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Investigating human pathogens in wastewater is crucial for identifying and predicting potential occupational health risks faced by wastewater treatment plant (WWTP) workers. This study aimed to determine the occurrence and levels of Legionella pneumophila, Mycobacterium spp., Arcobacter butzleri, and Aeromonas hydrophila in untreated municipal wastewater. Grab influent, activated sludge, and secondary settling tank (SST) effluent samples were collected bi-weekly over 6 months from 5 WWTPs in Tshwane, South Africa. Mycobacterium spp., A. butzleri, and A. hydrophila were detected using quantitative PCR (qPCR), while Legionella was detected using both a culture method and qPCR. The four pathogens were identified in most samples at varying levels. Legionella pneumophila had a positivity rate of 92%, ranging from 2 to 5.4 log10 MPN/100 mL. Detection rates of Legionella spp., L. pneumophila, and L. pneumophila serogroup 1 were 97%, 75%, and 69%, respectively, with up to 5.3 log10 gene copies (GC)/mL. Importantly, this study demonstrates molecular typing of L. pneumophila serogroup 1 in wastewater, a topic that has been rarely documented. Mycobacterium spp. were detected in all samples at varying levels (log10 GC/mL) in influent (2.8–7.6), activated sludge (4.8–8.9), and SST effluent (3.8–8.9) samples. Arcobacter butzleri and A. hydrophila were detected in 96% and 82% of the samples, respectively, with GC levels in influent, activated sludge, and SST effluent ranging from 0.8 to 6.6, 1.5 to 6.5, and 0.7 to 6.6 log10 GC/mL for A. butzleri, and similar levels for A. hydrophila. These findings underscore the presence of respiratory and enteric pathogens at various treatment points, suggesting potential occupational exposure for WWTP workers. This emphasises the need for microbiological risk assessments (RAs) or reviewing existing RAs and implementing necessary control measures to protect WWTP workers. [ABSTRACT FROM AUTHOR]

Background: The pollution of water bodies is a serious concern in most rural areas in low- and middle-income countries due to anthropogenic activities which pose the greatest risk of human hepatitis viruses to public health. The aim of the study was to determine the probability of hepatitis A virus (HAV) infection associated with human consumption of water from River Owena, Nigeria. Methods: Water samples were collected from points with intense anthropogenic activities during dry and wet periods. Loads of enteric bacteria and HAV were determined using culture-based method and molecular technique. Risks of HAV infection was estimated using dose-response model, and probabilities of clinical illness and mortality were also determined. Results: Results revealed that the levels E. coli and faecal coliforms were greater during the wet period than the dry period (p< 0.05). Concentration of HAV was greater during the dry period than the wet period (p< 0.05). Risks of HAV infection were higher during the dry period than the wet period, and were all above the US EPA acceptable risk limit. Risk of clinical illness and mortality due to HAV were higher during the dry period than the wet period. Conclusions: Ingestion of water from the river may result into liver inflammation, morbidity or death. Development of active water management plans to reduce pollutant fluxes and address contamination threats must be established.

Background: The pollution of water bodies is a serious concern in most rural areas in low- and middle-income countries due to anthropogenic activities which pose the greatest risk of human hepatitis viruses to public health. The aim of the study was to determine the probability of hepatitis A virus (HAV) infection associated with human consumption of water from River Owena, Nigeria. Methods: Water samples were collected from points with intense anthropogenic activities during dry and wet periods. Loads of enteric bacteria and HAV were determined using culture-based method and molecular technique. Risks of HAV infection was estimated using dose-response model, and probabilities of clinical illness and mortality were also determined. Results: Results revealed that the levels E. coli and faecal coliforms were greater during the wet period than the dry period (p< 0.05). Concentration of HAV was greater during the dry period than the wet period (p< 0.05). Risks of HAV infection were higher during the dry period than the wet period, and were all above the US EPA acceptable risk limit. Risk of clinical illness and mortality due to HAV were higher during the dry period than the wet period. Conclusions: Ingestion of water from the river may result into liver inflammation, morbidity or death. Development of active water management plans to reduce pollutant fluxes and address contamination threats must be established. [ABSTRACT FROM AUTHOR]

This study addresses the microbial risks associated with Underground Hydrogen Storage (UHS), a critical component in the transition towards renewable energy systems, by employing an innovative multi-reactor system (Bio-xplorer) to simulate UHS conditions in two Italian reservoirs. The microbiological risk assessment (MRA) of Reservoir A and B was evaluated by subjecting them to gas mixtures of 10 % H 2 and 90 % CH 4 , and 99 % H 2 and 1 % CO 2 , respectively. In Reservoir A, the stability of pressure and temperature, the negligible optical density, and lack of microbial metabolites suggested a low risk of microbial activation. Molecular analyses confirmed the absence of sulphate-reducing bacteria (SRB) and limited growth of hydrogenotrophic methanogens (HM). Similarly, in Reservoir B, the absence of SRB and limited occurrence of HM indicated a low microbiological risk. Overall, the present work supports the safe and efficient implementation of UHS , a promising mitigation technique for climate change, using an innovative tool for MRA. [Display omitted] • Microbial risk assessment for UHS in Italy. • Innovative HP & HT bioreactors system (Bio-xplorer) for UHS lab tests. • Novel approach for UHS Microbial risk assessment in two Italian NG reservoirs. • Reactor-based assessment of SRB, HM, AB activity by mimicking reservoirs environment. • No sensible hydrogen consumption registered for both the reservoirs. [ABSTRACT FROM AUTHOR]

The study estimated the risk due to Cryptosporidium, Giardia, and Ascaris, associated with non-potable water reuse in the city of Jaipur, India. The study first determined the exposure dose of Cryptosporidium, Giardia, and Ascaris based on various wastewater treatment technologies for various scenarios of reuse for six wastewater treatment plants (WWTPs) in the city. The exposure scenarios considered were (1) garden irrigation; (2) working and lounging in the garden; and (3) consumption of crops irrigated with recycled water. The estimated annual risk of infection varied between 8.57 × 10−7 and 1.0 for protozoa and helminths, respectively. The order of treatment processes, in decreasing order of annual risk of infection, was found to be: moving-bed bioreactor (MBBR) technology > activated sludge process (ASP) technology > sequencing batch reactor (SBR) technology. The estimated annual risk was found to be in this order: Ascaris > Giardia > Cryptosporidium. The study also estimated the maximum allowable concentration (Cmax) of pathogen in the effluent for a benchmark value of annual infection of risk equal to 1:10,000, the acceptable level of risk used for drinking water. The estimated Cmax values were found to be 6.54 × 10−5, 1.37 × 10−5, and 2.89 × 10−6 (oo) cysts/mL for Cryptosporidium, Giardia, and Ascaris, respectively. HIGHLIGHTS Use of the Sketcher tool for modelling concentrations of Cryptosporidium, Giardia, and Ascaris in treated wastewater.; Estimation of annual risk of infection due to Cryptosporidium, Giardia, and Ascaris during reuse of treated wastewater.; Estimation of concentrations of Cryptosporidium, Giardia, and Ascaris corresponding to annual risk of infection value (i.e., 1:10,000).;

