The effect of electrolyzed strong acid aqueous solution on hemodialysis equipment

Antibiofilm activity of electrochemically activated water (ECAW) in the control of Salmonella Heidelberg biofilms on industrial surfaces

Owing to its antimicrobial activity, electrochemically activated water (ECAW) is a potential alternative to chemical disinfectants for eliminating foodborne pathogens, including Salmonella Heidelberg, from food processing facilities. However, their antibiofilm activity remains unclear. This study aimed to evaluate the antibiofilm activity of ECAW against S. Heidelberg biofilms formed on stainless steel and polyethylene and to determine its corrosive capacity. ECAW (200 ppm) and a broad-spectrum disinfectant (0.2%) were tested for their antibiofilm activity against S. Heidelberg at 25 °C and 37 °C after 10 and 20 min of contact with stainless steel and polyethylene. Potentiostatic polarization tests were performed to compare the corrosive capacity of both compounds. Both compounds were effective in removing S. Heidelberg biofilms. Bacterial counts were significantly lower with ECAW than with disinfectant in polyethylene, regardless the time of contact. The time of contact and the surface significantly influenced the bacterial counts of S. Heidelberg. Temperature was not an important factor affecting the antibiofilm activities of the compounds. ECAW was less corrosive than the disinfectant. ECAW demonstrated a similar or even superior effect in the control of S. Heidelberg biofilms, when compared to disinfectants, reducing bacterial counts by up to 5 log10 CFU cm-2. The corrosion of stainless steel with ECAW was similar to that of commercial disinfectants. This technology is a possible alternative for controlling S. Heidelberg in the food production chain.

Virucidal Activities of Acidic Electrolyzed Water Solutions with Different pH Values against Multiple Strains of SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a threat to human health. Acidic electrolyzed water (AEW) has recently been suggested to demonstrate virucidal activity. Many types of AEW with different pH values, generated by the electrolysis of different chemicals, such as sodium chloride, potassium chloride, and hydrochloric acid, are commercially available. In this study, we compared the virucidal activities of these types of AEW against SARS-CoV-2, including the ancestral strain and variant Alpha, Beta, Gamma, Delta, and Omicron strains. Virus solution (viral titer, 6.9 log₁₀ 50% tissue culture infective dose [TCID₅₀]/mL) was mixed with AEW (free available chlorine concentration, 34.5 ppm) at mixing ratios of 1:9, 1:19, and 1:49. At mixing ratios of 1:9 and 1:19, AEW with a pH of 2.8 showed stronger virucidal activities than AEW with a pH of 4.1 to 6.5 against the SARS-CoV-2 ancestral strain in 20 s. From the strongest to the weakest virucidal activity, the AEW pH levels were as follows: pH 2.8, pH 4.1 to 5.4, pH 6.4 to 6.5. At a ratio of 1:49, the viral titers of viruses treated with all AEW solutions at pH 2.8 to 6.5 were almost below the detection limit, which was 1.25 log₁₀ TCID₅₀/mL. The virus inactivation efficiency of AEW was reduced in the presence of fetal bovine serum and other substances contained in the virus solution used in this study. AEW with pH values of 2.8 to 6.5 showed virucidal activity against all of the tested SARS-CoV-2 strains, including the ancestral and variant strains. These results provide useful knowledge for the effective application of AEW as a SARS-CoV-2 disinfectant. IMPORTANCE Acidic electrolyzed water (AEW) demonstrates virucidal activity against multiple viruses. Since AEW exhibits low toxicity, is inexpensive, and is environmentally friendly, it can be a useful disinfectant against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although the pH values of currently available AEW products vary, the impact of different pH values on SARS-CoV-2 inactivation has not previously been evaluated in detail. In this study, we compared the virucidal activities of multiple AEW solutions with different pH values, under the same experimental conditions. We found that AEW solutions with lower pH values demonstrated more potent virucidal activity. Also, we showed that the extent of virus inactivation by the AEW was based on the balance of the abundance of free available chlorine, virus, and other organic substances in the mixture. AEW exhibited rapid virucidal activity against multiple SARS-CoV-2 strains. This study demonstrated the usefulness of AEW as a disinfectant which can be applied to the inactivation of SARS-CoV-2.

