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Ana Allende - One of the best experts on this subject based on the ideXlab platform.
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impact of chlorine dioxide disinfection of Irrigation Water on the epiphytic bacterial community of baby spinach and underlying soil
PLOS ONE, 2018Co-Authors: Pilar Truchado, Trevor V. Suslow, Ana AllendeAbstract:The contamination of pathogenic bacteria through Irrigation Water is a recognized risk factor for fresh produce. Irrigation Water disinfection is an intervention strategy that could be applied to reduce the probability of microbiological contamination of crops. Disinfection treatments should be applied ensuring minimum effective doses, which are efficient in inhibiting the microbial contamination while avoiding formation and accumulation of chemical residues. Among disinfection technologies available for growers, chlorine dioxide (ClO2) represents, after sodium hypochlorite, an alternative disinfection treatment, which is commercially applied by growers in the USA and Spain. However, in most of the cases, the suitability of this treatment has been tested against pathogenic bacteria and low attention have been given to the impact of chemical residues on the bacterial community of the vegetable tissue. The aim of this study was to (i) to evaluate the continual application of chlorine dioxide (ClO2) as a Water disinfection treatment of Irrigation Water during baby spinach growth in commercial production open fields, and (ii) to determine the subsequent impact of these treatments on the bacterial communities in Water, soil, and baby spinach. To gain insight into the changes in the bacterial community elicited by ClO2, samples of treated and untreated Irrigation Water as well as the irrigated soil and baby spinach were analyzed using Miseq® Illumina sequencing platform. Next generation sequencing and multivariate statistical analysis revealed that ClO2 treatment of Irrigation Water did not affect the diversity of the bacterial community of Water, soil and crop, but significant differences were observed in the relative abundance of specific bacterial genera. This demonstrates the different susceptibility of the bacteria genera to the ClO2 treatment. Based on the obtained results it can be concluded that the phyllosphere bacterial community of baby spinach was more influenced by the soil bacteria community rather than that of Irrigation Water. In the case of baby spinach, the use of low residual ClO2 concentrations (approx. 0.25 mg/L) to treat Irrigation Water decreased the relative abundance of Pseudomonaceae (2.28-fold) and Enterobacteriaceae (2.5-fold) when comparing treated versus untreated baby spinach. Members of these two bacterial families are responsible for food spoilage and foodborne illnesses. Therefore, a reduction of these bacterial families might be beneficial for the crop and for food safety. In general it can be concluded that the constant application of ClO2 as a disinfection treatment for Irrigation Water only caused changes in two bacterial families of the baby spinach and soil microbiota, without affecting the major phyla and classes. The significance of these changes in the bacterial community should be further evaluated.
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demonstration tests of Irrigation Water disinfection with chlorine dioxide in open field cultivation of baby spinach
Journal of the Science of Food and Agriculture, 2018Co-Authors: Francisco Lopezgalvez, Ana Meireles, Pilar Truchado, Ana AllendeAbstract:Treatments for the disinfection of Irrigation Water have to be evaluated by demonstration tests carried out under commercial settings taking into account not only their antimicrobial activity but also the potential phytotoxic effects on the crop. The consequences of the treatment of Irrigation Water with chlorine dioxide (ClO2 ) used for sprinkler Irrigation of baby spinach in two commercial agricultural fields was assessed.; Results: Residual ClO2 levels at the sprinklers in the treated field were always below 1 mg L-1 . ClO2 treatment provoked limited but statistically significant reductions in culturable Escherichia coli counts (0.2-0.3 log reductions), but not in the viable E. coli counts in Water, suggesting the presence of viable but non-culturable cells (VBNC). Although disinfected Irrigation Water did not have an impact on the microbial loads of Enterobacteriaceae nor on the quality characteristics of baby spinach, it caused the accumulation of chlorates (up to 0.99 mg kg-1 in plants) and the reduction of the photosynthetic efficiency of baby spinach.; Conclusion: Low concentrations of ClO2 are effective in reducing the culturable E. coli present in Irrigation Water but it might induce the VBNC state. Presence of disinfection by-products and their accumulation in the crop must be considered to adjust doses in order to avoid crop damage and chemical safety risks. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.
