Alternative Sanitation Research Articles

Assessing the efficacy of electrolyzed water for sanitizing contaminated stainless-steel surfaces in the meat industry

Electrolyzed water (EW) presents promising potential as an alternative sanitation solution, offering cost savings and eliminating the need for harsh chemicals in food factories. This study investigates EW's efficacy in cleaning contaminated stainless-steel plates. Some plates were covered with meat residues, and the upper side of the plate's surfaces were inoculated with Escherichia coli ATCC 10536. Plates were then immersed in sterile distilled water (SDW) (pH: 7 ± 1), acidic electrolyzed water (AcEW) (free chlorine: 4.21 ± 0.05 mg/L, oxidation-reduction potential (ORP): 1168 ± 3.54 mV, pH: 2.74 ± 0.03), or alkaline electrolyzed water (AlEW) (ORP: 817 ± 8.49 mV, pH: 11.38 ± 0.01), at different temperatures (30 or 50 °C) for 30 s. The cleanliness of plates was confirmed microbiologically when no E. coli was detected, (below 1.0 log CFU/cm2). Treatment with SDW resulted in a modest reduction of the E. coli by 1.67 ± 0.84 log CFU/cm2 (±70% of the survived population). At 30 °C, E. coli was undetectable when AlEW was used without meat residue. At 50 °C, E. coli was undetectable when either AcEW or AlEW was used without meat residue. Visual and tactile inspections were conducted to validate cleanliness. The visual examination was performed after cleaning the plates with EW to ensure they appeared clean. However, tactile inspection indicated the presence of residues. Subsequent microbial analysis revealed 1.50 ± 0.87 log CFU/100 cm2 (±36% of the surviving population) of E. coli. This study demonstrated that meat residues on food-contact surfaces create a barrier to sanitation, necessitating mechanical action and heat for improved cleanliness.

Impact of In-Home Handwashing Stations on Hand Hygiene During the COVID-19 Pandemic in Unpiped Rural Alaska Native Homes.

More than 3300 rural Alaska Native homes lack piped water, impeding hand hygiene. During the COVID-19 pandemic, the Alaska Native Tribal Health Consortium and the Centers for Disease Control and Prevention partnered with 10 Tribal communities and regional Tribal health organizations to install a low-cost, intermediate-technology water and sanitation system, the Miniature Portable Alternative Sanitation System (Mini-PASS). We assessed the impact of the Mini-PASS handwashing station on handwashing, other water-related uses, and problems encountered over time. In this pre-postintervention study, we conducted semi-structured interviews by telephone seasonally with representatives of 71 households with the Mini-PASS from February 2021 through November 2022 to assess the impact of the units on water use and health. Before Mini-PASS installation, all participating households primarily used washbasins for handwashing. Postintervention, more than 70% of households reported using the Mini-PASS as their primary handwashing method in all 3 follow-up intervals (3, 6-9, and 12 months postintervention). The proportion of households using the handwashing station for other household tasks increased during 12 months, from 51.4% (19 of 37) at 3 months postintervention to 77.8% (21 of 27) at 12 months postintervention. Although approximately 20% to 40% of households reported problems with their handwashing station during the 12 months postintervention, a large proportion of interviewees (47% to 60%) said they were able to conduct repairs themselves. Households in rural Alaska quickly adopted the Mini-PASS for hand hygiene and other needs and were largely able to troubleshoot problems themselves. Further research evaluating the impact of improved handwashing behaviors facilitated by the Mini-PASS should be conducted.