The study estimated the risk due to Cryptosporidium, Giardia, and Ascaris, associated with non-potable water reuse in the city of Jaipur, India. The study first determined the exposure dose of Cryptosporidium, Giardia, and Ascaris based on various wastewater treatment technologies for various scenarios of reuse for six wastewater treatment plants (WWTPs) in the city. The exposure scenarios considered were (1) garden irrigation; (2) working and lounging in the garden; and (3) consumption of crops irrigated with recycled water. The estimated annual risk of infection varied between 8.57 × 10-7 and 1.0 for protozoa and helminths, respectively. The order of treatment processes, in decreasing order of annual risk of infection, was found to be: moving-bed bioreactor (MBBR) technology.activated sludge process (ASP) technology. sequencing batch reactor (SBR) technology. The estimated annual risk was found to be in this order: Ascaris. Giardia.Cryptosporidium. The study also estimated the maximum allowable concentration (Cmax) of pathogen in the effluent for a benchmark value of annual infection of risk equal to 1:10,000, the acceptable level of risk used for drinking water. The estimated Cmax values were found to be 6.54 × 10-5, 1.37 × 10-5, and 2.89 × 10-6 (oo) cysts/mL for Cryptosporidium, Giardia, and Ascaris, respectively. [ABSTRACT FROM AUTHOR]

Guanabara Bay has been known to be polluted with trash and sewage from the surrounding areas, but health risks from recreational contact with water in the basin have not been well characterized. In this paper, fecal indicator bacteria (FIB) monitoring data are used to predict risks in three different exposure scenarios: (1) bathing in freshwater rivers that discharge into Guanabara Bay, (2) wading in these freshwater rivers, and (3) sailing in Guanabara Bay. Concentrations of indicator bacteria in river samples were measured directly, and concentrations of indicator bacteria in bay samples were sourced from publicly available government data sets. Ratios between pathogens and fecal indicator concentrations were used to estimate risks for five selected pathogens based on the indicator concentrations. The median risk of disease estimated from E. coli indicator concentrations was 1.0, 9.9 × 10−1 and 8.2 × 10−4 for the swimming, wading, and sailing exposure pathways, respectively. Risks estimates based on concentrations of the enterococci indicator bacteria in the sailing exposure scenario were comparable, at 3.4 × 10−4. The sum of total risk estimated from the five selected pathogens was 5.9 × 10−1, 3.6 × 10−1, and 1.0 × 10−3 for the swimming, wading, and sailing exposure pathways, respectively. Estimated risks of swimming and wading in the rivers far exceeded risks associated with U.S. recreational contact standards, while estimated risks for sailing in the bay were well below these risk guidelines. The 95th percentile of the sailing risk was estimated to exceed the U.S. recreational contact risk level. This paper exemplifies an approach to conducting quantitative microbial risk assessments when only fecal indicator bacteria data are available. Context-specific data on the relevant exposure routes, exposure frequency, and site-specific indicator: pathogen ratios were lacking, which ultimately led to uncertainty in the model. This study is intended to provide a framework for estimating GI risk based on fecal indicator concentrations while acknowledging that the substantial variation in indicator:pathogen ratios make the results of such efforts uncertain. [ABSTRACT FROM AUTHOR]

Nontuberculous mycobacteria (NTM) infection is estimated as the most serious waterborne infectious disease. NTM are ubiquitous in drinking water supply systems, which could be one of the possible exposure pathways for NTM disease, posing a serious concern to human health. Characteristics of NTM, such as exposure via inhalation, disinfectant resistance, survival in oligotrophic conditions, and association with amoebae, are largely different from those of Escherichia coli (E. coli) which has been traditionally regarded as a model bacterium causing gastrointestinal diseases in water safety. However, the fate of NTM in water supply systems from source water to the point of use has not been systematically revealed yet. Thus, this review proposes that NTM should be regarded as alternative model bacteria in water use by updating the current knowledge on the occurrence, removal efficiency, and regrowth of NTM in water supply systems. Moreover, we demonstrate the need to establish a comprehensive quantitative microbial risk assessment to identify the critical control point, which is indispensable to mitigate NTM risk in water use. HIGHLIGHTS Waterborne NTM are posing a significant health threat in many countries.; NTM are persistent and can regrow in drinking water, which is so different from traditional model bacterium (E. coli).; The fate of NTM from source to the point of use remains unclear.; Comprehensive risk assessment is lacking for NTM in water supply systems.; NTM can be new model bacteria to revisit the management of water supply systems.;

Climate change is considered primarily as a human-created phenomenon that is changing the way humans live. Nowhere are the impacts of climate change more evident than in the food ecosphere. Climate-induced changes in temperature, precipitation, and rain patterns, as well as extreme weather events have already started impacting the yield, quality, and safety of food. Food safety and the availability of food is a fundamental aspect of ensuring food security and an adequate standard of living. With climate change, there have been increasing instances of observed changes in the safety of food, particularly from a microbiological standpoint, as well as its quality and yield. Thus, there is an urgent need for the implementation of advanced methods to predict the food safety implications of climate change (i.e., future food safety issues) from a holistic perspective (overall food system). Artificial Intelligence (AI) and other such advanced technologies have, over the years, permeated many facets of the food chain, spanning both farm- (or ocean-) to-fork production, and food quality and safety testing and prediction. As a result, these are perfectly positioned to develop novel models to predict future climate change-induced food safety risks. This article provides a roundup of the latest research on the use of AI in the food industry, climate change and its impact on the food industry, as well as the social, ethical, and legal limitations of the same. Particularly, this perspective review stresses the importance of a holistic approach to food safety and quality prediction from a microbiological standpoint, encompassing diverse data streams to help stakeholders make the most informed decisions.

Food production using recycled wastewater offers a sustainable way forward in light of limited freshwater resources. However, concerns of food safety should be addressed to protect public health. To this end, we developed a dynamic transport model to track norovirus from the irrigation water to the root and shoot of lettuce during the growth period. These processes were embodied in a system of ordinary differential equations that also incorporated plant growth, transpiration rate, viral attachment and detachment to culture media, viral decay, and plant barrier effects. Model parameters were either obtained from the literature or through fitting the model to experimental data from a study reporting human norovirus transport in hydroponically grown lettuce. The results showed that lettuce grown hydroponically resulted in a higher risk than lettuce grown in soil. In both cases, the risk predicted failed to meet the risk benchmarks established by the U.S. EPA and WHO. Viral attachment to growth media, such as the soil particles, was an important mechanism for risk reduction. A sensitivity analysis revealed that harvesting time and irrigation time are important factors influencing the viral loads in lettuce. Hence, this pathogen transport model provides a framework for investigating the effects of time and other factors on disease burdens from water reuse in agriculture, underscoring the utility of a dynamic model. In the absence of a routine monitoring of contaminants in the recycled irrigation water and food crops, a quantitative risk assessment based on objective scientific knowledge is the best approach to guide the policy decisions on water reuse practices.

