Analysing the interlinkage between diarrhoea and drinking water faecal contamination in India.

Diarrhoea is one of the major waterborne diseases spread through the faecal-oral route causing over 10 million cases and over 1,000 deaths per year in India. This study critically evaluates the interlinkage between bacteriological water quality, i.e. faecal coliforms and diarrhoea cases for the three pre-pandemic years 2017, 2018 and 2019 based on multiple sources. With around 17% of households tap water connectivity as of August 2019, the majority of the Indian population depends on raw groundwater (GW) and surface water sources. For this, faecal coliform (FC) levels in surface and GW have been mapped at district levels using data from India's National Water Quality Monitoring Programme. Health Management Information System's data on diarrhoea have been used to understand the monthly and district-wise variation of diarrhoea. The trends of FC, diarrhoea inpatient cases, and diarrhoea inpatient rates have been discussed. The analysis showed issues associated with the reliability and usefulness of these datasets with 43% of total India districts with no reported FC values for the study period. This study reveals a clear gap in the interlinkage between diarrhoea and bacteriological water quality with the unavailability of granular water quality data as a major challenge.

Examining drinking water quality: analysis of physico-chemical properties and bacterial contamination with health implications for Shangla district, Khyber Pakhtunkhwa, Pakistan.

A comprehensive understanding of water quality is essential for assessing the complex relationship between surface water and sources of pollution. Primarily, surface water pollution is linked to human and animal waste discharges. This study aimed to investigate the physico-chemical characteristics of drinking water under both dry and wet conditions, assess the extent of bacterial contamination in samples collected from various locations in District Shangla, and evaluate potential health risks associated with consuming contaminated water within local communities. For this purpose, 120 groundwater and surface water samples were randomly collected from various sources such as storage tanks, user sites, streams, ponds and rivers in the study area. The results revealed that in Bisham, lakes had the highest fecal coliform levels among seven tested sources, followed by protected wells, reservoirs, downstream sources, springs, rivers, and ditches; while in Alpuri, nearly 80% of samples from five sources contained fecal coliform bacteria. Similarly, it was observed that the turbidity level, total dissolved solids, electrical conductivity, biological oxygen demand, and dissolved oxygen in the surface drinking water sources of Bisham were significantly higher than those in the surface drinking water sources of Alpuri. Furthermore, the results showed that in the Alpuri region, 14% of the population suffers from dysentery, 27% from diarrhea, 22% from cholera, 13% from hepatitis A, and 16% and 8% from typhoid and kidney problems, respectively, while in the Bisham area, 24% of residents are affected by diarrhea, 17% by cholera and typhoid, 15% by hepatitis A, 14% by dysentery, and 13% by kidney problems. These findings underscore the urgent need for improved water quality management practices and public health interventions to mitigate the risks associated with contaminated drinking water. It is recommended to implement regular water quality monitoring programs, enhance sanitation infrastructure, and raise awareness among local communities about the importance of safe drinking water practices to safeguard public health.

Evaluation of physiochemical, heavy metals, and bacteriological parameters of celery and its irrigation water within Sulaymaniyah city of Iraq.

This study rigorously assesses the physicochemical, heavy metal concentrations, and bacteriological parameters of celery and its irrigation water across three rural areas of Sulaymaniyah city, Iraq. The investigation revealed that irrigation water's pH ranged significantly from 6.9 to 8.9. Notably, phosphate concentrations (PO43-) exceeded permissible levels in Tanjaro and Kanaswra across all seasons, with the highest recorded concentration being 10.4 mg L-1 during autumn in Kanaswra. Conversely, sulfate (SO42-) and sodium (Na+) concentrations remained within standard limits, with SO42- peaking at 115.1 mg L-1 in Tanjaro during summer. Celery samples reflected high Na+ concentrations in some seasons, with values exceeding 570 mg·kg in Kanaswra during summer. Heavy metal analysis indicated remarkably low levels in irrigation water, yet celery samples from Tanjaro and Aziz Awa exhibited Pb concentrations above the safety threshold of 0.3 mg·kg in all seasons. Furthermore, bacterial contamination, including total aerobic count and coliform in both water and celery, surpassed standard limits, highlighting significant health risks. This study underscores the imperative need for stringent water treatment processes to mitigate contamination and safeguard agricultural productivity and human health.

Changes of composition and antibiotic resistance of fecal coliform bacteria in municipal wastewater treatment plant.

