Human intestinal enteroids and predictive models validate the operational limits of sanitizers used for viral disinfection of vegetable process wash water.

Vegetables are globally associated with a considerable number of foodborne outbreaks caused by viral infections, specifically human norovirus. In fresh produce industry, washing represents a critical step for food safety as process wash water (PWW) needs to be maintained at appropriate microbial quality to prevent water-mediated cross-contamination. This study aimed to explore the disinfection efficacy of chlorine (free chlorine, FC), chlorine dioxide (ClO2) and peracetic acid (PAA) in PWW against infectious human norovirus and Tulane virus (TV). First, we tested the extent of TV inactivation in baby leaf, bell pepper, and vegetables mix PWW and monitored the viral decay by cell culture. Then, inactivation kinetics were defined for infectious human norovirus exposed to FC, ClO2 and PAA in baby leaves PWW using the human intestinal enteroids (HIE) system. Finally, kinetic inactivation models were fitted to TV reduction and decay of sanitizers to aid the implementation of disinfection strategies. Results showed that >8 log10 human norovirus and 3.9 log10 TV were inactivated by 20 ppm FC within 1 min; and by 3 ppm ClO2 in 1 min (TV) or 5 min (norovirus). PAA treatment at 80 ppm reduced ca. 2 log10 TV but not completely inactivated the virus even after 20 min exposure, while 5 min treatment prevented norovirus replication in HIE. TV inactivation in PWWs was described using an exponential decay model. Taking these data together, we demonstrated the value of applying the HIE model to validate current operational limits for the most commonly used sanitizers. The inactivation kinetics for human norovirus and TV, along with the predictive model described in this study expand the current knowledge to implement post-harvest produce safety procedures in industry settings.

Fluence requirements in existing UV disinfection facilities to comply with EU validation performance targets for reclaimed water: a case study.

Since 2020, there is a new European Regulation (EU, 2020/741) on minimum requirements for water reuse, where routine and validation monitoring requirements (log reductions of indicator microorganisms and reference pathogens) have been established. Many reclamation facilities that are already in operation might have difficulties to comply with these performance targets. Existing disinfection systems must be expanded and upgraded. In the case of UV disinfection systems, fluence requirements must be determined to properly design with a focus on the safety and economic-environmental viability of reclaimed water. This study can be used as a reference to develop fluence-response curves for Clostridium perfringens spores, Escherichia coli, and total and F-specific coliphages, indicator microorganisms referred to in the new European Regulation. Eight UV-LED collimated beam tests were performed. Samples were obtained from filtered effluent of secondary treatment from two wastewater treatment plants (WWTPs) which ranged between 30 and 54%. Results showed UV sensitivity of 33.46 mJ/cm2 log I for C. perfringens spores and 2.86 mJ/cm2 log I for E. coli, both from environmental origin. Coliphages were inactivated below the limit of quantitation. The non-dominance of MS2 phages in environmental F-specific coliphages was observed.

Intermittent hypoxia and respiratory patterns during sleep of preterm infants aged 3 to 18 months residing at high altitude.

STUDY OBJECTIVES: The aim of this study was to determine the impact of apneas on oxygen saturation and the presence of intermittent hypoxia, during sleep of preterm infants (PTIs) born at high altitudes and compare with full-term infants (FTIs) at the same altitude. METHODS: PTIs and FTIs from 3 to 18 months were included. They were divided into three age groups: 3-4 months (Group 1); 6-7 months (Group 2), and 10-18 months (Group 3). Polysomnography parameters and oxygenation indices were evaluated. Intermittent hypoxia was defined as brief, repetitive cycles of decreased oxygen saturation. Kruskal-Wallis test for multiple comparisons, t-test or Mann-Whitney U-test were used. RESULTS: 127 PTI and 175 FTI were included. Total apnea-hypopnea index (AHI) was higher in PTI that FTI in all age groups (Group 1: 33.5/h vs. 12.8/h, p = 0.042; Group 2: 27.0/h vs. 7.4/h, p < 0.001; and Group 3: 11.6/h vs. 3.1/h, p < 0.001). In Group 3, central-AHI (8.0/h vs. 2.3/h, p < 0.001) and obstructive-AHI (1.8/h vs. 0.6/h, p < 0.008) were higher in PTI than FTI. T90 (7.0% vs. 0.5, p < 0.001), oxygen desaturation index (39.8/h vs. 11.3, p < 0.001) were higher in PTI than FTI, nadir SpO2 (70.0% vs. 80.0, p<0.001) was lower in PTI. CONCLUSION: At high altitude, compared to FTI, PTI have a higher rate of respiratory events, greater desaturation, and a delayed resolution of these conditions, suggesting the persistence of intermittent hypoxia during the first 18 months of life. This indicates the need for follow-up of these infants for timely diagnosis and treatment of respiratory disturbances during sleep.