Water taps can be a reservoir for microorganisms and pose a risk for contamination and infection. In this work, water samples from different common taps were examined to determine the influence of certain parameters on the microbial load of drinking water. Methods: Four different types of taps were installed along the same water pipe. Over a period of six months, water samples were taken at specific intervals and analyzed for their colony-forming units (CFU/mL) and for the presence of the water pathogens Pseudomonas aeruginosa and Legionella pneumophilia. Two different flushing configurations were investigated: Setup A: the same flush intervals for all taps once a day to determine differences based on type, size and mode of operation. Experimental setup B: different flush cycles for manual and electronic taps to investigate the effects of water stagnation in the tap and whether electronic taps with automatic flushes improve water quality. Results: No Legionella pneumophilia and Pseudomonas aeruginosa were found during the study period. The size of the tap has a great influence on the number of CFU/mL—a maximum of 330 CFU/mL was found in the smallest tap and 1080 CFU/mL in the largest tap, with a significant difference. Stagnation in the tap leads to a significantly higher number of CFU/mL. The results of this work can be used as a basis for the development of innovative taps. There are many possibilities in terms of materials, tap size and intelligent action algorithms—such as automatic flushing—to maintain the quality of our drinking water in a resource-saving way. [ABSTRACT FROM AUTHOR]

Microbial contamination of private well systems continues to be a prominent drinking water concern, especially for areas impacted by floodwaters. Hurricane Harvey deposited nearly 60 inches of rain, resulting in extensive flooding throughout Houston, Texas, and neighboring counties. A sampling campaign to test private wells for fecal indicator bacteria was initiated in the weeks following flooding. Escherichia coli concentrations measured in wells were utilized in a quantitative microbial risk assessment to estimate the risk of infection for both drinking water and indirect ingestion exposure scenarios. Derived reference pathogen doses indicated that norovirus (1.60 × 10−4 to 8.32 × 10−5) and Cryptosporidium (2.37–7.80 × 10−6) posed the greatest health risk via drinking, with median health risk estimates exceeding the U.S. Environmental Protection Agency's modified daily risk threshold of 1 × 10−6 for a gastrointestinal infection. Bathing (1.78 × 10−6), showering (4.32 × 10−7), and food/dish washing (1.79 × 10−6) were also identified to be exposure pathways of health concern. A post-flood microbial risk assessment of private wells in the Gulf Coast has not previously been conducted. Estimating these health risks can provide scientifically supported guidance regarding which well water practices are safest, especially when well water quality is unknown. Developing this guidance is critical as coastal communities experience increased vulnerability to flooding. [ABSTRACT FROM AUTHOR]

Food‐borne microbial illness contributes up to one third of global disease burden. The largest category of food‐borne illness is gastroenteritis, the majority of which is caused by enteric viruses. Viruses like these are transmitted to food either by waste‐contaminated waters, or by handling and transfer during processing. An important tool for reducing or controlling food‐borne microbial risk is risk analysis. This framework has been adopted globally to manage risks associated with microbial contamination in food. Several hundred microbial risk assessments (MRAs) have been published by different national and international organisations, for different food‐hazard combinations. The use of MRAs in controlling and understanding virus risk has, to date, been limited, compared with the efforts made on bacterial pathogens. Given the large disease burden that viruses are responsible for, this disparity should be addressed. The main reasons for the relative lack of risk assessments are the difficulty in detecting and monitoring viruses compared with bacteria. This means less data on prevalence, concentration and inactivation, and allows viruses to remain silent contributors to global disease. There are also key conceptual differences between virus risk assessment and bacterial risk assessment. This project aimed to assess the current state of the art for food‐borne virus risk assessment, then to progress the field further by using the data available to produce risk rankings and risk assessments. This was done by a combination of literature reviewing and various risk assessment tools. The result was an assessment of the overall evidence base in the literature, a semi‐quantitative ranking comparison between the viruses and foods of most concern, and a survey of inactivation methods, leading to a quantitative ranking of the effectiveness of each in reducing and managing food‐borne virus risk. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic raised the public profile of wastewater-based infectious disease monitoring. General media coverage about wastewater detection of SARS-CoV-2 (the COVID-19 coronavirus) increased community awareness of the potential use of wastewater for the detection and surveillance of emerging diseases and also heightened recognition of the potential for wastewater to harbour and convey a variety of pathogens. This has also generated questions about the potential public health impacts of emerging pathogens, such as SARS-CoV-2 and mpox, in sewage and recycled water. To ensure water security in an era of climate change, water recycling is increasingly important in Australia and other water-stressed nations and managing disease risks in integrated water management is thus of critical importance. This paper demonstrates the existing risk management provisions for recycled water and explores potential issues posed by novel and emerging pathogens. First, a synopsis of some key emerging and re-emerging human pathogens is presented and the risks associated with these pathogens in the context of recycled water provision is considered. Then, an overview of the engineered treatment systems and regulatory framework used to manage these emerging risks in Australia is presented, together with a discusion of how emerging pathogen risks can be managed to ensure safe recycled water supply now and into the future.

This document is an editorial titled "Advancing molecular diagnostic tools for robust surveillance of microbial water quality." It emphasizes the importance of monitoring microbial water quality for human, animal, and environmental health. The presence of microbial pollutants in water can have negative impacts, including waterborne outbreaks. The editorial discusses the use of molecular diagnostic tools, such as next-generation sequencing and CRISPR technology, for detecting and assessing microbial contamination in water. It also highlights the importance of integrated assessment tools and modeling for evaluating and predicting microbial water quality and health risks. The document concludes by emphasizing the need for coordinated and validated methods to ensure effective and reliable water quality assessment. [Extracted from the article]

Studies have illustrated that wastewater treatment methods targeting bacteria do not remove all types of viruses and available epidemiological studies indicate bacteria concentrations may not always be predictive of viral illnesses associated with recreational water exposure. To address these challenges, coliphages have been proposed as an indicator of fecal contamination in recreational water. When compared to traditional fecal indicator bacteria, coliphages exhibit a longer persistence in the environment. The persistence of coliphages in the environment and through wastewater treatment more closely resembles that of pathogenic viruses. We conducted a systematic literature search of peer-reviewed publications to identify coliphage density data (somatic [SC] and male-specific [MSC]) in wastewater treatment plant (WWTP) effluent categorized as primary, secondary, tertiary treated, or disinfected. Scope, study quality, and data availability were included as literature review inclusion criteria. An analysis was conducted to estimate the coliphage densities for specific treatment types within each respective WWTP effluent category. Densities of MSC and SC in influent were significantly higher when compared to densities of MSC and SC in effluent subjected to secondary treatment using biological treatment processes both with and without nutrient removal, tertiary treatment using either a treatment pond or a phosphate removal process, or disinfection using either chlorine, UV, or a combination of both UV and chlorine. Distributions of coliphage in various wastewater effluents will be useful for evaluating the efficacy of treatment processes and disinfectants in future microbial risk assessments.

This study evaluated the risk of foodborne illness from highly pathogenic Vibrio spp. (Vibrio vulnificus and V. cholerae) by raw whip-arm octopus (Octopus minor) consumption. In total 180 samples of raw whip-arm octopus were collected from markets and examined for the prevalence of V. vulnificus and V. cholerae. Predictive models describing the kinetic behavior of Vibrio spp. in raw whip-arm octopus were developed, and the data on amounts and frequency of raw whip-arm octopus consumption were collected. Using the collected data, a risk assessment simulation was conducted to estimate the probability of foodborne illness raw whip-arm octopus consumption using @RISK. Initial contamination levels of Vibrio spp. in raw whip-arm octopus were –3.9 Log colony-forming unit/g, as estimated by beta distribution fitting. The developed predictive models were appropriate to describe Vibrio spp. in raw whip-arm octopus during distribution and storage with R2 values of 0.946–0.964. The consumption frequency and daily consumption amounts of raw whip-arm octopus per person were 0.47% and 57.65 g, respectively. The probability of foodborne illness from raw whip-arm octopus consumption was estimated to be 8.71 × 10−15 for V. vulnificus and 7.08 × 10−13 for V. cholerae. These results suggest that the risk of Vibrio spp. infection from raw whip-arm octopus consumption is low in South Korea.