The dynamics of the composition and antibiotic resistance of the fecal coliform bacteria (FCB) in a typical wastewater treatment plant (WWTP) were investigated concerning the seasonal changes. Results showed that WWTP could remove the FCB concentration by 3∼5 logs within the effluent of 104∼105 CFU/L, but the antibiotic resistant rate of FCB species increased significantly after WWTP. The dominant FCB changed from Escherichia coli in the influent (∼73.0%) to Klebsiella pneumoniae in the effluent (∼53.3%) after WWTP, where the Escherichia coli was removed the most, while Klebsiella pneumoniae was the most persistent. The secondary tank removed the most of FCB (by 3∼4 logs) compared to other processes, but increased all the concerned antibiotic resistant rate. The potential super bugs of FCB community showing resistance to all the target antibiotics were selected in the biological treatment unit of WWTP. The FCB showed the highest multiple antibiotic resistance (92.9%) in total which even increased to 100% in the effluent. Klebsiella has the highest antibiotic resistant rate in FCB, with a multiple antibiotic resistance rate of 98.4%. These indicated that the Klebsiella pneumoniae not just Escherichia coli should be specially emphasized after WWTP concerning the health risk associated with FCB community.

Examining the association between safe drinking water act violations and adverse birth outcomes in Virginia.

In 1974, the United States established the Safe Drinking Water Act (SDWA) to protect consumers from potential exposure to drinking water contaminants associated with health risks. Each contaminant is assigned a health-based standard meant to reflect the maximum level at which an adverse human health outcome is unlikely; measurements beyond that level have greater potential to result in adverse health outcomes. Although there is extensive research on human health implications following water contaminant exposure, few studies have specifically examined associations between fetal health and municipal drinking water violations. Therefore, the objective of this study is to assess whether SDWA drinking water violations are associated with fetal health outcomes, including preterm birth (PTB), low birth weight (LBW), and term-low birth weight (tLBW), in the Commonwealth of Virginia. Singleton births (n = 665,984) occurring between 2007 and 2015 in Virginia were geocoded and assigned to a corresponding estimated water service area. Health-based (HB) and monitoring and reporting (MR) violations for 12 contaminants were acquired from the US EPA Safe Drinking Water Information System, with exposure defined at the approximate service area level to limit exposure misclassification. A logistic regression model for each birth outcome assessed potential relationships with SDWA violations. When examining the association between individual MR violations and birth outcomes, Nitrate-Nitrite (OR = 1.10; 95% CI = 1.02, 1.18, P = 0.01) was positively associated with PTB and the total coliform rule was negatively associated with tLBW (OR = 0.93; 95% CI = 0.87, 1.00, P = 0.04). These findings indicate that a lack of regular monitoring and reporting by water providers (resulting in monitoring and reporting violations) may be concealing health-based violations as these health concerns cannot be revealed without testing, suggesting a need for additional technical, managerial, and financial support to enable often-underfunded water systems to adhere to monitoring and reporting requirements meant to protect public health.

Effectiveness of the tropical plants Rhynchospora corymbosa and Coix lacryma-jobi in vertical flow constructed wetlands for municipal primary sewage effluent treatment.

The performance of two tropical plants, Rhynchospora corymbosa L. (RC) and Coix lacryma-jobi, L (CL) in treatment of primary sewage effluent in lab-scale vertical-flow constructed wetlands (VFCW) along with no plant control wetland was investigated. A batch-flow VFCWs were operated under batch fill and drain hydraulic loading system with hydraulic retention times (HRT) of 0.5, 1, and 2 days and fill rate of 8 L/day. Removal of solids, organics, nutrients, and pathogens were monitored. The volumetric contaminant removal rates were best described by 1st order kinetics except for ammonia and phosphate, which was best described by Stover-Kincannon kinetics. Influent TSS, PO43-, COD, BOD5, and total coliform concentration were low but high in NH4+ concentration. CL was better in nutrient removal as HRT increases compared to RC. RC was more efficient at TSS, turbidity, and organics removal. Pathogen removal was independent of plant type but HRT. Solids and organic removal were lower in CL planted CWs due to preferential flow paths created by their bulky root. CL planted CWs removed more nutrients followed by RC planted CWs and then no-plant control CWs. The results of these tests demonstrate that both CL and RC are suitable for the treatment of municipal wastewater in VFCW system.

Real-time assessment of the Ganga river during pandemic COVID-19 and predictive data modeling by machine learning.

