Occurrence of human pathogenic viruses in drinking water and in its sources: A review.

Since many waterborne diseases are caused by human pathogenic viruses, virus monitoring of drinking water (DW) and DW sources is crucial for public health. Therefore, the aim of this review was to describe the occurrence of human pathogenic viruses in DW and DW sources; the occurrence of two viruses proposed as novel indicators of human faecal contamination (Pepper mild mottle virus and Tobacco mosaic virus) was also reported. This research was focused on articles that assessed viral occurrence using molecular methods in the surface water used for DW production (SW-D), groundwater used for DW production (GW-D), DW and bottled-DW (BW). A total of 1544 studies published in the last 10 years were analysed, and 79 were ultimately included. In considering the detection methods, filtration is the most common concentration technique, while quantitative polymerase chain reaction is the most common quantification technique. Regarding virus occurrence in SW-D, GW-D, and DW, high percentages of positive samples were reported for adenovirus, polyomavirus and Pepper mild mottle virus. Viral genomes were frequently detected in SW-D and rarely in GW-D, suggesting that GW-D may be a safe DW source. Viral genomes were also detected in DW, posing a possible threat to human health. The lowest percentages of positive samples were found in Europe, while the highest were found in Asia and South America. Only three articles assessed viral occurrence in BW. This review highlights the lack of method standardization and the need for legislation updates.

Occurrence of antibiotic-resistant bacteria and resistance genes in the urban water cycle.

This study investigates the antibiotic resistance fate in the urban water cycle, evaluating the dynamics of antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) in three different full-scale wastewater treatment plants (WWTPs) and two drinking water treatment plants (DWTPs) located in the same geographical area (North-West of Italy). ARB (tetracycline-, ampicillin-, and sulfonamide-resistant bacteria) were quantified by plate counting and the abundances of selected ARGs (i.e., tetA, blaTEM, and sulII) and intI1 gene were measured using quantitative real-time PCR (qPCR). Higher concentrations of ARB and ARGs were observed in the WWTPs with respect to the DWTPs identifying the WWTP as hotspot for the spread of antibiotic resistances. Although a significant reduction of ARB and ARGs was observed in WWTPs and DWTPs after the treatment, none of the detected ARB or ARGs was completely removed in drinking water. The stability of the antibiotic-resistant rates between inlet and outlet associated with the reduction of relative ARG abundances underlined that both the treatments (WWTs and DWTs) did not apply any selective pressure. The overall results highlighted the importance to investigate the antibiotic resistance dynamics in aquatic ecosystems involved in urban water cycle integrating the information obtained by culture-dependent method with the culture-independent one and the need to monitor the presence of ARB and ARGs mainly in drinking water that represents a potential route of transmission to human.

A Biomonitoring Pilot Study in Workers from a Paints Production Plant Exposed to Pigment-Grade Titanium Dioxide (TiO2).

Among particulate matter composing paints, titanium dioxide (TiO2) forms about 20% of the final suspension. Although TiO2 is broadly used in many applications, TiO2 powders represent an established respiratory hazard for workers with long-term exposure. In 35 workers of a paints production plant (15 exposed and 20 not exposed), we assessed pro-inflammatory cytokines (IL-1ß, TNF-α, IL-10, IL-17), surfactant protein D (SP-D) and Krebs von den Lungen-6 glycoprotein (KL-6) in exhaled breath condensate (EBC). In urine samples, we measured 8-isoprostane (Isop) and Malondialdehyde (MDA) as biomarkers of oxidative stress, and Titanium (Ti-U) as a biomarker of exposure. Health status, habits and occupational history were recorded. Airborne respirable dusts and Ti were quantified. Particle number concentration and average diameter (nm) were detected by a NanoTracer™ monitoring device. Ti was measurable in filters collected at the respiratory breathing zone (0.11−0.44 µg/m3 8-h TWA). IL-1ß and IL-10 values were significantly higher in exposed workers, whereas SP-D was significantly lower (p < 0.001). KL-6 was significantly higher in workers than in controls (p < 0.01). MDA levels were significantly increased in exposed workers and were positively correlated with Ti-U. Exposure to TiO2 in paint production is associated with the subtle alterations of lung pathobiology. These findings suggest the need for an integrated approach relying on both personal exposure and biomarker assessment to improve the hazard characterisation in occupational settings.