Use of Non-Chlorine Sanitizers in Improving Quality and Safety of Marketed Fresh Salad Vegetables

The safety of vegetable food is compromised by various factors, including the inefficient or excessive use of sanitizers. Instances of individuals falling ill after consuming raw vegetables have been reported, with outbreaks of diseases caused by pathogens on fresh vegetables becoming increasingly prevalent globally, attracting significant media coverage and impacting the economic viability of vegetable cultivation. Measures to enhance food safety in postharvest horticultural produce involve controlling microbial proliferation and minimizing cross-contamination. Sanitizers were utilized in the food safety arsenal for a variety of purposes, including pathogen elimination and microbe reduction, hand, tool, and vegetable contact surface cleaning, and produce shelf-life extension. Choosing an appropriate sanitizer for all vegetables is difficult due to a lack of knowledge on which sanitizers are ideal for the many types of vegetables grown on farms under different environmental circumstances. Although chlorine-based sanitizers, such as sodium or calcium hypochlorite, have been widely used for the past 50 years, recent research has revealed that chlorine reacts with an organic compound in fresh vegetables to produce trihalomethane, a carcinogen precursor, and as a result, many countries have prohibited the use of chlorine in all foods. As a result, horticulture research groups worldwide are exploring non-chlorine, ecologically friendly sanitizers for the vegetable industry. They also want to understand more about the present procedures in the vegetable business for employing alternative sanitizers, as well as the efficacy and potential dangers to the food safety of fresh salad vegetables. This review paper presents detailed information on non-chlorine sanitizers, such as their efficacy, benefits, drawbacks, regulatory requirements, and the need for additional research to lower the risk of marketed salad vegetable food safety.

Control of Pathogens in Pig Production Facilities Using Alternative Disinfection Strategies

HighlightsAlternative cleaning and disinfection (C&D) strategies are needed by pig producers which adopted antibiotic-free production practices in their effort to mitigate the emergence and spread of antimicrobial resistance (AMR).The use of slightly acidic electrolyzed water (SAEW) and peracetic acid (PAA) can be suitable alternatives to conventional disinfectants currently used in commercial swine barns.The cost associated with using SAEW and PAA translates only to a minimal increase (0.07 and 0.08%, respectively) in the total production cost, which can be compensated by their prolonged efficacy over time.Abstract. Implementing antibiotic-free production practices in pig barns to mitigate the emergence of AMR has led to a reported increase in certain pathogens in the barn environment. Hence, this study aimed to investigate alternative sanitization and disinfection procedures to reduce the prevalence of pathogens in pig production. Based on screening using developed assessment criteria (i.e., applicability, intrinsic property, cost, and safety) and laboratory-scale tests, the application of SAEW and PAA were selected for further evaluation under in-barn conditions. Conventional disinfectant (Virkon) was used as a control given its widespread use in commercial pig production barns. In the barn tests, the surviving microbial cells on different types of surfaces such as concrete (flooring), metal (drinkers), plastic (pens), and wood (partitions) in grow-finish, nursery, and farrowing rooms were assessed at various time points to compare the effectiveness of the selected disinfection strategies relative to a control (Virkon) treatment. Results showed that PAA (400 ppm) and SAEW (50 ppm) were more effective than Virkon in grow-finish and farrowing rooms 4 to 24 h after application, while all treatments showed reduced efficacy on concrete in nursery rooms, indicating that a longer contact time may be required for rough surfaces. Economic analysis showed that PAA and SAEW cost $0.81 and $0.84 per market pig per cycle compared to Virkon with $0.675; this 0.07% to 0.08% increase in total production cost of using PAA and SAEW relative to current conventional disinfectant (Virkon) can be compensated by their prolonged efficacy over time. Keywords: Animal buildings, Antibiotic-free pig production, Disinfection measures, Pathogen control.

Designing web-based designed for decision making process of upgrading slum sanitation

In Indonesia’s slum areas, Inadequate sanitation is a major challenge. This study introduces an interactive web-based platform, UPSS (“Upgrading Slum Sanitation”), to aid in selecting appropriate sanitation technologies for these regions. UPSS integrates a Decision Support System (DSS) to streamline the decision-making process. Our objective was to create UPSS to facilitate the selection of suitable sanitation technologies, tailored to the specific needs of Indonesia slum areas. We employed a mixed-methods approach to develop UPSS, focusing on user-friendly interfaces and streamlined decision-making processes. The first screen will help identify the slum classification (high, middle and low slum) by using the questionnaire. The following screens will identify alternative sanitation technologies. After that we apply the UPSS in the case study area, Manado Indonesia. The application of UPSS in slum areas of Indonesia demonstrated its effectiveness in reducing planning time for sanitation improvement. The results, presented in an easily interpretable format, showed a range of sanitation options and were well-received by facilitators in these areas. UPSS proves significant in improving sanitation planning in slums. It offers a quick, efficient, and user-friendly tool for stakeholders to identify and implement the most suitable sanitation technologies, thereby addressing a critical need in urban sanitation management