Occurrence and Accumulation of Human Enteric Viruses and Phages in Process Water from the Fresh Produce Industry.

The virological quality of process water (PW) used by the produce industry has received limited attention. As a first step to overcoming technical limitations in monitoring viruses in PW, the analytical performance of ultrafiltration was assessed to concentrate viral particles from 20 L of spiked PW. The selected method used for sample concentration of PW was carefully validated, thus enabling the accurate quantification and estimation of viral titers of human enteric viruses and phages. PW from the produce industry was collected periodically from the washing tanks of commercial facilities. The analysis of coliphages was performed by plaque assay, while the occurrence of enteric viruses and crAssphage was determined by molecular techniques. Significant differences in the physicochemical composition of PW, mostly due to the different nature of fresh produce types and differences in the sanitizer used in commercial operation, were observed. Accumulation of crAssphage and coliphages was observed in PW, but correlation with human enteric viruses was not possible due to the low prevalence of these pathogens in the PW analyzed. The obtained results showed that depending on the type of product washed, the product/water ratio and the residual concentrations of the sanitizers, the prevalence and concentration of bacteriophages changed significantly.

Suitability of centrifuge water for detecting the presence of Escherichia coli versus finished fresh-cut lettuce testing.

Fresh produce causes most foodborne outbreaks in the USA, and it is also considered a hazardous food product in other areas of the world such as Europe. The outbreaks attributed to fresh produce increase the focus of producers on hygiene to minimize exposure to food hazards. The fresh produce industry has the urgent need to detect if there are production lots contaminated with pathogenic microorganisms before distribution. Although the industry is mostly using end-product testing for the detection of target microorganisms, previous studies have evaluated the suitability of different sampling points within the production line of a fresh-cut processing plant. In the present study, the centrifuge effluent water was assessed as an alternative sampling point to end-product testing. E. coli was selected as an index microorganism of the presence of pathogens. The presence of E. coli was assessed in centrifuge effluent water, and fresh-cut lettuce from a commercial fresh-cut produce processing line (n = 95). The rate of false positives and negatives, as well as the specificity, sensitivity, and efficiency of the alternative method were calculated. The mean population of E. coli in positive water samples was 0.86 log cfu/100 mL, while the mean population of E. coli in positive fresh-cut lettuce samples was 0.23 log cfu/g. The proportion of positive samples in centrifuge effluent water and lettuce was similar (≈20%), and most of the results in both matrices were coincident (81.1%). However, the alternative method was not reliable due to its low sensitivity, as only 47.6% of the lettuce samples positive for E. coli could be matched with positive water samples.

Impact of weather conditions, leaf age and irrigation water disinfection on the major epiphytic bacterial genera of baby spinach grown in an open field.

The effects of factors such as weather conditions, leaf age and irrigation water disinfection on the main bacterial genera (total bacterial, Enterobacteriaceae and Pseudomonas) of baby spinach were studied. Culture-dependent and independent quantification techniques were compared. Cultivation was carried out over two consecutive trials in commercial open field divided in two plots: 1) baby spinach irrigated with untreated surface water and 2) baby spinach irrigated with chlorine dioxide (ClO2) treated water. In all the cases, higher concentrations of bacteria were detected using molecular quantification in comparison with culture dependent techniques. Based on the obtained results, wind speed, solar radiation and relative humidity seem to have an impact on the levels of total bacterial, Enterobacteriaceae and Pseudomonas during cultivation of baby spinach. However, further studies would be needed to confirm this tendency. Water disinfection treatments (ClO2), when applied to irrigation water, impacted differently the bacterial genera evaluated in the present study. Thus, although no significant effects were observed in total bacterial enumerations of baby spinach irrigated with ClO2 treated water; significant reductions were detected in Enterobacteriaceae (19%) and Pseudomonas spp. (14%) levels. These results were also confirmed using specific culture-dependent methods. On the other hand, leaf age did not influence the levels of the main bacterial genera of baby spinach. Considering that, a large proportion of foodborne and pathogenic bacteria associated to fresh produce belong to the Enterobacteriaceae family and Pseudomonas genera, reductions in these bacterial groups could be beneficial. However, these groups are very diverse, making difficult to link the measurement of Enterobacteriaceae and Pseudomonas levels with the presence/abundance of potential pathogenic and spoilage microorganisms.

Corporate Volunteering: a Tool for Promoting a Strategy for Internal Corporate Social Responsibility Integrating Retirees / Voluntariado Corporativo como Herramienta de Promoción de la Estrategia de Responsabilidad Social Corporativa Interna Integrando Aposentados / Voluntariado Empresarial: uma Ferramenta para Promover a Estratégia de Responsabilidade Social Corporativa Interna Integrando Aposentados

This paper aims to make an exploratory analysis of the effectiveness of implementing a Corporate Volunteering program aimed at the context of retired workers, as a tool for participatory and healthy aging. The research study focused on the importance of the social participation of retirees in a company as a priority interest for the development of Corporate Volunteering programs, and delved into the expression of the socially responsible performance of organizations in volunteering actions carried out by their retired employees. Results show that the performance of retirees in a company's volunteering activities can count on intimately connected theoretical supports and is closely related to Corporate Social Responsibility, fostering an active, healthy and fair old age, with social benefit to the community.

Este artículo tiene como objetivo realizar un análisis exploratorio de la efectividad de implementarse de un programa de Voluntariado Corporativo dirigido al contexto de los trabajadores jubilados de las empresas, herramienta para el envejecimiento participativo y sano. El estudio se centró en la importancia social de la participación de los jubilados en una empresa como interés prioritario para el desarrollo de programas de Voluntariado Corporativo y para adentrarse igualmente en la expresión de la actuación socialmente responsable de la organización en acciones de voluntariado realizadas a través de la figura de sus empleados jubilados. Los resultados muestran que el aprovechamiento de los jubilados en las actividades voluntarias de la empresa se puede contar con soportes teóricos estrechamente conectados y se encuentra íntimamente relacionado con la Responsabilidad Social Empresarial, contribuyendo para construir un envejecimiento participativo por una vejez más saludable y justa, con beneficio social a la comunidad.Palabras clave: Voluntariado Corporativo; Responsabilidad Social Empresarial; Ciclo del Voluntariado.

Este artigo tem como objetivo realizar uma análise exploratória da efetividade da implementação de um programa de Voluntariado Corporativo voltado ao contexto dos trabalhadores aposentados das empresas, como instrumento em prol de um envelhecimento participativo e saudável. O estudo centrou-se na importância social da participação social dos aposentados em uma empresa como interesse prioritário para o desenvolvimento de programas de Voluntariado Corporativo e aprofundamento do desempenho socialmente responsável das organizações, em ações de voluntariado realizadas por seus funcionários aposentados. Os resultados mostram que o desempenho dos aposentados nas atividades de voluntariado de uma empresa pode usufruir de suportes teóricos intimamente conectados e está diretamente relacionado à Responsabilidade Social Empresarial, contribuindo para promover uma velhice ativa, saudável e justa, com benefício social para a comunidade.

Impact of chlorine dioxide disinfection of irrigation water on the epiphytic bacterial community of baby spinach and underlying soil.

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.

Impact of relative humidity, inoculum carrier and size, and native microbiota on Salmonella ser. Typhimurium survival in baby lettuce.

The effects of relative humidity (RH), fluctuating climate conditions, inoculum size and carrier on the survival of Salmonella enterica serovar Typhimurium on baby lettuce in environmental test chambers were studied. Buffered peptone water (BPW), distilled water (DW), and irrigation water (IW) were compared as inoculum carriers. Additionally, survival of Salmonella in suspensions prepared using filtered and unfiltered IW was assessed. Salmonella Typhimurium survived better on baby lettuce plants at high RH independently of the inoculum size. When lettuce plants were grown under fluctuating environmental conditions, Salmonella survival was similar under both RH conditions. Regarding the inoculum carrier, the inoculated microorganism survived better on lettuce plants when BPW was used as carrier both at high and low RH. Survival rate of Salmonella in IW was affected by the presence of native microbiota. Native microbiota present in IW did not affect survival of Salmonella or the levels of mesophilic bacteria on the baby lettuce leaves. The information obtained in the present study contributes to the knowledge on the effect of environmental conditions on pathogenic bacteria survival on growing edible plants. These results are useful when selecting the methodology to carry out experimental studies on the survival of microbial pathogens under different pre-harvest conditions.

Quantitative contamination assessment of Escherichia coli in baby spinach primary production in Spain: Effects of weather conditions and agricultural practices.

A quantitative microbial contamination model of Escherichia coli during primary production of baby spinach was developed. The model included only systematic contamination routes (e.g. soil and irrigation water) and it was used to evaluate the potential impact of weather conditions, agricultural practices as well as bacterial fitness in soil on the E. coli levels present in the crop at harvest. The model can be used to estimate E. coli contamination of baby spinach via irrigation water, via soil splashing due to irrigation water or rain events, and also including the inactivation of E. coli on plants due to solar radiation during a variable time of culturing before harvest. Seasonality, solar radiation and rainfall were predicted to have an important impact on the E. coli contamination. Winter conditions increased E. coli prevalence and levels when compared to spring conditions. As regards agricultural practices, both water quality and irrigation system slightly influenced E. coli levels on baby spinach. The good microbiological quality of the irrigation water (average E. coli counts in positive water samples below 1 log/100mL) could have influenced the differences observed among the tested agricultural practices (water treatment and irrigation system). This quantitative microbial contamination model represents a preliminary framework that assesses the potential impact of different factors and intervention strategies affecting E. coli concentrations at field level. Taking into account that E. coli strains may serve as a surrogate organism for enteric bacterial pathogens, obtained results on E. coli levels on baby spinach may be indicative of the potential behaviour of these pathogens under defined conditions.

Safety assessment of greenhouse hydroponic tomatoes irrigated with reclaimed and surface water.

The impact of reclaimed and surface water on the microbiological safety of hydroponic tomatoes was assessed. Greenhouse tomatoes were irrigated with reclaimed and surface water and grown on two hydroponic substrates (coconut fiber and rock wool). Water samples (n=208) were taken from irrigation water, with and without the addition of fertilizers and drainage water, and hydroponic tomatoes (n=72). Samples were analyzed for indicator microorganisms, generic Escherichia coli and Listeria spp., and pathogenic bacteria such as Salmonella spp. and Shiga-toxigenic E. coli (STEC), using multiplex real-time PCR (RT-PCR) after enrichment. The correlation between climatological parameters such as temperature and the levels of microorganisms in water samples was also determined. In irrigation water, generic E. coli counts were higher in reclaimed than in surface water whereas Listeria spp. numbers increased after adding the fertilizers in both water sources. In drainage water, no clear differences in E. coli and Listeria numbers were observed between reclaimed and surface water. No positive samples for STEC were found in irrigation water. Presumptive positives for Salmonella spp. were found in 7.7% of the water samples and 62.5% of these samples were reclaimed water. Salmonella-positive samples by RT-PCR could not be confirmed by conventional methods. Higher concentrations of E. coli were associated with Salmonella-presumptive positive samples. Climatological parameters, such as temperature, were not correlated with the E. coli and Listeria spp. counts. Tomato samples were negative for bacterial pathogens, while generic E. coli and Listeria spp. counts were below the detection limit. The prevalence of presumptive Salmonella spp. found in irrigation water (reclaimed and surface water) was high, which might present a risk of contamination. The absence of pathogens on greenhouse hydroponic tomatoes indicates that good agricultural practices (GAP) were in place, avoiding the microbial contamination of the fruit.

Contribution of high-b-value diffusion-weighted imaging in determination of brain ischemia in transient ischemic attack patients.

