Chlorine Solution Research Articles

Seasonal Variety on Bacteriological Evaluation of Borehole Waters in Orumba South Local Government Area in Anambra State

Aims: This study was carried out to determine the seasonal variety on physico-chemical and bacteriological evaluation of Borehole waters.
 Place and Duration of Study: 10 selected borehole tanks in 5 different towns were collected from five towns from (ORS) Orumba South L. G. A; (Umunze, Onneh, Nawfija, Isulo and Ezira) in Anambra State, with one hundred and twenty samples each in both dry season (December, January, February) as January (peak of dry season) and rainy season (May, June, July) as June (peak of rainy season) within 2018.
 Methodology: A total of one hundred and twenty water samples were analyzed. (1) ml of water sample was added to 10 ml single strength of the Lactose fermentation broth and serially diluted. The isolated bacterial isolates were identified using their morphological characteristics, biochemical tests, microscopical and molecular characteristics. The DNA was extracted from the identified isolates and analyzed by 16S rRNA. The bacteria isolated from the studied water samples were identified to be Bacillus subtilis (BTC), Escherichia coli (RSS), klebsiella aerogenes (TSS) and staphylococcus aureus (GY), PC – Providencia stuartii, BCD – Bacillus toyonensis, FY- Bacillus spp and ANT – Proteus spp. Frequency rate of occurrence in percentage for the isolates in dry and rainy seasons in ORS L. G. A were determined and for removal of all the isolates were within the WHO limit of 0.08ct (mg.min L-1) by the use of chlorine solution. Confirmatory profile on bacteriological in chlorine treated borehole water samples was determined.
 Results: The highest TCC was recorded for sample 10 which was 27 MPN/100ml estimated during rainy season against (TCC) recorded for samples 10 which was 22 MPN/100ml during dry season. Out of eight isolates, Escherichia coli had the highest rate frequency of occurrence of 70% in rainy season against dry season. All the isolates 1 to 8 range from (0.01ct) (mg.min L-1) to (0.06ct (mg.min L-1) all the values were within the WHO recommended limit for water purity. The confirmatory test on sample locations form ORS 1 to ORS 10 for total coliform count in chlorine treated borehole water samples by most probable number estimation revealed that all the samples were within the WHO permissible limit of 0.00MPN/100ml.
 Conclusions: Chlorine solution may have proven to be the cheaper and better solution for achieving water purity in boreholes water.

Inactivation of Salmonella enterica, Listeria monocytogenes and murine norovirus (MNV-1) on fresh strawberries by conventional and water-assisted ultraviolet light (UV-C)

The efficacy of the water-assisted ultraviolet-C light (WUVC) strategy was evaluated as an alternative to chlorine sanitization and compared to ‘conventional’ dry technology (DUVC) for the inactivation of Salmonella enterica, Listeria monocytogenes and murine norovirus (MNV-1) on strawberries. Strawberries were washed in a laboratory scale prototype (LAB-UVC-Gama) consisting of a tank filled with water, equipped with 4 UV-C lamps emitting a dose of 0.6, 1.3, 3.2 and 6.3 kJ m−2. For DUVC, the same doses were used. Moreover, trials with the 4 lamps off with water, or with a chlorine solution (200 ppm, pH 6.5), were carried out as a control treatment. Reductions of artificially inoculated L. monocytogenes and S. enterica, and the infectivity of MNV-1 after WUVC treatments were comparable to those obtained with chlorine-wash, which were equivalent with all irradiation doses tested for all microorganisms studied (P < 0.05). The implementation of the WUVC strategy improved the DUVC system after 2-min exposure (1.3 kJ m−2), by 1.2 and 1.6 log for S. enterica and L. monocytogenes, respectively. At 3.2 kJ m-2 dose (5 min), WUVC enhanced the inactivation of S. enterica compared with control washing treatment by 1.5 log. After 10 min, pathogenic bacteria were reduced by > 4 log by WUVC treatment and chlorine sanitization. For MNV-1 reductions, we reported > 1.4 log TCID50 with 95 % certainty with the different treatments and exposure times after decontamination procedures. For MNV-1, the increase in the irradiation dose (kJ m−2) applied did not affect their reduction on strawberries. Moreover, WUVC light was effective at significantly reducing the microorganisms in wash water, avoiding cross-contamination and thus, allowing water recirculation. The results obtained in the present study provide new tools to ensure the safety of strawberries intended to be processed, contributing to affording a more innovative and sustainable future for the food industry. However, industry operation studies are needed to conclude that the treatments tested in the present study are a good alternative to chlorine.

Мікроструктурна характеристика яловичини за оброблення мийно-дезінфікуючими засобами

Мікроструктурна характеристика яловичини за оброблення мийно-дезінфікуючими засобами

Edible treatments of Capsicum extracts inactivate the microbial contaminations to improve the quality of fresh‐cut bell pepper ( Capsicum annuum L. var. grossum (L.) Sendt)

The present study aimed to examine the efficiency of ethanolic extract of Capsicum annuum L (CAE) in improving the shelf life and quality of fresh-cut C. annuum (FCCa). The uniformly sliced FCCa were prewashed with sodium hypochlorite solution (NaOCl) and then treated with 10% of CAE. The foodborne pathogens of Listeria monocytogenes and Salmonella enterica were patched on the surface of FCCa and stored at 15°C and 4°C for 12 days. The shelf life of FCCa was examined in terms of physical appearance, weight loss, total flavonoid, and phenolic content, antioxidant, and antimicrobial activity in a regular interval. The results revealed that the combinational treatment diminished the pathogen load, and the outcomes of the study suggested that the conventional method of NaOCl washing with CAE significantly improved the shelf life of FCCa by retaining its antioxidant, and phytochemical compositions at 4°C for 12 days. Practical applications Washing is an efficient strategy to extend the life span of fruits and vegetables, from this prospective NaOCl with ethanolic extract of Capsicum annuum extending the shelf life of fresh-cut bell pepper were detailed documented. The combinational treatment was markedly diminished the foodborne pathogen load with a notable antioxidant activity through maintaining its total phenolic and flavonoid content throughout the storage period. Taken together the possible practical outcome of this study suggested that conventional methods of chlorine solution with C. annuum extracts enhance the shelf life of the fresh-cut form of fruits and vegetables and prevent economic loss during the storing period.

Comparative Transport of Legionella and E. coli through Saturated Porous Media in a Two-Dimensional Tank

This study investigated bacterial transport in a two-dimensional (2-D) tank to evaluate the bacterial behavior of Legionella pneumophila as compared to Escherichia coli under saturated flow to simulate aquifer conditions. The experiments were performed in a 2-D tank packed with 3700 in3 (60,632 cm3) of commercially available bagged play sand under saturated conditions. The tank was disinfected by backwashing with 10% chlorine solution and subsequently neutralized by backwashing with tap water containing sodium thiosulphate (Na2S2O3) to ensure no chlorine residual. Bacterial transport was measured using samples collected from ports located at vertical transport distances of 5, 15 and 25 inches (12.7, 38.1 and 63.5 cm, respectively) below the sand surface along two vertical sections in the tank. An influent concentration of 105 CFU/mL was used for bacterial cells and the vertical fluid transport rate was 10.3 in/day (26.2 cm/day), controlled using a peristaltic pump at the bottom outlet. Legionella breakthroughs were recorded at 8, 22 and 35 h for the ports on the right side and 9, 24 and 36 h for the ports on the left side, at 5, 15 and 25 inch depths, respectively. At the same depths, E. coli breakthroughs were recorded at 5, 17 and 30 h for the ports on the right side and 7, 19 and 31 h for the ports on the left sides. The delay in Legionella transport compared to E. coli is homologous to Legionella’s pleomorphic nature. This study provides evidence of the mobility of both E. coli and Legionella in saturated aquifer conditions at a scale more representative of actual aquifer conditions. This study also provides a substantive basis for the premise that cell characteristics affect transport characteristics under those conditions.

