Download or read book Evaluation of a Novel Microbial Source Tracking Method for the Identification of Fecal Contamination in the Fresh Produce Production Environment written by Kruti Dilip Ravaliya and published by . This book was released on 2013 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbial Source Tracking written by Jorge W. Santo Domingo and published by Emerging Issues in Food Safety. This book was released on 2007 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents a state-of-the-art review of the current technology and applications being utilized to identify sources of fecal contamination in waterways. - Serves as a useful reference for researchers in the food industry, especially scientists investigating etiological agents responsible for food contamination. - Provides background information on MST methods and the assumptions and limitations associated with their use. - Covers a broad range of topics related to MST, including environmental monitoring, public health and national security, population biology, and microbial ecology. - Offers valuable insights into future research directions and technology developments.

Download or read book Quantitative Microbial Source Tracking Using Bacteroidales as Fecal Source Identifier written by Dan Wang and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fecal pollution is a primary concern for recreational water bodies in US. The current water quality criteria are based on the cultivability of fecal indicator bacteria like E. coli and enterococci. These indicators are ubiquitous in the digestive tract of warm-blooded animals but are also known to persist and even multiply in the environment given favorable conditions. Hence their presence does not provide information on the sources of fecal contamination. In the past decade microbial source tracking (MST), the research area that uses host-specific microbes to identify the sources of fecal pollution, has undergone rapid development. A brief historical overview is provided in Chapter 1 and state-of-the art methods are presented and analyzed in Chapter 2. Quantitative PCR (qPCR)-based MST methods have been widely used for two reasons: they can detect both cultivable and uncultivable microbes and their process time is shorter comparing to other MST methods. The results from qPCR reactions need to be further processed to achieve quantitative MST because of analytical complications caused by the environmental water matrix. Two of the most important aspects will be addressed in Chapters 3 and 4. Chapter 3 attempts to solve the imperfect specificity and sensitivity of the qPCR assays with a statistical procedure that evaluates the impact of false positive/negative information. Chapter 4 addresses the inaccuracy in qPCR data analysis caused by the high noise signal and inconsistent amplification efficiency frequently seen in environmental water samples. Corrective measures are proposed to improve the accuracy of estimated DNA concentrations.

Download or read book Assessment of Bacterial Source Tracking Using Rep PCR and Callification Method for Identification of Fecal Contamination written by John M. Albert and published by . This book was released on 2002 with total page 145 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Microbial Source Tracking to Identify Fecal Contamination Sources in Sag Harbor on Long Island New York written by Tristen N. Tagliaferri and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbial Source Tracking written by and published by . This book was released on 2008 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Microbial Source Tracking to Identify Fecal Contamination Sources in Patchogue and Bellport Bays on Long Island New York written by Tristen N. Tagliaferri and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Using Microbial Source Tracking to Identify Fecal Contamination Sources in an Embayment in Hempstead Harbor on Long Island New York written by Tristen N. Tagliaferri and published by . This book was released on 2021 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Novel Experimental Designs and Mathematical Models to Study Fecal Indicator Bacteria Persistence in Surface Water written by Lauren Elisabeth Brooks and published by . This book was released on 2016 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: High counts of fecal indicators, used to signal the potential presence of pathogens associated with untreated waste, result in the classification of water bodies throughout the United States as impaired. Nonpoint sources of unknown origin that contribute to fecal contamination make management of impaired waters challenging, as they are difficult to distinguish, and it is thus problematic to correctly target mitigation efforts. Genetic markers used for microbial source tracking provide valuable information by identifying hosts that contribute to fecal loading, but do not provide a method to detect specific sources that contribute to impairment of water bodies. Spatial modelling efforts have been proposed for use in conjunction with fecal indicators and host-specific markers, but have been limited by a lack of adequate modeling for the complex processes that cause indicator decay. We conducted a quantitative meta-analysis of published decay rate estimates for several common indicators using Bayesian hierarchical linear modeling. The meta-analysis revealed a large amount of variability across studies, including in findings of significance for environmental parameters that impact persistence. Additionally, the meta-analysis revealed gaps in the data for genetic markers, while sufficient data was available for the traditional, culture-based indicators. We determined that temperature was consistently a significant predictor of decay rate estimates for all indicators, but light was only significant for culture-based indicators. We provided synthesized estimates for the selected indicators, but recommend caution in their application for source tracking or quantitative risk assessment due to high variability in parameter estimates and uncertainty in their extension beyond artificial settings. We compared the decay profiles for general fecal indicators and markers associated with ruminants and cattle. We determined best fitting non-linear models based on information theory and used global model fitting to test for differences in curves for each combination of indicators. Additionally, we investigated the potential of the selected ruminant markers for use in source allocation using the ratio method, based on difference in the observed decay profiles. We found statistical differences between the decay curves of E. coli and all but one genetic marker. The differences across decay profiles suggest caution is necessary when interpreting microbial source tracking results using these markers, as differential decay may result in different findings depending on the marker selected. We assessed the possibility of studying fecal indicator persistence in a truly open system using simulations. Using the concept of a Continuous-flow Stirred Tank Reactor, we developed an adjustment that can be applied to observed fecal indicator concentrations from an open system so that only loss due to decay is considered. The simulations showed that this adjustment is an effective way to account for loss for this system. However, implementation of this system has limitations, as the removal of indicators through flow contributes to a decreased period of observations before a given indicator drops below the limits of detection. We used the results from the simulations to design and implement an open system for decay studies. We compared decay profiles generated for several indicators from two open systems with different flow rates to those of closed and partially closed systems that have been previously used in decay studies. We used the results of these comparisons to investigate the effects of artificial settings used to study decay for fecal indicators. We found that the systems used in decay studies significantly influence the results for all indicators used.