Kinetic Modeling of Slightly Acidic Electrolyzed Water Decay Characteristics in Fresh Cabbage Disinfection Against Human Norovirus

To consistently disinfect fresh vegetables efficiently, the decay of disinfectants such as chlorine, electrolyzed oxidizing water (EOW), ozonated water, and plasma-activated water during the disinfection maintenance stage needs to be understood. The aim of our study was to evaluate the changes in the inactivation kinetics of slightly acidic electrolyzed water (SAEW) against human norovirus (HuNoV), based on the cabbage-to-SAEW ratio. After disinfection of fresh cabbage with disinfected SAEW solution, SAEW samples were collected and analyzed for physicochemical properties such as pH, available chlorine concentrations (ACCs), and oxidation-reduction potential (ORP). SAEW virucidal effects were evaluated. We confirmed the decay of post-disinfection SAEW solution and demonstrated the different patterns of the decay kinetic model for HuNoV GI.6 and GII.4. In addition, the goodness of fit of the tested models based on a lower Akaike information criterion, root-mean-square error (RMSE), and residual sum of squares (RSS) was close to zero. In particular, the change in both the HuNoV GI.6 and GII.4 inactivation exhibited a strong correlation with the changes in the ACC of post-disinfection SAEW. These findings demonstrate that physicochemical parameters of SAEW play a key role in influencing the kinetic behavior of changes in the disinfection efficiency of SAEW during the disinfection process. Therefore, to optimize the efficiency of SAEW, it is necessary to optimize the produce-to-SAEW ratio in future studies.

Comparison of the SARS-CoV-2-inactivating activities of the differently manufactured hypochlorous acid water products with various pH

The use of effective disinfectants is a key method of controlling the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Hypochlorous acid water (HAW) has a broad spectrum of virucidal activities. We previously reported that acidic electrolyzed water, one of the HAW products, had potent SARS-CoV-2-inactivating activity and showed promise as a disinfectant. However, different manufacturing methods have produced several HAW products with various pH values. Here, we compared the SARS-CoV-2-inactivating activities of various HAW products. At sufficiently high volume and residual chlorine concentration (RCC), the HAW products inactivated SARS-CoV-2 efficiently regardless of pH or manufacturing method. However, although HAW products at pH 5.0-6.4 maintained high RCC and sustained virucidal activity for 21 days, the RCC rapidly decreased in HAW products at pH ≤ 3.0. Our results may guide in choosing appropriate HAW products for different usage situations.

Electrolyzed Water Generated On-Site as a Promising Disinfectant in the Dental Office During the COVID-19 Pandemic

Electrolyzed water is a safe, broad-spectrum bactericidal and viricidal agent, which can be used as a potent and effective alternative disinfectant in case of supply shortages. This report describes the on-site production of slightly acidic electrolyzed water (EW) from diluted salt solution and vinegar at a dental office using a portable EW generator unit. Such measures can ensure the safe continuity of important dental service provision for our patients during the coronavirus disease 2019 (CoVID-19) pandemic.

Acidic electrolyzed water potently inactivates SARS-CoV-2 depending on the amount of free available chlorine contacting with the virus

Alcohol-based disinfectant shortage is a serious concern in the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Acidic electrolyzed water (EW) with a high concentration of free available chlorine (FAC) shows strong antimicrobial activity against bacteria, fungi, and viruses. Here, we assessed the SARS-CoV-2-inactivating efficacy of acidic EW for use as an alternative disinfectant. The quick virucidal effect of acidic EW depended on the concentrations of contained-FAC. The effect completely disappeared in acidic EW in which FAC was lost owing to long-time storage after generation. In addition, the virucidal activity increased proportionately with the volume of acidic EW mixed with the virus solution when the FAC concentration in EW was same. These findings suggest that the virucidal activity of acidic EW against SARS-CoV-2 depends on the amount of FAC contacting the virus.

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Acidic electrolyzed water (EW) shows virucidal activity against SARS-CoV-2.

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Virucidal activity of acidic EW depends on free available chlorine (FAC).

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Acidic solution without FAC does not inactivate SARS-CoV-2 in a 1-min reaction.

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Large amounts of FAC are required to inactivate virus containing many proteins.

Decontamination of aerosolised bacteria from a pig farm environment using a pH neutral electrochemically activated solution (Ecas4 anolyte)

An electrochemically activated solution (ECAS), generated by electrolysis of a dilute sodium chloride solution in a four-chamber electrolytic cell (Ecas4), was tested as a sanitising aerosol in eliminating bacteria from the environment of a weaning room vacated 24-48h earlier, at a continuous flow pig farm. An ultrasonic humidifier was used to fill the environment with a fog (droplets with diameters of 1–5 μm) containing 0.25 ppm of hypochlorous acid. The weaning room was fogged for 3 min at 30 min intervals during five hours of aerosol disinfection. An innovative sample treatment with propidium monoazide dye in conjunction with cyclonic air sampling was optimised and adapted for discerning live/dead bacteria in subsequent molecular quantification steps. Without fogging, total bacterial load ranged from 5.06 ± 0.04 to 5.75 ± 0.04 Log₁₀ CFU/m³. After the first hour of fogging, a 78% total bacterial reduction was observed, which further increased to > 97% after the second hour, > 99.4% after the third and 99.8% after the fourth hour, finally resulting in a 99.99% reduction from the farm environment over five hours. Unlike the current formaldehyde spray disinfection protocol, which requires a long empty period because of its hazardous properties, this economically viable and environmentally friendly disinfection protocol may significantly lower downtime. Moreover, ECAS fogging can be easily adapted to a variety of applications, including the elimination of pathogens from livestock farm air environment for disease prevention, as well as decontamination after disease outbreaks.

Effect of electro-activated brine solution on the migration of metallic ions from the cans to the product in sterilized canned sweet corn

Tinplate cans were used to study if electro‐activated brine solution (EAS) is more corrosive than conventional one by ICP analysis. The results showed different effects of EAS on cans, alone or filled with product. Acidic EAS (pH 2–3) and Redox +900 to +1200 mV highly reacted with the cans. The concentrations of Zn, Fe, and Cu in the solution were 0.028, 28.81, and 0.022 ppm, respectively. No Sn migration was observed in this case. When neutral or acidic chlorine‐free EAS was used, no significant difference was observed in comparison with the corrosivity of standard NaCl brine. Alkaline EAS with pH>10 and negative E (≤−966 mV) did not affect Zn, Fe, and Cu migration. However, it affected tin migration. Nevertheless, it is important to mention that even if some corrosion was observed, it was in the limit of the permitted level of concentration when the cans were filled with a product.

Meta-analysis of the effects of sanitizing treatments on Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes inactivation in fresh produce

The aim of this study was to perform a meta-analysis of the effects of sanitizing treatments of fresh produce on Salmonella spp., Escherichia coli O157:H7, and Listeria monocytogenes. From 55 primary studies found to report on such effects, 40 were selected based on specific criteria, leading to more than 1,000 data on mean log reductions of these three bacterial pathogens impairing the safety of fresh produce. Data were partitioned to build three meta-analytical models that could allow the assessment of differences in mean log reductions among pathogens, fresh produce, and sanitizers. Moderating variables assessed in the meta-analytical models included type of fresh produce, type of sanitizer, concentration, and treatment time and temperature. Further, a proposal was done to classify the sanitizers according to bactericidal efficacy by means of a meta-analytical dendrogram. The results indicated that both time and temperature significantly affected the mean log reductions of the sanitizing treatment (P < 0.0001). In general, sanitizer treatments led to lower mean log reductions when applied to leafy greens (for example, 0.68 log reductions [0.00 to 1.37] achieved in lettuce) compared to other, nonleafy vegetables (for example, 3.04 mean log reductions [2.32 to 3.76] obtained for carrots). Among the pathogens, E. coli O157:H7 was more resistant to ozone (1.6 mean log reductions), while L. monocytogenes and Salmonella presented high resistance to organic acids, such as citric acid, acetic acid, and lactic acid (∼3.0 mean log reductions). With regard to the sanitizers, it has been found that slightly acidic electrolyzed water, acidified sodium chlorite, and the gaseous chlorine dioxide clustered together, indicating that they possessed the strongest bactericidal effect. The results reported seem to be an important achievement for advancing the global understanding of the effectiveness of sanitizers for microbial safety of fresh produce.

Sterilization using Electrolyzed Water Highly Retains the Biological Properties in Tissue-Engineered Porcine Liver Scaffold

Purpose

The aims of this study were to investigate the effects of sterilization with peracetic acid (PAA) and ethanol on the biological activity of porcine liver scaffolds and to develop a new technique for sterilization using slightly acidic electrolyzed water (SAEW).

Methods

Decellularization of liver slices was performed using 0.1% sodium-dodecyl-sulfate, then evaluated by histological and polymerase chain reaction analyses. Decellularized slices were treated with either PAA or ethanol or SAEW, and then DNA content was quantified. We determined sterilization efficiency by culturing scaffolds in culture medium and on blood agar. We next analyzed the glycosaminoglycan and collagen contents of the scaffolds. Finally, we tested the cytotoxicity of the scaffolds as well as the effects of sterilization on host cell attachment and proliferation.