Highly antifouling and chlorine resistance polyamide reverse osmosis membranes with g-C3N4 nanosheets as nanofiller

Improvement of antifouling and chlorine resistance properties of polyamide (PA) reverse osmosis (RO) membranes have been major challenges for desalination of seawater. In this work, graphitic carbon nitride nanosheets (g-C3N4 NS) were incorporated into PA membranes (PA/CN) through an in-situ interfacial polymerization process. With the optimized g-C3N4 NS loading within the PA-RO membranes (PA/CN100), the water permeability was improved by about 30% with a high salt rejection ratio of 99.23%. More importantly, due to the attractive features of g-C3N4 NS, including NH bonds to provide more chlorine attack sites, rich oxygen-containing functional groups to capture and react with chlorine radicals, negatively charged membrane surface to repel and isolate active chlorine and pollutants, the chlorine resistance and antifouling performance of PA RO membranes were greatly enhanced. After being immersed in an active chlorine solution of 1000 ppm for 24 h, the PA/CN100 membranes show a higher chlorine resistance compared to that of pure PA RO membranes, with salt rejection decreased by 1.08% and 2.95%, respectively. Moreover, after 200 ppm bovine serum albumin (BSA) treatment, the total fouling rate was 31.2% for PA membrane and 18.3% for PA/CN100 membrane. This work provides a promising approach to improve the comprehensive performance for desalination and the trend of industrialization.

Investigation of hospital indoor air quality for the presence of SARS-Cov-2.

PurposeUnidentified dynamics for the causative agent of COVID-19, SARS-Cov-2, led to the critical public health issue. Suspicion for the airborne potential of SARS-Cov-2 is an important problem for its transmission and relevant epidemics. This research investigated hospital indoor air quality to SARS-Cov-2 occurrence and determination its air born potential.MethodsThe site study was a referral hospital with 630 beds for admitting of COVID-19 patients. Air sampling was done (n = 31) on selected wards including Emergency 1, Emergency 2, bedridden (4-B, 10-D), ICU 2, ICU 3, CT-SCAN, and laundry. The average temperature and relative humidities were 22 ± 1 °C and 43 percent respectively. All glass impinger used for sampling in which the sampling pumps capacities were 5 and 40 L.min− 1. Sampling duration time was 20 and 15 minutes and 100 to 1000 L of air were gathered. All parts of the sampling equipment were completely disinfected by hot water, ethanol (70%), chlorine solution (1000 ppm), hot water (70 °C for 1 min) and washed with distilled water. The transmitting media (7 ml) was injected into impinger and residual of this media (2 ml) was sent to the virology laboratory within 2 hours and preserved on refrigerator < 4 °C. Analysis of samples was performed by RT-PCR and repeated for accuracy control.ResultsAll of the samples were negative for SARS-Cov-2 occurrence. These results showed that SARS-Cov-2 had not airborne potential in this hospital.ConclusionsAlthough SARS-Cov-2 similar to the SARS virus but, SARS-Cov-2 is not an airborne virus.