Lifestyle-Related Risk Factors of Orthorexia Can Differ among the Students of Distinct University Courses.

Orthorexia nervosa (ON) is defined as the excessive attention on healthy eating, and studies especially focused on food quality ON prevalence in university students can be extremely variable. The objective of this study is to investigate whether there was a difference in ON risk between health-scientific, economic-humanistic, sport sciences and dietetics and nutrition students, and to evaluate if lifestyle-related ON risk factors (dieting, physical activity, drugs and supplements use) could have an impact in different ways in determining ON risk among students attending these four programs. Participants were recruited at the University of Pavia and received a two-section questionnaire including demographic and lifestyle information and the ORTO-15 questionnaire. A total of 671 students (54% F e 46% M) completed the questionnaire (median age 21.00 (IQR 20.00−23.00), median BMI 21.77 kg/m2 (IQR 20.06−23.66 kg/m2)). The 31.2% had ORTO-15 test scores < 35, and were considered at risk of having ON. No differences were found in ON risk among the students attending the four university courses. Dieting was confirmed as the major ON risk factor for health-scientific, economic-humanistic and sport sciences students. The type of sport practiced was an important determinant of ON risk only for the economic-humanistic course, while supplements use was statistically different between sport sciences students with or without ON. Our findings may suggest that lifestyle-related risk factors of orthorexia can differ among the students of distinct university courses, but these results need to be supported by further longitudinal and prospective studies.

Use of online and paper-and-pencil questionnaires to assess the distribution of orthorexia nervosa, muscle dysmorphia and eating disorders among university students: can different approaches lead to different results?

PURPOSE: Administration of questionnaires to assess the diffusion of disordered eating behaviours via the web is becoming common today. The aim of this study is to assess whether two different approaches of administering a test to assess traits of eating disorders (EDs), orthorexia nervosa (ON) and muscle dysmorphia (MD) by email recruitment and online completion (web-based survey-WBS) and by in person recruitment and paper-and-pencil completion (paper-based survey-PBS), gives different results. METHODS: During 2 consecutive academic years, a self-reported questionnaire consisting of questions about personal characteristics and three tests for the evaluation of ON (ORTO-15), MD (MDDI-ITA), and EDs (EAT-26) were administered to two groups of undergraduates, respectively, as a WBS and a PBS. RESULTS: The WBS response rate was 6.7% (N = 137), and the PBS response rate was 86.5% (N = 372). The WBS group showed a statistically significant higher prevalence of students with eating disordered behaviours (21.2% vs 5.4%) and registered a higher mean score on the EAT-26 test (13.5 ± 11.1 vs 6.0 ± 8.0); no differences between the two groups emerged for ON and MD prevalence and test scores. Moreover, in the WBS group, the number of students with one or more tests with test scores above the cut-off values was significantly higher (46.0% vs 32.3%). CONCLUSION: The choice of the approach to administer a questionnaire to assess the diffusion of EDs and related issues must take into account all the factors that can result in selection bias and that can affect the reliability of the results. LEVEL OF EVIDENCE: Level V, descriptive cross-sectional survey.

Comparison of UV, Peracetic Acid and Sodium Hypochlorite Treatment in the Disinfection of Urban Wastewater.

One source of water contamination is the release of wastewater that has not undergone efficient treatment. The aim of this study was to evaluate the reduction obtained with sodium hypochlorite (NaClO), UV and peracetic acid disinfection treatment of Salmonella spp., pathogenic Campylobacter, STEC and bacterial indicators in three full-scale municipal wastewater plants. A general reduction in Salmonella was observed after disinfection, but these bacteria were detected in one UV-treated sample (culture method) and in 33%, 50% and 17% of samples collected after NaClO, UV and PAA disinfection treatments, respectively (PCR method). A better reduction was also observed under NaClO disinfection for the microbial indicators. Independent of the disinfection treatment, E. coli O157:H7 was not detected in the disinfected samples, whereas some samples treated with UV and PAA showed the presence of the stx1 gene. No reduction in the presence of stx2 genes was verified for any of the disinfection treatments. Campylobacter was not detected in any of the analysed samples. The overall results highlight a better reduction in microbiological parameters with a NaClO disinfection treatment in a full-scale municipal wastewater plant compared with UV and PAA. However, the results indicate that a complete and specific monitoring program is necessary to prevent a possible risk to public health.

