to water disinfected with the two chlorinated compounds clearly indicate DNA/by-product interaction. PAA did not induce either clastogenic/aneugenic effects or DNA damage on this bioindicator.

Topics: Animals; Bivalvia; Chlorine Compounds; Comet Assay; Disinfection; DNA Damage; Micronucleus Tests; Mutagens; Oxides; Peracetic Acid; Sodium Hypochlorite; Water Pollutants; Water Purification

A battery of in vitro short-term tests revealing different genetic end-points was set up in order to study surface-water genotoxicity after disinfection with different biocides: sodium hypochlorite (NaClO), chlorine dioxide (ClO(2)) and peracetic acid (PAA). The surface water both before and after disinfection was concentrated by adsorption on C(18) silica cartridges and the concentrates containing non-volatile organics were divided into different portions for chemical analyses and biological assays. The following in vitro tests were conducted on the water concentrates dissolved in DMSO: the Salmonella mutagenicity assay with S. typhimurium strains TA98 and TA100; the SOS Chromotest with Escherichia coli, the Microtox and Mutatox assays with Vibrio fischeri; and gene conversion, point mutation and mitochondrial DNA mutability assays with D7 diploid Saccharomices cerevisiae strain. The results show that the SOS Chromotest and the yeast assays are highly sensitive in detecting genotoxicity. The surface-water extracts were very often toxic to most of the test organisms considered, partially masking their potential mutagenic activity. Therefore, the assays with E. coli and with S. cerevisiae are more likely to show a mutagenic effect because these organisms are generally less sensitive to most toxic compounds. Among the tested disinfectants, NaClO and ClO(2) increased water genotoxicity, whereas PAA was able to slightly reduce raw water activity. However, because the organic compounds in the lake water varied with the season of the year, the disinfection processes, at times, both increased and decreased the raw water activity.

Topics: Chlorine Compounds; Disinfectants; Fresh Water; Italy; Linear Models; Mutagenicity Tests; Oxides; Peracetic Acid; Saccharomyces cerevisiae; Salmonella typhimurium; Seasons; Sodium Hypochlorite; Vibrio; Water Purification; Water Supply

Disinfection of surface drinking water, in particular water chlorination, results in many by-products with potential genotoxic and/or carcinogenic activity. In the present study, we evaluated the genotoxicity of surface water after treatment with different disinfectants by means of in situ plant genotoxicity assays (micronucleus and chromosomal aberration tests) which can detect both clastogenic and aneugenic effects. The study was carried out at a pilot plant using lake water after sedimentation and filtration. This water supplied four stainless steel basins: three basins were disinfected with sodium hypochlorite, chlorine dioxide, and peracetic acid and the fourth basin containing untreated lake water was used as a control. Plants were exposed in situ in the basins. The study was carried out using water collected in different seasons over a period of about 1 year in order to assess the treatments in different physical and chemical lake water conditions. The micronucleus test in root cells of Vicia faba (Vicia faba/MCN test) revealed genotoxicity in many samples of disinfected water. The micronucleus test in Tradescantia pollen cells and the chromosome aberration test in root cells of Allium cepa showed genotoxic effects only in some disinfected samples, but also revealed genotoxicity in raw water. The results of the study indicated that the Vicia faba/MCN test was the most sensitive plant assay for disinfected water and that peracetic acid disinfection produced similar or lower genotoxicity than sodium hypochlorite or chlorine dioxide treatment.

Topics: Chlorine Compounds; Chromosome Aberrations; Disinfectants; Fresh Water; Gas Chromatography-Mass Spectrometry; Micronucleus Tests; Mutagenicity Tests; Onions; Oxides; Peracetic Acid; Plant Roots; Plants; Sodium Hypochlorite; Tradescantia; Vicia faba; Water Purification

Topics: Anthrax; Bioterrorism; Chlorine Compounds; Decontamination; District of Columbia; Humans; Oxides; Sodium Hypochlorite

This study evaluated the effectiveness of three different disinfectant solutions against denture bioburden absorbed within the depth of acrylic resin. Specimens were taken from dentures that had been worn by the patients for 15 to 20 years and were scheduled for replacement.

