When well water becomes contaminated to the extent that is does not meet EPA drinking water quality standards, it is considered unsafe for consumption. Nitrate and total coliform bacteria are both health contaminants and are both regulated in public water systems. A nitrate concentration of 10 mg/L or higher is considered unsafe, as is the presence of total coliform bacteria. Well degradation, inadequate well construction, and aquifer contamination can all result in contamination of well water. Factors such as well type, well age, well depth, treatment devices, population density, household plumbing pipe materials, and nearby pollution sources may affect household water quality. The specific objective of this study was to determine which factors influence nitrate levels and total coliform presence/absence of household well water. If possible, these influencing factors would be used to develop a relationship that would allow household residents to predict the nitrate level and total coliform presence/absence of their well water. As a result, a means of predicting the contamination risk to a specific well water supply under a given set of conditions, in addition to increasing awareness, could provide the homeowner with a rationale for further investigating the possibility of contamination. Existing data from the Virginia Cooperative Extension Household Water Quality Testing and Information Program were assembled for analyses in this project. The data consisted of 9,697 private household water supplies sampled from 1989-1999 in 65 Virginia counties. Initially, the entire state of Virginia was analyzed, followed by the five physiographic provinces of Virginia: the Blue Ridge, Coastal Plain, Cumberland Plateau, Ridge & Valley, and Piedmont. Ultimately, Louisa County was investigated to evaluate the possibility that better models could be developed using smaller land areas and, consequently, less geological variation. Least squares regression, both parametrically and non-parametrically, was used to determine the influence of various factors on nitrate levels. Similarly, logistic regression was used to determine the influence of the same parameters on nitrate categories, presence/absence of total coliform, and risk categories. Using stepwise model-building techniques, based primarily on statistical significance (p-values) and partial coefficient of determination (partial-R2), first and second-order linear models were evaluated. The best-fitting model only explained 58.5% of the variation in nitrate and none of the models fit well enough to be used for prediction purposes. However, the models did identify which factors were, in a statistical sense, significantly related to nitrate levels and total coliform presence/absence and quantified the strength of these relationships in terms of the percent of variation explained. / Master of Science

Yes / Water scarcity is a huge problem in Africa, and hence rainwater becomes a crucial water source for fulfilling basic human needs. However, less attention has been given by African countries to the effectiveness of common rainwater treatments to ensure the population's health. This study investigates the impact of different household treatment techniques (HHTTs), i.e. treatments by chlorine, boiling, alum, and a combination of alum and chlorine, on its storage system using a case study at the Ikorodu area of Lagos state, which is a rural area in Nigeria. The first-flush quality has been particularly studied here, where the microbial reduction through its practice has been examined from five different roofs. One of the investigated roofs was from a residential building, and four were constructed for the purpose of this study. In this study, the physical parameters (i.e. total suspended solids and turbidity) and the microbial parameters (i.e. total coliform and Escherichia coli) of the collected rainwater have been investigated. From the results, it has been observed that: (1) the water quality at the free phase zone is better than that at the tank's bottom; (2) the combination of chlorine and alum gives the best rainwater quality after comparing the application of different HHTTs; and (3) a reduction of about 40% from the original contaminant load occurs in every 1 mm diversion. / Hidden Histories of Environmental Science Grant Project (at Seed-grant Stage), funded by the Natural Environment Research Council (NERC) and Arts and Humanities Research Council (AHRC), part of UK Research and Innovation (UKRI)