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modelling of e coli inactivation by chlorine dioxide in Irrigation Water
Agricultural Water Management, 2017Co-Authors: Francisco Lopezgalvez, Imca Sampers, Ana AllendeAbstract:Irrigation Water has been highlighted as a potential contamination source of fresh produce with foodborne pathogens. Water disinfection treatments can be used to improve its microbiological safety. Growers should ascertain the minimum effective disinfectant doses able to achieve the desired microbiological goals. Furthermore, potential unwanted effects both on crop health and on chemical risks associated with the accumulation of disinfection by-products (DBPs) on the crop must be taken into account. The minimum effective doses vary depending on intrinsic factors (e.g. physicochemical characteristics of the Irrigation Water, concentration of the target microorganism) and also extrinsic factors (e.g. geographical and weather conditions). In the present study, different types of surface Irrigation Water were treated with various doses of a stable solution of chlorine dioxide (ClO2) (0.1–2.5mg/L) at 21±2°C for a contact time of 1min. Escherichia coli concentration (before and after treatment) and the residual ClO2 (after treatment) were analyzed. Several Water physicochemical parameters were measured (chemical oxygen demand (COD), turbidity, pH, oxidation-reduction potential (ORP), conductivity and absorbance of filtered Water samples at 254nm (UV254)). Data obtained was used to develop a model for ClO2 decay and a model for E. coli inactivation by linear regression. The ClO2 decay model (adjusted R2=0.93) included the initial ClO2 concentration and the UV254 as explanatory variables. The E. coli inactivation model (adjusted R2=0.77) included the initial ClO2 concentration, the initial E. coli concentration, and the UV254 as explanatory variables. The development of these models would help growers in making decisions regarding the minimum effective doses they might use to treat their Irrigation Water when using a stable solution of ClO2 to reduce microbial risk of fresh produce.
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microbial quality of Irrigation Water used in leafy green production in southern brazil and its relationship with produce safety
Food Microbiology, 2017Co-Authors: Luana Tombini Decol, Leticia Sopena Casarin, Ana Carolina Fosch Batista, Claudia Titze Hessel, Ana Allende, Eduardo Cesar TondoAbstract:Abstract Irrigation Water has been recognized as an important microbial risk factor for fruits and vegetables in many production areas, but there is still a lack of information about how the microbiological quality of different Irrigation Water sources and climatic conditions influence the safety of vegetables produced in Brazil. This study evaluated the distribution of generic E. coli and the prevalence of E. coli O157:H7 in two different Water sources (ponds and streams bordering farmlands and urban areas) used for Irrigation and on commercially produced lettuces in Southern Brazil. We also evaluated the effect of agricultural factors and meteorological conditions in the potential contamination of Water and produce samples. A longitudinal study was conducted on four farms during a year (July 2014 to August 2015). The results showed generic E. coli prevalence of 84.8% and 38.3% in Irrigation Water samples and on lettuces, respectively, indicating Irrigation Water as an important source of contamination of lettuces. No significant differences were detected in the counts of E. coli between the two different surface Water sources. The climatic conditions, particularly rainfall and environmental temperature, have influenced the high concentration of E. coli . The highest loads of E. coli in Irrigation Water and on lettuces were found during the warmest time of the year. E. coli O157:H7 was detected by qualitative polymerase chain reaction (qPCR) in 13 Water samples but only 4 were confirmed by isolation in culture media.
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suitability of different escherichia coli enumeration techniques to assess the microbial quality of different Irrigation Water sources
Food Microbiology, 2016Co-Authors: Pilar Truchado, Francisco Pedrerosalcedo, Francisco Lopezgalvez, J J Alarcon, Ana AllendeAbstract:The use of fecal indicators such as Escherichia coli has been proposed as a potential tool to characterize microbial contamination of Irrigation Water. Recently, not only the type of microbial indicator but also the methodologies used for enumeration have been called into question. The goal of this study was to assess the microbial quality of different Water sources for Irrigation of zucchini plants by using E. coli as an indicator of fecal contamination and the occurrence of foodborne pathogens. Three Water sources were evaluated including reclaimed secondary treated Water (RW-2), reclaimed tertiary UV-C treated Water (RW-3) and surface Water (SW). The suitability of two E. coli quantification techniques (plate count and qPCR) was examined for Irrigation Water and fresh produce. E. coli levels using qPCR assay were significantly higher than that obtained by plate count in all samples of Irrigation Water and fresh produce. The microbial quality of Water samples from RW-2 was well predicted by qPCR, as the presence of foodborne pathogens were positively correlated with high E. coli levels. However, differences in the Water characteristics influenced the suitability of qPCR as a tool to predict potential contamination in Irrigation Water. No significant differences were obtained between the number of cells of E. coli from RW-2 and RW-3, probably due to the fact that qPCR assay cannot distinguish between viable and dead cells. These results indicated that the selection of the most suitable technique for enumeration of indicator microorganisms able to predict potential presence of fecal contamination might be influenced by the Water characteristics.