Traits of orthorexia nervosa and muscle dysmorphia in Italian university students: a multicentre study.

PURPOSE: This study aimed to evaluate the prevalence of traits of orthorexia nervosa (ON) and muscle dysmorphia (MD) in a group of undergraduates, investigate the associations between the risk of these conditions and the type of university course attended, the individual characteristics (gender, BMI, amount of physical activity, supplements and medicines use, dieting) and the risk of eating disorders (EDs). METHODS: A self-reported questionnaire consisting of a socio-demographic section and three tests validated for the evaluation of a risk of ON (ORTO-15), MD (MDDI-ITA) and EDs (EAT-26) was completed by 918 students from three Italian universities. RESULTS: 29.0% of participants demonstrated traits of ON and 5.0% of MD, without differences in prevalence in the three areas of study investigated (health-scientific, economic-humanistic, sport sciences); students of sport sciences exhibited a significantly higher score for MDDI-ITA (F = 6.493, p = 0.002). Participants with ON and MD traits were more on a diet (OR = 0.47, p ≤ 0.001 and OR = 0.428, p = 0.020, respectively) and showed a higher prevalence of EDs risk (OR = 3.55, p < 0.001 and OR = 10.23, p ≤ 0.001, respectively). The simultaneous presence of ON, MD, and EDs traits was seen in 5.4% of the students and the three test scores were correlated. CONCLUSIONS: The prevalence of ON and MD traits was found similar to that reported in the literature on undergraduates. Some associations observed improvement in the knowledge about these conditions, especially the association of participants with ON and MD traits with dieting and EDs traits and the correlation of the three test scores suggests a connection among these potential conditions. LEVEL OF EVIDENCE: Level V, descriptive cross-sectional survey.

Cryptosporidium Oocyst Contamination in Drinking Water: A Case Study in Italy.

The aim of this study was to evaluate the occurrence of Cryptosporidium oocysts in a drinking water treatment plant (DWTP) located in a rural area of northern Italy. Influent and effluent samples were collected at the DWTP over three years (2013-2016). In parallel, tap water samples from a public drinking fountain were collected as well. All samples were analyzed for the presence of Cryptosporidium spp. oocysts by a common method based on an immunomagnetic separation (IMS)/immunofluorescence assay (IFA), complemented by 4,6-diamidino-2-phenylindole (DAPI) staining. A reverse transcriptase-PCR (RT-PCR) protocol was added to evaluate oocyst viability. The results highlighted a high variability of oocyst concentrations across all samples (mean 4.3 ± 5.8/100 L) and a high variability in the percentage of DAPI-positive specimens (mean 48.2% ± 40.3%). Conversely, RT-PCR did not reveal the presence of viable C. parvum and C. hominis oocysts. A nested PCR targeting Cryptosporidium 18S ribosomal DNA, carried out in two water samples, confirmed the presence of a Cryptosporidium genotype associated with wild animals in the river and in tap water. The results obtained underline the vulnerability of the investigated surface water to Cryptosporidium spp. contamination. Although the recovered Cryptosporidium genotype is not a human pathogen, its presence demonstrates the existence of a potential pathogen Cryptosporidium spp. contamination risk. Moreover, these results underline the importance of also considering unconventional (not bacterial) biological contaminations (protozoa) in water resources in rural areas, including those of developed countries.

Mutagenic and genotoxic effects induced by PM0.5 of different Italian towns in human cells and bacteria: The MAPEC_LIFE study.

Particulate matter (PM) is considered an atmospheric pollutant that mostly affects human health. The finest fractions of PM (PM2.5 or less) play a major role in causing chronic diseases. The aim of this study was to investigate the genotoxic effects of PM0.5 collected in five Italian towns using different bioassays. The role of chemical composition on the genotoxicity induced was also evaluated. The present study was included in the multicentre MAPEC_LIFE project, which aimed to evaluate the associations between air pollution exposure and early biological effects in Italian children. PM10 samples were collected in 2 seasons (winter and spring) using a high-volume multistage cascade impactor. The results showed that PM0.5 represents a very high proportion of PM10 (range 10-63%). PM0.5 organic extracts were chemically analysed (PAHs, nitro-PAHs) and tested by the comet assay (A549 and BEAS-2B cells), MN test (A549 cells) and Ames test on Salmonella strains (TA100, TA98, TA98NR and YG1021). The highest concentrations of PAHs and nitro-PAHs in PM0.5 were observed in the Torino, Brescia and Pisa samples in winter. The Ames test showed low mutagenic activity. The highest net revertants/m3 were observed in the Torino and Brescia samples (winter), and the mutagenic effect was associated with PM0.5 (p < 0.01), PAH and nitro-PAH (p < 0.05) concentrations. The YG1021 strain showed the highest sensitivity to PM0.5 samples. No genotoxic effect of PM0.5 extracts was observed using A549 cells except for some samples in winter (comet assay), while BEAS-2B cells showed light DNA damage in the Torino, Brescia and Pisa samples in winter, highlighting the higher sensitivity of BEAS-2B cells, which was consistent with the Ames test (p < 0.01). The results obtained showed that it is important to further investigate the finest fractions of PM, which represent a relevant percentage of PM10, taking into account the chemical composition and the biological effects induced.

Effectiveness of a neutral electrolysed oxidising water (NEOW) device in reducing Legionella pneumophila in a water distribution system: A comparison between culture, qPCR and PMA-qPCR detection methods.

Disinfection of hot water systems is critical for reducing Legionnaires' disease in high-risk buildings. The use of neutral electrolysed oxidising water (NEOW) is a promising method for the control of microorganisms in hot water systems. However, full-scale evaluations of the efficacy of NEOW devices to control Legionella pneumophila are currently lacking. The aim of this study was to assess the effectiveness of a NEOW device in reducing L. pneumophila in a hotel water network. Water samples (n = 67) were collected from different sites of a hotel distribution system before and after the installation of the NEOW device at the 1st, 4th, 8th and 12th week. Detection of L. pneumophila was performed comparing culture, qPCR and PMA-qPCR methods. Total bacterial counts (22 °C and 37 °C), Pseudomonas spp. and physico-chemical parameters were also monitored. The NEOW treatment resulted in a reduction of the amount of L. pneumophila positive samples (-32%) and of the number of heavily contaminated points (>104 CFU/L and >103 CFU/L) (-100% and -96%, respectively). Treatment maintained L. pneumophila at low levels (<102 CFU/L), which do not require specific intervention measures. The effectiveness of the disinfection system was also confirmed by PMA-qPCR (p < 0.001). The use of PMA resulted in a signal decrease in almost all samples upon the disinfection treatment. The NEOW disinfection device appears to be a promising approach to reduce the colonisation of hot water systems by L. pneumophila; however, further investigations are needed to ascertain its efficiency over longer time periods.

Physical Activity, Lifestyle Factors and Oxidative Stress in Middle Age Healthy Subjects.

Oxidative stress (OS) has been recognized to play a primary role in many acute and chronic diseases. Environmental and lifestyle factors, such as physical activity and dietary intake are involved in the oxidative balance, but their specific influence remains unclear. In order to contribute to a greater characterization of the oxidative status in relation to exercise training and to environmental and lifestyle factors, different biomarkers-pro-oxidant capacity (d-ROMs), anti-oxidant capacity (BAP), radical scavenging activity (DPPH) and DNA damage (8-OHdGuo)-were measured in biological samples of a group of healthy middle aged subjects. The evaluation of the investigated biomarkers highlighted a significant effect of exercise training on OS, measured as d-ROMs and 8OhdGuo, in subjects playing regular physical activity. An association of the OS status measured by DPPH and 8-OhdGuo with the condition of living in urban high traffic areas was also found. Otherwise dietary habits did not reveal any significant effect on OS levels by the investigated biomarkers. As a whole the results obtained in this investigation suggested that a correct lifestyle, with regular physical activity practice, contributes to control the OS status in middle age subjects.

Viability of Legionella pneumophila in Water Samples: A Comparison of Propidium Monoazide (PMA) Treatment on Membrane Filters and in Liquid.

Legionella pneumophila is a ubiquitous microorganism widely distributed in aquatic environments and can cause Legionellosis in humans. A promising approach to detect viable cells in water samples involves the use of quantitative polymerase chain reaction (qPCR) in combination with photoactivatable DNA intercalator propidium monoazide (PMA). However, the PMA efficiency could be different depending on the experimental conditions used. The aim of this study was to compare two PMA exposure protocols: (A) directly on the membrane filter or (B) in liquid after filter washing. The overall PMA-induced qPCR means reductions in heat-killed L. pneumophila cells were 2.42 and 1.91 log units for exposure protocols A and B, respectively. A comparison between the results obtained reveals that filter exposure allows a higher PMA-qPCR signal reduction to be reached, mainly at low concentrations (p < 0.05). This confirms the potential use of this method to quantify L. pneumophila in water with low contamination.

Lifestyles and socio-cultural factors among children aged 6-8 years from five Italian towns: the MAPEC_LIFE study cohort.

BACKGROUND: Lifestyles profoundly determine the quality of an individual's health and life since his childhood. Many diseases in adulthood are avoidable if health-risk behaviors are identified and improved at an early stage of life. The aim of the present research was to characterize a cohort of children aged 6-8 years selected in order to perform an epidemiological molecular study (the MAPEC_LIFE study), investigate lifestyles of the children that could have effect on their health status, and assess possible association between lifestyles and socio-cultural factors. METHODS: A questionnaire composed of 148 questions was administered in two different seasons to parents of children attending 18 primary schools in five Italian cities (Torino, Brescia, Pisa, Perugia and Lecce) to obtain information regarding the criteria for exclusion from the study, demographic, anthropometric and health information on the children, as well as some aspects on their lifestyles and parental characteristics. The results were analyzed in order to assess the frequency of specific conditions among the different seasons and cities and the association between lifestyles and socio-economic factors. RESULTS: The final cohort was composed of 1,164 children (50.9 boys, 95.4% born in Italy). Frequency of some factors appeared different in terms of the survey season (physical activity in the open air, the ways of cooking certain foods) and among the various cities (parents' level of education and rate of employment, sport, traffic near the home, type of heating, exposure to passive smoking, ways of cooking certain foods). Exposure to passive smoking and cooking fumes, obesity, residence in areas with heavy traffic, frequency of outdoor play and consumption of barbecued and fried foods were higher among children living in families with low educational and/or occupational level while children doing sports and consuming toasted bread were more frequent in families with high socio-economic level. CONCLUSIONS: The socio-economic level seems to affect the lifestyles of children enrolled in the study including those that could cause health effects. Many factors are linked to the geographical area and may depend on environmental, cultural and social aspects of the city of residence.

Socio-Economic and Environmental Factors Associated with Overweight and Obesity in Children Aged 6-8 Years Living in Five Italian Cities (the MAPEC_LIFE Cohort).

The prevalence of obesity among Italian children has reached such alarming levels as to require detailed studies of the causes of the phenomenon. A cross-sectional study was carried out in order to assess the weight status of 1164 Italian children aged 6-8 years (the Monitoring Air Pollution Effects on Children for Supporting Public Health Policy (MAPEC_LIFE) cohort) and to identify any associations between selected socio-economic and environmental factors and overweight/obesity. The data were obtained by means of a questionnaire given to parents, and any associations were examined by binomial logistic regression analyses. Overweight was found to be positively associated with male gender, parents of non-Italian origin, and parents who smoke, and negatively associated with the parents' level of education and employment. In addition, the frequency of overweight varied in relation to the geographical area of residence, with a greater prevalence of overweight children in the cities of central-southern Italy. This study highlights the need to implement appropriate obesity prevention programs in Italy, which should include educational measures concerning lifestyle for parents from the earliest stages of their child's life.