In this study, four water quality parameters were reviewed at 14 stations of river Ganga in pre-, during and post-lockdown and these parameters were modeled by using different machine learning algorithms. Various mathematical models were used for the computation of water quality parameters in pre-, during and post- lockdown period by using Central Pollution Control Board real-time data. Lockdown resulted in the reduction of Biochemical Oxygen Demand ranging from 55 to 92% with increased concentration of dissolved oxygen at few stations. pH was in range of 6.5-8.5 of during lockdown. Total coliform count declined during lockdown period at some stations. The modeling of oxygen saturation deficit showed supremacy of Thomas Mueller model (R2 = 0.75) during lockdown over Streeter Phelps (R2 = 0.57). Polynomial regression and Newton's Divided Difference model predicted possible values of water quality parameters till 30th June, 2020 and 07th August, 2020, respectively. It was found that predicted and real values were close to each other. Genetic algorithm was used to optimize hyperparameters of algorithms like Support Vector Regression and Radical Basis Function Neural Network, which were then employed for prediction of all examined water quality metrics. Computed values from ANN model were found close to the experimental ones (R2 = 1). Support Vector Regression-Genetic Algorithm Hybrid proved to be very effective for accurate prediction of pH, Biochemical Oxygen Demand, Dissolved Oxygen and Total coliform count during lockdown. Supplementary Information: The online version contains supplementary material available at 10.1007/s13762-022-04423-1.

Prevalence of Listeria monocytogenes and indicator microorganisms in Florida cantaloupe packinghouses, 2013-2014.

Prior to the 2013 cantaloupe season, the US Food and Drug Administration notified the industry that inspections of a subset of packinghouses would commence that year in response to the 2011 Listeria monocytogenes outbreak associated with cantaloupe. In May 2013, five Florida cantaloupe packinghouses participated in an environmental monitoring survey to evaluate their sanitary conditions prior to a potential FDA inspection. Two facilities participated again in 2014. Surface swabs (n = 374) were collected in each facility and included up to 60 food contact and non-food contact surfaces, including water. Samples were enumerated for total plate counts (TPC), generic Escherichia coli, and coliforms, and enriched for Listeria. Listeria were confirmed and speciated by sequencing of the partial sigB gene, and further characterized by pulsed field gel electrophoresis (AscI and Apal). In 2013, two zone 1 surfaces in same facility, were positive for L. monocytogenes (2/233). No L. monocytogenes was detected (n = 103) in the two facilities sampled the following year, including the previously L. monocytogenes-positive facility. Prevalence of L. monocytogenes in FL cantaloupe packinghouses was generally low (2/374), compared to other food environments. TPC, coliforms, E. coli and Listeria spp. were poor indicators of L. monocytogenes contamination in Florida packinghouses.

Evaluation of the purification capacity of soils: case of the Kouogouo and Djeleng V quarters in Bafoussam City (West Cameroon).

This work aimed at evaluating the purification capacity of the Kouogouo and Djeleng V quarters' soils (West Cameroon). Soil mapping was carried out, from which representative soil samples were collected, followed by their physical, chemical, and hydrodynamic characterization. Two types of effluents were identified, characterized, and subjected thereafter to filtration into these soil samples. The filtrates were then analyzed, in view of evaluating the performance of these soils through influent-effluent indicator level (physico-chemical parameters and fecal coliforms). The main results show four soil units in the study area, among which the indurated red brown clay soils and red clay loam soils with rock fragments were dominant, with 51.8% and 35.4%, respectively. The clayey texture was dominant (94.7%). These soils were classified as neutral to slightly acidic (5.83 to 7.19), while the permeability values ranged from 25.59 to 0.014 cm/h. Moreover, the hydrologic balance indicated a surplus of about 989.3 mm, which can contribute to the recharge of the water table at low depth, traditionally supplying wells and sources of drinking water, but also potentially to their pollution by the influx of organic and mineral matter. Two types of effluents were identified: these are latrines and domestic waste. They had contrasted physico-chemical and bacteriological pollution potentials, but sufficient to have a harmful effect on the population, compared to the WHO standards. The persistence of coliforms in some filtrates confirmed that water was exposed to pollution by the previous effluents and argued in favor of the installation of a safety distance between potential sources of pollution and water supply on the other hand.

Aquifer vulnerability assessment for fecal coliform bacteria using multi-threshold logistic regression.

