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Enabling the sustainable Faecal Sludge Management service delivery chain-A case study of dense settlements in Kigali, Rwanda.

Int J Hyg Environ Health; 2017 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-28596087


The lack of access to basic sanitation is a global concern and alarmingly prevalent in low- and middle- income countries. In the densely populated settlements of these countries, on-site sanitation systems are usually the only feasible option because dwellers there have no sewers in place to connect to. Using on-site sanitation facilities results in an accumulation of faecal sludge which needs to be properly managed to ensure the well-being of the users as well as the surrounding environment. Unfortunately, often the conditions for faecal sludge management (FSM) within dense settlements are adverse and thus hamper sustainable FSM. We use the normative framework of the FSM enabling environment to gather empirical evidence from densely populated settlements of Kigali city in Rwanda to examine current FSM practices and the extent to which these are being influenced and affected by the setting within which they are taking place. The analysis of the study findings confirms that the existing conditions for FSM in these settlements are inadequate. The specific constraints that hinder the achievement of sustainable FSM include limited government focus on the sanitation sector, high turnover of staff in relevant government institutions, pit sludge management is not placed on the sanitation projects agenda, the existing relevant bylaws are not pro-poor oriented, a lack of clear responsibilities, a lack of relevant local professional training opportunities, unaffordability of FSM services and an inhibition to discuss FSM. Drawing on the involved stakeholders' own perceptions and suggestions, we identify possible approaches to overcome the identified constraints and to allow all actors in the FSM chain to contribute effectively to the management of faecal sludge in densely populated low-income urban settlements. Finally, our study also presents a contribution to the theoretical conceptualisation of the enabling environment for sustainable FSM.

Examining the safety of menstrual cups among rural primary school girls in western Kenya: observational studies nested in a randomised controlled feasibility study.

BMJ Open; 7(4): e015429, 2017 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-28473520


OBJECTIVE: Examine the safety of menstrual cups against sanitary pads and usual practice in Kenyan schoolgirls. DESIGN: Observational studies nested in a cluster randomised controlled feasibility study. SETTING: 30 primary schools in a health and demographic surveillance system in rural western Kenya. PARTICIPANTS: Menstruating primary schoolgirls aged 14-16 years participating in a menstrual feasibility study. INTERVENTIONS: Insertable menstrual cup, monthly sanitary pads or 'usual practice' (controls). OUTCOME MEASURES: vaginal colonization, growth on sampled used cups, toxic shock syndrome or other adverse health outcomes. RESULTS: Among 604 eligible girls tested, no adverse event or TSS was detected over a median 10.9 months follow-up. prevalence was 10.8%, with no significant difference over intervention time or between groups. Of 65 positives at first test, 49 girls were retested and 10 (20.4%) remained positive. Of these, two (20%) sample isolates tested positive for toxic shock syndrome toxin-1; both girls were provided pads and were clinically healthy. Seven per cent of cups required replacements for loss, damage, dropping in a latrine or a poor fit. Of 30 used cups processed for growth, 13 (37.1%, 95% CI 21.1% to 53.1%) had growth. growth was greatest in newer compared with established users (53%vs22.2%, p=0.12). CONCLUSIONS: Among this feasibility sample, no evidence emerged to indicate menstrual cups are hazardous or cause health harms among rural Kenyan schoolgirls, but large-scale trials and post-marketing surveillance should continue to evaluate cup safety.

Associating liver partition and portal vein ligation for bleeding hepatocellular carcinoma in HBV cirrhosis: a safety strategy.

Artículo en Inglés | MEDLINE | ID: mdl-28447055


The incidence of hepatocellular carcinoma (HCC) spontaneous tumor rupture varies between 3% and 26%. For resectable HCC ruptures, emergency hepatectomy or staged hepatectomy after transcatheter arterial embolization (TAE) are life-saving procedures, and efficient therapeutic methods. We report a multimodal therapy including TAE, associating liver partition and portal vein ligation (ALPPS) and immunoglobuline infusion for a huge bleeding HCC with portal vein tumor thrombosis (PVTT) in hepatitis B virus (HBV) cirrhosis. ALPPS first step began with an abdominal toilette due to the massive hemoperitoneum and a portal vein incision at the bifurcation of the right and left portal veins was performed. A freely floating left part of the thrombus was extracted from the left portal vein in order to restore the left portal vein. The right portal vein with complete thrombosis was closed. Liver partition was then performed. The second step was performed without complications. A HCC Edmondson grade 4 (pT3b) and a cirrhotic liver parenchyma were described. Postoperative ascites decompensation was treated and patient was discharged in postoperative day 21. The reported triple strategy allowed us to prolong patient live. A multimodal therapy including TAE, ALPPS and immunoglobuline is a good option for a life treatment in case of huge bleeding hepatocellular carcinoma with PVTT in HBV cirrhosis.