Prospects for the use of probiotic organisms to develop alternative strategies for disinfection and prevention of infectious diseases

Introduction: An important feature of microorganisms is the ability to adapt to adverse external influences, including the development of multiple antimicrobial resistance, leading to such negative consequences for humans as nosocomial infections, problems with cleaning rooms, medical and industrial equipment. The active use of chemical disinfectants for high-quality disinfection and cleaning has a number of disadvantages, including the risks of pathogens with new mechanisms of resistance to antimicrobial agents. The search for new, effective and safe antimicrobial agents as an alternative to chemical disinfectants is relevant. The use of probiotic strains of microorganisms, including lactic acid bacteria, in this capacity may be a promising area of research.Objective: to analyze the literature data on studies of the potential of probiotic organisms, including lactic acid bacteria, to develop alternative disinfection and prevention strategies.Materials and methods: This review of the subject field has been prepared based on the guiding principles of PRISMA-ScR. SCOPUS, Google Scholar, and RSCI databases were used. The works in Russian and English were considered, for the period 1995-2023.Results: The review included 89 articles exploring the disadvantages of traditional disinfection methods and the search for alternative sanitation strategies. The description of various solutions for the introduction of probiotic purification methods is systematized – using bacteriophages, probiotic microorganisms of R. Bacillus and representatives of lactic acid bacteria as active agents.Conclusions: A system of sanitary measures based on probiotic biodesinfectants, including lactic acid bacteria, can be included among the tools for countering pathogens, including their biofilms and forms with multidrug resistance. The introduction of a probiotic hygienic cleaning system, without having a negative impact on the environment, can increase the effectiveness of traditional hygienic preventive measures both in medical institutions and in production.

Experimental evaluation of fresh human feces biogas and compost potential: Evidence for circular economy from waste streams in Ethiopia

Biogas toilets are one of the most resource-efficient sanitation technologies. The technology has dual purposes of generating energy and stabilizing waste-producing biofertilizers. In Ethiopia, knowledge of human feces' energy potential is limited to optimize the development of biogas toilet facilities. Therefore, this study was aimed to evaluate the biogas and biofertilizer potential of human feces in Jimma City, Ethiopia, which may contribute to the development of sustainable sanitation technologies. The study was lab-based experimental design. In the lab-scale batch experiment, fresh human excreta samples were collected using a urine diversion raised toilet. Using ultimate and proximate laboratory analyses, the theoretical yield of biogas was predicted. Then a series of anaerobic digestion batch experiments were conducted to determine the practical energy yield. The bio-fertilizer potential of human feces was determined by analyzing the nutrient contents of human feces. The findings of this study showed that the bio-methane yield from the experimental results has a mean of 0.393 m3 kg−1, which is 14.16 MJ kg−1. The bio-methane meter cube per capita per head per year were 28.71 (28.03–29.27) from the experimental result and 45.26 for the theoretical yield of methane. In this study, the bio-fertilizer potential of human feces was evaluated using nutrient analysis, specifically the NPK (nitrogen, phosphorus, and potassium). Accordingly, human feces contain potassium (2.29 mg kg−1), phosphorus (1.12 mg kg−1), and nitrogen (3.71 mg kg−1). This finding suggests the bio-methane potential of human feces can be used for energy recovery and alternative sanitation options, providing a positive remedy for the sanitation crisis in urban settings.

Influence of sanitation facilities on diarrhea prevalence among children aged below 5 years in flood-prone areas of Bangladesh: a multilevel analysis.

Although the improvement of sanitation facilities has been a major contributor to improving public health, it is not guaranteed to prevent negative health outcomes. This is especially true in areas affected by severe natural disasters, such as flooding or extreme rainfall. Previous studies have examined the association between catastrophic natural disasters and negative health outcomes. However, studies on disaster-prone areas are limited. This study focused on the impact of flood risks and examined whether the improvement of sanitation facilities would be sufficient to suppress the prevalence of diarrhea in flood-prone areas. Two secondary datasets including geodata on flood-prone areas were used for the analysis: one each was obtained from the Bangladesh Demographic and Health Survey and Bangladesh Agricultural Research Council. Two models with categorizations of sanitation facilities based on containment type and excreta flow were applied for analysis. Results showed that the severe flood-prone areas and "diffused" type of sanitation, where the feces are diffused without any containment, had significant positive associations with diarrhea prevalence; however, the interaction between them was negative. Moderate flood-prone areas had a significant positive association with diarrhea prevalence; however, the interaction with unimproved sanitation, which includes containment without clear partition from feces, was significantly negative. These findings indicate that improved sanitation or containment type of sanitation may not positively contribute to the prevention of diarrhea in these severe- and moderate-flood prone areas. The urgent need for alternative sanitation technologies should be addressed in flood-prone regions.

Ultraviolet-c Radiation Induced Changes on Bioactive Compounds Content, Antioxidant Capacity and Microbial Quality of Minimally Processed Molokhia (Corchorus Olitorius L.) Leaves

Minimally processed or fresh-cut leafy vegetables are very popular for consumption due to their convenience and ready-to-use properties, but they provide an ideal medium for microbial development and degradation of functional properties. Thus, this industry commonly uses chemical agents for disinfection. However, certain problems with the disinfectant agents’ usage have been raised and led to the investigation of alternative sanitization treatments. In this respect, ultraviolet (UV-C) radiation could be of interest because no residues are released and the cost is relatively low. The present study was carried out to investigate the influence of UV-C treatment on bioactive compounds content, antioxidant capacity and microbial quality of minimally processed molokhia (Corchorus olitorius L.) leaves. Data indicated that UV-C irradiation dose (11.35 kJ m−2) of molokhia leaves led to an initial increasing in bioactive compounds including total polyphenols (41.20%), carotenoids (37.41%), flavonoids (26.43%), chlorophyll (11.93%) and lutein (51.73%) in accompanying with slightly decreasing in antioxidant capacity (-11.78%) on processing day. Also, reduction in mesophilic (-11.50), psychrophilic (-18.90) and enterobacteria (-17.10%) counts was also recorded. The initial bioactive compounds and total antioxidant capacity content decreased as well as the bacterium count gradually increased during the storage period in UV-C treated samples for 9 days at 8 0C, especially after 6 days. In conclusion, data of the present study should be taken in our consideration when the UV-C radiation used as alternative to chemical agents for sanitizing minimally processed molokhia leaves and preserving their quality. How to Cite: Yousif A. Elhassaneen, Areeg A. Nour El-Deen, Amal Z. Nasef, 2023. "Ultraviolet-c Radiation Induced Changes on Bioactive Compounds Content, Antioxidant Capacity and Microbial Quality of Minimally Processed Molokhia (Corchorus Olitorius L.) Leaves." Journal of Agriculture and Crops, vol. 9, pp. 309-322.

Development of ecological sanitation approaches for integrated recovery of biogas, nutrients and clean water from domestic wastewater

Access to adequate sanitation services and the treatment of domestic wastewater becomes a critical problem in developing countries. Domestic wastewater treatment based on conventional sanitation concept is the most common approach, which is neither ecological nor economical sound to realize sustainable sanitation solution. Therefore, there is a need to block the sanitation-linked concerns and limitations of the conventional systems through the development of an alternative sustainable sanitation systems. With the rising demand to improve the existing sanitation system for environmental protection and resources conservation (energy, nutrient, and water), ecological sanitation approach appealed the attention of scientific communities. This paper presents the comprehensive review of domestic wastewater characteristics, conventional sanitation systems and its sustainability challenges; ecological sanitation technologies, process conditions and their performances in terms of resource recovery efficiency (i.e. biogas, struvite-based nutrients and clean water). The outcome of these approaches are resource oriented and closed-loop systems, which promotes the sustainable sanitation by overwhelmed the limitations of conventional systems. Moreover, the application of these technologies to treat domestic wastewater also helps to improve public health by reducing the introduction of disease causing pathogens in to the water cycle and minimizes the negative environmental impacts. Accordingly, the applications of ecological sanitation technologies to treat domestic wastewater would be a viable option to solve the existing sanitation problems; and simultaneously promoting energy-food-water-health nexus, especially in developing country. • Eco-San approaches of DWW in biogas, struvite and clean water recovery is reviewed. • COD removal and biogas recovery potential of various technologies are reported. • Nutrients removal and struvite recovery efficiencies from DWW are described. • The water reuse is based on the stringent water quality standards. • Future research is needed for an integrated recovery of valuables from mixed DWW.

Utilization of Piper betle L. Extract for Inactivating Foodborne Bacterial Biofilms on Pitted and Smooth Stainless Steel Surfaces.

Biofilms are a significant concern in the food industry. The utilization of plant-derived compounds to inactivate biofilms on food contact surfaces has not been widely reported. Also, the increasing negative perception of consumers against synthetic sanitizers has encouraged the hunt for natural compounds as alternatives. Therefore, in this study we evaluated the antimicrobial activities of ethanol extracts, acetone extracts, and essential oils (EOs) of seven culinary herbs against Salmonella enterica serotype Typhimurium and Listeria innocua using the broth microdilution assay. Among all tested extracts and EOs, the ethanol extract of Piper betle L. exhibited the most efficient antimicrobial activities. To evaluate the biofilm inactivation effect, S. Typhimurium and L. innocua biofilms on pitted and smooth stainless steel (SS) coupons were exposed to P. betle ethanol extract (12.5 mg/ml), sodium hypochlorite (NaClO; 200 ppm), hydrogen peroxide (HP; 1100 ppm), and benzalkonium chloride (BKC; 400 ppm) for 15 min. Results showed that, for the untreated controls, higher sessile cell counts were observed on pitted SS versus smooth SS coupons. Overall, biofilm inactivation efficacies of the tested sanitizers followed the trend of P. betle extract ≥ BKC > NaClO > HP. The surface condition of SS did not affect the biofilm inactivation effect of each tested sanitizer. The contact angle results revealed P. betle ethanol extract could increase the surface wettability of SS coupons. This research suggests P. betle extract might be utilized as an alternative sanitizer in food processing facilities.

Behaviors of Salmonella enterica serovar Typhimurium and Listeria monocytogenes on whole avocado during storage at 21 or 7°C and their reduction by aqueous chlorine dioxide and peroxyacetic acid

The microbiological safety of avocado is concerning in light of associated foodborne illness outbreaks. Avocados were inoculated with 7 log CFU/fruit of Salmonella enterica serovar Typhimurium or Listeria monocytogenes and stored at 21 °C for 10 days and 7 °C for 14 days. S. Typhimurium level increased by 0.71 log CFU/fruit at 21 °C and decreased by 0.93 log CFU at 7 °C (P < 0.05). L. monocytogenes remained stable at 6.95–7.27 log CFU/fruit at both temperatures. In the sanitation experiment, avocados were inoculated with 8 log CFU/fruit of the bacteria and treated with chlorine dioxide (ClO2) produced with HCl or malic acid (10, 15, 20 ppm) and peroxyacetic acid (PAA; 60, 80, 100 ppm) for 5 min. Fifteen and twenty ppm malic-acid-produced ClO2 and 100 ppm PAA reduced S. Typhimurium to an undetectable level. Twenty ppm ClO2 produced with malic acid showed the highest L. monocytogenes reduction of 6.93 log CFU. This study revealed the potential survival and growth of pathogenic bacteria on fresh avocado stored under household conditions. ClO2 or PAA showed potential to serve as alternative sanitizers in avocado washing, although further confirmation in the industrial settings and the evaluation of their impact on avocado sensory properties are warranted.

Origanum dubium (Cypriot Oregano) as a Promising Sanitizing Agent against Salmonella enterica and Listeria monocytogenes on Tomato and Cucumber Fruits.

In recent years, the use of natural products such as essential oils (EOs) and other plant extracts for the preservation of fresh produce has attracted much interest from the food industry. Many endemic medicinal and aromatic plants, such as Cypriot oregano (Origanum dubium), present a plethora of properties that can be utilized by the fruit and vegetable sectors of the food industry. The purpose of the present study was to assess the effects of O. dubium EO and hydrosol (at different concentrations and durations of dipping application) for the preservation of tomato and cucumber fruit quality, and their effectiveness as sanitizing agents against two foodborne pathogens (Listeria monocytogenes and Salmonella enterica). The results of this study indicated that increased concentrations of EO, combined with a longer duration of application, resulted in less marketable fruit compared to hydrosol application. Interestingly, EO application at lower concentrations and shorter durations of application (i.e., 0.01% for 5 min) increased fruit antioxidant, ascorbic acid and carotenoid levels (for tomato fruit), suggesting an increase in the nutritional value of the treated fruit, compared to the control. EO and hydrosol were able to decrease the bacterial populations (both bacteria) on fruits. Both products were especially effective against L. monocytogenes, even seven days after their application and storage at 11 °C (up to an approx. 3 log reduction with the EO application). Overall, the results of this study suggest that the use of O. dubium EO and hydrosol could be considered as alternative sanitation means for tomatoes and cucumbers.

Pelatihan Pembuatan Eco-Enzyme Sebagai Alternatif Hand Sanitizer pada Masa Pandemi Covid-19 Bagi Masyarakat Desa Mekarsari

Covid-19 health protocol regulations cause limited space for people to move, which has an impact on the social and economic life of the community. This condition gives rise to new habits, people must always maintain cleanliness which causes an increasing people's consumption of cleaners such as hand sanitizers, soaps, disinfectants, and others. In addition, people also often consume nutritious foods such as vegetables and fruit, thereby increasing the amount of household waste. However, housing conditions with limited yards and far from Final Disposal Sites (TPA) create a new problem, namely the accumulation of household waste. This condition is also experienced by the people of Mekarsari Village. The technique of converting organic waste into eco-enzymes plays an important role in reducing the amount of organic waste that ends up in landfill. Through community service activities, the team held an Eco-enzyme Making Training as an Alternative Hand Sanitizer during the Covid-19 Pandemic for the people of Mekarsari Village. Community service activities have been carried out and have been able to educate the public in processing household waste, especially organic waste, into eco-enzymes. Furthermore, the eco-enzyme can be used as a hand sanitizer.

Unraveling the mechanism of the synergistic antimicrobial effect of cineole and carvacrol on Escherichia coli O157:H7 inhibition and its application on fresh-cut cucumbers

The objective of this study was to evaluate the mechanism of the synergistic antimicrobial effect of cineole (CN) and carvacrol (CR) on E. coli and its application on fresh-cut cucumbers. Herein, the CN/CR synergy could effectively inhibit E. coli by destroying its bacterial cell structure and causing the leakage of intracellular organic matters. For the first time, CN/CR synergy interaction on E. coli DNA and the possible mechanism of action on bacterial genetic material was revealed at the molecular level by molecular docking technology. Furthermore, CN/CR could significantly inhibit E. coli biofilm, mobility, and exopolysaccharides (EPS) production (p < 0.05). Supporting these findings, CN/CR suppressed E coli virulence genes shiga toxin (stx1), intimin (eae), flagella regulation (flhD), and AI-2 quorum-sensing gene (luxS) at transcriptional levels. Finally, CN/CR application at 1MIC+1MIC was satisfactory in significantly inhibiting E. coli on fresh-cut cucumbers but had a sensorial defect. Moreover, CN/CR at ½MIC+½MIC were generally acceptable with a better sensorial score. This study thus confirmed the CN/CR antimicrobial efficacy and maybe used as an alternative natural food sanitizer of fresh produce.

Sodium Hypochlorite and its Environmental Impacts; Time to Switch for Herbal Alternatives

Sanitizers are anti-microbial products in the form of spray, lotions, and creams. Sodium hypochlorite now plays an essential role in preserving hand cleanliness by denaturing microbial proteins by lysing the cell. These Sanitizers have also been used in medical, dental, and surgical treatments. If consumed, or through cutaneous or ocular exposure, sodium hypochlorite can be hazardous. When combined with acid it forms chlorine gas and when combined with basic solutions, chloramine is formed, both of which contribute to harmful consequences and it is an incredibly powerful oxidant. Furthermore, chlorination of drinking water with sodium hypochlorite oxidase organic pollutants, resulting in trihalomethanes, which are hazardous. It is critical for health care practitioners, particularly physicians, to understand the ways in which NaOCl can cause toxicity. The study of natural cures used to treat human sickness over millennia has laid the foundation for pharmaceutical development. The adaptation of alternative hand sanitizer formulations based on natural and herbal resources is one reasonable solution to address this toxicity problem. More extensive screens of indigenous plants with elevated flavonoids levels for antibacterial activities and the development of ecofriendly and efficient hand sanitizers should be conducted as contrast to artificial formulations.

The efficacy and safety of electrolyzed water against Covid-19 as an alternative hand sanitizer.

Aim To investigate the efficacy of electrolyzed water against viruses and its safety to the skin. Methods Virus culture was carried out at level-3 Bio-Safety (BSL3) facilities. The test material was prepared at room temperature mixed with one part virus suspension and one organic load. As an antiseptic and disinfectant control, 0.7% formaldehyde was used. Cytotoxic effects of electrolyzed water were performed on Vero cells. In order to assess the safety of electrolyzed water, a skin sensitivity test was conducted for electrolyzed water exposure. Results Electrolyzed water has a higher value of reduction factor than antiseptic and disinfectant control, formaldehyde, and it was statistically different from control. Cytotoxicity test results on Vero cells showed that electrolyzed water demonstrated safety in Vero cell viability. As many as 58 participants who met the inclusion criteria took electrolyzed water sensitivity test to the skin. The sensitivity test showed that participants with reactions to electrolyzed water were all female, with a mean age of 32.6 years. The patch-test was positive in 3 of 4 participants who reacted to the product. Conclusion Electrolyzed water is effective as a new antiseptic and disinfectant against viruses and safe for human skin.

Rural Sanitation: Scenarios and Public Policies for the Brazilian Semi-Arid Region

Brazil’s primary sanitation sector has been neglected, especially concerning rural sanitation. Population dispersion and the difficulty of access in many rural communities bring more significant challenges to the universalization of the service and, consequently, vulnerabilities for the population. The present work builds a theoretical framework about the context of rural sanitation in Brazil, with history, weaknesses in the sector, the impact of COVID-19 and new technologies, and central public policies in the State of Pernambuco. It is known that COVID-19 has caused considerable challenges that, added to the obstacles to national sanitation, result in greater vulnerability to the population, especially for indigenous peoples, quilombolas, and diffuse rural communities. In the State of Pernambuco, certain policies, such as the One Million Rural Cisterns Program (P1MC), One Land and Two Waters Program (P1 + 2), Água Doce Program and Operação Pipa Program, significantly improved the quality of life of the rural population. However, these measures are not enough to remedy the sector’s shortcomings. Although alternative sanitation technologies bring hope to the sector, there is a long way to go towards the universalization of sanitation.

Hydrothermal carbonization as an alternative sanitation technology: process optimization and development of low-cost reactor.

Background: The provision of safe sanitation services is essential for human well-being and environmental integrity, but it is often lacking in less developed communities with insufficient financial and technical resources. Hydrothermal carbonization (HTC) has been suggested as an alternative sanitation technology, producing value-added products from faecal waste. We evaluated the HTC technology for raw human waste treatment in terms of resource recovery. In addition, we constructed and tested a low-cost HTC reactor for its technical feasibility. Methods: Raw human faeces were hydrothermally treated in a mild severity range (≤ 200 °C and ≤ 1 hr). The total energy recovery was analysed from the energy input, higher heating value (HHV) of hydrochar and biomethane potential of process water. The nutrient contents were recovered through struvite precipitation employing process water and acid leachate from hydrochar ash. A bench-scale low-cost reactor (BLR) was developed using widely available materials and tested for human faeces treatment. Results: The hydrochar had HHVs (23.2 - 25.2 MJ/kg) comparable to bituminous coal. The calorific value of hydrochar accounted for more than 90% of the total energy recovery. Around 78% of phosphorus in feedstock was retained in hydrochar ash, while 15% was in process water. 72% of the initial phosphorus can be recovered as struvite when deficient Mg and NH 4 are supplemented. The experiments with BLR showed stable operation for faecal waste treatment with an energy efficiency comparable to a commercial reactor system. Conclusions: This research presents a proof of concept for the hydrothermal treatment of faecal waste as an alternative sanitation technology, by providing a quantitative evaluation of the resource recovery of energy and nutrients. The experiments with the BLR demonstrate the technical feasibility of the low-cost reactor and support its further development on a larger scale to reach practical implementation.

Sodium benzoate and sodium bisulfate as preservatives in apple juice and alternative sanitizers for washing cherry tomatoes

Unpasteurized apple ciders and fresh produce have been linked to multistate outbreaks due to contamination by foodborne pathogens. Organic acids such as benzoic acid are effective antimicrobials, and acidified sodium benzoate (NaB) has been reported to be effective in reducing pathogens inoculated on cherry tomatoes and preventing cross-contamination. Sodium bisulfate (SBS) is a powerful acidulant but has not been studied in combination with NaB. The objective of the present study was to characterize the antibacterial activity of SBS and its combination with NaB in tryptic soy broth (TSB) and apple juice, as well as washing cherry tomatoes. The minimum inhibitory concentration and minimum bactericidal concentration of SBS were all 0.5% w/v (corresponding to TSB medium pH of 4.30) and 1.0% w/v (corresponding to TSB medium pH of 2.88), respectively, for Escherichia coli O157:H7 ATCC 43895, Salmonella Enteritidis ATCC 13076, and Listeria monocytogenes Scott A. In TSB, the triple combination of 1.0% w/v SBS, 0.1% w/v NaB, and 0.02% w/v oregano oil (OO) showed the faster inactivation rate of the three bacteria than treatments with one or two antimicrobials; the activity of double combinations followed the order of 0.1% w/v NaB +1.0% w/v SBS > 0.1% w/v NaB +0.5% w/v SBS + 0.02% w/v OO > 0.1% w/v NaB +0.5% w/v SBS. pH was a critical factor in the activity of antimicrobial combinations in TSB, and L. monocytogenes was more resistant than Gram-negative E. coli O157:H7 and S. Enteritis. In apple juice added with 0.05% w/v NaB, 0.25% w/v SBS, and 0.01% w/v OO alone or in combinations, 5 log CFU/mL or greater reductions in 72 h were observed for E. coli O157:H7 and S. Enteritidis in double and triple combinations, while only the triple combination and the SBS-OO combination resulted in the same effect for L. monocytogenes. For cherry tomatoes inoculated with 6.8 log CFU/g E. coli O157:H7, complete decontamination (>6 log CFU/g) was achieved after soaking for 1 min in solutions containing 0.5–1.5% w/v SBS and 0.1% w/v NaB or 1.5% w/v SBS alone, and no pathogens were detected in all wash solutions containing 0.5–1.5% w/v SBS with and without NaB. The lower pH of wash solutions with a higher amount of SBS was a dominant factor in decontamination and prevention of cross-contamination. The present study showed the potential of SBS and its combination with NaB to enhance the safety of apple juice and cherry tomatoes.