Orientador: Luiz Francisco Prata / Banca: Gener Tadeu Pereira / Banca: Anna Monteiro Correia Lima Ribeiro / Resumo: Este trabalho teve por finalidade avaliar o resultado dos controles ambientais e operacionais, rotineiros e derivados do plano APPCC - Análise de Perigos e Pontos Críticos de Controle, aplicados ao abate de bovinos, e da pesquisa de microrganismos potencialmente patogênicos (Escherichia coli O157:H7, Salmonella enterica e Listeria monocytogenes). Com duração de um ano, a pesquisa foi desenvolvida em abatedouro-frigorífico habilitado à exportação localizado no Estado de São Paulo, Brasil. Foram analisadas 411 amostras ambientais para pesquisa de Listeria spp., 1.192 amostras de superfície de contato para a Contagem Bacteriana Total (CBT), 200, 100, 775, 264 e 100 amostras de superfície de carcaça para CBT, Coliformes totais, E. coli, Salmonella spp. e E. coli O157:H7, respectivamente, além de 256 amostras de recortes cárneos para a pesquisa de E. coli O157:H7. Os resultados evidenciaram condição higiênica aceitável para 51,1% das amostras ambientais de CBT, com 62,9% de amostras não aceitáveis no setor de abate. Um valor elevado de amostras (15,1%) foi positivo para Listeria spp. e para Listeria monocytogenes (4,6%). Observou-se que 89,6%, 2,8% e 7,6% das amostras de carcaça foram satisfatórias, aceitáveis e insatisfatórias para E. coli, respectivamente. Para a amostragem comparativa, 88,5% das amostras apresentaram-se satisfatórias para CBT, 84% para Coliformes Totais e 83,6% para E. coli. Nenhuma das amostras de carcaça analisadas foi positiva para Salmonella spp. ou para E. coli O157:H7. A frequência da ocorrência de E. coli O157:H7 em amostras de recortes cárneos (carne industrial) foi de 0,31%, com apenas uma amostra positiva / Abstract: This study aimed to evaluate the result of the environmental and operational controls which are routine or derived from HACCP Plan - Hazard Analysis and Critical Control Points, applied to slaughter cattle, and potentially pathogenic microorganisms research (Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes). During one year, the research was developed in a slaughterhouse, enabled to export, located in the state of São Paulo, Brazil. We analyzed 411 environmental samples for Listeria spp. research, 1.192 samples of surface contact for Total Bacterial Count (TBC), 200, 100, 775, 264 and 100 samples of carcass surface for TBC, Total Coliform, E. coli, Salmonella spp. and E. coli O157:H7, respectively, besides 256 samples of meat cuts for E. coli O157:H7 research. The results showed that 51,1% of the environmental samples of TBC were in acceptable hygienic condition and 62,9% of samples were not acceptable in the slaughter industry. A high value of samples (15,1%) was positive for Listeria spp. and Listeria monocytogenes (4,6%). It was observed that 89,6%, 2,8% and 7,6% of the samples of carcass were satisfactory, acceptable and unsatisfactory for E. coli, respectively. For comparative sampling, 88,5% of the samples were satisfactory for TBC, 84% for Total Coliform and 83, 6% for E. coli. None of the samples of carcass tested was positive for Salmonella spp. or E. coli O157:H7. The frequency of the occurrence of E. coli O157:H7 in samples of meat cuts (meat industry) was 0,31%, with only one positive sample / Mestre

The soil pile system (SPS) is a wastewater infiltration system used for secondary and tertiary treatment of wastewater. The purpose of this study is to perform a feasibility study to assess the applicability of SPS for treatment and safe disposal of domestic wastewaters, using a simplistic steady-state flow analytical modeling and a numerical transient unsaturated flow and transport modeling approaches. It is also aimed to develop guidelines for the design and operation of field scale SPS using the results of modeling studies. The analytical modeling approach (AMA) was used to assess total coliform and chlorine attenuation efficiency in a SPS with clay loam soil. Analytical modeling results showed that SPS can treat wastewater in terms of total coliform and chlorine. Thus, in the light of findings of analytical modeling study, a pilot scale field study was conducted for the identifying the design and operational characteristics of a field scale system. Numerical modeling approach was used to evaluate the impact on contaminant removal of transient nature of wastewater infiltration and redistribution through clay loam soil pile. The results of numerical and analytical models were compared to assess the effect of flow regime on contaminant removal efficiencies. Results show that there is no significant difference between removal efficiencies achieved by numerical and analytical models. Whereupon, analytical model was used to assess behavior of SPS with different soil types, namely silt loam, loam, and sandy loam soils. Model results indicated that SPS can be effective reducing chlorine and total coliform concentrations of wastewater below discharge standards. Results also indicated that SPS is highly sensitive to soil thickness, infiltration rate, soil bulk density and most importantly decay rate coefficients and the performance of SPS is dependent on the design, construction, operation characteristics and soil-environmental conditions of the system.