Towards sustainable sanitation management: Establishing the costs and willingness to pay for emptying and transporting sludge in rural districts with high rates of access to latrines.

PLoS One; 12(3): e0171735, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28323885


MOTIVATION: Proper management of fecal sludge has significant positive health and environmental externalities. Most research on managing onsite sanitation so far either simulates the costs of, or the welfare effects from, managing sludge in situ in pit latrines. Thus, designing management strategies for onsite rural sanitation is challenging, because the actual costs of transporting sludge for treatment, and sources for financing these transport costs, are not well understood. METHODS: In this paper we calculate the actual cost of sludge management from onsite latrines, and identify the contributions that latrine owners are willing to make to finance the costs. A spreadsheet-based model is used to identify a cost-effective transport option, and to calculate the cost per household. Then a double-bound contingent valuation method is used to elicit from pit-latrine owners their willingness-to-pay to have sludge transported away. This methodology is employed for the case of a rural subdistrict in Bangladesh called Bhaluka, a unit of administration at which sludge management services are being piloted by the Government of Bangladesh. RESULTS: The typical sludge accumulation rate in Bhaluka is calculated at 0.11 liters/person/day and a typical latrine will need to be emptied approximately once every 3 to 4 years. The costs of emptying and transport are high; approximately USD 13 per emptying event (circa 14% of average monthly income); household contributions could cover around 47% of this cost. However, if costs were spread over time, the service would cost USD 4 per year per household, or USD 0.31 per month per household-comparable to current expenditures of rural households on telecommunications. CONCLUSION: This is one of few research papers that brings the costs of waste management together with financing of that cost, to provide evidence for an implementable solution. This framework can be used to identify cost effective sludge management options and private contributions towards that cost in other (context-specific) administrative areas where onsite sanitation is widespread.

Evaluation of thermal hydrolysis efficiency of mechanically dewatered sewage sludge via rheological measurement.

Water Res; 116: 34-43, 2017 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-28292678


In this study, laboratory tests of both low temperature (60-90 °C) and high temperature (120-180 °C) thermal hydrolysis (LTHP and HTHP) were performed on mechanically dewatered high-solid sludges (at total solid of 14.2 wt% and 18.2 wt%) to evaluate the extent of organic solubilization through rheological measurements. The effects of treatment temperature and duration on organic solubilization and viscoelastic behavior of the sludge were comprehensively investigated. The results indicated that the organic solubilization contents including soluble chemical oxygen demand, soluble protein, and soluble polysaccharides increased logarithmically with the treatment time. Protein solubilized considerably faster than polysaccharides during thermal hydrolysis. The rheological curves exhibited the Payne effect in the amplitude sweep oscillation test. The elastic modulus in linear viscoelastic regime decreased logarithmically with treatment time. The viscoelastic behavior of sludge was well modeled by the Kaye-Bernstein-Kearsly-Zapas (KBKZ) model with paralleled Maxwell elements to describe the frequency dependence of elastic modulus and viscous modulus. With respect to the relaxation spectrum, the relaxation modulus first decreased with relaxation time and then increased. The relaxation modulus in each Maxwell element decreased with the treatment temperature and duration. Furthermore, in the HTHP, the influence of treatment temperature on enhancing organic solubilization and decreasing viscoelasticity exceeded the influence of treatment duration. In contrast, the treatment duration played a more important role than temperature in the LTHP. The content of organic matters was linearly related and logarithmically related to the elastic modulus in the LTHP and in the HTHP, respectively. The rheology analyses demonstrated that viscoelastic properties could be used as indicators to estimate the extent of organic matter solubilization in thermal hydrolysis process. The developed viscoelastic model provided insights for future research in numerically simulating the fluid dynamics of sludge.

Removal of hydrogen sulfide generated during anaerobic treatment of sulfate-laden wastewater using biochar: Evaluation of efficiency and mechanisms.