Reduction of foodborne illness caused by norovirus (NoV) continues to be a focus for the food safety community. Using a previously published quantitative risk assessment model, we evaluated more than 60 scenarios examining the impact of implementation of and compliance with risk management strategies identified in the U.S. Food and Drug Administration Food Code for (a) surface cleaning and sanitizing, (b) hand hygiene, (c) exclusion, or (d) restriction of ill employees. Implementation of and compliance with hand hygiene and ill food employee exclusion strategies had the largest impact on the predicted number of highly contaminated food servings and associated consumer illnesses. In scenarios in which gloves were always worn and hand washing compliance was 90%, the model estimated reductions in the number of highly contaminated food servings and ill consumers to 39 and 43% of baseline estimates (i.e., typical practice), respectively. Reductions were smaller when gloves were never worn. Hand washing compliance after using the restroom strongly impacted predicted numbers of highly contaminated servings and consumer illnesses. Ten percent compliance with removing or excluding ill food employees was predicted to increase the number of highly contaminated food servings and ill consumers to 221 and 213% of baseline estimates, respectively. Ninety-four percent compliance with exclusion of ill food employees was predicted to decrease these numbers to 69 and 71% of baseline estimates, respectively. Surface cleaning in food establishments had a relatively small impact on these measures. Restriction of food employees (removed from contact with food and food contact equipment and utensils) was not effective for reducing NoV illness unless this restriction included additional provisions. The results from this study can help risk managers prioritize mitigation strategies and their implementation for controlling the transmission of NoV and subsequent consumer foodborne illness. [ABSTRACT FROM AUTHOR]

Summary: Thirty‐four different ready‐to eat (RTE) vegetable salads were inoculated with a cocktail of three Salmonella enterica strains, and stored under a modified atmosphere for up to 168 h at 4, 7, 12 and 16°C. Eighteen (18) of the salad samples comprised of two or more vegetable ingredients (also referred to as MV RTE salads), and 16 were made up of single vegetable ingredients (SV RTE salads). Generally, the growth potential of inoculated S. enterica varied depending on temperature and type of RTE vegetable salad. The higher temperature was generally more favourable for the growth of S. enterica. Among all 34 salad samples, 5, 11, 18 and 24 salad samples supported the growth of Salmonella at 4, 7, 12 and 16°C, respectively. All salads consisting of multiple vegetable ingredients except two: one comprised of carrots, lettuce and beetroot and another comprised of white cabbage and purple cabbage, supported the growth of Salmonella at high temperatures (either 12 or 16 or both 12 and 16°C). Although the growth of Salmonella was variable in the different types of RTE salads, and growth was generally low at 4°C, Salmonella exhibited consistently minimal growth in some vegetable salads such as those comprised of carrots, lettuce and beetroot, carrots, beetroots, cabbage and cucumber, as well as one comprised of beetroot and corn at all temperature conditions tested. [ABSTRACT FROM AUTHOR]

The microbial quality of two groundwater sources (well and borehole) and associated risks were quantitatively assessed. Water samples from the selected borehole and well were collected over a period of 12 weeks (n = 48). The concentrations of Escherichia coli, faecal coliforms, Salmonella, Shigella, Clostridium, Bifidobacterium and Campylobacter were determined using standard microbiological methods, which involve the use of a membrane filter technique. The water samples were filtered through a 0.45 μm membrane filter using vacuum pump pressure and plated on selective agar for the bacteria under test. The number of colonies of the bacterial growth observed after the incubation period was counted and recorded. The physicochemical properties of the water were determined using standard methods. The risk of Salmonella, Shigella, Clostridium and Campylobacter infections resulting from the ingestion of water from the borehole and well was estimated. The results showed that the levels of enteric bacteria in the borehole were higher than those in the well. The mean levels of E. coli in water from the borehole and well were 3.3 and 1.7 log10 cfu/100 ml, respectively, and exhibited a negative relationship with salinity (r = −0.53). The estimated risks of infection associated with the pathogens in water from the borehole and well were greater than the acceptable risk limit of 10−4 and followed this order Clostridium < Salmonella < Campylobacter < Shigella. The findings of this study suggest recent and continuous faecal contamination of the two groundwater sources, thus exposing the residents relying on the water for drinking to potential risks of gastrointestinal infections. HIGHLIGHTS Levels of E. coli, faecal coliforms, Salmonella, Shigella, Clostridium, Bifidobacterium and Campylobacter in the borehole and well water exceeded 1.5 log.; Temperature and Salmonella had direct relationship while electrical conductivity and Clostridium had inverse relationship in borehole and well water.; The risks of gastrointestinal illness from consumption of water from the borehole were greater than the well.; Estimated risks of infection associated with Salmonella, Shigella, Clostridium and Campylobacter in water samples were greater than acceptable risk limit of 10−4.; The risks of infection for Shigella and Campylobacter were more than 10 times greater than for Salmonella.;

Aim: This study was carried out to determine the microbial health risks associated with surface water commonly used for bathing, drinking, domestic and irrigational activities in Akure, Nigeria. Methods and Results: Water samples were collected from the river from March to June, 2018. The load of enteric bacteria, somatic coliphages and rotavirus in the water samples was determined using culture‐based methods and molecular technique. The physicochemical characteristics of the water samples were determined using standard methods. The risks of rotavirus, Salmonella and Shigella infections resulting from ingestion of the water from the river, were estimated using dose–response model. Redundancy analysis revealed that the levels of E. coli and Salmonella were highly associated with salinity and turbidity. The risks of infection associated with rotavirus (3.3 × 10−3) were higher than those associated with Salmonella (1.3 × 10−4) and Shigella (1.3 × 10−3), and were all above the WHO acceptable risk limit (10−4). Conclusion: Accidental or intentional ingestion of water from the river may pose potential risks of gastrointestinal illness to humans. Significance and Impact of study: Quantitative microbial risk assessment is essential in establishing adequate water management practices that must be strictly followed in order to protect human health. [ABSTRACT FROM AUTHOR]

The decay and distribution of bacterial pathogens in water is an important information for the health risk assessment to guide water safety management, and suspended algae might affect bacterial pathogens in water. This study established microcosms to investigate the effects of algae-related factors on the representative indicators and opportunistic pathogen species in water. We found that suspended algae increased the persistence of targeted species by 1-2 orders of magnitude of concentrations compared to microcosms without algae; and the effect of algae on microbial survival was affected by water nutrient levels (i.e., carbon, nitrogen and phosphorus), as the increased microbial persistence were correlated to the increased algae concentrations with more nutrient supplies. Moreover, decay and distribution profiles of representative species were determined. The three opportunistic pathogen species (Pseudomonas aeruginosa, Aeromonas hydrophila and Staphylococcus aureus) showed lower decay rates (0.82–0.98/day, 0.76–0.98/day, 0.63–0.87/day) largely affected by algae-related factors, while the enteric species (Escherichia coli and Enterococcus faecalis) had higher decay rates (0.94–1.31/day, 0.89–1.21/day) with little association with algae, indicating the propensity for attachment to algae is an important parameter in microbial fate. Together results suggest suspended algae played an evident role in the decay and distribution of bacterial pathogens, providing important implications regarding microbial safety in recreational water. [Display omitted] [ABSTRACT FROM AUTHOR]

Campylobacter spp continues to remain a critical bacterial pathogen of public health interest. They are responsible for approximately 500 million cases of gastroenteritis per year worldwide. Infection occurs through the consumption of contaminated food and water. To effectively monitor the outbreak of campylobacteriosis, microbial risk assessment and source tracking are crucial epidemiological strategies. Various methods have been proposed for microbial source tracking and risk assessment, most of which rely on conventional microbiological techniques such as detecting fecal indicator organisms and other novel microbial source tracking methods, including library-dependent microbial source tracking and library-independent source tracking approaches. However, both the traditional and novel methods have their setbacks. For example, while the conventional techniques are associated with a poor correlation between indicator organism and pathogen presence, on the other hand, it is impractical to interpret qPCR-generated markers to establish the exact human health risks even though it can give information regarding the potential source and relative human risk. Therefore, this article provides up-to-date information on campylobacteriosis and various approaches for source attribution and risk assessment of bacterial pathogens, including the use of next-generation sequencing approaches such as shotgun metagenomics, which effectively answer the questions of what potential pathogens are there and in what quantities.