Chlorination and bromination of olefins: Kinetic and mechanistic aspects

Hypochlorous acid (HOCl) is typically assumed to be the primary reactive species in free available chlorine (FAC) solutions. Lately, it has been shown that less abundant chlorine species such as chlorine monoxide (Cl2O) and chlorine (Cl2) can also influence the kinetics of the abatement of certain organic compounds during chlorination. In this study, the chlorination as well as bromination kinetics and mechanisms of 12 olefins (including 3 aliphatic and 9 aromatic olefins) with different structures were explored. HOCl shows a low reactivity towards the selected olefins with species-specific second-order rate constants <1.0 M−1s−1, about 4-6 orders of magnitude lower than those of Cl2O and Cl2. HOCl is the dominant chlorine species during chlorination of olefins under typical drinking water conditions, while Cl2O and Cl2 are likely to play important roles at high FAC concentration near circum-neutral pH (for Cl2O) or at high Cl− concentration under acidic conditions (for Cl2). Bromination of the 12 olefins suggests that HOBr and Br2O are the major reactive species at pH 7.5 with species-specific second-order rate constants of Br2O nearly 3-4 orders of magnitude higher than of HOBr (ranging from <0.01 to >103 M−1s−1). The reactivities of chlorine and bromine species towards olefins follow the order of HOCl < HOBr < Br2O < Cl2O ≈ Cl2. Generally, electron-donating groups (e.g., CH2OH- and CH3-) enhances the reactivities of olefins towards chlorine and bromine species by a factor of 3-102, while electron-withdrawing groups (e.g., Cl-, Br-, NO2-, COOH-, CHO-, -COOR, and CN-) reduce the reactivities by a factor of 3-104. A reasonable linear free energy relationship (LFER) between the species-specific second-order rate constants of Br2O or Cl2O reactions with aromatic olefins and their Hammett σ+ was established with a more negative ρ value for Br2O than for Cl2O, indicating that Br2O is more sensitive to substitution effects. Chlorinated products including HOCl-adducts and decarboxylated Cl-adduct were identified during chlorination of cinnamic acid by high-performance liquid chromatography/high resolution mass spectrometry (HPLC/HRMS).

SURVEY OF SAFETY PRACTICES IN DIARRHEAL TREATMENT CENTERS: CHOLERA TREATMENT CENTERS IN YEMEN

Objectives: Monitoring of Diarrheal treatment centers (DTCs) was conducted so as to assess the quality of care and help draw evidence-based decisions on the current and future support of DTCs and other cholera prevention interventions.&#x0D; Methods: This monitoring exercise was included 102 DTCs, data were collected by a trained team of 18 doctors, 18 nurses, and 2 supervisors during the month of June, 2019 to cover the center’s performance in the prior month i.e. May2019. Specially designed forms were used for data collection applying mixed methods: direct observation, record review, direct and phone interviews with the staff and patients as well as discussions with the health offices and community leaders whenever feasible.&#x0D; Results: No more than 23% of DTCs have water for hand washing, showering and washing clothes at all times and in all important locations such as hand washers and toilets; and 76% have one toilet for every 50 patients, but only 57% of toilets are regularly disinfected. Hazardous practices ranged from 32 to 62% leading to cholera infection among 4 out of 10 health workers and 5 visitors of the DTCs. Around 27 % of the DTCs do not have a designated area to bury body excreta from severe cases; only 23% have an isolated area for the deceased. A high of 59% of designated staff are neither trained nor equipped to deal appropriately with dead bodies and only 39% of dead bodies are disinfected with chlorine solution 2%.&#x0D; Conclusions: The DTC network provides much-needed services over the width of the country. Lives are being saved on a daily basis despite the ongoing conflict and other humanitarian interventions. However, despite the efforts made so far, there are remaining areas for the quality of the improvement, most importantly availing water and strengthening the infection control measures and preventions of hazardous practices.&#x0D; Peer Review History: &#x0D; Received 30 July 2020; Revised 15 August; Accepted 28 August, Available online 15 September 2020&#x0D; UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency.&#x0D; Received file &#x0D; &#x0D; Average Peer review marks at initial stage: 7.0/10&#x0D; Average Peer review marks at publication stage: 8.0/10&#x0D; Reviewer(s) detail:&#x0D; Name: Ali Awadallah Saeed&#x0D; Affiliation: National University, Sudan&#x0D; E-mail: alimhsd@gmail.com&#x0D; &#x0D; Name: Dr. Wadhah Hassan Edrees&#x0D; Affiliation: Hajjah University, Yemen&#x0D; E-mail: edress2020@gmail.com&#x0D; &#x0D; Comments of reviewer(s): &#x0D; &#x0D; Similar Articles:&#x0D; EPIDEMICITY OF VIBRIO CHOLERA IN SANA’A CITY, YEMEN: PREVALENCE AND POTENTIAL DETERMINANTS&#x0D;