BACKGROUND AND PURPOSE: High-b-value diffusion-weighted imaging (DWI) (b = 2,000 and b = 3,000 second/mm(2)) offers theoretical advantages over DWI examinations at b = 1,000 second/mm(2) for detection of acute ischemic stroke. The purpose of this study was to determine whether high-b-value DWI are better than b = 1,000 images in TIA patients. METHODS: We compared DWI obtained with 3 different b-values (1,000, 2,000, and 3,000 second/mm(2)) and fluid-attenuated inversion recovery (FLAIR) sequences in 75 consecutive TIA patients. DWI examinations were performed within 3.25 ± 1.5 days after the onset of symptoms. Presence of ischemic lesion, volume, lesion conspicuity, and lesion distinction were determined. RESULTS: A total of 40 (53.3%) patients revealed ischemic acute lesions with b = 1,000 while 34 (45.3%) were positive on FLAIR. High-b-value DWI did not increase the sensitivity for the detection of acute brain ischemia. The median lesion value increased as the b-value did: .17 mL (interquartile range [IQR] .12-.78) at b = 1,000; .19 mL (IQR .13-1.00) at b = 2,000; .29 mL (IQR .14-1.02) at b = 3,000; and .12 mL (IQR .04-.62 mL) on FLAIR (P < .001). As b-value increased, we observed hyperintensities in white matter that could erroneously be considered as acute ischemia. CONCLUSION: High-b-value DWI did not improve the conspicuity and distinction of the ischemic lesions.

Higher carotid intima media thickness predicts extracranial vascular events and not stroke recurrence among transient ischemic attack patients.

BACKGROUND: Increased common carotid artery intima-media thickness has been associated with an increased risk of vascular ischemic events. We investigated the relationship between common carotid artery intima-media thickness and extracranial vascular events (coronary heart disease and peripheral arterial disease) or stroke recurrence in a cohort of transient ischemic attack patients from the REGITELL registry. METHODS: High-resolution B-mode ultrasonographic measurements of the common carotid artery intima-media thickness were performed in a series of 283 consecutive transient ischemic attack patients. Clinical, neuroimaging, ultrasonographic, and etiological data were collected. Patients were followed prospectively for six-months or more. Extracranial vascular events and stroke recurrence were recorded. RESULTS: Fifteen extracranial vascular events (12 coronary heart disease and three peripheral arterial disease) and 29 recurrent strokes occurred during a median follow-up period of 12.3 months. Patients who experienced extracranial vascular events had significantly (P < 0.001) higher common carotid artery intima-media thickness values (1.087 (standard deviation 0.189) mm) than subjects who were free of extracranial vascular events (0.887 (standard deviation 0.195) mm). Nevertheless, common carotid artery intima-media thickness was not found to correlate with stroke recurrence. Cox proportional hazards multivariate analyses identified hypercholesterolemia (hazard ratio 6.87, 95% confidence interval: 1.93-24.39, P = 0.003) and common carotid artery intima-media thickness > 0.939 mm (hazard ratio 8.90, 95% confidence interval: 2.00-39.49, P = 0.004) as independent predictors of extracranial vascular events after transient ischemic attack. Almost one of every three patients with hypercholesterolemia and high common carotid artery intima-media thickness had extracranial vascular events. CONCLUSIONS: An elevated common carotid artery intima-media thickness value was associated with a higher long-term risk of extracranial vascular events but no with stroke recurrence. Hypercholesterolemia was the main risk factor for extracranial vascular events. The combination of hypercholesterolemia and common carotid artery intima-media thickness > 0.939 mm justify the establishment of aggressive therapies and the study of subclinical coronary heart disease and peripheral arterial disease.

[Diagnostic lessons of recurrence pattern after transient ischemic attacks]. / Implicaciones diagnósticas del perfil de recurrencia tras un ataque isquémico transitorio.

BACKGROUND AND OBJECTIVE: Early stroke recurrence risk alter a transient ischemic attack (TIA) is high. We studied the diagnostic implications of the recurrence pattern after TIA. METHODS: 210 consecutive TIA patients were studied. Ultrasonographic (US), neuroimaging and cardiologic data were collected. RESULTS: At 90 day follow-up, 14 patients (6.7%; 95% CI: 3.3-10.1) among 209 suffered an ischemic infarction (II), 9 (4.3%; 1.5-7.1) a TIA and 6 (2.9%; 0.6-5.1) a cardiac ischemic event. Moreover, 13 patients (6.2%; 2.8-9.6) among 210 with a seven-day follow-up had an II. Multivariate analyses only identified the presence of intracranial stenoses (HR, 23.29; 95% CI, 3.49 to 23.57; p<0.018) as independent predictors of stroke within the first 7 days, and large-artery occlusive disease (HR, 9.07; CI, 3.49 to 23.57; p<0.001) as a predictor of stroke recurrence at 90 day follow-up. A new diagnosis of atrial fibrillation was observed in 21 subjects (10.0%), and it was documented in the baseline ECG in 62% cases. Acute diffusion abnormalities were identified in 81 (44,5%) of 182 patients, and chronic ischemic lesions were observed in 110 (60.4%) on MRI vs 56 (26.7%) among 210 on CT scan. CONCLUSION: Due to very early recurrence, the routine use of ultrasonography within the first hours after an index TIA will be useful to identify those patients at high risk. The prognostic usefulness of diffusion-weighted studies will be only achieved if it is performed early. Routine noninvasive cardiac rhythm monitoring has a low detection rate.

The California, ABCD, and unified ABCD2 risk scores and the presence of acute ischemic lesions on diffusion-weighted imaging in TIA patients.

BACKGROUND AND PURPOSE: Some clinical models, like California ABCD and unified ABCD2 scores, are now available to predict the early risk of stroke after a TIA. Despite the transitivity of symptoms, DWI identified an area of acute brain ischemia in almost half of patients. It would be interesting to know how the presence of DWI abnormalities relates to clinical risk scores to plan other prognostic variables or to recommend the performance of DWI. METHODS: We prospectively studied 135 consecutive TIA patients visited by the neurologists in our institution. All patients underwent DWI (3.8+/-1.7 days after symptoms onset). Clinical risk scores (California, ABCD, and ABCD2) were calculated prospectively for each patient. The identification of acute ischemic lesions (positive DWI) was related to the presence of clinical features and clinical risk scores. RESULTS: DWI were positive in 67 (49.6%) patients. After Bonferroni adjustment, elevated ABCD, ABCD2, and California scores were not associated with a positive DWI. However, some clinical symptoms such as facial palsy and motor weakness were associated with a positive DWI (P<0.001). The logistic regression model identified only facial palsy as an independent predictor of acute ischemic lesions (odds ratio 6.26, 95% CI 2.49 to 15.71, P<0.001). CONCLUSIONS: Clinical symptoms such as motor impairment, but not clinical risk scores, were associated with a positive DWI. Performing a DWI may add prognostic information to clinical risk scales as a predictor of stroke recurrence after TIA in future large studies.

Heterogeneous photocatalytic disinfection of wash waters from the fresh-cut vegetable industry.

The effectiveness of photocatalytic disinfection for control of natural and potentially pathogenic microflora in wash waters used for fresh-cut vegetables was evaluated. Wash waters for lettuce, escarole, chicory, carrot, onion, and spinach from a fresh-cut vegetable processing plant were treated with a titanium dioxide (TiO2) photocatalytic system. The vegetable wash waters were impelled out with a pump at a flow rate of 1,000 liters/h and conducted through a stainless steel circuit to the filtration system to reach the TiO2 photocatalyst fiber, which was illuminated with a 40-W UV-C lamp. The microbial and physicochemical qualities of the wash water were analyzed. Heterogeneous photocatalysis was an effective disinfection method, reducing counts of bacteria, molds, and yeasts. Most of the treated wash waters had total bacteria reductions of 4.1 +/- 1.3 to 4.8 +/- 0.4 log CFU/ml after 10 min of treatment when compared with untreated water. Higher decontamination efficacy was observed in carrot wash water (6.2 +/- 0.1-log reductions), where turbidity and organic matter were lower than those in the wash waters for other vegetables. The tested heterogeneous photocatalytic system also was effective for reducing water turbidity, although chemical oxygen demand was unaffected after the treatments. The efficacy of the photocatalytic system for reducing microbial load depended on the physicochemical characteristics of the wash water, which depended on the vegetable being washed. The conclusions derived from this study illustrate that implementation of a heterogeneous photocatalytic system in the fresh-cut vegetable washing processes could allow the reuse of wash water.

Elimination by ozone of Shigella sonnei in shredded lettuce and water.