Assessing aquifer vulnerability is crucial for preventing groundwater pollution. In this study, aquifer vulnerability to fecal coliform (FC) pollution was assessed using auxiliary environmental data in the Pingtung Plain, Taiwan. Moreover, key environmental factors inducing different fecal pollution levels were determined. First, 23 explanatory variables on land uses, population density, livestock and poultry densities, sanitary condition, antecedent precipitation, groundwater quality, aquifer characteristics, and subsurface hydrology were obtained using geographic information systems in 2014. As dependent variables, groundwater FCs were also simultaneously obtained. Then, multi-threshold logistic regression (LR) was adopted to model aquifer vulnerability assessment after cross validation. The thresholds of aquifer vulnerability causing risks of incidental ingestion were analyzed by risk assessment. Risks to human health were acceptable for a low-level threshold and exceeded the acceptable level for medium- and high-level thresholds when residents incidentally ingested FC-polluted groundwater. Finally, key environmental factors inducing low, medium, and high levels of groundwater FC pollution were characterized. The key environmental factors for the LR with low- and medium-level thresholds were sand and gravel soil textures of unsaturated aquifers and antecedent 3-day cumulative precipitation, and those for the LR with high-level thresholds were chicken farming, urban land use, and ratio of tap water use. Thus, the multi-threshold LR indicated that environmental factors must be ranked for assessing aquifer vulnerability.

Bacterial prediction using internet of things (IoT) and machine learning.

Water is a basic and primary resource which is required for sustenance of life on the Earth. The importance of water quality is increasing with the ascending water pollution owing to industrialization and depletion of fresh water sources. The countries having low control on reducing water pollution are likely to retain poor public health. Additionally, the methods being used in most developing countries are not effective and are based more on human intervention than on technological and automated solutions. Typically, most of the water samples and related data are monitored and tested in laboratories, which eventually consumes time and effort at the expense of producing fewer reliable results. In view of the above, there is an imperative need to devise a proper and systematic system to regularly monitor and manage the quality of water resources to arrest the related issues. Towards such ends, Internet of Things (IoT) is a great alternative to such traditional approaches which are complex and ineffective and it allows taking remote measurements in real-time with minimal human involvement. The proposed system consists of various water quality measuring nodes encompassing various sensors including dissolved oxygen, turbidity, pH level, water temperature, and total dissolved solids. These sensors nodes deployed at various sites of the study area transmit data to the server for processing and analysis using GSM modules. The data collected over months is used for water quality classification using water quality indices and for bacterial prediction by employing machine learning algorithms. For data visualization, a Web portal is developed which consists of a dashboard of Web services to display the heat maps and other related info-graphics. The real-time water quality data is collected using IoT nodes and the historic data is acquired from the Rawal Lake Filtration Plant. Several machine learning algorithms including neural networks (NN), convolutional neural networks (CNN), ridge regression (RR), support vector machines (SVM), decision tree regression (DTR), Bayesian regression (BR), and an ensemble of all models are trained for fecal coliform bacterial prediction, where SVM and Bayesian regression models have shown the optimal performance with mean squared error (MSE) of 0.35575 and 0.39566 respectively. The proposed system provides an alternative and more convenient solution for bacterial prediction, which otherwise is done manually in labs and is an expensive and time-consuming approach. In addition to this, it offers several other advantages including remote monitoring, ease of scalability, real-time status of water quality, and a portable hardware.

The ß-galactosidase assay in perspective: Critical thoughts for biosensor development.

Recently, the ß-galactosidase assay has become a key component in the development of assays and biosensors for the detection of enterobacteria and E. coli in water quality monitoring. The assay has often performed below its maximum potential, mainly due to a poor choice of conditions. In this study we establish a set of optimal conditions and provide a rough estimate of how departure from optimal values reduces the output of the assay potentially decreasing its sensitivity. We have established that maximum response for detecting low cell concentrations requires an induction of the samples using IPTG at a concentration of 0.2 mM during 180 min. Permeabilization of the samples is mandatory as lack of it results in an almost 60% reduction in assay output. The choice of enzyme substrate is critical as different substrates yield products with different extinction coefficients or fluorescence yields. The concentration of substrate used must be high enough (around 3 to 4 times Km) to ensure that the activity measured is not substrate limited. Finally, as the color/fluorescence of the reaction products is highly dependent on pH, care must be taken to ensure that pH at the time of reading is high enough to provide maximum signal.

Microbial contamination of packaged drinking water in Nigeria.

OBJECTIVES: About 18% of urban households in Nigeria depend on packaged sachet water as the primary source of drinking water. This review assessed microbial contamination of these products with an emphasis on total coliforms and the faecal indicator bacteria (FIB) - Escherichia coli (E. coli) and thermotolerant coliforms (TTC). METHODS: PubMed/Medline, African Index Medicus, AfroLib, Global Health Library, Embase and the ISI Web of Science databases were searched to identify original research published up to October 2020. The literature findings were synthesised narratively in line with the review objectives. To assess prevalence of microbial contamination, a random effects meta-analysis, was also conducted using the R metafor package in RStudio. The protocol for this review is registered on PROSPERO with reference number CRD 42019128474. RESULTS: Fifty-two of 429 studies were identified for inclusion. At 53.27%, contamination prevalence was higher for total coliforms (95% CI: 39.05-66.98, I2  = 81%, p < 0.01, 42 studies) than FIB (12.38%, 95% CI: 7.92-18.85, I2  = 61%, p < 0.01, 33 studies) suggesting that treatment failure is a major contributor to the poor microbial quality reported in the included studies. Within the FIB group, the prevalence of contamination with E. coli was 13.30% (95% CI: 8.23-20.80, I2  = 65%, p < 0.01, 27 studies) versus 6.24% (95% CI: 1.12-28.06, I2  = 72%, p < 0.01, six studies) for TTCs. Other microbial contaminants reported were Pseudomonas aeruginosa, Klebsiella and Enterococcus faecalis and these showed multidrug antibiotic resistance. CONCLUSIONS: The findings of this review highlight the need for improved regulatory oversight with more stringent monitoring of the microbial quality of sachet water products in Nigeria.

Nucleic acid lateral flow assay for simultaneous detection of hygiene indicator bacteria.

A simple and rapid polymerase chain reaction (PCR)-based lateral flow assay (LFA) was developed for multiplex detection of hygiene indicator bacteria. Specifically, new PCR primers were designed for accurately detecting Escherichia coli, coliform bacteria, and total bacteria, and the results obtained as a colorimetric signal (generated by the accumulation of gold nanoparticles at distinct test zones on flow strips) could be identified by the naked eye in <10 min after the completion of PCR. The proposed LFA system did not exhibit any cross-reactivities with 8 distinct bacterial strains and can detect down to 1 colony forming unit (CFU)/mL. Furthermore, three species of cultured bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa) inoculated onto sterilized ham were successfully analyzed using the LFA system, which demonstrated that this system shows sufficient sensitivity and specificity for food hygiene monitoring. The speed and simplicity of this LFA make it suitable for use in the food industry as part of routine screening analysis.

Paper currency harbours antibiotic-resistant coliform bacteria and integron integrase.

AIMS: This study was designed to analyse the prevalence of class 1 and class 2 integron integrase genes among antibiotic-resistant coliform bacteria isolated from paper currency circulating in Pakistan. METHODS AND RESULTS: A total of 500 individual currency notes were collected from different food vending sites at Lahore, Pakistan. Bacterial population were identified by biochemical and PCR techniques. Antimicrobial susceptibility testing was performed by disc diffusion assay. The highest bacterial population on currency was found from street vendors and butcher shops. Escherichia coli was found to be the most prevalent coliform bacteria followed by Klebsiella sp. and Enterobacter sp. PCR amplification of antimicrobial resistance gene showed the presence of ampC, blaTEM , blaNDM-1 , qnrA, tet(A) and tet(B) genes among coliform isolates. A total of 47 integron integrase bearing strains of coliform bacteria were analysed. Sequence analysis showed the presence of dfrA1-aadA1, dfrA1, dfrA5, dfrA7, aadA1, aadA4 cassette arrays in class 1 integron and dfrA1-sat2-aadA1 in class 2 integrase genes. CONCLUSION: Circulating currency was heavily contaminated with antimicrobial-resistant coliform bacteria bearing class 1 and class 2 integron integrase genes. SIGNIFICANCE AND IMPACT OF THE STUDY: This study describes a potential threat of severe bacterial infections due to improper hand hygiene and community sanitation when dealing with the currency notes.

Bacterial quality and safety of raw beef: A comparison between Finland and Nigeria.

Beef can easily be contaminated with bacteria during the meat production chain. In this work, we studied the contamination levels of mesophilic aerobic bacteria (MAB) and thermotolerant coliform bacteria (TCB) on raw beef surfaces from small shops in Helsinki, Finland and meat markets in Benin City, Nigeria. We also investigated the prevalence of Salmonella, Campylobacter, Yersinia, Shiga toxin-producing Escherichia coli (STEC), Listeria, and cephalosporin-resistant E. coli (CREC). In total, one hundred unpacked raw beef samples from Finland and Nigeria were collected in 2019. The median MAB and TCB counts were significantly (P < 0.001) higher on beef from Nigeria than from Finland. The median MAB and TCB counts in Nigeria were 7.5 and 4.0 log10 cfu/cm2, respectively, and 6.5 and 2.8 log10 cfu/cm2 in Finland, respectively. Most (94%) Nigerian samples were unacceptable according to limits set by the EU. Beef samples from meat markets in Benin City were significantly (P < 0.05) more frequently contaminated with Salmonella, STEC, and CREC than beef samples from small shops in Helsinki. Salmonella, STEC, and CREC were isolated from 30, 36, and 96% of Nigerian samples, respectively, and from <2, 12, and 2% of Finnish samples, respectively. Our study demonstrates a significant difference between the bacterial contaminations of raw beef in Nigeria and Finland, along with a possible misuse of cephalosporins in animal husbandry in Nigeria.

Short communication: Diagnostic accuracy of the Petrifilm culture system for identifying colostrum with excessive bacterial contamination in Quebec dairy herds.

The objective of this study was to validate the diagnostic accuracy of the Petrifilm culture system (3M, St. Paul, MN) for identifying colostrum with excessive bacterial contamination. An observational cross-sectional study was conducted between October 2015 and February 2016. Two colostrum aliquots were collected during the first meal of 332 calves (33 commercial Holstein dairy farms) in Quebec, Canada. One aliquot per calf was used to quantify the total bacteria count and the total coliform count using standard bacteriological laboratory testing (reference test). These results were dichotomized to identify colostrum with excessive bacterial contamination [aerobic count plate (AC) >100,000 cfu/mL; coliform count plate (CC) >10,000 cfu/mL]. The Petrifilm system was used to quantify both aerobic and coliform contamination of the other colostrum aliquot from each calf. As such, AC and CC were used according to the manufacturer's recommendations. The area under the curve of the receiver operating characteristic curve of AC and CC compared with the laboratory were 0.83, and 0.95, respectively. Using the optimal threshold of >24,000 cfu/mL for AC results, the Petrifilm system had a sensitivity (Se) of 69%, specificity (Sp) of 86%, and a kappa value of 0.54. Using the optimal threshold of >4,000 cfu/mL for CC results, the Petrifilm system had a Se of 93%, Sp of 90%, and kappa value of 0.64. Overall, these results suggest that the Petrifilm system is an appropriate alternative for identifying colostrum with excessive bacterial contamination.

Population dynamics of coliforms in a commercial Cheddar cheese production facility.

The detection of coliforms in young cheese is a potential indication of undesirable microbial growth within the processing environment. The aim of this study was to investigate sources and conditions that lead to the intermittent detection of coliforms (1-3 log cfu/g) in young Cheddar cheese at a single commercial facility. Analysis of historical production data, in combination with iterative investigative sampling events, was performed to determine coliform levels in milk, whey, curd, and surfaces at the beginning, middle, and end of the production day. After sanitation, conveyor belt pieces from the draining and matting conveyor (DMC) were collected and evaluated for bacterial survivors using culture-based methods and scanning electron microscopy. Production data analysis indicated that cheese produced later in the production day (≥16 h) was significantly more likely to test positive for coliforms than cheese made earlier in the production day (<12 h). Enumeration of coliforms in raw and heat-treated milk demonstrated that the subpasteurization thermal treatment (67-70°C, 26-28 s) was effective at reducing, but not eliminating, coliforms. Repeated sampling identified the DMC, particularly the drain belt and belt 1, as a critical area that supported coliform growth during the production day. Coliform levels in whey entering the weir maintained a level of <1 cfu/mL throughout production; however, coliform levels in whey below the drain belt increased from <1 cfu/mL at midday (8 h) to 5.04 log cfu/mL by the end of the production day (~18 h). Routine sanitation inside the DMC resulted in undetectable coliform levels on easily accessible surfaces. However, enrichment and scanning electron microscopy of belt sections revealed pockets of viable coliforms and other bacteria in cracks and defects in conveyor belts, indicating that sanitation did not eliminate all viable bacteria. Low levels of coliforms are present in heat-treated milk and survive sanitation in the DMC and could serve as the initial seed for high levels of coliforms at the end of the production day.