Human norovirus (NoV) is the leading cause of foodborne illness in the United States and Canada. Bivalve molluscan shellfish is one commodity commonly identified as being a vector of NoV. Bivalve molluscan shellfish are grown in waters that may be affected by contamination events, tend to bioaccumulate viruses, and are frequently eaten raw. In an effort to better assess the elements that contribute to potential risk of NoV infection and illness from consumption of bivalve molluscan shellfish, the U.S. Department of Health and Human Services/Food and Drug Administration (FDA), Health Canada (HC), the Canadian Food Inspection Agency (CFIA), and Environment and Climate Change Canada (ECCC) collaborated to conduct a quantitative risk assessment for NoV in bivalve molluscan shellfish, notably oysters. This study describes the model and scenarios developed and results obtained to assess the risk of NoV infection and illness from consumption of raw oysters harvested from a quasi‐steady‐state situation. Among the many factors that influence the risk of NoV illness for raw oyster consumers, the concentrations of NoV in the influent (raw, untreated) and effluent (treated) of wastewater treatment plants (WWTP) were identified to be the most important. Thus, mitigation and control strategies that limit the influence from human waste (WWTP outfalls) in oyster growing areas have a major influence on the risk of illness from consumption of those oysters. [ABSTRACT FROM AUTHOR]

Owing to convenience, ease of preparation, and price, the consumption of commercial kimchi is gradually rising in South Korea. Here, we estimated the risk level posed by pathogenic Escherichia coli in commercial kimchi products using the quantitative microbial risk assessment (QMRA) approach to develop measures for preventing potential foodborne outbreaks from kimchi consumption. We collected 610 samples of commercial kimchi products produced in Korea, 267 kimchi samples from foreign countries imported to Korea, and 187 raw materials used in kimchi preparation, and analyzed them for contamination with pathogenic E. coli. A Predictive model was developed to observe the survival characteristics of pathogenic E. coli. A dose–response model was selected, and the risk level was estimated using @RISK software. Although a prior epidemiological study indicated the frequent occurrence of foodborne outbreaks arising from contaminated kimchi products consumed in food service facilities, we found a low probability of foodborne illness caused by pathogenic E. coli in commercial kimchi products. [ABSTRACT FROM AUTHOR]

Fresh vegetables are prone to foodborne pathogen infection due to improper cultivation methods and poor post-harvest handling practices. This paper describes the prevalence of foodborne pathogens in three vegetables (tomato, brinjal, and lablab) cultivated by small-scale producers (SSP) of India. We assessed the possible entry of pathogens into the vegetable production chain. Samples from soil, manure, irrigation water, harvesting bins, and workers' hands were assessed as sources of possible pathogen entry. In addition, further sampling was done to determine prevalence of these pathogens in the produce from the agricultural fields and markets. Total plate counts, yeast and mold count, total coliforms like general microbial indices, and possible foodborne pathogens like Salmonella , Escherichia coli O157, Staphylococcus aureus , Pseudomonas aeruginosa , and norovirus were assessed in all the samples by standard microbiological, biochemical, and molecular methods. The results revealed that among the three vegetables we studied, brinjal had the highest load of general microbial indicators. Moreover, the total coliforms count of market vegetables was higher than that of on-farm vegetables, indicating poor hygiene in post-harvest operations. The pathogen Pseudomonas aeruginosa was found in the market tomatoes (0.35 log 10 cfu/g), and E. coli was detected in the market samples of brinjal (2.98–3.89 log 10 cfu/g) and lablab (0.59–2.21 log 10 cfu/g), thereby revealing fecal cross-contamination during pre or post-harvest operations. None of the vegetable samples were contaminated with E. coli O157:H7, Staphylococcus aureus , Salmonella sp., and norovirus. However, the microbiological source tracking of primary production farms showed that E. coli O157:H7 was present in manure (9/27), soil (6/27), harvest bins (6/27), and irrigation water samples (3/27) of SSP farms. In addition, soil (33%), manure (11%), and harvest bins (11%) had Pseudomonas aeruginosa. In conclusion, our study suggests that adequate knowledge of good agricultural practices for small-scale producers to cultivate microbiologically safe vegetable production and proper handling strategies for vegetable vendors is crucial to mitigate foodborne pathogen outbreaks through fresh vegetables. • The work delineates food safety issues of fresh vegetables of small-scale producers. • Field and market samples of tomato, brinjal and lablab had high microbial indices. • Pseudomonas aeruginosa and Escherichia coli found in fresh produces. • Manure, soil, irrigation water, and harvest bin are sources of contamination. • Good agricultural practices for microbial safe vegetable production identified. [ABSTRACT FROM AUTHOR]

This study proposes a modified methodology for semi-quantitative microbial risk assessment (SQMRA) based on the risk matrix presented in the World Health Organization (WHO) Sanitation Safety Planning manual adding the variable ranking for probability of infection in the estimations of risk scores, which composes the risk matrix. The approach is applied to cases where quantitative microbial risk assessment (QMRA) studies are hindered by the lack of information regarding pathogens in the (waste)water, collected as a set of primary data. The methodology is fully described and its application is demonstrated by comparing the microbial risk to which individuals are exposed within a residence in different scenarios of direct or indirect exposure to wastewater. Three current scenarios and one proposed scenario, with four sub-scenarios, focused on the use of a decentralized treatment system and greywater reuse in a single-family residence. Scenarios were selected for application of the SQMRA to elucidate if solutions considering source separation and reuse would bring more health-related risks, or attenuate the existing ones related to the conventional onsite wastewater treatment and soil disposal. None of the studied alternatives achieved risk score above 160 (very high). Considering the average score of each alternative by exposed group, the current scenarios, representing low-cost, informal solutions, posed the highest risks for children. All proposed reuse types reduced the risks from high to medium (score 43.9) for children and from medium to low (score 22.2) for adults. The adapted approach was demonstrated to be a useful tool, aiding the decision-making process and clarifying uncertainties raised when source separation and household reuse are proposed.