Several outbreaks of shigellosis have been attributed to the consumption of contaminated fresh-cut vegetables. The minimal processing of these products make it difficult to ensure that fresh produce is safe for consumer. Chlorine-based agents have been often used to sanitize produce and reduce microbial populations in water applied during processing operations. However, the limited efficacy of chlorine-based agents and the production of chlorinated organic compounds with potential carcinogenic action have created the need to investigate the effectiveness of new decontamination techniques. In this study, the ability of ozone to inactivate S. sonnei inoculated on shredded lettuce and in water was evaluated. Furthermore, several disinfection kinetic models were considered to predict S. sonnei inactivation with ozone. Treatments with ozone (1.6 and 2.2 ppm) for 1 min decreased S. sonnei population in water by 3.7 and 5.6 log cfu mL(-1), respectively. Additionally, it was found that S. sonnei growth in nutrient broth was affected by ozone treatments. After 5.4 ppm ozone dose, lag-phases were longer for injured cells recovered at 10 degrees C than 37 degrees C. Furthermore, treated cells recovered in nutrient broth at 10 degrees C were unable to grow after 16.5 ppm ozone dose. Finally, after 5 min, S. sonnei counts were reduced by 0.9 and 1.4 log units in those shredded lettuce samples washed with 2 ppm of ozonated water with or without UV-C activation, respectively. In addition, S. sonnei counts were reduced by 1.8 log units in lettuce treated with 5 ppm for 5 min. Therefore, ozone can be an alternative treatment to chlorine for disinfection of wash water and for reduction of microbial population on fresh produce due to it decomposes to nontoxic products.

Effect of ozone on the inactivation of Yersinia enterocolitica and the reduction of natural flora on potatoes.

Fresh vegetables contaminated with Yersinia enterocolitica have been implicated in foodborne disease outbreaks. Surfaces of vegetables can become contaminated with pathogenic microorganisms through contact with soil, irrigation water, fertilizers, equipment, humans, and animals. One approach to reduce this contamination is to treat fresh produce with sanitizers. In this study, the ability of ozone to inactivate Y. enterocolitica inoculated in water and on potato surfaces was evaluated. Furthermore, the efficacy of ozone in reducing natural flora on whole potato was determined. Total aerobic mesophilic and psychrotrophic bacteria, total coliforms, and Listeria monocytogenes were enumerated. Finally, several disinfection kinetic models were considered to predict Y. enterocolitica inactivation with ozone. Treatments with ozone (1.4 and 1.9 ppm) for 1 min decreased the Y. enterocolitica population in water by 4.6 and 6.2 log CFU ml(-1), respectively. Furthermore, ozonated water (5 ppm) for 1 min decreased Y. enterocolitica and L. monocytogenes from potato surfaces by 1.6 and 0.8 log CFU g(-1), respectively. Therefore, ozone can be an effective treatment for disinfection of wash water and for reduction of potato surface contamination.

L-galactono-gamma-lactone dehydrogenase aand vitamin C content in fresh-cut potatoes stored under controlled atmospheres.

L-galactono-gamma-lactone dehydrogenase (GLDH) activity and vitamin C content as ascorbic acid (AA) plus dehydroascorbic acid (DHA) were evaluated in five potato tuber cultivars (Agata, Altesse, Franceline, Manon, and Monalisa). The effect of fresh-cutting and subsequent refrigerated storage of Manon potato under different atmospheres (air, 20% CO(2) + air, 100% N(2), and vacuum packaging) on GLDH activity and vitamin C content was also determined. GLDH from the five potato tuber cultivars showed typical inhibition kinetics by high substrate concentration in the synthesis of AA from its physiological precursor L-galactonic acid-gamma-lactone (GL). GLDH activity was not correlated with the corresponding vitamin C content in any potato tuber cultivar. GLDH from all the cultivars presented a major isoform with isoelectric point (IEP) 5, which changed to IEP = 4.3 after minimal processing. In addition, the GLDH-catalyzed synthesis of AA by the new isoform showed typical Michaelis kinetics, in which the enzyme became more efficient to catalyze the reaction. Whether the change in the isoform pattern was due to either post-translational modifications or de novo synthesis of a new isoenzyme remains unanswered. Fresh-cutting increased GLDH activity from 4.7-fold (vacuum packaging) to 11-fold (air) after 6 days. In addition, 100% of vitamin C content was retained in air and decreased in the rest of atmospheres after this storage period, following the sequence vacuum packaging (89%) > 100% N(2) (78%) > 20% CO(2) + air (63%). This tendency was correlated with the corresponding GLDH activity detected in each storage atmosphere, except in the case of 20% CO(2) + air. Vacuum packaging proved to be the best storage condition, because fresh-cut potatoes did not turn brown and retained 89% of initial vitamin C content.