Bioresour Technol; 234: 115-121, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28319759


Removal of hydrogen sulfide (H S) from biogas was investigated in a biochar column integrated with a bench-scale continuous-stirred tank reactor (CSTR) treating sulfate-laden wastewater. Synthetic wastewater containing sulfate concentrations of 200-2000mg SO /L was used as substrate, and the CSTR was operated at an organic loading rate of 1.5g chemical oxygen demand (COD)/L·day and a hydraulic retention time (HRT) of 20days. The biochar was able to remove about 98.0 (±1.2)% of H S for the ranges of concentrations from 105-1020ppmv, especially at high moisture content (80-85%). Very high H S adsorption capacity (up to 273.2±1.9mg H S/g) of biochar is expected to enhance the H S oxidation into S and sulfate. These findings bring a potentially novel application of sulfur-rich biochar as a source of sulfur, an essential but often deficient micro-nutrient in soils.

Long-term stability and nutrient removal efficiency of aerobic granules at low organic loads.

Bioresour Technol; 234: 336-342, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28340438


The feasibility of application of aerobic granular sludge cultivated with high organic loads for biological nutrient removal (BNR) from low-strength wastewater was studied. Granules obtained with high-strength (COD=1400mg/L) wastewater were fed with medium (COD=700mg/L) and then low-strength (COD=400mg/L) wastewater. The granules rapidly acclimated to the medium-strength wastewater. However, feeding with low-strength wastewater reduced the F/M ratio from 0.4 to 0.2gCOD/gVSSd and granules disintegration occurred. Re-granulation was obtained after poor settling biomass was washed out and the F/M ratio reached 0.4gCOD/gVSSd. Disintegration of granules coincided with the decrease in extracellular polymeric substances (EPS) content and protein-to-carbohydrate ratio and re-granulation was assisted with the increase in EPS and protein-to-carbohydrate ratio. The results indicated that cultivation of aerobic granules with high organic loads and its implication for BNR treatment of low-strength wastewater while balancing the F/M ratio can be an alternative to reduce start-up period.

Multiple approaches to assess the safety of artisanal marine food in a tropical estuary.

Environ Monit Assess; 189(3): 125, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28238170


In this study, metal and metalloid concentrations and pathogens were measured in shellfish at different locations in a tropical estuary, including sites impacted by sewage and industry. Oyster, mangrove snails and mud snails did not exceed Australian and New Zealand Food Standards maximum levels for copper, lead or estimated inorganic arsenic at any site although copper concentrations in oysters and mud snails exceeded generally expected levels at some locations. Bacterial community composition in shellfish was species-specific regardless of location and different to the surrounding water and sediment. In the snails Telescopium telescopium, Terebralia palustris and Nerita balteata, some bacterial taxa differed between sites, but not in Saccostrea cucullata oysters. The abundance of potential human pathogens was very low and pathogen abundance or diversity was not associated with site classification, i.e. sewage impact, industry impact and reference.

Efficiency of sewage sludge biochar in improving urban soil properties and promoting grass growth.

Chemosphere; 173: 551-556, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28142113


It is meaningful to quickly improve poor urban soil fertility in order to establish the green land vegetation. In this study, a series rates (0%, 1%, 5%, 10%, 20% and 50%, in mass ratio) of biochar derived from municipal sewage sludge was applied into an urban soil and then turf grass was grown in pots. The results showed that biochar amendment induced significant increases in soil total nitrogen, organic carbon, black carbon, and available phosphorus and potassium by more than 1.5, 1.9, 4.5, 5.6 and 0.4 times, respectively. Turf grass dry matter increased proportionally with increasing amount of added biochar (by an average of 74%), due to the improvement in plant mineral nutrition. Biochar amendment largely increased the total amounts of soil heavy metals. However, 43-97% of the heavy metals in the amended soil were concentrated in the residual fraction with low bioavailability. So the accumulation of heavy metals in turf grass aboveground biomass was highly reduced by the addition of biochar. These results indicated that sewage sludge biochar could be recommended in the poor urban raw soil as a soil conditioner at a rate of 50%. However, the environmental risk of heavy metal accumulation in soil amended with sewage sludge biochar should be carefully considered.

Fertilisers production from ashes after sewage sludge combustion - A strategy towards sustainable development.

Environ Res; 154: 171-180, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-28086102


Sustainable development and circular economy rules force the global fertilizer industry to develop new phosphorous recovery methods from alternative sources. In this paper a phosphorus recovery technology from Polish industrial Sewage Sludge Ashes was investigated (PolFerAsh - Polish Fertilizers form Ash). A wet method with the use of mineral acid and neutralization was proposed. Detailed characteristic of SSA from largest mono-combustion plans were given and compared to raw materials used on the market. The technological factors associated with such materials were discussed. The composition of the extracts was compared to typical industrial phosphoric acid and standard values characterizing suspension fertilizers. The most favorable conditions for selective precipitation of phosphorus compounds were revealed. The fertilizers obtained also meet EU regulations in the case of the newly discussed Cd content. The process was scaled up and a flow mass diagram was defined.

Food safety knowledge, attitudes and practices of institutional food-handlers in Ghana.

BMC Public Health; 17(1): 40, 2017 Jan 06.
Artículo en Inglés | MEDLINE | ID: mdl-28061850


BACKGROUND: In large scale cooking, food is handled by many individuals, thereby increasing the chances of food contamination due to improper handling. Deliberate or accidental contamination of food during large scale production might endanger the health of consumers, and have very expensive repercussions on a country. The purpose of this study was to evaluate the food safety knowledge, attitudes, and practices among institutional food- handlers in Ghana. METHODS: The study was conducted using a descriptive, cross-sectional survey of 29 institutions by conducting face to face interview and administration of questionnaire to two hundred and thirty-five (235) institutional food-handlers. The questionnaire was peer-reviewed and pilot tested in three institutions in the Upper East Region of Ghana, before the final version was distributed to food-handlers. The questionnaire was structured into five distinctive parts to collect information on (i) demographic characteristics, (ii) employees' work satisfaction, (iii) knowledge on food safety, (iv) attitudes towards food safety and (v) food hygiene practices. RESULTS: Majority of the food-handlers were between 41-50 years (39.1%). Female respondents were (76.6%). In our study, the food-handlers were knowledgeable about hygienic practices, cleaning and sanitation procedures. Almost all of the food-handlers were aware of the critical role of general sanitary practices in the work place, such as hand washing (98.7% correct answers), using gloves (77.9%), proper cleaning of the instruments/utensils (86.4%) and detergent use (72.8%). On disease transmission, the results indicates that 76.2% of the food- handlers did not know that Salmonella is a food borne pathogens and 70.6% did not know that hepatitis A is a food borne pathogen. However, 81.7% handlers agreed that typhoid fever is transmitted by food and 87.7% agreed that bloody diarrhea is transmitted by food. Logistic regression analysis testing four models showed statistically significant differences (p < 0.05), for models in which the explanatory variable was the level of education. CONCLUSIONS: In generally, the institutional food-handlers have satisfactory knowledge in food safety but this does not translate into strict hygienic practices during processing and handling food products.

Three-step effluent chlorination increases disinfection efficiency and reduces DBP formation and toxicity.

Chemosphere; 168: 1302-1308, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27919529


Chlorination is extensively applied for disinfecting sewage effluents, but it unintentionally generates disinfection byproducts (DBPs). Using seawater for toilet flushing introduces a high level of bromide into domestic sewage. Chlorination of sewage effluent rich in bromide causes the formation of brominated DBPs. The objectives of achieving a disinfection goal, reducing disinfectant consumption and operational costs, as well as diminishing adverse effects to aquatic organisms in receiving water body remain a challenge in sewage treatment. In this study, we have demonstrated that, with the same total chlorine dosage, a three-step chlorination (dosing chlorine by splitting it into three equal portions with a 5-min time interval for each portion) was significantly more efficient in disinfecting a primary saline sewage effluent than a one-step chlorination (dosing chlorine at one time). Compared to one-step chlorination, three-step chlorination enhanced the disinfection efficiency by up to 0.73-log reduction of Escherichia coli. The overall DBP formation resulting from one-step and three-step chlorination was quantified by total organic halogen measurement. Compared to one-step chlorination, the DBP formation in three-step chlorination was decreased by up to 23.4%. The comparative toxicity of one-step and three-step chlorination was evaluated in terms of the development of embryo-larva of a marine polychaete Platynereis dumerilii. The results revealed that the primary sewage effluent with three-step chlorination was less toxic than that with one-step chlorination, indicating that three-step chlorination could reduce the potential adverse effects of disinfected sewage effluents to aquatic organisms in the receiving marine water.

Sterols indicate water quality and wastewater treatment efficiency.

Water Res; 108: 401-411, 2017 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-27839832


As the world's population continues to grow, water pollution is presenting one of the biggest challenges worldwide. More wastewater is being generated and the demand for clean water is increasing. To ensure the safety and health of humans and the environment, highly efficient wastewater treatment systems, and a reliable assessment of water quality and pollutants are required. The advance of holistic approaches to water quality management and the increasing use of ecological water treatment technologies, such as constructed wetlands and waste stabilisation ponds (WSPs), challenge the appropriateness of commonly used water quality indicators. Instead, additional indicators, which are direct measures of the processes involved in the stabilisation of human waste, have to be established to provide an in-depth understanding of system performance. In this study we identified the sterol composition of wastewater treated in WSPs and assessed the suitability of human sterol levels as a bioindicator of treatment efficiency of wastewater in WSPs. As treatment progressed in WSPs, the relative abundance of human faecal sterols, such as coprostanol, epicoprostanol, 24-ethylcoprostanol, and sitostanol decreased significantly and the sterol composition in wastewater changed significantly. Furthermore, sterol levels were found to be correlated with commonly used wastewater quality indicators, such as BOD, TSS and E. coli. Three of the seven sterol ratios that have previously been used to track sewage pollution in the environment, detected a faecal signal in the effluent of WSPs, however, the others were influenced by high prevalence of sterols originating from algal and fungal activities. This finding poses a concern for environmental assessment studies, because environmental pollution from waste stabilisation ponds can go unnoticed. In conclusion, faecal sterols and their ratios can be used as reliable indicators of treatment efficiency and water quality during wastewater treatment in WSPs. They can complement the use of commonly used indicators of water quality, to provide essential information on the overall performance of ponds and whether a pond is underperforming in terms of stabilising human waste. Such a holistic understanding is essential when the aim is to improve the performance of a treatment plant, build new plants or expand existing infrastructure. Future work should aim at further establishing the use of sterols as reliable water quality indicators on a broader scale across natural and engineered systems.

Monitoring sanitation and hygiene in the 2030 Agenda for Sustainable Development: A review through the lens of human rights.

Sci Total Environ; 580: 1108-1119, 2017 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-27989472


International monitoring of drinking water and sanitation has been jointly carried out by WHO and UNICEF through their Joint Monitoring Programme (JMP). With the end of the Millennium Development Goals (MDGs) era in 2015, the JMP has proposed a post-2015 framework for integrated monitoring of water and sanitation targets included in the Sustainable Development Goal no. 6. This article discusses how each element of the proposed sanitation target and corresponding indicators can be understood from a human rights perspective. Building on the MDGs, and although some of the weaknesses and gaps persist, the discussion suggests that the post-2015 proposal is a step forward towards a monitoring framework where human rights elements related to sanitation are effectively promoted. In addition, to support the interpretation and implementation of the normative content of human rights obligations related to sanitation, the study proposes a reduced set of easy-to-assess indicators to measure the normative criteria of this right, which are then grouped in a multidimensional framework to describe increasing levels of sanitation service. To do this, the study combines literature review and specific local experience from three case studies. It is shown that the proposed monitoring tools, namely the indicators and the multidimensional indicator framework, provide guidance on monitoring the human right to sanitation. In doing so, they might ultimately help sector stakeholders in the realization of this right.

On constitutive functions for hindered settling velocity in 1-D settler models: Selection of appropriate model structure.

Water Res; 110: 38-47, 2017 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-27984804


Advanced 1-D models for Secondary Settling Tanks (SSTs) explicitly account for several phenomena that influence the settling process (such as hindered settling and compression settling). For each of these phenomena a valid mathematical expression needs to be selected and its parameters calibrated to obtain a model that can be used for operation and control. This is, however, a challenging task as these phenomena may occur simultaneously. Therefore, the presented work evaluates several available expressions for hindered settling based on long-term batch settling data. Specific attention is paid to the behaviour of these hindered settling functions in the compression region in order to evaluate how the modelling of sludge compression is influenced by the choice of a certain hindered settling function. The analysis shows that the exponential hindered settling forms, which are most commonly used in traditional SST models, not only account for hindered settling but partly lump other phenomena (compression) as well. This makes them unsuitable for advanced 1-D models that explicitly include each phenomenon in a modular way. A power-law function is shown to be more appropriate to describe the hindered settling velocity in advanced 1-D SST models.

Non-destructive soil amendment application techniques on heavy metal-contaminated grassland: Success and long-term immobilising efficiency.