Water UV-C treatment alone or in combination with peracetic acid: A technology to maintain safety and quality of strawberries

Disinfection of fruits is one of the most important steps since they are going to be eaten fresh-or minimally-processed. This step affects quality, safety, and shelf-life of the product. Despite being a common sanitizer in the fruit industry, chlorine may react with organic matter leading to the formation of toxic by-products. Alternative sustainable disinfection strategies to chlorine are under study to minimize environmental and human health impact. Water-assisted UV-C light (WUV-C) is proposed here as an alternative sanitizing method for strawberries. In this study, strawberries were washed for 1 or 5 min in a tank with 2 or 4 lamps on, each emitting UV-C light at 17.2 W/cm2, or in a chlorine solution (200 ppm, pH 6.5). Moreover, trials with 4 lamps on, together with a washing solution consisting on peracetic acid at 40 or 80 ppm, were carried out. Overall, quality and nutritional parameters of strawberries after treatments were maintained. Changes in color were not noticeable and fruits did not lose firmness. No major changes were observed in antioxidant activity, organic acid, anthocyanin, vitamin C, and total phenolic content. Yeasts and molds were not affected by the WUV-C treatment, and 5 min were needed to significantly reduce total aerobic mesophylls population. However, reductions of artificially inoculated Listeria innocua and Salmonella Typhimurium after WUV-C treatments were comparable to those obtained with chlorine-wash, which were 3.0 log CFU / g. Moreover, WUV-C light was effective to minimize microorganisms remaining in washing water, avoiding cross-contamination and thus, allowing water recirculation. This effect was improved when combining the action of UV-C light with peracetic acid, showing the suitability of this combined treatment, understood as an alternative to chlorine sanitation, for sanitizing strawberries and keeping the populations of pathogenic bacteria in washing water lower than 0.6 ± 0.1 log CFU / mL.

Household spraying in cholera outbreaks: Insights from three exploratory, mixed-methodsfield effectiveness evaluations.

Household spraying is a commonly implemented, yet an under-researched, cholera response intervention where a response team sprays surfaces in cholera patients’ houses with chlorine. We conducted mixed-methods evaluations of three household spraying programs in the Democratic Republic of Congo and Haiti, including 18 key informant interviews, 14 household surveys and observations, and 418 surface samples collected before spraying, 30 minutes and 24 hours after spraying. The surfaces consistently most contaminated with Vibrio cholerae were food preparation areas, near the patient’s bed and the latrine. Effectiveness varied between programs, with statistically significant reductions in V. cholerae concentrations 30 minutes after spraying in two programs. Surface contamination after 24 hours was variable between households and programs. Program challenges included difficulty locating households, transportation and funding limitations, and reaching households quickly after case presentation (disinfection occurred 2–6 days after reported cholera onset). Program advantages included the concurrent deployment of hygiene promotion activities. Further research is indicated on perception, recontamination, cost-effectiveness, viable but nonculturable V. cholerae, and epidemiological coverage. We recommend that, if spraying is implemented, spraying agents should: disinfect surfaces systematically until wet using 0.2/2.0% chlorine solution, including kitchen spaces, patients’ beds, and latrines; arrive at households quickly; and, concurrently deploy hygiene promotion activities.