Investigating the Role of Physical Education in Physical Activity Promotion: An Italian Multicenter Study.

BACKGROUND: Physical education (PE) can be considered an instrument for active lifestyle promotion, and PE teachers can motivate youths to continue their studies in the field of Movement Sciences (MS). METHODS: To evaluate the role of PE in higher secondary school in promoting physical activity (PA) and MS careers, previous PE experiences and current PA practice were investigated in a sample of Italian freshmen enrolled in different university degree courses. RESULTS: A total of 7033 questionnaires were completed by students from 14 universities (41.3% males, mean age 20 ± 2.76 years). Recreation seemed to be the principal aim (42.2%) pursued during PE lessons, which are based mainly on practical activities (51.7%). Of all respondents, 67.2% were satisfied with the PE received during higher secondary school, and 51.6% participated in extracurricular PA. Current practice of PA was reported by 58.1% of the sample. Extracurricular activities were associated with choice of MS curricula (odds ratio: 2.15; 95% confidence interval, 1.85-2.50) and with current practice of PA (odds ratio: 1.68, 95% confidence interval, 1.51-1.87). Geographical differences concerning lessons organization and satisfaction were registered (P < .01). CONCLUSIONS: To enhance its role in health promotion, PE teaching should be improved by increasing the time allocated to PE and by strengthening the provision of school-based extracurricular PA.

The role and working conditions of Movement Science students employed in sport and recreational facilities: An Italian multicenter study.

BACKGROUND: In Italy, students from Movement Science (MS) Degree Courses often work in sport and recreational facilities before graduation. OBJECTIVE: The employment conditions of Movement Science students working in sport/recreational facilities were investigated, and the management and structural features of the facilities were evaluated, including safety policies. Regional differences were also considered. METHODS: Questionnaires were administered to undergraduate and graduate students (N = 4,217) in 17 Universities. Students' perceptions of the quality of the facilities where they had been employed was evaluated using multivariate analysis. A latent class model with covariates was used to evaluate how variables relating to participants, employment facilities or regions influence their opinions. RESULTS: A high proportion of MS students were employed in sporting facilities (undergraduate level: 33% ; graduate level: 55%), in most cases without any formal employment contracts. Both the structural and hygienic features, as well as the professional knowledge of the staff, were considered good to excellent by the majority of participants (about 70%). Communication of the basic behavioral rules was considered adequate by 61-63% of undergraduate students and 71-75% of graduate students, while nearly half of the participants were dissatisfied with the staff safety training. Correlations between the perceived good structural/hygienic conditions, the presence of regulations and training programs for the staff were investigated. Differences regarding occupational level and safety training among different regions of Italy were also observed. CONCLUSIONS: Italian students in Movement Science were easily employed in sport/recreational facilities, but frequently without a formal contract. This is a consequence of the lack of specific regulations in the field of recreational/leisure employment and could have negative implications, especially in terms of safety.

Green job bio-aerosol exposure during anaerobic digestion for biomass energetic valorisation.

The continued expansion of the green economy increases the risk profile for green occupational jobs. One of the broadest green sectors in terms of growth is the anaerobic digestion of biomasses. In recent years, this development has also interested Italian regions. The management of biomass includes biological risk and the risk of particulate and endotoxin exposure. In the present study, we evaluated airborne exposure for anaerobic digestion workers at two real-scale plants. Digested biomass has different origins, ranging from cattle sludge and manure to poultry manure to agricultural harvesting or processing residues, particularly from maize and fruits. Two sampling points were chosen: at the first, the input biomasses were stored, and the hopper was loaded; at the second, the digested sludge exited the digester. The microbiological parameters, assessed using an active sampler and cultural method, were the total bacteria counts (at 22, 37, and 55°C), yeasts, fungi, Pseudomonaceae, Clostridia spp., Enterobacteriaceae and Actinomycetes. Moreover, at the same sampling points, we evaluated six PM10 fraction levels (10.0-7.2, 7.2-3.0, 3.0-1.5, 1.5-0.95, 0.95-0.49, and <0.49µm) and the endotoxin content of each fraction. In this investigation, the microbe contamination of the air varied from low to high levels, while the PM10 and endotoxin levels were limited, reaching rural environmental levels (61.40µg/m(3) and 18.88EU/m(3), respectively). However, contamination and occupational risk must be evaluated individually for each plant because numerous variables influence the risk magnitude, particularly digested sludge treatments, such as input biomass nature, storage, movement conditions, building configuration and technological processes.