Pilar Truchado - One of the best experts on this subject based on the ideXlab platform.
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impact of chlorine dioxide disinfection of Irrigation Water on the epiphytic bacterial community of baby spinach and underlying soil
PLOS ONE, 2018Co-Authors: Pilar Truchado, Trevor V. Suslow, Ana AllendeAbstract:The contamination of pathogenic bacteria through Irrigation Water is a recognized risk factor for fresh produce. Irrigation Water disinfection is an intervention strategy that could be applied to reduce the probability of microbiological contamination of crops. Disinfection treatments should be applied ensuring minimum effective doses, which are efficient in inhibiting the microbial contamination while avoiding formation and accumulation of chemical residues. Among disinfection technologies available for growers, chlorine dioxide (ClO2) represents, after sodium hypochlorite, an alternative disinfection treatment, which is commercially applied by growers in the USA and Spain. However, in most of the cases, the suitability of this treatment has been tested against pathogenic bacteria and low attention have been given to the impact of chemical residues on the bacterial community of the vegetable tissue. The aim of this study was to (i) to evaluate the continual application of chlorine dioxide (ClO2) as a Water disinfection treatment of Irrigation Water during baby spinach growth in commercial production open fields, and (ii) to determine the subsequent impact of these treatments on the bacterial communities in Water, soil, and baby spinach. To gain insight into the changes in the bacterial community elicited by ClO2, samples of treated and untreated Irrigation Water as well as the irrigated soil and baby spinach were analyzed using Miseq® Illumina sequencing platform. Next generation sequencing and multivariate statistical analysis revealed that ClO2 treatment of Irrigation Water did not affect the diversity of the bacterial community of Water, soil and crop, but significant differences were observed in the relative abundance of specific bacterial genera. This demonstrates the different susceptibility of the bacteria genera to the ClO2 treatment. Based on the obtained results it can be concluded that the phyllosphere bacterial community of baby spinach was more influenced by the soil bacteria community rather than that of Irrigation Water. In the case of baby spinach, the use of low residual ClO2 concentrations (approx. 0.25 mg/L) to treat Irrigation Water decreased the relative abundance of Pseudomonaceae (2.28-fold) and Enterobacteriaceae (2.5-fold) when comparing treated versus untreated baby spinach. Members of these two bacterial families are responsible for food spoilage and foodborne illnesses. Therefore, a reduction of these bacterial families might be beneficial for the crop and for food safety. In general it can be concluded that the constant application of ClO2 as a disinfection treatment for Irrigation Water only caused changes in two bacterial families of the baby spinach and soil microbiota, without affecting the major phyla and classes. The significance of these changes in the bacterial community should be further evaluated.
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demonstration tests of Irrigation Water disinfection with chlorine dioxide in open field cultivation of baby spinach
Journal of the Science of Food and Agriculture, 2018Co-Authors: Francisco Lopezgalvez, Ana Meireles, Pilar Truchado, Ana AllendeAbstract:Treatments for the disinfection of Irrigation Water have to be evaluated by demonstration tests carried out under commercial settings taking into account not only their antimicrobial activity but also the potential phytotoxic effects on the crop. The consequences of the treatment of Irrigation Water with chlorine dioxide (ClO2 ) used for sprinkler Irrigation of baby spinach in two commercial agricultural fields was assessed.; Results: Residual ClO2 levels at the sprinklers in the treated field were always below 1 mg L-1 . ClO2 treatment provoked limited but statistically significant reductions in culturable Escherichia coli counts (0.2-0.3 log reductions), but not in the viable E. coli counts in Water, suggesting the presence of viable but non-culturable cells (VBNC). Although disinfected Irrigation Water did not have an impact on the microbial loads of Enterobacteriaceae nor on the quality characteristics of baby spinach, it caused the accumulation of chlorates (up to 0.99 mg kg-1 in plants) and the reduction of the photosynthetic efficiency of baby spinach.; Conclusion: Low concentrations of ClO2 are effective in reducing the culturable E. coli present in Irrigation Water but it might induce the VBNC state. Presence of disinfection by-products and their accumulation in the crop must be considered to adjust doses in order to avoid crop damage and chemical safety risks. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.