Effect of chlorination on anti-acetylcholinesterase activity of organophosphorus insecticide solutions and contributions of the parent insecticides and their oxons to the activity

Organophosphorus insecticides are known to be partly transformed to their respective oxons during the chlorination step of drinking water treatment. For most organophosphorus insecticides, the toxicological endpoint for determining acceptable daily intake levels is inhibition of acetylcholinesterase (AChE). Like the parent insecticides, oxons also inhibit AChE, so the presence of oxons in drinking water is also evaluated. However, no attention is paid to the possible presence of transformation products (TPs) other than oxons. In the present study, we determined whether the anti-AChE activity observed for chlorinated solutions of the organophosphorus insecticides malathion and methidathion could be solely attributed to the parent compounds and their oxons. Upon chlorination, both malathion and methidathion were immediately transformed to their oxons; the maximum transformation ratios were 60% and 30%, respectively, indicating that at least 40% and 70% of these compounds were transformed into other TPs. Before chlorination, malathion- and methidathion-containing solutions exhibited little to no anti-AChE activity, but the solutions showed strong activity after chlorination. The contributions of the parent insecticides and their oxons to the activities of the chlorinated samples were calculated from the concentrations of the compounds in the samples and dose–response curves for chemical standards of the compounds. For both the malathion-containing solution and the methidathion-containing solution, the calculated anti-AChE activities were almost the same as the observed activities at every chlorination time. This suggests that the observed activities could be attributed solely to the parent insecticides and their oxons, indicating that other TPs need not be considered.

Cling film for mobile phones to prevent cross-infection during the COVID-19 pandemic

Mobile phones have become an inseparable part of dermatology practice, and dermatologists use mobile phones in various ways while clinically examining patients. They are often used as a flashlight or a camera to take images of the lesions. In the COVID-19 pandemic era, mobile phones are more likely to be contaminated with the virus in health care settings, and they must be sanitized properly after use because they can be possible carriers of the virus.1Van Doremalen N. Bushmaker T. Morris D.H. et al.Aerosol and surface stability of SARS-CoV-2 as compared with SARS-CoV-1.N Engl J Med. 2020; 382: 1564-1567Crossref PubMed Scopus (5627) Google Scholar However, it is not practically feasible to sanitize mobile phones with alcohol-containing sanitizer or chlorine solutions because these chemical solutions may have ill effects on mobile phone screens. Cling film roll can be a better solution for this challenge. These are thin, transparent plastic wraps with smooth surfaces, that can be used to wrap a mobile phone thoroughly before reaching the hospital (Fig 1). Because it is transparent, the plastic wrap gives a clear view of the mobile screen. We did not find a significant rise in temperature of the mobile phone or a marked change in the resolution of images taken with the mobile camera after applying the cling film (Fig 2). After use, the phone wrapped with cling film can be sanitized with alcohol-based sanitizer because it is waterproof. In the end, the film can be removed completely from the phone and discarded.Fig 2Temperature of a mobile phone wrapped with cling film (A) before and (B) after 6 hours of use. Resolution of an image taken with a mobile phone (C) without cling film and (D) with cling film.View Large Image Figure ViewerDownload Hi-res image Download (PPT) At a time when there is intense focus on ways to prevent the spread of the disease, cling film is a plausible and cost-effective method for preventing cross-infection of severe acute respiratory syndrome coronavirus 2. Comment on “Cling film for mobile phones to prevent cross-infection during the COVID-19 pandemic”Journal of the American Academy of DermatologyVol. 84Issue 1PreviewTo the Editor: We read with great interest the article by Sethy et al1 providing an easy solution for the safe use of mobile phones in the clinics during the coronavirus disease 19 (COVID-19) pandemic. We have used the same solution since the beginning of the outbreak in our center, and yet, we believe some shortcomings of the proposed method need to be mentioned. Full-Text PDF

Know your enemy: Unexpected, pervasive and persistent viral and bacterial contamination of primary cell cultures.