Microbial-chemical indicator for anaerobic digester performance assessment in full-scale wastewater treatment plants for biogas production.

Anaerobic digestion was introduced into wastewater treatment plants several years ago, but anaerobic digestion performance has not yet been achieved. The variability of the microbial community in digesters is poorly understood, and despite the crucial role of anaerobic digestion reactors, the microbial equilibrium that yields the best performance in these reactors has only recently been hypothesised. In this study, two full-scale continuous anaerobic reactors, placed in Torino's main wastewater treatment plant in northern Italy, were followed to develop a summary indicator for measuring anaerobic digestion performance. A total of 100 sludge samples were collected. The samples were characterised chemically and physically, and microbial groups were quantified by qRT-PCR. A chemical biological performance index strictly correlated to specific biogas production (rho=0.739, p<0.01) is proposed. This approach will produce new management tools for anaerobic digestion in wastewater treatment plants.

Inactivation of Escherichia coli and Staphylococcus aureus by pulsed electric fields increases with higher bacterial population and with agitation of liquid medium.

Inactivation of Escherichia coli, E. coli O157:H7, and Staphylococcus aureus in liquid media by pulsed electric fields (PEF) was conducted at varying bacterial populations with and without sample agitation. A laboratory-scale PEF batch unit with a rectangular electric pulse was used, operating under the following conditions: 25 kV/cm (E. coli, E. coli O157:H7) and 30 kV/cm (S. aureus) electric field strengths, 1-µs pulse width, 1-Hz pulse repetition rate, and 20 to 350 pulses for all samples. Not surprisingly, bacterial inactivation (for all three strains) increased with increasing pulse number, achieving the highest reduction at 350 pulses. Log CFU per milliliter microbial inactivation increased commensurately with increasing bacterial population (P < 0.05) but only when samples were treated with more than 200 pulses. For example, when E. coli was treated with 200 pulses at 10(5) CFU/ml, inactivation was only 3.0 Log versus 4.8 Log at the 10(10) inoculation level. When E. coli O157:H7 was treated with 200 pulses at 10(5) CFU/ml, inactivation was only 2.5 Log versus 4.6 Log at the 10(10) inoculation level. When S. aureus was treated with 200 pulses at 10(6) CFU/ml, inactivation was only 2.6 Log versus 4.8 Log at the 10(10) inoculation level. Inactivation of populations was also found to be statistically greater (P < 0.05) when liquid samples were agitated, in comparison to nonagitated samples. Because PEF inactivation activity is influenced by bacterial population and sample agitation, future studies should carefully consider these factors in experimental designs and/or scaled-up industry application.

Photocatalytic bacterial inactivation by TiO2-coated surfaces.

The aim of this study was the evaluation of the photoactivated antibacterial activity of titanium dioxide (TiO2)-coated surfaces. Bacterial inactivation was evaluated using TiO2-coated Petri dishes. The experimental conditions optimized with Petri dishes were used to test the antibacterial effect of TiO2-coated ceramic tiles. The best antibacterial effect with Petri dishes was observed at 180, 60, 30 and 20 min of exposure for Escherichia coli, Staphylococcus aureus, Pseudomonas putida and Listeria innocua, respectively. The ceramic tiles demonstrated a photoactivated bactericidal effect at the same exposure time. In general, no differences were observed between the antibacterial effect obtained with Petri dishes and tiles. However, the photochemical activity of Petri dishes was greater than the activity of the tiles.Results obtained indicates that the TiO2-coated surfaces showed a photoactivated bactericidal effect with all bacteria tested highlighting that the titania could be used in the ceramic and building industry for the production of coated surfaces to be placed in microbiologically sensitive environments, such as the hospital and food industry.