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suitability of different escherichia coli enumeration techniques to assess the microbial quality of different Irrigation Water sources
Food Microbiology, 2016Co-Authors: Pilar Truchado, Francisco Pedrerosalcedo, Francisco Lopezgalvez, J J Alarcon, Ana AllendeAbstract:The use of fecal indicators such as Escherichia coli has been proposed as a potential tool to characterize microbial contamination of Irrigation Water. Recently, not only the type of microbial indicator but also the methodologies used for enumeration have been called into question. The goal of this study was to assess the microbial quality of different Water sources for Irrigation of zucchini plants by using E. coli as an indicator of fecal contamination and the occurrence of foodborne pathogens. Three Water sources were evaluated including reclaimed secondary treated Water (RW-2), reclaimed tertiary UV-C treated Water (RW-3) and surface Water (SW). The suitability of two E. coli quantification techniques (plate count and qPCR) was examined for Irrigation Water and fresh produce. E. coli levels using qPCR assay were significantly higher than that obtained by plate count in all samples of Irrigation Water and fresh produce. The microbial quality of Water samples from RW-2 was well predicted by qPCR, as the presence of foodborne pathogens were positively correlated with high E. coli levels. However, differences in the Water characteristics influenced the suitability of qPCR as a tool to predict potential contamination in Irrigation Water. No significant differences were obtained between the number of cells of E. coli from RW-2 and RW-3, probably due to the fact that qPCR assay cannot distinguish between viable and dead cells. These results indicated that the selection of the most suitable technique for enumeration of indicator microorganisms able to predict potential presence of fecal contamination might be influenced by the Water characteristics.
Andreas Schumann - One of the best experts on this subject based on the ideXlab platform.
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global Irrigation Water demand variability and uncertainties arising from agricultural and climate data sets
Geophysical Research Letters, 2008Co-Authors: Dominik Wisser, Steve Frolking, Ellen M Douglas, B M Fekete, Charles J Vorosmarty, Andreas SchumannAbstract:[1] Agricultural Water use accounts for around 70% of the total Water that is withdrawn from surface Water and groundWater. We use a new, gridded, global-scale Water balance model to estimate interannual variability in global Irrigation Water demand arising from climate data sets and uncertainties arising from agricultural and climate data sets. We used contemporary maps of Irrigation and crop distribution, and so do not account for variability or trends in Irrigation area or cropping. We used two different global maps of Irrigation and two different reconstructions of daily weather 1963–2002. Simulated global Irrigation Water demand varied by ∼30%, depending on Irrigation map or weather data. The combined effect of Irrigation map and weather data generated a global Irrigation Water use range of 2200 to 3800 km3 a−1. Weather driven variability in global Irrigation was generally less than ±300 km3 a−1, globally (<∼10%), but could be as large as ±70% at the national scale.
Francisco Lopezgalvez - One of the best experts on this subject based on the ideXlab platform.
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demonstration tests of Irrigation Water disinfection with chlorine dioxide in open field cultivation of baby spinach
Journal of the Science of Food and Agriculture, 2018Co-Authors: Francisco Lopezgalvez, Ana Meireles, Pilar Truchado, Ana AllendeAbstract:Treatments for the disinfection of Irrigation Water have to be evaluated by demonstration tests carried out under commercial settings taking into account not only their antimicrobial activity but also the potential phytotoxic effects on the crop. The consequences of the treatment of Irrigation Water with chlorine dioxide (ClO2 ) used for sprinkler Irrigation of baby spinach in two commercial agricultural fields was assessed.; Results: Residual ClO2 levels at the sprinklers in the treated field were always below 1 mg L-1 . ClO2 treatment provoked limited but statistically significant reductions in culturable Escherichia coli counts (0.2-0.3 log reductions), but not in the viable E. coli counts in Water, suggesting the presence of viable but non-culturable cells (VBNC). Although disinfected Irrigation Water did not have an impact on the microbial loads of Enterobacteriaceae nor on the quality characteristics of baby spinach, it caused the accumulation of chlorates (up to 0.99 mg kg-1 in plants) and the reduction of the photosynthetic efficiency of baby spinach.; Conclusion: Low concentrations of ClO2 are effective in reducing the culturable E. coli present in Irrigation Water but it might induce the VBNC state. Presence of disinfection by-products and their accumulation in the crop must be considered to adjust doses in order to avoid crop damage and chemical safety risks. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.