The identification of appropriately conservative statistical distributions is needed to predict microbial peak events in drinking water sources explicitly. In this study, Poisson and mixed Poisson distributions with different upper tail behaviors were used for modeling source water Cryptosporidium and Giardia data from 30 drinking water treatment plants. Small differences (<0.5‐log) were found between the "best" estimates of the mean Cryptosporidium and Giardia concentrations with the Poisson–gamma and Poisson–log‐normal models. However, the upper bound of the 95% credibility interval on the mean Cryptosporidium concentrations of the Poisson–log‐normal model was considerably higher (>0.5‐log) than that of the Poisson–gamma model at four sites. The improper choice of a model may, therefore, mislead the assessment of treatment requirements and health risks associated with the water supply. Discrimination between models using the marginal deviance information criterion (mDIC) was unachievable because differences in upper tail behaviors were not well characterized with available data sets (n<30). Therefore, the gamma and the log‐normal distributions fit the data equally well but may predict different risk estimates when they are used as an input distribution in an exposure assessment. The collection of event‐based monitoring data and the modeling of larger routine monitoring data sets are recommended to identify appropriately conservative distributions to predict microbial peak events. [ABSTRACT FROM AUTHOR]

In the U.S., spray irrigation is the most common method used in agriculture and supplementing with animal wastewater has the potential to reduce water demands. However, this could expose individuals to respiratory pathogens such as Legionella pneumophila and nontuberculosis Mycobacteria (NTM). Disinfection with methods like anaerobic digestion is an option but can increase concentrations of cytotoxic ammonia (personal communication). Our study aimed to model the annual risks of infection from these bacterial pathogens and the air concentrations of ammonia and determine if anaerobically digesting this wastewater is a safe option. Air dispersion modeling, conducted in AERMOD, generated air concentrations of water during the irrigation season (May–September) for the years 2013–2018. These values fed into the quantitative microbial risk assessments for the bacteria and allowed calculation of ammonia air concentrations. The outputs of these models were compared to the safety thresholds of 10−4 infections/year and 0.5 mg/m3, respectively, to determine their potential for negative health outcomes. It was determined that infection from NTM was not a concern for individuals near active spray irrigators, but that infection with L. pneumophila could be a concern, with a maximum predicted annual risk of infection of 3.5 × 10−3 infections/year and 25.2% of parameter combinations exceeding the established threshold. Ammonia posed a minor risk, with 1.5% of parameter combinations surpassing the risk threshold of 0.5 mg/m3. These findings suggest that animal wastewater should be anaerobically digested prior to use in irrigation to remove harmful pathogens. [ABSTRACT FROM AUTHOR]

The microbial quality of two groundwater sources (well and borehole) and associated risks were quantitatively assessed. Water samples from the selected borehole and well were collected over a period of 12 weeks (n=48). The concentrations of Escherichia coli, faecal coliforms, Salmonella, Shigella, Clostridium, Bifidobacterium and Campylobacter were determined using standard microbiological methods, which involve the use of a membrane filter technique. The water samples were filtered through a 0.45 µm membrane filter using vacuum pump pressure and plated on selective agar for the bacteria under test. The number of colonies of the bacterial growth observed after the incubation period was counted and recorded. The physicochemical properties of the water were determined using standard methods. The risk of Salmonella, Shigella, Clostridium and Campylobacter infections resulting from the ingestion of water from the borehole and well was estimated. The results showed that the levels of enteric bacteria in the borehole were higher than those in the well. The mean levels of E. coli in water fromthe borehole and well were 3.3 and 1.7 log10 cfu/100 ml, respectively, and exhibited a negative relationship with salinity (r=0.53). The estimated risks of infection associated with the pathogens in water from the borehole and well were greater than the acceptable risk limit of 10-4 and followed this order Clostridium

Microbial risk assessment in food safety is a valuable tool to reduce the risks of infection by pathogens. The dose-response relation is aimed to establish the relationship between the dose of a pathogen that populations are exposed to and the probability of the adverse health effect by the pathogen. Among many dose-response models ever proposed, the exponential and beta-Poisson models have been internationally applied, but the decision on which model is selected between them solely depends on the goodness of fit to specific data sets. On the other hands, the log-logistic model, one of the alternative models, has been little studied on the dose-response relation. In the present study, thus, the application of the log-logistic model to dose-response relation was studied with hypothetical and experimental data sets of infection (or death), comparing to the above two models. Here the experimental data sets were for pathogenic organisms such as pathogenic Escherichia coli, Listeria monocytogenes, and Cryptosporidium pavrum. Consequently, this model successfully fit to those data sets in comparison to the two models. These results suggested that log-logistic model would have the potential to apply to the dose-response relation, similar to the exponential and beta-Poisson models. [ABSTRACT FROM AUTHOR]

As the use of hydrogen gas (H 2) as a renewable energy carrier experiences a major boost, one of the key challenges for a constant supply is safe and cost-efficient storage of surplus H 2 to bridge periods with low energy demand. For this purpose, underground gas storage (UGS) in salt caverns, deep aquifers and oil-/gas reservoirs has been proposed, which are environments with potentially high microbial abundance and activity. Subsurface microorganisms can use H 2 in their metabolism and thus may lead to a variety of undesired side effects such as H 2 loss, H 2 S formation, methane formation, acid formation, clogging and corrosion. In this review, we summarize the current knowledge and methodologies on microbial related risks related to H 2 UGS, including basic research on subsurface microbiology, results from field trials, and experience from other industries including oil & gas. For safe underground storage of H 2 gas we recommend to analyze the relevant microbiological and geochemical characteristics of each site to be able to predict the most suitable storage strategy and establish a good monitoring and mitigation approach to follow and counter potential microbial side effects. • Microorganisms can be present in all locations intended for H 2 underground storage. • Microbial-associated risks include H 2 loss, souring, corrosion and clogging. • Microbial activity is field specific and should be assessed prior to implementation. • More experience from field-specific tests is needed to predict microbial influence. [ABSTRACT FROM AUTHOR]

This study developed dose response models for determining the probability of eye or central nervous system infections from previously conducted studies using different strains of Acanthamoeba spp. The data were a result of animal experiments using mice and rats exposed corneally and intranasally to the pathogens. The corneal inoculations of Acanthamoeba isolate Ac 118 included varied amounts of Corynebacterium xerosis and were best fit by the exponential model. Virulence increased with higher levels of C. xerosis. The Acanthamoeba culbertsoni intranasal study with death as an endpoint of response was best fit by the beta‐Poisson model. The HN‐3 strain of A. castellanii was studied with an intranasal exposure and three different endpoints of response. For all three studies, the exponential model was the best fit. A model based on pooling data sets of the intranasal exposure and death endpoint resulted in an LD50 of 19,357 amebae. The dose response models developed in this study are an important step towards characterizing the risk associated with free‐living amoeba like Acanthamoeba in drinking water distribution systems. Understanding the human health risk posed by free‐living amoeba will allow for quantitative microbial risk assessments that support building design decisions to minimize opportunities for pathogen growth and survival. [ABSTRACT FROM AUTHOR]

Urban rainwater samples, collected in various districts of Kraków during the period from the spring of 2019 to the winter of 2020, were investigated, and relevant risk implications were assessed. The contents of 31 components were determined, including: bacteria, fungi, pH, EC, Cl-, N-NO3, P-PO4, SO42-, SiO2, K, Mg, Ag, Al, Ba, Ca, Cu, K, Mg, Mo, Na, Pb, Sb, and Zn. The highest contents of the investigated elements were determined in the industrial (eastern) part of Kraków. The values of toxicity potential were <1, indicating a lack of ecological risk. The value of contamination degree indicated moderate rainwater contamination in all analyzed elements (Cdeg = 9.44). The total non-carcinogenic risk values, in both adults (hazard quotient (HQ) = 1.38) and children (HQ = 2.54), exceeded the acceptable level of one. Regarding individual elements in dermal contact, the acceptable level of 1 × 10−6 was exceeded in Pb (adults carcinogenic risk (CR) = 4.87 × 10−5, children CR = 2.23 × 10−5). The contents of the analyzed chemical compounds did not exceed the permissible levels adopted for drinking water; however, rainwater was significantly contaminated with respect to its microbiological parameters. Rainwater was suitable for non-potable use. [ABSTRACT FROM AUTHOR]