J Environ Manage; 186(Pt 2): 167-174, 2017 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-27594691


Extensive contamination of grassland with cadmium (Cd), lead (Pb) and zinc (Zn) is a typical problem close to Pb/Zn smelter sites. The entry of Cd or Pb into the food chain is very likely, as are toxicity effects of Zn in plants. Previous promising results from pot and field experiments showed the high potential of using amendments for immobilisation to reduce metal input into the food chain via crops grown on smelter-contaminated soils at Arnoldstein (Austria) (Friesl et al., 2006). The aim of this study was to find a practical solution for large-scale contaminations in hilly regions that avoids erosion. Field application of amendments without destroying the vegetation cover (grassland) involved two approaches: (a) slurrying (Slu) the amendments into cut gaps in the vegetation cover and (b) injecting (Inj) the amendments through the vegetation cover. Here, we investigate the immobilising and long-term efficiency of treatments [gravel sludge (2.5%) + red mud (0.5%) (GS + RM)]. Risk assessment was based on soil, plant and water samples taken over a period of 10 years. Ammonium-nitrate-extractable Cd was reduced up to 50%, Pb up to 90%, and Zn over 90%. Plant uptake into the grass mixture and narrow leaf plantain was significantly reduced for Cd, Pb, and Zn. Harvesting early in vegetation period can further reduce uptake and meet the threshold for fodder crops. The reduction of these elements in the seepage water in 24 samplings within these 10 years reached 40%, 45% and 50%, respectively. Immobilisation increased microbial biomass and decreased human bioaccessibility for Pb. Our investigation of the long-term efficiency of GS + RM in all treatments shows that the Slu and Inj amendment application techniques have promising potential as a realistic and practical method for extensively contaminated hilly land. Slurrying performed best. We conclude that grassland remediation methods involving tillage are counterproductive from the viewpoint of bioaccessibility and soil protection and therefore should be avoided.

Flugzeugdesinfektion : Geeignete Desinfektionsmittel und Standardverfahren bei hochansteckenden Krankheiten. / Disinfection of aircraft : Appropriate disinfectants and standard operating procedures for highly infectious diseases.

Artículo en Inglés | MEDLINE | ID: mdl-27785522


For infectious diseases caused by highly pathogenic agents (e. g., Ebola/Lassa fever virus, SARS-/MERS-CoV, pandemic influenza virus) which have the potential to spread over several continents within only a few days, international Health Protection Authorities have taken appropriate measures to limit the consequences of a possible spread. A crucial point in this context is the disinfection of an aircraft that had a passenger on board who is suspected of being infected with one of the mentioned diseases. Although, basic advice on hygiene and sanitation on board an aircraft is given by the World Health Organization, these guidelines lack details on available and effective substances as well as standardized operating procedures (SOP). The purpose of this paper is to give guidance on the choice of substances that were tested by a laboratory of Lufthansa Technik and found compatible with aircraft components, as well as to describe procedures which ensure a safe and efficient disinfection of civil aircrafts. This guidance and the additional SOPs are made public and are available as mentioned in this paper.

Efficiency of a cleaning protocol for the removal of enterotoxigenic Staphylococcus aureus strains in dairy plants.

Int J Food Microbiol; 238: 295-301, 2016 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-27716472


Staphylococci are considered a major concern in dairy plants mainly due to the intensive production flow, automation of processing plants and increased demand in the microbiological quality of dairy products. This study aimed to identify S. aureus strains isolated from three Brazilian dairy plants, evaluate the influence of time, temperature and contact surface on the bacterial adhesion process, as well as the efficiency of simulated hygiene and sanitation protocol in removing adhered cells. For genotypic analyses, the presence of icaA and icaD in strains was evaluated. Adherence assays were performed in biofilm reactor, comparing the influence of 2 temperatures (5°C and 35°C), 2 surfaces (stainless steel and polypropylene) and 4 contact times (3, 6, 12h and post-sanitization). To evaluate the process effectiveness in removing adhered cells, neutral detergent and sanitizing agent based on sodium hypochlorite were used in order to simulate the situation observed in one of the dairy plants analyzed. The presence of icaA and icaD genes was determined in 75.3% and 77.6% of strains, respectively; 70.6% of isolates showed both genes, whereas 17.6% showed no genes. Genes for enterotoxin production were found in all samples, relating to SEG and SEH toxins. The number of cells adhered on both surfaces was about 3 and 6 log CFU/cm at temperatures of 5°C and 35°C, respectively, for most situations evaluated, with significant increase over the evaluation period. In general, the temperature of 35°C favored greater adherence of S. aureus. At 5°C, there was a considerable number of adhered cells, but in populations significantly lower than those observed at 35°C. The cleaning and sanitizing protocol was ineffective in removing adhered cells; better performance of sodium hypochlorite was observed at 5°C, which should be related to lower adherence observed at this temperature. Thus, the process was not able to reduce the number of S. aureus bacteria adhered on both surfaces to safe levels under the conditions evaluated.
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