Microbial contamination of harvested colostrum on Czech dairy farms.

The objective of this study was to perform a quantitative and qualitative evaluation of microbial contamination of harvested colostrum on 39 Czech dairy farms. The study identified the proportion of colostrum samples that met the recommended goals for total plate count (TPC), total coliform count (TCC), and gram-negative noncoliform count (NCC), and evaluated the effect of the farm, breed, parity, season of the year, time of calving, and colostrum volume on these 3 microbiological parameters. Colostrum samples from cows (n = 1,241; 57.6% from Czech Fleckvieh, and 42.4% from Holstein breed) were collected on dairy farms between autumn of 2015 and spring of 2017. The samples were collected after the first milking directly from milking buckets. In 155 out of 1,241 colostrum samples (26 farms, 6 samples each, except 1 farm), the species of microorganisms obtained by culture were determined, and the findings were classified into 4 groups according to the probable source of contamination as follows: (1) normal inhabitants of bovine skin and mucosa, (2) fecal contaminants, (3) environmental contaminants, and (4) potential gram-positive mammary pathogens. Our results showed heavy microbial contamination of collected colostrum samples (TPC median = 408,000 cfu/mL; TCC median = 200 cfu/mL; NCC median = 80 cfu/mL). Only 28.4% of samples met the requirement for TPC (<100,000 cfu/mL), 88.2% for TCC (<10,000 cfu/mL), and 86.0% for NCC (<5,000 cfu/mL). Among the tested factors, we found that farm had a significant effect on all 3 microbiological parameters, volume of colostrum had an effect on TPC (the highest TPC in <3.0 L of colostrum), and season had an effect on TCC and NCC (higher TCC in summer than in autumn and winter; the highest NCC in summer and higher in autumn than in spring and winter). Our results showed that most microbes isolated from colostrum belonged to normal inhabitants of bovine skin and mucosa, fecal, or environmental contaminants (i.e., 82.6%, 81.9%, and 75.5% of colostrum samples, respectively). Potential gram-positive mammary pathogens were found in 13.5% of samples. Escherichia coli was isolated from 9.0% of colostrum samples, and Streptococcus uberis and Streptococcus parauberis were each isolated from 5.2% of samples. Our study showed high microbial contamination of colostrum collected on dairy farms. Therefore, better hygiene and sanitation around colostrum harvest should be addressed by farmers.

A constructed wetland system with aquatic macrophytes for cleaning contaminated runoff/storm water from urban area in Florida.

A community of aquatic macrophytes has an important role in reducing nutrient load and organic and inorganic contaminants in storm/runoff water. However, minimal information is available regarding the efficiency of constructed wetlands for cleaning runoff water from urban areas, especially in the tropical and subtropical regions. This study investigated the effectiveness of constructed wetland integrated with aquatic macrophytes for removal of chemical and microbial contaminants in the storm/runoff water from the urban areas. Water samples were monthly collected in the constructed wetland from the inlet of storm/runoff water, middle and outlet of discharge, and analyzed for physical and chemical properties, concentrations of nutrients, metals, and fecal coliform (FC) during the period of November, 2016 to April, 2018 in St. Lucie county, Florida, USA. The dominant plant species in the constructed wetland included cattail (Typha latifolia), waterthyme (Hydrilla verticillata) and water hyacinth (Eichhornia crassipes), and periphyton filamentous algae (Spirogyra). The improvement of pH and electrical conductivity (EC) was not obvious, but the concentration of total suspended solids was significantly reduced. This system was effective in the removal of fecal coliform (by 68%) and particulate phosphorus (P, 72%), followed by total P (42%) and N (35%). Concentrations of metallic pollutants including cadmium (Cd), lead (Pb), chromium (Cr), and copper (Cu) were mostly below the detection limit (<1 ppb) except for zinc (Zn), of which concentration was reduced by 23%. The removal of FC was consistently effective all the year round, whereas the removal of total N, P and particulate-P was effective in spring and summer, and less in autumn and winter. These results indicate that constructed wetland with a natural aquatic plant community can effectively reduce the loads of nutrients, metals, and fecal coliforms in water column. Regular harvest of aquatic macrophytes communities and collecting litters may further improve the system efficiency for cleaning storm water from urban areas.