This study develops dose–response models for Ebolavirus using previously published data sets from the open literature. Two such articles were identified in which three different species of nonhuman primates were challenged by aerosolized Ebolavirus in order to study pathology and clinical disease progression. Dose groups were combined and pooled across each study in order to facilitate modeling. The endpoint of each experiment was death. The exponential and exact beta‐Poisson models were fit to the data using maximum likelihood estimation. The exact beta‐Poisson was deemed the recommended model because it more closely approximated the probability of response at low doses though both models provided a good fit. Although transmission is generally considered to be dominated by person‐to‐person contact, aerosolization is a possible route of exposure. If possible, this route of exposure could be particularly concerning for persons in occupational roles managing contaminated liquid wastes from patients being treated for Ebola infection and the wastewater community responsible for disinfection. Therefore, this study produces a necessary mathematical relationship between exposure dose and risk of death for the inhalation route of exposure that can support quantitative microbial risk assessment aimed at informing risk mitigation strategies including personal protection policies against occupational exposures. [ABSTRACT FROM AUTHOR]

The aim of this study was to detect, quantify, and assess the risk of infection and illness for Group A Rotavirus (RVA) in the watersheds of the Santa Lucia and Uruguay rivers in Uruguay. Monthly sampling was carried out for one year in six sites in the watershed of the Santa Lucía River and four in the Uruguay River. All the collection sites are used for recreational activities. Viral concentration was performed with the adsorption–elution method, and detection and quantification of RVA was carried out by TaqMan quantitative PCR (qPCR). Quantitative microbial risk assessment was applied to estimate the daily and annual risk of RVA infection, as well as the daily risk of illness considering direct exposure through recreational activity. RVA was detected in 42% (20/48) of the analyzed samples in the Uruguay River and 40% (29/72) in the Santa Lucía River. The virus was present in all the analyzed points in both watersheds. A pattern of seasonality, characterized by a higher detection frequency of the virus during coldest month of the year, was observed in both basins. The mean concentration for RVA was 1.3 × 105 genomic copies/L. The microbiological risk assessment shows that Santa Lucía watershed presented the highest daily risk of infection (6.41E–01) and illness (3.20E–01) estimated for the point downstream of Florida City; meanwhile for Uruguay River, the highest probabilities of infection (6.82E–01) and illness (3.41E–01) were estimated for the collection site for drinking water intake in Salto city. These results suggest that RVA contamination of these important rivers negatively impact on their microbiological quality since they are used for recreation and drinking water intake, demonstrating that the disposal of waste from cities located in their riverside confers a constant threat of infection for the general population, especially for children. [ABSTRACT FROM AUTHOR]

Risk assessments and intervention trials have been used by the U.S. Environmental Protection Agency to estimate drinking water health risks. Seldom are both methods used concurrently. Between 2001 and 2003, illness data from a trial were collected simultaneously with exposure data, providing a unique opportunity to compare direct risk estimates of waterborne disease from the intervention trial with indirect estimates from a risk assessment. Comparing the group with water treatment (active) with that without water treatment (sham), the estimated annual attributable disease rate (cases per 10,000 persons per year) from the trial provided no evidence of a significantly elevated drinking water risk [attributable risk=-365 cases/year, sham minus active; 95% confidence interval (CI) , -2,555 to 1,825]. The predicted mean rate of disease per 10,000 persons per person-year from the risk assessment was 13.9 (2.5, 97.5 percentiles: 1.6, 37.7) assuming 4 log removal due to viral disinfection and 5.5 (2.5, 97.5 percentiles: 1.4, 19.2) assuming 6 log removal. Risk assessments are important under conditions of low risk when estimates are difficult to attain from trials. In particular, this assessment pointed toward the importance of attaining site-specific treatment data and the clear need for a better understanding of viral removal by disinfection. Trials provide direct risk estimates, and the upper confidence limit estimates, even if not statistically significant, are informative about possible upper estimates of likely risk. These differences suggest that conclusions about waterborne disease risk may be strengthened by the joint use of these two approaches. Key words: drinking water, gastrointestinal, intervention trial, microbial risk assessment, waterborne pathogens.

Abstract This Opinion considers the application of whole genome sequencing (WGS) and metagenomics for outbreak investigation, source attribution and risk assessment of food‐borne pathogens. WGS offers the highest level of bacterial strain discrimination for food‐borne outbreak investigation and source‐attribution as well as potential for more precise hazard identification, thereby facilitating more targeted risk assessment and risk management. WGS improves linking of sporadic cases associated with different food products and geographical regions to a point source outbreak and can facilitate epidemiological investigations, allowing also the use of previously sequenced genomes. Source attribution may be favoured by improved identification of transmission pathways, through the integration of spatial‐temporal factors and the detection of multidirectional transmission and pathogen–host interactions. Metagenomics has potential, especially in relation to the detection and characterisation of non‐culturable, difficult‐to‐culture or slow‐growing microorganisms, for tracking of hazard‐related genetic determinants and the dynamic evaluation of the composition and functionality of complex microbial communities. A SWOT analysis is provided on the use of WGS and metagenomics for Salmonella and Shigatoxin‐producing Escherichia coli (STEC) serotyping and the identification of antimicrobial resistance determinants in bacteria. Close agreement between phenotypic and WGS‐based genotyping data has been observed. WGS provides additional information on the nature and localisation of antimicrobial resistance determinants and on their dissemination potential by horizontal gene transfer, as well as on genes relating to virulence and biological fitness. Interoperable data will play a major role in the future use of WGS and metagenomic data. Capacity building based on harmonised, quality controlled operational systems within European laboratories and worldwide is essential for the investigation of cross‐border outbreaks and for the development of international standardised risk assessments of food‐borne microorganisms.

Meat products are one of the categories of food that is increasingly appreciated by consumers. The presence in meat products of psychrotrophs is of particular importance for their quality, safety and freshness. Psychrotrophs can decrease their quality or make them non-edible, either by their pathogenic action or by the degradation and production of toxic metabolites. The aim of the study was to carry out a microbiological risk assessment regarding contamination of some meat products with psychrotrophs. The research material was represented by 36 samples of heat treated meat products: frankfurter, extra baloney and Victoria ham salami, collected between February - May 2019 from a meat processing company, located in Transylvania. All the samples were analyzed for the presence of the main psychrotrophs involved in spoilage processes: Acinetobacter spp., Pseudomonas spp., Moraxella spp., Lactobacillus spp., Aeromonas spp., Yersinia spp., and other bacteria from Enterobacteriaceae family. Psychrotrophic microbial load ranged between 7.0x10² and 5x104 cfu/g, 2x10² cfu/g and 8x10² and 3.2x106 for Victoria ham salami, extra baloney and frankfurters, respectively. In case of frankfurters, the microbial population was represented by: Pseudomonas fluorescens, Pseudomonas putida, Micrococcus spp., lactic acid bacteria, Moraxella lacunata, Ochrabactrum anthropi, and unidentified Gram positive rods. Microbial populations in case of Victoria ham salami were represented by: Pseudomonas fluorescens, Pseudomonas putida, Acinetobacter lwofii, Moraxella lacunata, Staphylococcus spp., Stenotrophomonas maltophilia, Streptococcus spp., and unidentified Gram positive rods. Microbial populations in case of extra baloney were represented by: Pseudomonas fluorescens, Psychrobacter phenylpiruvicus, Micrococcus spp., Staphylococcus spp., Streptococcus spp., and unidentified Gram-positive bacteria. Following the microbiological risk assessment regarding the presence of psychrotrophs in meat products, we conclude that psychotrophic microflora must be monitored permanently, being dependent on the initial loading of the raw material, as well as on the hygiene practices and temperature from storage area. [ABSTRACT FROM AUTHOR]