Topics: Acrolein; Acrylic Resins; Bacteria; Chlorine Compounds; Colony Count, Microbial; Dental Disinfectants; Denture Bases; Denture Cleansers; Denture, Complete; Equipment Contamination; Humans; Hypochlorous Acid; Iodophors; Oxides; Sodium Hypochlorite

We conducted an epidemiological study in Liguria, Italy, on the association between somatic parameters at birth and drinking water disinfection with chlorine dioxide and/or sodium hypochlorite. Over 2 years (1988-1989), 676 births at two public hospitals, one in Genoa (548 cases) and another in Chiavari (128 cases) were examined and data regarding both mother and child were obtained from hospital records. Results indicate a higher frequency of small body length (< or = 49.5 cm) and small cranial circumference (< or = 35 cm) in infants born to mothers who drank water treated with chlorine compounds. In particular, the statistical analysis (by simultaneous variance analysis and Scheffé test) indicated that there may be an association between infants with smaller body length and mothers who drank water treated with chlorine dioxide [adjusted odds radio (OR) = 2.0; 95% CI = 1.2-3.3] or sodium hypoclorite (adjusted OR = 2.3; 95% CI = 1.3-4.2) and between infants with smaller cranial circumference and mothers who drank water treated with chlorine dioxide (adjusted OR = 2.2; 95% CI = 1.4-3.9) or sodium hypochlorite (adjusted OR = 3.5; 95% CI = 2.1-8.5). The presence of neonatal jaundice is almost twice as likely (adjusted OR = 1.7; 95% CI = 1.1-3.1) in infants whose mothers drank water treated with chlorine dioxide.

Topics: Adult; Birth Weight; Body Constitution; Chlorine; Chlorine Compounds; Cross-Sectional Studies; Disinfection; Female; Humans; Infant, Newborn; Jaundice, Neonatal; Male; Maternal Age; Oxides; Pregnancy; Prenatal Exposure Delayed Effects; Sodium Hypochlorite; Water Purification

This study demonstrated that bacteria penetrate three kinds of dental acrylic resin after a short time period. Samples of acrylic resin were contaminated with a variety of bacteria and were then placed in three different disinfecting solutions as directed by the manufacturers. After the specific dilution and immersion time, cultures were made from the resin samples. The only effective disinfectant was a 0.525% solution of sodium hypochlorite at a 10-minute immersion. It disinfected not only the surfaces but also the bacteria that penetrated the surfaces to a depth of 3 mm.

Topics: Acrylic Resins; Biofilms; Chlorine; Chlorine Compounds; Colony Count, Microbial; Dental Prosthesis; Disinfectants; Escherichia coli; Oxides; Pseudomonas aeruginosa; Sodium Hypochlorite; Staphylococcus aureus; Streptococcus pneumoniae; Sulfones

This investigation examined the gypsum compatibility of two antimicrobial alginates after spray disinfection. Subjective compatibility evaluations were compared with objective quantitative profilometer readings of gypsum cast surface roughness.. COE Hydrophilic Gel Alginate, Jeltrate Plus, Antimicrobial Alginate, and their nonantimicrobial counterparts, Coe Alginate and Jeltrate Plus, were used in this study. After spray disinfection with water (control), Alcide LD, Biocide, OMC II, and 0.5% NaOCI, impressions of the American National Standards Institute/American Dental Association (ANSI/ADA) specification no. 18 detail reproduction die and impressions made simultaneously of a smooth glass die were cast in Microstone, Silky-Rock, and Die-Keen. Five specimens were made for each alginate/disinfectant/gypsum combination for a total of 300 samples each for both the subjective and objective analyses. For the subjective analysis of gypsum compatibility, the specimens made from the ANSI/ADA specification no. 18 test die were evaluated by using a 1-to-4 visual rating system at magnification x12. For the objective analysis, the arithmetic average surface roughness of each specimen made from the smooth glass die was recorded three times with a 200-mg skidless stylus instruments.. The results of the ANSI/ADA specification no. 18 testing for gypsum compatibility showed that 11 of 60 possible combinations did not pass the test. All impressions made with nonantimicrobial COE Alginate passed the test regardless of the disinfectant/gypsum combination. The results of the three-factor analysis of variance for the subjective and objective analyses showed significant interactions between alginates, disinfectants, and stones at the P < .05 level. To further delineate these differences, unpaired t tests (P < .05) within brands for each disinfectant/gypsum combination were performed.. The addition of 1% chlorhexidine diacetate to COE Hydrophilic Gel Alginate has decreased its compatibility with the dental stones and disinfectants tested when compared with its nonantimicrobial counterpart. In terms of gypsum compatibility, the nonantimicrobial COE Alginate was compatible with all disinfectant and gypsum combinations tested. The addition of 1.70% didecyldimethyl ammonium chloride to Jeltrate Plus Antimicrobial Alginate has increased its compatibility with all the dental stones tested. A strong positive correlation (r = 0.7398) was found between visual gypsum compatibility evaluation scores and surface roughness of gypsum casts.