Made available in DSpace on 2014-06-11T19:27:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-12Bitstream added on 2014-06-13T20:16:21Z : No. of bitstreams: 1 caselani_k_me_jabo.pdf: 1897501 bytes, checksum: 58d7092f2bddb55a69e072e202d99cf8 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Este trabalho teve por finalidade avaliar o resultado dos controles ambientais e operacionais, rotineiros e derivados do plano APPCC – Análise de Perigos e Pontos Críticos de Controle, aplicados ao abate de bovinos, e da pesquisa de microrganismos potencialmente patogênicos (Escherichia coli O157:H7, Salmonella enterica e Listeria monocytogenes). Com duração de um ano, a pesquisa foi desenvolvida em abatedouro-frigorífico habilitado à exportação localizado no Estado de São Paulo, Brasil. Foram analisadas 411 amostras ambientais para pesquisa de Listeria spp., 1.192 amostras de superfície de contato para a Contagem Bacteriana Total (CBT), 200, 100, 775, 264 e 100 amostras de superfície de carcaça para CBT, Coliformes totais, E. coli, Salmonella spp. e E. coli O157:H7, respectivamente, além de 256 amostras de recortes cárneos para a pesquisa de E. coli O157:H7. Os resultados evidenciaram condição higiênica aceitável para 51,1% das amostras ambientais de CBT, com 62,9% de amostras não aceitáveis no setor de abate. Um valor elevado de amostras (15,1%) foi positivo para Listeria spp. e para Listeria monocytogenes (4,6%). Observou-se que 89,6%, 2,8% e 7,6% das amostras de carcaça foram satisfatórias, aceitáveis e insatisfatórias para E. coli, respectivamente. Para a amostragem comparativa, 88,5% das amostras apresentaram-se satisfatórias para CBT, 84% para Coliformes Totais e 83,6% para E. coli. Nenhuma das amostras de carcaça analisadas foi positiva para Salmonella spp. ou para E. coli O157:H7. A frequência da ocorrência de E. coli O157:H7 em amostras de recortes cárneos (carne industrial) foi de 0,31%, com apenas uma amostra positiva / This study aimed to evaluate the result of the environmental and operational controls which are routine or derived from HACCP Plan - Hazard Analysis and Critical Control Points, applied to slaughter cattle, and potentially pathogenic microorganisms research (Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes). During one year, the research was developed in a slaughterhouse, enabled to export, located in the state of São Paulo, Brazil. We analyzed 411 environmental samples for Listeria spp. research, 1.192 samples of surface contact for Total Bacterial Count (TBC), 200, 100, 775, 264 and 100 samples of carcass surface for TBC, Total Coliform, E. coli, Salmonella spp. and E. coli O157:H7, respectively, besides 256 samples of meat cuts for E. coli O157:H7 research. The results showed that 51,1% of the environmental samples of TBC were in acceptable hygienic condition and 62,9% of samples were not acceptable in the slaughter industry. A high value of samples (15,1%) was positive for Listeria spp. and Listeria monocytogenes (4,6%). It was observed that 89,6%, 2,8% and 7,6% of the samples of carcass were satisfactory, acceptable and unsatisfactory for E. coli, respectively. For comparative sampling, 88,5% of the samples were satisfactory for TBC, 84% for Total Coliform and 83, 6% for E. coli. None of the samples of carcass tested was positive for Salmonella spp. or E. coli O157:H7. The frequency of the occurrence of E. coli O157:H7 in samples of meat cuts (meat industry) was 0,31%, with only one positive sample

Este estudo teve por finalidade buscar informações sobre a qualidade da água do rio Una, por meio de análises de coliformes totais e coliformes termotolerantes, bem como de estudos sobre os impactos causados no entorno. Foram coletadas oito amostras ao longo do Rio Una. As taxas de coliformes totais foram de 1000 e ≥ 1600 NMP/mL, nos meses de dezembro de 2006, janeiro e março de 2007, enquanto nos meses de fevereiro e abril os resultados variaram de 17 a 300 por 100 mL. Os coliformes termotolerantes nos meses de dezembro de 2006, janeiro e março de 2007 em alguns pontos de coleta apresentaram-se fora do valor permitido para rio pertencente à classe 2. Desta forma, pode-se concluir que esses valores de coliformes evidenciam que o foco de contaminação é de despejos de esgotos "in natura" e a animais que ficam na margem do rio. A má ocupação do espaço vem causando sérios danos à conservação dos recursos hídricos. / The aim of this work is to determine the water quality of Rio Una, through analysis of total coliforms and thermotolerants coliform as well as studies on the environmental impacts. Eight samples were collected along the Rio Una. The rates of total coliforms were 1000 and ≥ 1600 MPN/100 mL, in the December 2006, January and March 2007, while in February and April results varied from 17 to 300/100 mL. Thermotolerants coliforms in December 2006, January and March 2007, in some points of collection had been out of the amount allowed for to the class 2 river. Thus, it was concluded that these values of coliforms show that the focus of contamination from sewage waste is "in natura" and to animals that are around the river. The bad occupation of the area has caused serious damage to the conservation of water resources.

There are rural residents of Central Appalachia that collect their drinking water from roadside springs despite having access to in-home piped point-of-use (POU) water. Residents have cited perceptions about water availability/quality as primary motivators for collecting drinking water from roadside springs. Water from roadside springs has been found to contain total coliform and E. coli, suggesting that consumers may be at an increased risk of contracting gastrointestinal illnesses. This research effort seeks to better understand roadside spring usage in Central Appalachia, by exploring motivations influencing potable water source selection and comparing household and spring water quality to Safe Drinking Water Act recommendations. Households were recruited from communities surrounding springs in three states (Kentucky, Virginia, and West Virginia). 24 tap water samples were collected from participating households and paired with samples from six roadside springs. Samples were analyzed for fecal indicator bacteria and inorganic ions. Study participants also completed short surveys to inventory their perceptions of their household drinking water. The majority of participants did not trust their home tap water, indicating water aesthetics as primary motivators for distrust of their homer water source. Statistical comparisons indicated that 10 water quality constituents (Cd, F, NO3-, Cu, Pb, Ag, Mn, Zn, Na, and Sr) were significantly higher in tap water samples and four constituents (total coliform, U, Al, and SO2-4) were significantly higher in spring samples. These results suggest that residents might be exposed to different risks based on their drinking water source and that water quality solutions must be devised case-by-case. / Master of Science / Some rural residents of Central Appalachia collect their drinking water from roadside springs, despite having access to piped drinking water at their homes. Water collected from roadside springs can contain harmful bacteria, suggesting that people may risk exposure to illness when consuming spring water. Through a household water quality study, this research effort aims to compare roadside spring and in-home tap water quality in order to determine what contaminants are present at each source, and why residents are choosing spring water over tap water. Households were recruited from communities surrounding roadside springs in three states (Kentucky, Virginia, and West Virginia). A total of 24 tap water samples were collected from participating households, and compared with samples from six nearby roadside springs. Samples were analyzed for bacteria, metals, and nutrients. Study participants were also asked to complete short surveys to better understand their perceptions of their drinking water sources. The majority of participants did not trust their home tap water, citing aesthetic concerns as the primary reason behind their distrust. When comparing roadside spring and home samples, 10 contaminants (Cd, F, NO3-, Cu, Pb, Ag, Mn, Zn, Na, and Sr) had greater concentrations in home tap water samples and four (total coliform, U, Al, and SO2- 4) had greater concentrations in spring samples. While home water samples had higher levels of metals, roadside spring samples had higher levels of bacteria, suggesting that residents might be exposed to different risks based on water source and that water quality solutions must be developed case-by-case.

The quality of marine bathing water is currently assessed by monitoring the levels of faecal indicator bacteria. Among other drawbacks, results are retrospective using the traditional culture based methods. A rapid method is thus needed as an early warning to bathers for bacterial contamination in marine bathing waters. Total lipopolysaccharide (LPS) was chosen here as a potential general biomarker for bacterial contamination. Levels of total LPS, measured using a Kinetic QCL™ Limulus Amebocyte Lysate (LAL) assay, highly correlated with enumerated Escherichia coli and Bacteroides species. Levels of LPS in excess of 50 EU mL-1 were found to equate with water that was unsuitable for bathing under the current European Union regulations. Results showed that monitoring the levels of total LPS has a potential applicability as a rapid method for screening the quality of marine bathing water. More importantly, the LAL assay overcome the retrospective results when using culture based assessment since the LAL assay takes less than 30 minutes. Although false positive events were not detected, the occurrence of a false positive has been hypothesised, hence a more specific faecal biomarker was also investigated. LPS of five Bacteroides species (B. fragilis, B. caccae, B. ovatus, B. xylanisolvens and B. finegoldii) isolated from marine bathing waters samples were successfully profiled and showed high similarity between isolates in LPS gel electrophoresis banding pattern. Similar results were shown when investigating the endotoxic activity of Bacteroides species with the Kinetic QCL™ LAL assay. The potential biological relevance of Bacteroides LPS was also investigated in cell culture models indicating that Bacteroides showed similar induction of proinflammatory cytokines (TNF-α, IL-6 and IL-1α) and generally the biological activity was approximately 100 fold less than E. coli LPS. In addition, an ELISA assay was designed for the detection of Bacteroides LPS. Results showed that the Bacteroides LPS has a high potential to be used as a faecal biomarker, however, further work is required to develop a fully functional assay. The potential biological relevance of LPS present in contaminated bathing waters was also investigated in cell culture models. Results showed that there is a significant difference in the production of proinflammatory cytokines in comparison to “clean” bathing waters. Thus, results suggest that the European Directive regulations should be extended to cover the levels of total LPS in bathing waters to assure safety to the users of marine recreational water.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-23T20:01:22Z No. of bitstreams: 1 JULYANNA DAMASCENO PESSOA - DISSERTAÇÃO PPGEQ 2015..pdf: 3056060 bytes, checksum: f1c90789fd3af9574cb10fbc1d69a075 (MD5) / Made available in DSpace on 2018-03-23T20:01:22Z (GMT). No. of bitstreams: 1 JULYANNA DAMASCENO PESSOA - DISSERTAÇÃO PPGEQ 2015..pdf: 3056060 bytes, checksum: f1c90789fd3af9574cb10fbc1d69a075 (MD5) Previous issue date: 2014-12-15 / Em decorrência da degradação dos recursos hídricos e da crescente preocupação com microrganismos específicos na água, a utilização de membranas cerâmicas para separação de materiais contaminantes, passa a ser uma opção de tratamento para a produção de água potável, devido a motivos como, por exemplo, sua resistência ao ataque de produtos químicos, requerer uma menor área de construção do equipamento, maior economia de energia, dentre outros. O presente trabalho objetivou estudar o desempenho de um sistema híbrido, composto por membrana cerâmica tubular de microfiltração, recheadas por resinas trocadoras iônicas, para tratamento de água de qualidade inferior. As membranas utilizadas nesse trabalho são do tipo α-alumina (α-Al2O3), tamanho nominal de poro de aproximadamente 0,8 µm, produzidas pelo Laboratório de Membranas Cerâmicas (LABCEM) do Laboratório de Referência em Dessalinização (LABDES) na Universidade Federal de Campina Grande (UFCG). O sistema foi avaliado em função do fluxo e vazão do permeado, nas pressões de operação 0,5; 1,0; 2,0 e 3,0 bar; teste de presença / ausência e contagem bacteriológicas na água da alimentação e permeado para o sistema: membrana cerâmica; análises físicoquímicas realizadas para o sistema: membrana cerâmica/ RTI; e tempo de residência hidráulica ( ), nas pressões de operação 1,0; 2,0 e 3,0 bar. A membrana cerâmica removeu completamente os Coliformes totais e fecais (Escherichia coli) da água. O comportamento do fluxo do permeado variou com a pressão de operação. No sistema híbrido: membrana cerâmica/ RTI, o tempo de residência foi de 15,55 segundos na pressão de operação 1,0 bar, removendo 71,9% dos íons da água de alimentação, para 66% na pressão 2,0 bar ( =11,73 segundos) e 61% na de 3,0 bar ( = 10,11 segundos). O sistema híbrido mostrou-se eficiente na remoção dos parâmetros físico-químicos e produziu água tratada de boa qualidade quanto aos parâmetros bacteriológicos nas águas de qualidade inferior, com baixo consumo energético. / Due to the degradation of water resources and the increasing concern about specific microorganisms in water, the use of ceramic membranes for separation of contaminating materials, becomes a treatment option for the production of drinking water, due to reasons such as its resistance to chemicals, requires a smaller area of equipment construction, greater energy savings, among others. This study investigated the performance of a hybrid system consisting of a tubular microfiltration ceramic membrane, filled with ion exchange resins for substandard water treatment. The membranes used in this work are the α-alumina type (α-Al2O3), with pores which have a nominal diameter of about 0.8 microns produced by Laboratório de Membranas Cerâmicas (LABCEM), at Desalination in Reference Laboratory (LABDES) at the Federal University of Campina Grande (UFCG). The system was evaluated by the flow and permeate flow, the operating pressure 0.5; 1.0; 2.0 and 3.0 bar; presence / absence and bacteriological count tests in the feed and permeate water for the system: ceramic membrane; Physical and chemical analysis for the system: ceramic membrane / RTI; and hydraulic residence time (τ), at the operating pressures of 1.0; 2.0 and 3.0 bar. The ceramic membrane completely removed the Total and fecal (Escherichia coli) Coliform of the water. The permeate flux behavior varied with the operating pressure. In the hybrid system: ceramic membrane / RTI residence time was 15.55 seconds at the operating pressure of 1.0 bar by removing 71.9% of the feed water ions, to 66% at 2.0 bar pressure ( = 11.73 seconds), and 61% for the 3.0 bar ( = 10.11 seconds). The hybrid system was efficient in the removal of physical and chemical parameters and produced good quality treated water as for the bacteriological parameters in lower quality water with low power consumption.

Made available in DSpace on 2016-12-08T16:24:13Z (GMT). No. of bitstreams: 1 PGCA13MA102.pdf: 258664 bytes, checksum: d3d029859f1ae232cdc1f3a89a0983b3 (MD5) Previous issue date: 2013-02-22 / The handmade serrano cheese of Santa Catarina is a typical product made on small farms in the Serrana Region Catarinense. Its main feature is to be manufactured from raw milk without suffering any heat treatment in order to eliminate pathogenic microorganisms that may be present. This fact has major implications, especially for the public health risk that product cause foodborne illness. Current law allows handmade cheeses from raw milk to be aged for a period less than 60 days, however, but also declares the need for technical-scientific studies to prove the best time of maturation, to ensure the quality and safety of the product. The present study aimed to realize the isolation and identification of Listeria monocytogenes and Salmonella sp. and isolating and quantifying Staphylococcus aureus, Escherichia coli and total coliforms and relate the maturation time with contamination of handmade cheeses, thus verifying the best time of maturation to make a product that is safe for consumers. The experiment was conducted using 108 samples of handmade serranos cheese from various cities in the mountainous region of SC, with maturity periods of between 14, 28, 42 and 63 days. In Animal Microbiological Diagnostic Center - CEDIMA were performed the following analyzes: isolation of Listeria monocytogenes using the method USDA/2009 and of Salmonella sp. methodology according to ISO 6579/2007. The bacteria identified as Listeria monocytogenes were sent for serotyping the Instituto Oswaldo Cruz Foundation. The enumeration of Staphylococcus aureus, Escherichia coli and Total Coliform was performed on petrifilm plates. The sanitary quality of the cheeses analyzed was unsatisfactory, because the presence of Staphylococcus aureus, Escherichia coli and total coliform was found above the levels permitted by law, indicating deficiency in hygiene procedures during manufacture of the product. Salmonella sp. not detected in any sample, but, the presence of Listeria monocytogenes makes cheese unfit for human consumption, as it offers potential risk to consumer health .The maturing period up to 60 days did not affect the isolation of the microorganisms statistically analyzed / O queijo artesanal serrano de Santa Catarina é um produto típico produzido em pequenas propriedades rurais na Serrana Catarinense. Sua principal característica é ser fabricado a partir do leite cru, sem sofrer nenhum tratamento térmico que elimine os microrganismos patogênicos que podem estar presente. Este fato traz grandes implicações, principalmente, para saúde pública pelo risco desse produto causar doenças transmitidas por alimentos. A legislação vigente permite que queijos artesanais elaborados a partir de leite cru sejam maturados por um período inferior a 60 dias, porém, declara a necessidade de estudos técnico-científicos a fim de comprovarem a melhor época de maturação, para que se possa garantir a qualidade e a inocuidade do produto. O presente estudo teve por objetivo realizar o isolamento e a identificação de Listeria monocytogenes e Salmonella sp. e o isolamento e quantificação de Staphylococcus aureus, Escherichia coli e coliformes totais e relacionar o tempo de maturação com a contaminação dos queijos artesanais, verificando assim, a melhor época de maturação para comercializar um produto que seja seguro ao consumidor. O experimento foi conduzido utilizando 108 amostras de queijo artesanais serranos provenientes de várias cidades da Região Serrana de SC, com períodos de maturação entre 14, 28, 42 e 63 dias. No Centro de Diagnóstico Microbiológico Animal - CEDIMA foram realizadas as seguintes análises: pesquisa de Listeria monocytogenes segundo o método USDA/2009 e isolamento de Salmonella sp. segundo a metodologia ISO 6579/2007. As bactérias identificadas como Listeria monocytogenes foram enviadas para sorotipificação na Fundação Instituto Oswaldo Cruz. A contagem de Staphylococcus aureus, Coliformes Totais e Escherichia coli foi realizada em placas de petrifilm . A qualidade higiênicosanitária dos queijos analisados foi insatisfatória, pois a presença de Staphylococcus aureus, Escherichia coli e coliformes totais encontrou-se acima dos valores permitidos pela legislação, indicando deficiência nos procedimentos de higiene durante a fabricação do produto. A Salmonella sp. não detectada em nenhuma das amostras, porém, a presença de Listeria monocytogenes torna o queijo impróprio para o consumo humano, uma vez que oferece risco potencial a saúde do consumidor. O período até 60 dias maturação não influenciou estatisticamente no isolamento dos microrganismos analisados