Results

Complete cell and antigenic epitopes removal emphasized the decellularization efficiency. PAA and SAEW treatments achieved the highest efficiency of sterilization compared to that of the ethanol treated scaffolds, and were able to remove a considerable fraction of DNA from decellular-ized livers. The retained glycosaminoglycan content decreased in all treatments in the following order: SAEW, ethanol, and PAA. Ethanol caused a significant loss in collagen content compared to the other groups. A cytotoxicity evaluation revealed that all scaffolds were nontoxic. SAEW-treated scaffolds supported cell attachment and proliferation at a significantly higher rate than other groups.

Conclusions

These data suggest that SAEW is highly efficient for sterilizing scaffolds and allowed the scaffolds to retain their bioactivity in addition to its high efficiency for cell remnant removal.

The effect of long-term storage on the physiochemical and bactericidal properties of electrochemically activated solutions

Electrochemically activated solutions (ECAS) are generated by electrolysis of NaCl solutions, and demonstrate broad spectrum antimicrobial activity and high environmental compatibility. The biocidal efficacy of ECAS at the point of production is widely reported in the literature, as are its credentials as a "green biocide." Acidic ECAS are considered most effective as biocides at the point of production and ill suited for extended storage. Acidic ECAS samples were stored at 4 °C and 20 °C in glass and polystyrene containers for 398 days, and tested for free chlorine, pH, ORP and bactericidal activity throughout. ORP and free chlorine (mg/L) in stored ECAS declined over time, declining at the fastest rate when stored at 20 °C in polystyrene and at the slowest rate when stored at 4 °C in glass. Bactericidal efficacy was also affected by storage and ECAS failed to produce a 5 log(10) reduction on five occasions when stored at 20 °C. pH remained stable throughout the storage period. This study represents the longest storage evaluation of the physiochemical parameters and bactericidal efficacy of acidic ECAS within the published literature and reveals that acidic ECAS retain useful bactericidal activity for in excess of 12 months, widening potential applications.

The use of electrolyzed solutions for the cleaning and disinfecting of dialyzers

Recently, the use of electrolyzed solutions has attracted considerable interest in Japan. This study investigates the efficiency of electrolyzed solutions as disinfecting agents (DA) in the reuse of dialyzers and compares their efficiency to that of other disinfectants currently in use. The following 3 methods were employed. First, the rinsing time and rebound release of reused dialyzers were measured and compared after electrolyzed solutions, electrolyzed strong acid aqueous solution (ESAAS) and electrolyzed strong basic aqueous solution (ESBAS), made from reverse osmosis (RO) water (ESAAS, ESBAS; Generating apparatuses: Super Oxseed alpha 1000, Amano Corporation, Yokohama, Japan), 2% Dialox-cj (Teijin Gambro Medical, Tokyo, Japan), and 3.8% formalin were used as DAs. This involved performing dialysis with 2 types of dialyzers: a cellulose acetate membrane (CAM) dialyzer and a polysulfone membrane (PSM) dialyzer. The dialyzers were cleaned and disinfected using the different DA and left for 48 h. Next, after performing dialysis the dialyzer membranes were cleaned with a saline solution (0.9% NaCl) and RO water and then cleaned with the various DA. These membranes were observed using a scanning electron microscope (SEM) to check for the presence of physical and biological contaminants. Finally, in vitro tests were performed to determine the level of dialyzer clearance when PSM dialyzers were reused after having been cleaned and disinfected with the electrolyzed solutions. The rinsing time results for both the CAM and PSM dialyzers showed the electrolyzed solutions (ESBAS and ESAAS) as being undetectable within 10 min. With regard to the rebound release, for both the CAM and PSM dialyzers, the electrolyzed solutions were undetectable at all checking times between 30 and 240 min. Observation by SEM showed that cleaning with both ESAAS and ESBAS left the fewest contaminants, and cleaning with 2% Dialox-cj left the highest level of contaminants in the CAM dialyzers. With regard to experiments concerning use in vitro, no major changes in the dialyzer clearance were noticed after 6 uses. In every experiment, the previous investigations showed the electrolyzed solutions to be superior to 3. 8% formalin and 2% Dialox-cj DA for the reuse of dialyzers.