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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Hong Kong's impacts from the seafood trade and its role in affecting endangered species /

Kan, Wing-sze, Iris. January 2005 (has links)
Thesis (M. Sc.)--University of Hong Kong, 2005.
62

Essays on environmental economics and resource management

Sun, Bin, January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 118-123).
63

Fisheries in the News: How the Media Sets the Agenda for Seafood Sustainability in the United States

January 2016 (has links)
abstract: The media is a powerful force in shaping public discussions about marine issues. Many people lack first-hand experiences and direct sources of information about fisheries topics, so they rely heavily on the information presented to them in the news. Thus, the media has the potential to influence public agendas based on their selective coverage of topics, which primes people to take certain information into account when making decisions. This study examines the contents of 412 newspaper articles from five national newspapers to determine which topics are receiving the most coverage and how they are being communicated to the public. The analysis considers fisheries and seafood discussions overall, as well as focusing on the three most commonly consumed seafood items in the United States: salmon, shrimp, and tuna. Systematic coding of newspaper articles shows that economic and social fisheries concerns are emphasized more than environmental concerns. Additionally, fisheries articles tend to be emphasize the importance of fishermen’s livelihoods, the dangers of international seafood trade, the economic utility of fish, and a consumer’s right to make informed decisions about seafood. Overall, there are a number of conflicts and weaknesses in the media’s coverage of fisheries, which would likely make it challenging for Americans to make informed, sustainability-minded decisions about seafood purchases and fisheries policies. / Dissertation/Thesis / Masters Thesis Sustainability 2016
64

Características microbiológicas de salmão (Salmo salar) comercializado em algumas cidades da região nordeste do estado de São Paulo

Nespolo, Natália Maramarque [UNESP] 03 July 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:27:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-03Bitstream added on 2014-06-13T18:31:13Z : No. of bitstreams: 1 nespolo_nm_me_jabo.pdf: 317079 bytes, checksum: b5a59555adeaded005ddc00b0895ba68 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Tem sido evidente o aumento no consumo de pescado, especialmente do salmão (Salmo salar) sob a forma “in natura”, em pratos da cozinha oriental. Como conseqüência, tem havido maior preocupação quanto às suas características higiênico-sanitárias, tendo em vista a facilidade que microrganismos encontram para se desenvolverem em sua carne, o que pode expor os consumidores a agentes que causam desde uma simples gastrenterite até o óbito. Diante desta preocupação, desenvolveu-se este estudo com objetivos de avaliar características microbiológicas do salmão por meio da quantificação de microrganismos heterotróficos mesófilos, coliformes totais e termotolerantes, o perigo de veiculação de Vibrio parahaemolyticus, Staphylococcus aureus, Salmonella sp., Escherichia coli e Aeromonas sp. através da carne e contribuir com subsídios técnicos para criar uma legislação brasileira com padrões microbiológicos específicos para o pescado consumido cru. Foram colhidas 31 amostras de salmão, 16 refrigeradas e 15 congeladas, no comércio varejista de cidades da região nordeste do estado de São Paulo. Os resultados obtidos mostram populações de microrganismos heterotróficos mesófilos variando entre 1,0 x 10 e 3,9 x 106 UFC/g, coliformes totais e termotolerantes em, respectivamente, 32,24% e 19,33% das amostras e Aeromonas sp. em 35,48% das amostras com variação populacional de 2,0 x 102 a 8,0 x 103 UFC/g. Ainda houve a presença de Staphylococcus aureus em uma amostra e ausência de Vibrio parahaemolyticus, Salmonella sp. e Escherichia coli. Os resultados obtidos podem servir de parâmetro para a criação de um padrão microbiológico específico para o pescado consumido cru e servem também de alerta para os consumidores do produto tendo em vista a veiculação de microrganismos potencialmente patogênicos. / The increasing of seafood consumption has become evident especially in the use of salmon (Salmo salar) consumed raw in oriental dishes. Consequently, it has risen up the concern related to their hygienic-sanitary characteristics due to the facility that microorganisms multiply in the meat which can expose consumers to the causative agents of a mild gastroenteritis until the death. Regarding such informations, this study was aimed to evaluate microbiological characteristics of salmon by quantifying microrganisms heterotrophic mesophiles, total coliforms and thermotolerant. It was also evaluated the danger of transmission of Vibrio parahaemolyticus, Staphylococcus aureus, Salmonella sp., Escherichia coli and Aeromonas sp. on the fish muscle and contributed to technical informations to create a Brazilian regulations about specific microbiological standards for consumption of raw seafood. Thirty-one samples of salmon were collected, 16 chilled and 15 frozen, from the retail market in cities of the northeast region of São Paulo State. The results show populations of mesophilic heterotrophic microorganisms ranging from 1.0 x 10 and 3.9 x 106 CFU/g, in total and fecal coliforms, respectively, 32.24% and 19.33% of samples and Aeromonas sp. in 35.48% of samples ranging population of 2.0 x 102 to 8.0 x 103 CFU/g. Staphylococcus aureus was present in one sample and were not found Vibrio parahaemolyticus, Salmonella sp. and Escherichia coli. The results may serve as a parameter for the establishment of a microbiological standard for the consumption of raw seafood and also as a warning to consumers of the product for the presence of potentially pathogenic microorganisms.
65

Characterisation of allergens in pilchard, responsible for the development of occupational allergy in the seafood processing industry in the Western Cape

Hikuam, Christopher Willem January 2006 (has links)
Thesis (MTech (Tourism and Hospitality Management))--Cape Peninsula University of Technology, 2006. / The increase in popularity of fish, coupled with technological advances in the fishing industry and changes in the control and management of fishing resources, has led to a significant increase of fish processing workers from 13 million in 1970 to 38 million in 2002. Whereas allergic reactions to fish proteins were previously only documented in consumers, increasing reports of occupational fish allergies of fish processing workers has become evident. In South Africa, the reported prevalence of occupational asthma associated with fish processing workers is 2 - 8%, and the prevalence of occupational protein contact dermatitis 3 - 11%. Pilchard is one of the most consumed fish species in South Africa and the immunological analysis of this species will therefore contribute to the provision of occupational health services in the pilchard processing industry. Proteins extracted from fresh, frozen and canned pilchard (Sardinops sagax), as well as fresh samples of six other processed and consumed South African fish were characterised by denaturing protein electrophoresis and immunoblotted with different monoclonal and polyclonal antibodies. Sera from sensitised workers were subsequently used to characterise the membrane-bound pilchard proteins and analysed for human Immunoglobulin G (lgG) and Immunoglobulin E (IgE) antibodies to determine antigen recognition. A protein of 12 kDa molecular weight was found to be present in all fish protein extracts, however, at various concentrations. With the aid of the monoclonal and polyclonal antibodies, the 12 kDa protein was postulated to be parvalbumin, a known allergen in some fish species. Immunoblotting experiments for the identification of workers' IgG- and IgE-reactivities to fresh, frozen and canned pilchard showed a 12 kDa protein as an immunolgically reactive fish protein. This protein was also found to occur in dimeric, trimeric and tetrameric forms, which may have significant implications in the diagnosis and management of occupational sensitisation to pilchard.
66

Occurrence and control of Vibrio species as contaminants of processed marine fish

Shikongo-Nambabi, Martha Naita Namwaala Nangulohi 19 October 2011 (has links)
Marine water contains large numbers of fish spoilage bacteria and pathogens including V. cholerae, V. parahaemolyticus, and V. vulnificus. Consumption of contaminated seafood could lead to the transmission of these pathogens to humans. Accurate identification of suspected pathogens and spoilage organisms is important to ensure consumer safety and a long shelf life. This project assessed the bacterial quality of hake during processing. Some attention was also given to pilchards and horse mackerel. The results showed a sharp increase in the mesophilic and sucrose fermenting Vibrio species counts in hake after filleting. It has been suggested that this contamination occurred during processing from biofilms present in the sea-water distribution system. During the study 257 strains isolated from Thiosulphate citrate bile salts sucrose (TCBS) agar were screened to determine the presence of the pathogenic Vibrios amongst these isolates. It was difficult to distinguish between V. alginolyticus and V. parahaemolyticus species due to high sequence similarity in their 16S rRNA genes. Final identification of the isolates required a polyphasic approach and it was found that none of the pathogenic Vibrios were present but that the Vibrio isolates mainly belonged to V. alginolyticus. As it was suspected that the main source of contamination was the treated sea water used during processing the ability of chlorine, ozone and hydrogen peroxide to prevent biolfilm formation was examined. The behaviour of two V. alginolyticus strains (V590 and V595) isolated from the processed hake was evaluated. These strains formed biofilms faster than the V. alginolyticus LMG4409 type strain, but were similar to V. parahaemolyticus LMG2850. Biofilms formed by these bacteria were resistant to 4 mg/l chlorine and to 2 mg/l ozone, but were inhibited by 0.05 % and 0.2 % hydrogen peroxide for biofilms initiation and mature biofilms respectively. The close resemblance of atypical V. alginolyticus isolates to V. parahaemolyticus may indicate the ability of pathogens to survive under similar conditions. Effective decontamination and quality assurance strategies are therefore required when processing fish to prevent disease outbreaks. / Thesis (PhD)--University of Pretoria, 2011. / Microbiology and Plant Pathology / unrestricted
67

When seafood feeds the spirit yet poisons the body : developing health indicators for risk assessment in a Native American fishing community

Donatuto, Jamie 11 1900 (has links)
Current US government risk assessment and management regulations and policies are based on a position that views risk as an objective measure of a predictable physiological morbidity or mortality outcome that is not otherwise connected to social or cultural beliefs and values. Whereas human health risk assessments are meant to determine the probability of adverse impacts from particular hazards, the conventional risk assessment framework fails to consider Native American definitions of health and so risk. This study was conducted with the Coast Salish Swinomish Indian Tribal Community of Washington State, where contamination of their aquatic natural resources has been found. By conducting two series of interviews with traditional high-use seafood consumers, experts and elders from the Swinomish Indian Tribal Community, and by averting use of what I describe herein as ‘conventional’ fish consumption survey, the study allowed interviewees to provide a more complex narrative set of details and information that bestowed a much more accurate picture of the reasoning behind seafood consumption habits within the community. Among the more salient points that emerged from the interviews was that seafood represents a symbolic, deeply meaningful food source that is linked to a multi-dimensional ‘Swinomish’ concept of health. Yet drastic changes in access, harvest and consumption have occurred over time, and continue to this day. A health evaluation tool was also devised using simple descriptive scaled rankings to elucidate non-physiological health risks and impacts in relation to contaminated seafood. Findings demonstrate that community cohesion, food security, ceremonial use and knowledge transmission all play primary roles as concerns the Swinomish notions of health, and that these indicators are regarded as equally important when juxtaposed to physical indicators of health. Thus, to eat less seafood—as prescribed by current policy and decision-making procedures when contamination is present—is actually detrimental to the multi-dimensional concept of health as defined by the Swinomish. The evaluation tool may be used in conjunction with the conventional risk assessment framework to more accurately and comprehensively deduce risks and impacts. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate
68

Motivations and sustainability perceptions for following a pescatarian diet

Schot, Emil January 2023 (has links)
In the past sixty years, demand for seafood products for human consumption has increased sixfold. With increasing wealth, increased attention for healthy diets and increasing concerns for environmental issues, it is expected that people will shift away from the consumption of terrestrial animals and move towards pescatarian, vegetarian and vegan dietary patterns. As a result, it is expected that the demand for aquatic animals will keep increasing in the upcoming decade. This thesis project examines the dietary motivations and sustainability concerns of pescatarians, a specific group of individuals who exclude the consumption of meat from terrestrial animals and while still consuming aquatic animals. The study aims to gain insights into the factors driving dietary choices and explore the relationship between these choices and sustainability considerations. Furthermore, by investigating the consumption choices made by pescatarians, the research sheds light on the broader implications for sustainable food systems.
69

Developing cultivated mollusks through establishing primary cell culture methods of Eastern Oyster, Crassostrea virginica, as a model bivalve

Aung, Thet Me Me 17 August 2022 (has links)
Cultivated seafood is a potential alternative protein source that can address the rising global food demand with exponentially rising human population growth. Cultivated seafood is made by growing animal cells in vitro using stem cells for edible food, eliminating the need to raise the entire animal. A crucial first step in developing cultivated seafood is creating a well-characterized cell line that can continuously grow and differentiate into desired cell types. Due to difficulties in determining optimal primary cell culture conditions, no continuous cell lines of food-relevant mollusks have been established so far. This study used the adult Eastern Oyster, Crassostrea virginica, as a model bivalve to study the decontamination, cell dissociation, and culture conditions suited for mollusk adductor muscle cells. Oyster adductor (OAD) cells were obtained via tissue explant, mechanical and enzymatic digestion. The cells were routinely monitored using an inverted microscope for phase-contrast and fluorescence imaging. Culture vessels were coated with surface proteins such as fibronectin, laminin, matrigel, and poly-d-lysine to promote cell attachment. The tissue decontamination with Penicillin-Streptomycin (100 µg/mL), Amphotericin B (0.25 µg/ml), and algaecide solution (0.03%) was effective in controlling microbial growth. OAD cells grew best at lower nutrient levels in a one-to-one ratio of Lebovitz L-15 media and artificial seawater. Lower fetal bovine serum levels, 1-5%, provided a high number of cell attachments and consistent growth in combination with 1% adult oyster whole-body or larvae extract. The tissue explant method resulted in the optimal cell dissociation from the three methods, and proceeding cultures had attached cells surviving for up to 10 days. All the plate coatings promoted cell attachment, but fibronectin provided optimal cell attachment of OAD cells. Fibroblast-like, neuron-like, epithelial-like, and rounded cells were observed. Fluorescence cell staining confirmed the presence of cytoskeleton and nuclei in the OAD cell cultures. These advances in primary cell culture methods of OAD cells may be beneficial for establishing mollusk cell lines for cultivated seafood production. / Master of Science in Life Sciences / For sustainable seafood production, alternative sources of seafood proteins are essential in ensuring food security in the future. Cultivated seafood is an alternative protein source to address this rising food demand without the need to raise, farm, or slaughter animals. In developing cultivated seafood, self-renewing stem cells of the animal of interest are grown and made into edible products. A crucial first step in making cultivated seafood is understanding the growth conditions of the primary cells taken from animal tissue. Marine mollusk composes a significant part of seafood consumption, and developing cultured mollusks can address the growing food demand as a seafood alternative. However, there are many gaps in understanding the biological and physiological requirements of mollusk cells. No continuous, self-renewing mollusk cells of food-relevant species have yet been established. This study used the adult Eastern Oyster, Crassostrea virginica, as a model bivalve to study the tissue decontamination, cell dissociation, and culture conditions suited for oyster adductor muscle (OAD) cells. OAD cells were obtained via three cell dissociation methods. Cell growth was routinely monitored using an inverted microscope. Cell-surface proteins such as fibronectin, laminin, matrigel, and poly-d-lysine were used to promote cell attachment. The tissue decontamination was effective with Penicillin-Streptomycin, Amphotericin B, and algaecide. OAD cells grew best at lower nutrient levels in the one-to-one ratio of Lebovitz L-15 media and artificial seawater. Lower fetal bovine serum levels, 1-5%, provided a high number of cell attachments and consistent growth in combination with 1% adult oyster whole-body or larvae extract. Various cell morphologies were observed in the OAD cell cultures. Fluorescence cell staining confirmed the presence of cytoskeleton and nuclei in the OAD cell cultures. These advances in cell culture methods of OAD cells may be beneficial for establishing mollusk cell lines for cultivated seafood production.
70

Optimization of the Quality and Safety of Cooked Seafood Products

Brookmire, Lauren 29 October 2010 (has links)
Seafood products are a common consumer choice and a variety of cooking methods are used in seafood preparation. Although often cooked, products such as shrimp and salmon remain some of the most common carriers of foodborne disease. Cooking these products at elevated temperatures efficiently reduces foodborne disease causing pathogens to a safe level, but applying too much heat to seafood products can produce an overcooked, low quality food. It is necessary to investigate the cooking processes used in seafood preparation and establish appropriate consumer cooking parameters that optimize both the quality and microbial safety of the products. To achieve these goals, this study develops mathematical models for the inactivation of Salmonella sp., change in quality attributes, and the product heating profiles during the cooking process for shrimp and Atlantic salmon. Studies were performed to monitor the product heating profile during the baking and boiling of shrimp and the baking and pan-frying of salmon. Product color, texture, moisture content, mass loss, and pressed juice were evaluated during the cooking processes as the products reached the internal temperature recommended by the FDA. Studies were also performed on the inactivation of Salmonella cocktails in homogenized and non-homogenized shrimp and salmon. To effectively predict inactivation during cooking, the Bigelow, Fermi distribution, and Weibull distribution models were applied to the homogenized data. Minimum cooking temperatures necessary to destroy Salmonella sp. in shrimp and salmon were also determined. The heating profiles of the two products were modeled using the finite difference method. Temperature data directly from the modeled heating profiles was then used in the kinetic modeling of quality change and Salmonella inactivation during cooking. It was concluded that consumers need to judge the doneness of both shrimp and Atlantic salmon by the lightness factor (CIE L*) of the core region of both products. The core region's lightness factor, which a consumer may consider as opaqueness, more accurately represented the thermal doneness than the external qualities. The FDA's current recommendations for a 3 log reduction for intact seafood products and homogenized seafood products were each analyzed. Results were in agreement with the recommended 68°C plus 15 seconds for homogenized products. For intact products, shrimp inactivation results were in agreement with the recommended 63°C plus 15 seconds, but intact salmon achieved only a 2 log reduction by the temperature-time combination. It was also found that predictive models can effectively describe the survival data for two Salmonella cocktails. The Weibull distribution model, which takes into account any tailing effect in survival data, fit the survival data of Salmonella in shrimp acceptably. The Fermi distribution model, which incorporates any shouldering effect in data, was an acceptable fit for the inactivation data for salmon. Using three-dimensional slab geometry for salmon fillets and two-dimensional frustum cone geometry for shrimp resulted in acceptable model predictions of thermal distributions for the cooking methods studied. The temperature data attained directly from the modeled heating profiles was effectively used in the predictive quality and inactivation models. Agreeable first-order kinetic models were formulated for Î L and Î C color parameters in shrimp and salmon. Other kinetic models formulated were for texture change in salmon and pressed juice in both salmon and shrimp. Using a fixed inactivation level of 3 logs and a fixed quality of 95% best quality, optimal cooking conditions were determined that both provide a high quality product and assure microbial safety. Based on the specific cooking methods in this study, the optimal boiling times for extra jumbo and colossal sized shrimp were 100 seconds and 159 seconds, respectfully. The optimal oven baking times were 233 seconds for extra jumbo shrimp and 378 seconds for colossal shrimp. For Atlantic salmon, the optimal oven baking time was 1132 seconds and the optimal pan frying time was 399 seconds. / Master of Science

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