Download or read book Human Virology in Latin America written by Juan Ernesto Ludert and published by Springer. This book was released on 2017-07-19 with total page 469 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a compilation of some of the most remarkable contributions made by scientists currently working in Latin America to the understanding of virus biology, the pathogenesis of virus-related diseases, virus epidemiology, vaccine trials and antivirals development. In addition to recognizing the many fine virologists working in Latin America, Human Virology in Latin America also discusses both the state-of-the-art research and the current challenges that are being faced in the region, in hopes of inspiring young scientists worldwide to become eminent virologists.

Download or read book Microbial Source Tracking MST written by and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microbial Source Tracking of Bacteroides to Identify Human and Bovine Fecal Loading in McDaniel Lake written by Kalie M. Somerville and published by . This book was released on 2015 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fecal waste enters waterways from run-off during rain events, and is especially high in agricultural areas due to manure application and livestock. Increased fecal waste may also be due to direct human influence. This fecal loading may lead to eutrophication and poses health hazards to humans. By determining the source of fecal pollution, practices can be implemented to reduce the amount entering waterways. Bacteroides sp. have previously shown high host specificity allows for species-specific identification of fecal sources. Using quantitative real-time PCR (qPCR), human-associated and bovine-associated Bacteroides DNA, as well as total Bacteroides DNA can be quantified and concentrations of fecal contamination in lakes and streams can be determined. Amplification control plasmids containing 16S rDNA from human and bovine specific Bacteroides were constructed using TOPO cloning. Samples taken from McDaniel Lake in Springfield, MO Dec. 2013-Dec. 2014 were analyzed with end-point PCR and fecal concentrations determined with qPCR. Quantitative PCR showed increased sensitivity and selectivity, compared to end-point PCR. While Bacteroides sp. were present in all samples, less than 1% of total Bacteroides in McDaniel Lake was identified as human- or bovine-associated Bacteroides for the sample period. The use of qPCR is shown to be a valuable tool in identifying and quantifying fecal inputs and monitoring nonpoint source pollution as urban and agricultural areas encroach on natural systems.

Download or read book Workshop on Microbial Source Tracking in Water written by Paul A. Rochelle and published by IWA Publishing. This book was released on 2006-07-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The drinking water and wastewater industries are interested in developing a better understanding of sources of fecal contamination. Microbial source tracking (MST) offers the potential to apportion the contribution of various animal groups to this contamination. However, while there are many methods available there is no clear indication as to the most appropriate approach. There has been little systematic comparison of methods and only a few blind trials, and issues of reproducibility, accuracy, sensitivity, specificity, resolution, and robustness need to be addressed. There is confusion among potential end-users and some disagreement among scientists. Therefore, due to the uncertainty surrounding the most appropriate tools and applications of MST, a workshop of 45 experts representing water and wastewater utilities, academia, state and federal government agencies, medical institutions, and private laboratories was convened in San Antonio, Texas over a three-day period (February 16 – 18, 2005). The overall objective of the workshop was to identify the knowledge gaps and research needs for application of MST technologies by the wastewater and drinking water industries.

Download or read book The Use of Drugs in Food Animals written by National Research Council and published by National Academies Press. This book was released on 1999-01-12 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of drugs in food animal production has resulted in benefits throughout the food industry; however, their use has also raised public health safety concerns. The Use of Drugs in Food Animals provides an overview of why and how drugs are used in the major food-producing animal industriesâ€"poultry, dairy, beef, swine, and aquaculture. The volume discusses the prevalence of human pathogens in foods of animal origin. It also addresses the transfer of resistance in animal microbes to human pathogens and the resulting risk of human disease. The committee offers analysis and insight into these areas: Monitoring of drug residues. The book provides a brief overview of how the FDA and USDA monitor drug residues in foods of animal origin and describes quality assurance programs initiated by the poultry, dairy, beef, and swine industries. Antibiotic resistance. The committee reports what is known about this controversial problem and its potential effect on human health. The volume also looks at how drug use may be minimized with new approaches in genetics, nutrition, and animal management.