The control of bacterial reduction is important to maintain food safety during thermal processing. The goal of this study was to illustrate and describe variability in bacterial population behavior during thermal processing as a probability distribution based on individual cell heterogeneity regarding heat resistance. Toward this end, we performed a Monte Carlo simulation via computer, and compared and validated the simulated estimations with observed values. Weibullian fitted parameters were estimated from the kinetic survival data of Bacillus simplex during thermal treatment at 94 °C. The variability in reductions of bacterial sporular populations was illustrated using Monte Carlo simulation based on the Weibull distribution of the parameters. In particular, variabilities in viable spore counts and survival probability of the B. simplex spore population were simulated in various replicates. We also experimentally determined the changes in survival probability and distributions of survival spore counts; notably, these were successfully predicted by the Monte Carlo simulation based on the kinetic parameters. The kinetic parameter-based Monte Carlo simulation could thus successfully illustrate bacterial population behavior variability during thermal processing as a probability distribution. The simulation approach may contribute to improving food quality through risk-based processing designs and enhance risk assessment model accuracy. • Appropriate modeling which can bring minimum processing should be used for keeping food quality. • Prior models for predicting bacterial survival do not describe heterogeneity in survival cell count. • We used a kinetic parameter-based Monte Carlo simulation to model distribution in bacterial counts. • Variability as a probability distribution were derived through 60 replicates experiment. • Simulation may improve food quality and safety via risk-based processing design. [ABSTRACT FROM AUTHOR]

Abstract In recent years, there has been a growing interest on the occurrence of antibiotic-resistant bacteria (ARB) and antibiotic resistant genes (ARGs) in treated and untreated drinking water. ARB and ARGs pose a public health concern when they transfer antibiotic resistance (AR) to human pathogens. However, it is still unclear whether the presence of environmental ARB and ARGs in source water, drinking water treatment plants, and drinking water distribution systems has any significant impact on human exposure to pathogenic ARB. In this review, we critically examine the occurrence of AR in groundwater, surface water, and treated distributed water. This offered a new perspective on the human health threat posed by AR in drinking water and helped in crafting a strategy for monitoring AR effectively. Using existing data on removal of ARB and ARGs in drinking water treatment plants, presence and proliferation of AR in drinking water distribution systems, and mechanisms and pathways of AR transfer in drinking water treatment plants, we conclude that combining UV-irradiation with advanced oxidative processes (such as UV/chlorine, UV/H 2 O 2 , and H 2 O 2 /UV/TiO 2) may enhance the removal of ARB and ARGs, while disinfection may promote horizontal gene transfer from environmental ARB to pathogens. The potential human health risks of AR were determined by examining human exposure to antibiotic resistant human pathogens and re-evaluating waterborne disease outbreaks and their links to environmental AR. We concluded that integrating disease outbreak analysis, human exposure modelling, and clinical data could provide critical information that can be used to estimate the dose-response relationships of pathogenic ARB in drinking water, which is required for accurate risk assessments. Graphical abstract Unlabelled Image Highlights • Pathogenic antibiotic-resistant bacteria (ARB) have been detected in drinking water. • Disinfection may increase the transfer of antibiotic resistant genes (ARGs) to pathogens. • Combining UV-irradiation and advanced oxidation may enhance ARG and ARB removal. • Antibiotic resistance removal strategies in drinking water are critically examined. • Monitoring priority ARB in drinking water is vital for human health risk assessment. [ABSTRACT FROM AUTHOR]

Next‐generation sequencing (NGS) data present an untapped potential to improve microbial risk assessment (MRA) through increased specificity and redefinition of the hazard. Most of the MRA models do not account for differences in survivability and virulence among strains. The potential of machine learning algorithms for predicting the risk/health burden at the population level while inputting large and complex NGS data was explored with Listeria monocytogenes as a case study. Listeria data consisted of a percentage similarity matrix from genome assemblies of 38 and 207 strains of clinical and food origin, respectively. Basic Local Alignment (BLAST) was used to align the assemblies against a database of 136 virulence and stress resistance genes. The outcome variable was frequency of illness, which is the percentage of reported cases associated with each strain. These frequency data were discretized into seven ordinal outcome categories and used for supervised machine learning and model selection from five ensemble algorithms. There was no significant difference in accuracy between the models, and support vector machine with linear kernel was chosen for further inference (accuracy of 89% [95% CI: 68%, 97%]). The virulence genes FAM002725, FAM002728, FAM002729, InlF, InlJ, Inlk, IisY, IisD, IisX, IisH, IisB, lmo2026, and FAM003296 were important predictors of higher frequency of illness. InlF was uniquely truncated in the sequence type 121 strains. Most important risk predictor genes occurred at highest prevalence among strains from ready‐to‐eat, dairy, and composite foods. We foresee that the findings and approaches described offer the potential for rethinking the current approaches in MRA. [ABSTRACT FROM AUTHOR]

Abstract Coliphage have been proposed as indicators of fecal contamination in recreational waters because they better reflect the persistence of pathogenic viruses in the environment and through wastewater treatment than traditional fecal indicator bacteria. Herein, we conducted a systematic literature search of peer-reviewed publications to identify coliphage density data (somatic and male-specific, or MSC) in raw wastewater and ambient waters. The literature review inclusion criteria included scope, study quality, and data availability. A non-parametric two-stage bootstrap analysis was used to estimate the coliphage distributions in raw wastewater and account for geographic region and season. Additionally, two statistical methodologies were explored for developing coliphage density distributions in ambient waters, to account for the nondetects in the datasets. In raw wastewater, the analysis resulted in seasonal density distributions of somatic coliphage (SC) (mean 6.5 log 10 plaque forming units (PFU)/L; 95% confidence interval (CI): 6.2–6.8) and MSC (mean 5.9 log 10 PFU/L; 95% CI: 5.5–6.1). In ambient waters, 49% of MSC samples were nondetects, compared with less than 5% for SC. Overall distributional estimates of ambient densities of coliphage were statistically higher for SC than for MSC (mean 3.4 and 1.0 log 10 PFU/L, respectively). Distributions of coliphage in raw wastewater and ambient water will be useful for future microbial risk assessments. Highlights • Systematic review conducted of coliphage levels in raw wastewater and ambient waters. • Studies conducted in 19 countries provided 2124 individual coliphage data points. • Somatic coliphage outnumber MSC densities in raw wastewater and in ambient waters. • Overall coliphage densities were significantly higher in colder seasons. • Coliphage distributions will inform quantitative microbial risk assessment efforts. [ABSTRACT FROM AUTHOR]