Topics: Alginates; Analysis of Variance; Anti-Infective Agents; Calcium Sulfate; Chi-Square Distribution; Chlorine; Chlorine Compounds; Colloids; Dental Impression Materials; Disinfectants; Iodophors; Materials Testing; Observer Variation; Organic Chemicals; Oxides; Phenols; Sodium Hypochlorite; Surface Properties

This study compared the biocidal effectiveness of chlorine dioxide and 5.25% sodium hypochlorite (diluted 1:10) on acrylic resin strips inoculated with Staphylococcus aureus, Candida albicans, or Escherichia coli in the presence of an organic load. Sterile acrylic resin strips were immersed in a solution containing 10% horse serum and 10(5) to 10(7) organisms/ml for each type of organism, then disinfected in chlorine dioxide, sodium hypochlorite, or 0.9 sterile saline for 30 seconds or 1, 2, or 4 minutes. After disinfection, the strips were neutralized and incubated for 72 hours. The results showed a difference between the ability of chlorine dioxide and sodium hypochlorite to kill the test organisms on acrylic resin strips when organic matter is present. Chlorine dioxide achieved complete disinfection of all three organisms within 2 minutes. Sodium hypochlorite achieved complete disinfection of all three organisms within 4 minutes.

Topics: Bacteria; Candida albicans; Chlorine; Chlorine Compounds; Denture Bases; Disinfectants; Escherichia coli; Methylmethacrylates; Oxides; Sodium Hypochlorite; Staphylococcus aureus; Time Factors

Topics: Chlorine; Chlorine Compounds; Chromium Alloys; Corrosion; Disinfectants; Microscopy, Electron, Scanning; Oxides; Sodium Hypochlorite

A comparative study of the different reactions of herpes simplex virus types 1 and 2 to Lysol, Listerine, bleach, rubbing alcohol, Alcide disinfectant (Alcide Corp., Westport, Conn.), and various pHs, temperatures, and UV light exposures was performed. Both types of stock virus (titers of approximately 10(6) and 10(5.5) for types 1 and 2, respectively) were inactivated by 0.5% Lysol in 5 min; by Listerine (1:1 mixtures) in 5 min; by 2,000 ppm (2,000 microliters/liter) of bleach in 10 min; by rubbing alcohol (1:1 mixtures) at zero time; by Alcide disinfectant (0.2 ml of virus plus 2.0 ml of Alcide) at zero time; by pHs 3, 5, and 11 in 10 min; and by a temperature of 56 degrees C in 30 min. A germicidal lamp (model G30TB; General Electric Co., Schenectady, N.Y.) (30 W) at a distance of 48 cm failed to completely inactivate the two types in 15 min. Type 1 showed slightly more resistance to Listerine and bleach and significantly more resistance to heat; moreover, pH 9 did not affect the infectivity of either type after 10 min.

Topics: 1-Propanol; Animals; Anti-Infective Agents, Local; Chlorine; Chlorine Compounds; Disinfectants; Humans; Hydrogen-Ion Concentration; Oxides; Simplexvirus; Sodium Hypochlorite; Temperature; Ultraviolet Rays; Vero Cells

Female SENCAR mice were treated with aqueous solutions of hypochlorous acid (HOCl), sodium hypochlorite (NaOCl), chlorine dioxide (ClO2), and monochloramine (NH2Cl) by whole body exposure (except head) for a 10-min period for 4 days in the first experiment and for 1 day (except NH2Cl) in the second experiment. Animals were sacrificed the day following the last treatment (experiment 1) or on day 1, 2, 3, 4, 5, 8, 10, and 12 following treatment (experiment 2), and skin thickness was measured by light microscopy at X400 by use of an eyepiece micrometer. Concentrations of disinfectants were 1, 10, 100, 300, and 1000 mg/L, for experiment 1 and 1000 mg/L for experiment 2. Thickness of the interfollicular epidermis (IFE) for control animals was 15.4 +/- 1.5 micron. After 4 days of treatment at 1000 mg/L, HOCl and ClO2 increased thickness to 39 +/- 7.0 and 40.2 +/- 11.8, and NaOCl increased thickness to 25.2 +/- 6.1 micron. Only HOCl and ClO2 were tested at 300 mg/L, yielding an IFE thickness of 30.0 +/- 13.1 and 16.8 +/- 0.8 micron, respectively. The response to HOCl was found to be dose-related; the minimally effective dose was 100 mg/L. In earlier, preliminary tests to determine optimum treatment schedule, the response to HOCl appeared to be maximal after 4 days of treatment and tended to decrease with further treatment. The time-course study following a single treatment of 1000 mg/L HOCl, however, showed a progression of IFE thickening of from 18.3 +/- 1.4 at 1 day to 30.8 +/- 8.0 at 8 days, decreasing to 19.1 +/- 6.2 micron at 12 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Chloramines; Chlorine; Chlorine Compounds; Disinfectants; Disinfection; Female; Hyperplasia; Hypochlorous Acid; Mice; Oxides; Skin; Sodium Hypochlorite; Water Supply

Topics: Animals; Brain; Cell Fusion; Chlorine; Chlorine Compounds; Cricetinae; Mesocricetus; Mice; Oxides; Scrapie; Sheep; Sodium Hypochlorite