In biomedical research, cell culture contamination is one of the main culprits of experimental failure. Contamination sources and concomitant remedies are numerous and challenging to manage. We herein describe two cases of uncommon contamination of cell cultures that we encountered, and the successful determination and eradication strategies. The first case describes the infection with human adenovirus C that originated from pharyngeal tonsils used for isolation of primary tonsillar epithelial cells. It is known that viral contamination of in vitro cell cultures can occur symptomless and is therefore difficult to identify. The contamination was pervasive and persistent, as it was widely spread in flow cabinets and apparatus, and has caused a serious delay to our research projects and the inevitable loss of valuable (patient‐derived) cell sources. Eradication was successful by formalin gas sterilization of the flow cabinet and elimination of all infected cell lines from our biobank after PCR‐guided determination. Secondly, we encountered a spore‐forming bacterium, namely Brevibacillus brevis, in our cell culture facility. This bacterium originated from contaminated tap water pipes and spread via regular aseptic culture techniques due to survival of the bacterial spores in 70% ethanol. B brevis overgrew the cultures within a few days after seeding of the primary cells. Chlorine solution effectively killed this spore‐forming bacterium. Both cases of contamination were identified using DNA sequencing which enabled the deployment of targeted aseptic techniques for the elimination of the persistent contamination.

COVID-19 Preparedness Within the Surgical, Obstetric, and Anesthetic Ecosystem in Sub-Saharan Africa.

COVID-19 Preparedness Within the Surgical, Obstetric, and Anesthetic Ecosystem in Sub-Saharan Africa.

Inactivation of Coronaviruses in food industry: The use of inorganic and organic disinfectants, ozone, and UV radiation

Currently there is a worldwide pandemic due to Covid-19, which has caused a great impact on humanity in social, economic, psychological aspects and unfortunately on health. Due to the risk that food can also be a medium to cause virus diseases, the procedures in the food industry safety programs must be revised; and, to be more specific, to disinfect Covid-19. Some effective disinfectants that have been proved to inactivate the coronavirus are: chlorine dioxide, sodium hypochlorite, quaternary compound, ozone and UV-C (shortwave ultraviolet light). In this review, some treatments used to inactivate a virus, with an emphasis to the coronavirus family, and other influenza viruses, are reported. It has been concluded that the coronavirus could be inactivated using free chlorine solutions at 30 mg/L, sodium hypochlorite 0.25 %, or Chlorine Dioxide (99% purity) diluted at 1/2.5 relation. Also, alcohol is an effective disinfectant at concentrations of 62 to 71% of ethanol. With respect to the use of the quaternary compound, it can be used at concentrations of 0.10%. Ozone is another promising disinfectant to inactivate the coronavirus and Covid-19. Doses of ozone between 10 to 20 ppm for 10 to 15 minutes are recommended to inactivate the coronavirus with 3.5 log10 reductions. However, a warning should be reported to the use of high doses of exposure because it can be a risk to human health. UV-C can inactivate the coronavirus at a value of 67 J/m2 by 1 to 30 minutes of exposure.

Improving chlorine resistance and separation performance of thin-film composite nanofiltration membranes with in-situ grafted melamine

Nanofiltration (NF) membranes exhibit great performance deterioration when contacting with high concentration chlorine solutions, which is unbeneficial to their sustainable operation. Herein, a chlorine-stable melamine was surface-grafted to the polyamide membrane by a covalent modification method to improve the anti-chlorine property of NF membranes. The grafting of melamine significantly changed the surface features of NF membranes. The grafted membranes owned rougher morphology, narrower pore size, higher hydrophilicity, and greater positive charge compared to the unmodified membrane. Higher salt rejections (NaCl, MgCl2, MgSO4, and Na2SO4) with slightly declined water permeability were obtained for the grafted membranes. Importantly, the optimized membrane with melamine grafting could maintain a high separation performance when contacting with 2000 ppm NaClO solution for 10 h at a pH of 10.5. For the control membrane without modification, more defects appeared on the membrane surface when the pH of the chlorine solution decreased from 10.5 to 3.5. In contrast, the original surface characteristics and chemical structures of the grafted membranes were well preserved under the same conditions. The grafting layer endowed the grafted membrane outstanding chlorine resistance and high separation performance, making it attractive for the construction of chlorine tolerant desalination membranes for the environmental process.

Use of chlorine solutions as disinfectant agents in health units to contain the spread of COVID-19

Objective: This study aimed to gather information available in different disinfection protocols for establishments that provide care to suspected or confirmed patients with COVID-19, to contain the spread of the virus, besides proposing different ways of preparing the bleach solution for the most varied purposes within a Health Unit. Methods: It was realized bibliographic research about disinfection protocols to contain COVID-19, as well as disinfectant agents used to inactivate the virus. Results: Many hospitals and basic health units perform disinfection in many hospitals based on disinfection protocols that are not suitable due to the insufficient amount of daily cleaning recommended, as well as the use of ineffective agents or in inadequate concentrations. Among the most used disinfectant agents chlorine solutions have been described as the most efficient and most applicable, thus, we recommend the use of solutions containing chlorine in its composition, such as commercial bleach, as well as highlight its finalities, correct way of use and application at environments that take care of patients with disease COVID-19 or suspected. Conclusion: the use of solutions containing chlorine in its composition, such as commercial bleach, is a viable alternative for disinfecting hospitals and health basic units, due to its efficiency against the coronavirus, low cost, accessibility, and greater applicability when detected by other widespread disinfectant agents.

Evaluation of an Inexpensive Handwashing and Water Treatment Program in Rural Health Care Facilities in Three Districts in Tanzania, 2017

Unsafe water, sanitation, and hygiene (WASH) conditions in healthcare facilities (HCFs) can increase the risk of disease transmission, yet WASH coverage is inadequate in HCFs in most low- and middle-income countries. In September 2017, we conducted a baseline survey of WASH coverage in 100 HCFs in three rural Tanzanian districts. Based on needs calculated from the baseline, we distributed handwashing and drinking water stations, soap, and chlorine solution; we repeated the survey 10 months later. The intervention improved coverage with handwashing stations (82% vs. 100%, p &lt; 0.0001), handwashing stations with water (59% vs. 96%, p &lt; 0.0001), handwashing stations with soap and water (19% vs. 46%, p &lt; 0.0001), and handwashing stations with soap and water within 5 m of latrines (26% vs. 53%, p &lt; 0.0001). Coverage of drinking water stations increased from 34% to 100% (p &lt; 0.0001) HCFs with at least one drinking water station with free chlorine residual (FCR) &gt; 0.2mg/ml increased from 6% to 36% (p &lt; 0.0001), and in a sample of HCFs, detectable E. coli in stored drinking water samples decreased from 46% to 5% (p &lt; 0.001). Although the program increased access to handwashing stations, drinking water stations, and safe drinking water in HCFs in rural Tanzania, modest increases in soap availability and water treatment highlighted persistent challenges.

Inactivation modeling of microorganisms using organic chlorine and acetic acid solutions and estimation of growth kinetics of adhered Enterobacteriaceae to lettuce (Lactuca sativa L.)

AbstractThis study was aimed to evaluate the efficiency of the organic chlorine and acetic acid solutions on the inactivation of adhered cells of Escherichia coli, Cronobacter sakazakii and Klebsiella pneumoniae to lettuce. Besides, the growth and inactivation of K. pneumoniae adhered to lettuce was modeled. According to the findings, the use of chlorine solution (170 mg/ml of total residual chlorine) caused reductions of 1.8, 1.9, and 1.9 log for E. coli, C. sakazakii, and K pneumoniae, respectively, were recorded. In this regard, the organic chloramine was more effective in controlling the adhered microorganisms while compared with 1.5% acetic acid solution, while the addition of 0.5% sodium chloride to 1.5% acetic acid solution increased microbial inactivation. K. pneumoniae RC‐34 inactivation was characterized by the presence of two sub‐populations with different resistances against the proposed sanitizers. Moreover, the growth kinetic parameters of K. pneumoniae RC‐34 adhered to lettuce leaves were very similar to that reported in the literature for nonadhered microorganisms. The predictive data generated can be valuable to assess the growth and inactivation of produce adhered microorganisms in leafy produce.