Download or read book Understanding Sources and Determinants of Fecal Contamination of Water Hands Food and Household Floors in Low income Countries written by Angela R. Harris and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Diarrheal disease is one of the leading causes of death in children under 5 years, causing approximately 0.8 million annual deaths globally. Almost 50% of these deaths come from Africa and 30% from Southeast Asia, where diarrheal diseases account for 11% of all child-deaths. Diarrheal pathogens are transmitted primarily through a fecal-oral route, with illness being predominately caused by ingestion of the pathogens from water, food, or hands, which have been contaminated by inadequate sanitation and hygiene. Additionally, contaminated surfaces can serve as a reservoir for fecal pathogens within the household. Fecal pathogens can come from both human and non-human, animal sources. In order to develop effective strategies to protect human health, understanding the levels of contamination on different surfaces or media in household environments is important. Furthermore, it is important to understand how the different vehicles of transmission (i.e., water, hands, food, floors) become contaminated; that is, identifying the sources of the fecal contamination and the behaviors and practices associated with contamination. In Tanzania, a structured observation study was conducted coupled with intensive sampling to measure levels of fecal contamination in drinking water to determine mechanisms for post-supply contamination of drinking water. The storage container and extraction methods were found to introduce fecal indicator bacteria in the stored water. Also, stored water quality and female caregiver hand contamination data from 1200 households in Tanzania was collected. Three different data-driven statistical methods, ordinary least squares regression, logistic regression, and classification tree, were used to explain variation of levels of contamination in stored water and female caregiver hands. Our study results highlight the complexity of predicting stored water quality and hand contamination. Despite using three different analytical techniques for modeling stored water quality and hand contamination, contamination was incorrectly predicted for a large fraction of samples. In rural Kenya and rural and urban Bangladesh, a validation of molecular microbial source tracking assays was conducted to determine if these techniques could be used on environmental samples to identify the human and animal sources of contamination. The human-specific assays performed well in the rural sites but the assays were not sensitive or specific in Dhaka, Bangladesh. The ruminant assay, BacR, performed well across all study sites, exhibiting high sensitivity and specificity. The Avian GFD assay was sensitive and specific in the rural sites, but was not specific in Dhaka, Bangladesh. Evidence of ruminant fecal contamination was found on household floors and child hand rinse samples in Dhaka, Bangladesh. Therefore, even in dense urban slums, the transmission pathway of ruminant feces should be considered in order to reduce contamination in household environments. Researchers should consider that non-host specific fecal indicator bacteria detected in environmental samples in these settings could be of animal origin. Finally, levels of fecal contamination on produce from neighborhood distribution markets and wholesale markets in Dhaka, Bangladesh were assessed. Fecal contamination, as measured by E. coli and enterococci, was found on carrots, eggplants, lal shak leaves, and tomatoes. Items from the neighborhood markets had higher levels of general fecal indicators than items from wholesale markets. The results of the study suggest that market-level mechanisms, such a vendor handling practices, could be influencing produce contamination. Evidence of fecal contamination from ruminants was also found on produce items, both from the wholesale and neighborhood distribution markets. Therefore, not only the pathway of human fecal contamination, but also that of animals, should be considered when developing interventions to reduce contamination on produce. This dissertation assesses the levels of fecal contamination in stored drinking water and on female caregiver hands in Tanzania, and of household floors, child hands, and vegetable produce in Bangladesh. The use of different models to explain variation of fecal contamination in water and on hands was explored. In addition, the dissertation evaluates the use of molecular techniques to identify the fecal source of contamination found in environmental samples in Kenya and Bangladesh. Data-driven understanding of the environmental conditions that are associated with fecal contamination will help inform studies to develop interventions and policies to protect human health. This dissertation work provides insight to the sources and correlates of fecal contamination of stored drinking water, female caregiver and child hands, household floors, and vegetable produce in low income countries. It also critically assesses methods for measuring and explaining fecal contamination in these setting.

Download or read book Technique for Detecting Sources of Human Pollution in Water Using an Enterococcus Biomarker written by Tracie Michelle Jenkins and published by . This book was released on 2005 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development Validation and Application of Molecular Microbial Source Tracking Methods to be Used in the Assessment of Environmental Waterways written by Richard Charles Sawdey and published by . This book was released on 2009 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: