Hypochlorite Products Research Articles

Quantifying sodium hypochlorite content in hypochlorite-based disinfectants via phase-conversion headspace technique

In this work, a novel and efficient approach for sodium hypochlorite analysis is proposed via phase-conversion headspace technique, which is based on the gas chromatography (GC) detection of generated carbon dioxide (CO2) from the redox reaction of sodium hypochlorite with sodium oxalate. The data obtained by the proposed method suggest the high detecting precision and accuracy. In addition, the method has low detection limits (limit of quantification (LOQ) = 0.24 μg/mL), and the recoveries of added standard ranged from 98.33 to 101.27 %. The proposed phase-conversion headspace technique is efficient and automated, thereby offering an efficient strategy for highly efficient analysis of sodium hypochlorite and related products.

Non-chlorine detergent formulations as an alternative for unpasteurised milk removal from stainless steel surfaces

Hygiene is a major concern in the dairy industry, and detergents based on hypochlorite have commonly been utilised for cleaning-in-place (CIP) regimes. However, due to concerns about chlorate residues entering the milk processing chain, new detergent alternatives that are free of chlorate sources are required. Two new formulations were developed based on ethylenediaminetetraacetic acid (EDTA) and wetting agents. Stainless steel surfaces were fouled with milk and cleaned once or 10 times using water, a caustic-EDTA product, a sodium hypochlorite product, an acid, or new cleaning formulations (Product A and Product B). The results demonstrated that the use of acid did not result in successful cleaning. The two new products performed well, with Product B performing equivalently during cleaning compared with the established hypochlorite or caustic-EDTA products. Product A exhibited better cleanliness than the other detergents tested. When allergen removal was considered, residual material was found to be retained on the surfaces, regardless of the cleaning type used. This study suggests that the new product formulations may be used to replace hypochlorite-based detergents to increase the hygienic status of a surface.

Appropriate cleaning reduces potential risk of spore transmission from patients with Clostridioides difficile infection treated in outpatient infusion centers

ObjectivesPatients with Clostridioides difficile infection (CDI) who receive treatment at outpatient infusion centers (OICs) pose a risk for spore transmission. We investigated C. difficile contamination in the environment of CDI and non-CDI patients and evaluated the effectiveness of standard cleaning. MethodsThis is a multicenter, non-conventional study including 8 OICs between October 2019 and December 2020. Samples were collected at baseline, after infusion, and after cleaning CDI and non-CDI areas. Cleaning was performed using hypochlorite and non-hypochlorite products for CDI and non-CDI, respectively. Samples were cultured for toxigenic C. difficile and strain-typed via fluorescent PCR ribotyping and whole-genome sequencing. ResultsThe overall C. difficile contamination rate was 7.9% (156/1969) with 8.1% in patient and 5.6% in non-patient care areas, respectively. For CDI areas, contamination rates were 5.9% at baseline, 15.0% after infusion, and significantly reduced to 6.2% after cleaning (P = 0.004). For non-CDI areas, contamination was similar at baseline (9.5%), after infusion (7.6%), and after cleaning (4.3%). The difference in C. difficile-positive samples after infusion was significant for CDI vs. non-CDI (15.0% vs. 7.6%, P = 0.004). Overall contamination was 11.5% for floors, 7.9% for infusion chairs, and 3.8% for equipment (P = 0.001). The most frequent ribotypes were F014-020 (42.6%), F106 (15.6%), F255 (6.1%), F001 (5.2%) and F027 (3.5%). Cleaning resulted in elimination of F106, F255, F001, F027 and partial reduction of F014-020. ConclusionsEnvironmental C. difficile contamination was increased after CDI infusions and significantly reduced after cleaning with a hypochlorite solution, reducing the potential risk of spore transmission to others.

Effect of Cavity Disinfectants on Dentin Bond Strength and Clinical Success of Composite Restorations-A Systematic Review of In Vitro, In Situ and Clinical Studies.

Cavity disinfection becomes an important step before a dental restorative procedure. The disinfection can be obtained cleaning the dental cavity with antimicrobial agents before the use of adhesive systems. The aim of this study was to conduct a systematic review on the effect of different cavity disinfectants on restorations’ adhesion and clinical success. A search was carried out through the Cochrane Library, PubMed, and Web of Science. In vitro and in situ studies reporting results on dentin bond strength tests, and clinical studies published until August 2020, in English, Spanish and Portuguese were included. The methodological quality assessment of the clinical studies was carried out using the Revised Cochrane risk-of-bias tool. Chlorhexidine could preserve adhesion to dentin. EDTA and ethanol had positive results that should be further confirmed. Given the significant lack of scientific evidence, the use of lasers, fluoridated agents, sodium hypochlorite, or other products as cavity disinfectants should be avoided. Chlorhexidine is a safe option for cavity disinfection with adequate preservation of adhesion to dentin. Moreover, future researches should be focused on the efficacy of these disinfectants against cariogenic bacteria and their best application methods.

1222. Are Reduced Concentrations of Chlorine-Based Disinfectants Effective Against Candida auris?

BackgroundCurrently, sporicidal disinfectants such as bleach are recommended for daily and terminal disinfection of the rooms of patients with Candida auris colonization and/or infection. However, bleach and other chlorine-based disinfectants can have adverse effects on surfaces and personnel. Disinfectant solutions with reduced chlorine concentrations are commonly used for other pathogens, but it is not known if diluted or alternative products maintain efficacy against C. auris both in vitro and in vivo.MethodsWe tested the efficacy of different concentrations of a sodium dichloroisocyanurate (NaDCC) product and sodium hypochlorite using the method recommended by the Environmental Protection Agency (EPA) for evaluation of the efficacy of liquid disinfectants against C. auris (EPA MLB SOP MB-35-00) and in a simulated patient room. Carriers were exposed to each disinfectant for 1 and 2 minutes. Log reductions were calculated by subtracting viable organisms recovered after disinfectant exposure vs. deionized water controls.ResultsAs shown in the figure, the NaDCC product at 4306 ppm tested with a 2 minute contact time reduced C. auris by ≥5 log10 colony-forming units (CFU) but had reduced efficacy with shorter exposure time or lower concentrations. Sodium hypochlorite was effective with 1 or 2 minute exposure times at a concentration of 6,500 ppm, and was effective at 4,000 ppm with an exposure time of 2 minutes. In the simulated patient room, NaDCC reduced C. auris contamination by ≥6 log10 CFUs on all surfaces.ConclusionA chlorine-based NaDCC product was effective at reducing C. auris. Both NaDCC and sodium hypochlorite products exhibited reduced efficacy at lower concentrations, particularly at concentrations below 4000 ppm. The NaDCC products were also effective in reducing contamination in the simulated patient room. UV-C treatment was an effective adjunct to manual cleaning. Disclosures All authors: No reported disclosures.

Role of Cysteines in the Stability and DNA-Binding Activity of the Hypochlorite-Specific Transcription Factor HypT

Reactive oxygen species are important components of the immune response. Hypochlorite (HOCl) is produced by neutrophils to kill invading microorganisms. The bactericidal activity of HOCl is due to proteome-wide unfolding and oxidation of proteins at cysteine and methionine residues. Escherichia coli cells are protected from HOCl-killing by the previously identified dodecameric transcription factor HypT (YjiE). Here, we aimed to unravel whether HOCl activates HypT directly or via a reaction product of HOCl with a cellular component. Bacterial viability assays and analysis of target gene regulation indicate that HypT is highly specific to activation by HOCl and that no reaction products of HOCl such as monochloramine, hydroxyl radicals, or methionine sulfoxide activate HypT in vivo. Surprisingly, purified HypT lost its DNA-binding activity upon incubation with HOCl or reaction products that oxidize HypT to form a disulfide-linked dimer, and regained DNA-binding activity upon reduction. Thus, we postulate that the cysteines in HypT contribute to control the DNA-binding activity of HypT in vitro. HypT contains five cysteine residues; a HypT mutant with all cysteines substituted by serine is aggregation-prone and forms tetramers in addition to the typical dodecamers. Using single and multiple cysteine-to-serine mutants, we identified Cys150 to be required for stability and Cys4 being important for oligomerization of HypT to dodecamers. Further, oxidation of Cys4 is responsible for the loss of DNA-binding of HypT upon oxidation in vitro. It appears that Cys4 oxidation upon conditions that are insufficient to stimulate the DNA-binding activity of HypT prevents unproductive interactions of HypT with DNA. Thus, Cys4 oxidation may be a check point in the activation process of HypT.

Sanitizing alternatives for Escherichia coli and Salmonella typhimurium on bell peppers at household kitchens

Fresh fruits and vegetables are known to play an important role as carriers of disease-causing organisms in household kitchens. The aims of this study were to assess and compare the effectiveness of sodium hypochlorite, organic acid-based and silver-based products to reduce Escherichia coli and Salmonella typhimurium inoculated on individual bell pepper pieces. Inoculated bell pepper pieces (n = 5) were submerged in sodium hypochlorite, organic acid-based and silver-based product solutions, at the concentration specified in the product label for sanitization of fruits and vegetables. Sodium hypochlorite reduced E. coli and Salmonella typhimurium by 3.13 Log10/25cm2 and 2.73 Log10/25cm2, respectively. Organic-based and silver-based products reduced E. coli and S. typhimurium by 2.23 Log10/25cm2, 1.74 Log10/25cm2 and 2.10 Log10/25cm2, 1.92 Log10/25cm2, respectively. The results showed that greater attention is needed in selecting sanitizing products to kill or remove human pathogens from fresh produce to minimize risk of foodborne infections.

Occurrence of perchlorate in sodium hypochlorite

Perchlorate is a contaminant of health concern because exposure to high levels over extended periods may adversely affect thyroid activity. In response to recent findings of perchlorate in sodium hypochlorite, NSF International surveyed sodium hypochlorite products used to treat drinking water to better understand the occurrence of perchlorate as a contaminant. Perchlorate contamination was found to occur in more than 90% of sodium hypochlorite samples from production facilities across North America. Results also indicated a trend of increasing perchlorate concentration as the hypochlorite aged. The duration and conditions of storage can affect the levels of the contaminant in a utility's hypochlorite supplies and ultimately its drinking water. The investigation provided a basis for recommendations to minimize perchlorate formation and lower the potential for its unintended addition to drinking water. Sodium hypochlorite should be stored in the dark at cool temperatures, diluted if possible, and used within a few weeks of manufacture.

The impact of home cleaning on quality of life for homes with asthmatic children

Treatment with common household bleach containing hypochlorite destroys dust mites and denatures protein allergens. The purpose of this study was to determine if home use of hypochlorite products results in lowered exposure to bacteria, fungi, and protein allergens and improved quality of life (QOL) for asthmatic persons in the home. Asthmatic and nonasthmatic households containing at least three persons (between 2 and 17 years of age) were recruited. Households were supplied one of three sets of cleaning products (regular products, some containing hypochlorite; regular products plus three additional products with dilute hypochlorite; control, no products). Participants were supplied with cleaning instructions and asthma education. The control group was instructed to clean as usual. Participants completed general health and QOL questionnaires. Asthmatic participants completed an additional asthma QOL questionnaire. Families participated in the study for 8 weeks and completed the full set of questions every 2 weeks. Homes were visited at the beginning of the study and twice thereafter at monthly intervals. Samples evaluated were surface bacteria, viable and nonviable airborne spores, and dust antigen content. Reductions in surface bacteria, airborne fungal spores, and dust antigen levels were achieved. Significant improvement in general health parameters was seen for the asthmatic product groups over the control group. Significant improvement in general QOL and asthma-specific QOL was seen in the asthmatic group. Emphasis on cleaning and cleaning education combined with hypochlorite-based cleaning supplies resulted in significantly improved QOL for families with asthmatic children.

EFFECTS OF PROCESSING AND STORAGE OF FRESH-CUT ONION ON QUERCETIN

Total quercetin concentration in unprocessed 'Grano de Oro' onions was 557 mg/kg f.w. (fresh weight). No significant statistical differences in total quercetin concentration were shown between products packed under vacuum and modified atmosphere packaging (MAP), at the end of 30 days at 4°C. No significant statistical differences in total quercetin concentration were shown between water-washing and hypochlorite solution-washing products at the end of 30 days at 4°C, packed under vacuum or MAP. Only slight significant differences in total quercetin concentration were shown between whole onion and cut onion product, in all the treatments after long-term refrigerated storage at 4°C (11-30 days). Chopped samples packed in MAP after washing in either water (462 mg/kg f.w.) or hypochlorite (471 mg/kg f.w.) had increases in quercetin concentration of 19.5% and 22%, respectively, when compared to whole onions stored in MAP after washing in water (386 mg/kg f.w.) or hypochlorite (387 mg/kg f.w.). Minimal processing did not seem to significantly affect the quercetin concentration in onion products, and consequently the health-promoting characteristics described for raw onion are preserved.

Effectiveness of Commercial Germicide Products Against the Ropy Slime-Producing Lactic Acid Bacteria

The effectiveness of certain commercial germicides against ropy slime-producing lactic acid bacteria was studied using the 5-5-5-suspension test and a tray test which simulated surface disinfection conditions in actual use. The rate of the destruction of the bacteria was lower in the tray test, and the bacteria seemed to be more resistant to the germicides on a steel surface than in vitro. The sanitizer products proved to be more effective than the detergent-sanitizer products. Quaternary ammonium products and an acid sanitizer with hydrogen peroxide were more effective than products containing chlorine compounds and polyhexamethylene biguanide chloride. The effectiveness of hypochlorite products appeared to be dependent on the concentration of available chlorine. The resistance of the ropy slime-producing bacteria may prove problematic if ineffective germicides are used. The use of detergent sanitizers and low-concentration hypochlorite products is not recommended.

A comparison of sodium hypochlorite and sodium dichloroisocyanurate products

A comparison of commercial sodium hypochlorite (NaOCl) and sodium dichloroisocyanurate (NaDCC) products was made. Solutions of NaOCl and NaDCC containing the same levels of available chlorine (av.Cl) exhibited very similar bactericidal activities, despite significant differences in pH. A level of 12.5 ppm av. Cl achieved a greater than 5 log 10 reduction of Staphylococcus aureus in 2 min. A level of 5 ppm av.Cl achieved a greater than 5 log 10 reduction of Pseudomonas aeruginosa in 2 min whilst approximately 100 ppm av.Cl achieved the same reduction in the presence of 1% horse serum, and approximately 200 ppm av.Cl in the presence of 2% horse serum, indicating inactivation levels of around 95 and 97.5% respectively. Tablets of NaDCC were stable but solutions were unstable and decomposed much faster than NaOCl solutions of the same strength. Batch-to-batch variability of different NaOCl and NaDCC products was investigated; whilst NaDCC products always contained the minimum level of av.Cl specified, concentrated NaOCl products sometimes did not due to inherent instability.

A Method for Assessing the Sanitizing Efficiency of Quaternary Ammonium and Hypochlorite Products

A Method for Assessing the Sanitizing Efficiency of Quaternary Ammonium and Hypochlorite Products