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modelling of e coli inactivation by chlorine dioxide in Irrigation Water
Agricultural Water Management, 2017Co-Authors: Francisco Lopezgalvez, Imca Sampers, Ana AllendeAbstract:Irrigation Water has been highlighted as a potential contamination source of fresh produce with foodborne pathogens. Water disinfection treatments can be used to improve its microbiological safety. Growers should ascertain the minimum effective disinfectant doses able to achieve the desired microbiological goals. Furthermore, potential unwanted effects both on crop health and on chemical risks associated with the accumulation of disinfection by-products (DBPs) on the crop must be taken into account. The minimum effective doses vary depending on intrinsic factors (e.g. physicochemical characteristics of the Irrigation Water, concentration of the target microorganism) and also extrinsic factors (e.g. geographical and weather conditions). In the present study, different types of surface Irrigation Water were treated with various doses of a stable solution of chlorine dioxide (ClO2) (0.1–2.5mg/L) at 21±2°C for a contact time of 1min. Escherichia coli concentration (before and after treatment) and the residual ClO2 (after treatment) were analyzed. Several Water physicochemical parameters were measured (chemical oxygen demand (COD), turbidity, pH, oxidation-reduction potential (ORP), conductivity and absorbance of filtered Water samples at 254nm (UV254)). Data obtained was used to develop a model for ClO2 decay and a model for E. coli inactivation by linear regression. The ClO2 decay model (adjusted R2=0.93) included the initial ClO2 concentration and the UV254 as explanatory variables. The E. coli inactivation model (adjusted R2=0.77) included the initial ClO2 concentration, the initial E. coli concentration, and the UV254 as explanatory variables. The development of these models would help growers in making decisions regarding the minimum effective doses they might use to treat their Irrigation Water when using a stable solution of ClO2 to reduce microbial risk of fresh produce.
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suitability of different escherichia coli enumeration techniques to assess the microbial quality of different Irrigation Water sources
Food Microbiology, 2016Co-Authors: Pilar Truchado, Francisco Pedrerosalcedo, Francisco Lopezgalvez, J J Alarcon, Ana AllendeAbstract:The use of fecal indicators such as Escherichia coli has been proposed as a potential tool to characterize microbial contamination of Irrigation Water. Recently, not only the type of microbial indicator but also the methodologies used for enumeration have been called into question. The goal of this study was to assess the microbial quality of different Water sources for Irrigation of zucchini plants by using E. coli as an indicator of fecal contamination and the occurrence of foodborne pathogens. Three Water sources were evaluated including reclaimed secondary treated Water (RW-2), reclaimed tertiary UV-C treated Water (RW-3) and surface Water (SW). The suitability of two E. coli quantification techniques (plate count and qPCR) was examined for Irrigation Water and fresh produce. E. coli levels using qPCR assay were significantly higher than that obtained by plate count in all samples of Irrigation Water and fresh produce. The microbial quality of Water samples from RW-2 was well predicted by qPCR, as the presence of foodborne pathogens were positively correlated with high E. coli levels. However, differences in the Water characteristics influenced the suitability of qPCR as a tool to predict potential contamination in Irrigation Water. No significant differences were obtained between the number of cells of E. coli from RW-2 and RW-3, probably due to the fact that qPCR assay cannot distinguish between viable and dead cells. These results indicated that the selection of the most suitable technique for enumeration of indicator microorganisms able to predict potential presence of fecal contamination might be influenced by the Water characteristics.
B Pascual - One of the best experts on this subject based on the ideXlab platform.
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response of drip irrigated chufa cyperus esculentus l var sativus boeck to different planting configurations yield and Irrigation Water use efficiency
Agricultural Water Management, 2016Co-Authors: N Pascualseva, San A Bautista, S Lopezgalarza, J V Maroto, B PascualAbstract:Abstract A two-year study was conducted to analyze the yield and Irrigation Water-use efficiency of chufa crop in response to planting configuration and drip Irrigation scheduling as a function of the volumetric soil Water content. The planting configurations were: beds with three plant rows and three driplines (B3), beds with three plant rows and two driplines (B2), beds with two plant rows and two driplines (b), and ridges (R). The yield was affected by the planting configuration; greater yields were obtained in beds (on average 2.36 kg m−2) than in R (2.14 kg m−2). Considerably less Irrigation Water was applied in R and in B2 than in beds B3 and b. The Irrigation Water-use efficiency was affected by the planting configuration in the same line that the Irrigation Water was applied, with greater values being obtained in B2 (7.58 kg m−3) than in the R (6.63 kg m−3), which in turn was higher than B3 (5.92 kg m−3) and b (5.69 kg m−3). These values of the Irrigation Water-use efficiency were considerably higher than those obtained in previous experiments (based on the volumetric soil Water content in the ridges). Neither the yield nor the average tuber weight were affected by the position of the different planting rows in the bed.
