L'arsenic est un élément présent dans tous les compartiments de l'environnement, et les produits de la pêche représentent une source majeure d'exposition à l'arsenic par le biais de l'alimentation. Même s'il n'existe pas à ce jour de législation sur les teneurs en arsenic dans les aliments en France, les agences gouvernementales évaluent généralement les risques liés à la présence d'arsenic dans les produits de la pêche en se basant essentiellement sur la concentration totale de l'élément, sans tenir compte des différentes espèces présentes ni de leur bioaccessibilité. Par conséquent, le développement de méthodes d'analyse de spéciation revêt un intérêt particulier dans le cadre de l'évaluation des risques. La première partie de ce mémoire présente des informations générales sur les propriétés de l'arsenic, son occurrence dans les différents compartiments de l'environnement et sa toxicité, ainsi qu'une étude bibliographique des méthodes analytiques existantes pour étudier la spéciation de l'arsenic dans les matrices alimentaires, en particulier les produits de la pêche (extraction et séparation/détection). Les différentes approches pour l'évaluation de sa bioaccessibilité et de celle d'autres éléments traces métalliques d'intérêt sont également présentées. La deuxième partie de ces travaux porte sur la validation d'une méthode d'analyse de spéciation des principales espèces d'arsenic dans les produits la pêche (As(III), MA,DMA, As(V), AsB, TMAO, AsC) par couplage entre la chromatographie d'échange d'ions (IEC) et la spectrométrie de masse à plasma induit (ICP-MS) après extraction assistée par micro-ondes (MAE). L'évaluation des performances analytiques de la méthode, les contrôles qualités internes et externes mis en place et les différentes applications, en particulier les données d'occurrence des différentes espèces d'arsenic dans les produits de la pêche les plus consommés par la population française sont présentés et discutés. Dans la troisième partie, la bioaccessibilité maximale de l'arsenic et d'autres éléments d'intérêt est estimée à l'aide d'une méthode de lixiviation en ligne (impliquant la mesure en temps réel par ICP-MS de la fraction libérée par les différents fluides digestifs artificiels). La combinaison de ce procédé avec la méthode d'analyse de spéciation validée permet ainsi d'estimer la bioaccessibilité des différentes espèces d'arsenic. / Arsenic is an element present in all compartments of the environment, and seafood constitutes a major source of exposure to arsenic through human consumption. Although there is currently no legislation on arsenic in food in France, government agencies generally assess the safety of food items based solely on the total concentration of the element, without taking into account its different species or their bioaccessibility. Therefore, the development of speciation analysis methods is particularly relevant in the context of risk assessment. The first part of this thesis focuses on the properties of arsenic, its occurrence in the different compartments of the environment and its toxicity, and a literature review of existing analytical methods to study the speciation of arsenic in food matrices, especially seafood products (extraction and separation / detection). Different approaches for evaluating its bioaccessibility and that of other trace metals of interest are also presented.The second part of this work concerns the validation of a speciation analysis method for major arsenic species in seafood (As (III), MA, DMA, As (V), AsB, TMAO, AsC) by coupling ion exchange chromatography (IEC) with inductively coupled plasma mass spectrometry (ICP-MS) after microwave-assisted extraction (MAE). Evaluation of the analytical performance of the method, internal and external quality controls in place and applications of the method, particularly occurrence data of arsenic species in seafood most consumed by the French population are presented and discussed. In the third part, the maximum bioaccessibility of arsenic and other elements of interest is assessed using a continuous leaching method (involving the real-time measurement by ICP-MS of the fraction released by the different artificial digestive fluids). By coupling this leaching method with the above validated speciation analysis method, the bioaccessibility of different arsenic species is also assessed.

Très appréciés des consommateurs du fait de leur qualité nutritionnelle, les produits de la mer jouent un rôle important dans l'alimentation humaine. Toutefois, la confiance du consommateur vis-à-vis de leur qualité est affectée par les riques associés à une exposition aux contaminants chimiques et à la fraîcheur des produits. Si le premier aspect résulte de la pollution des eaux marines sous l'effet d'une forte anthropisation des littoraux, le second est lié à la haute périssabilité de ces produits. Évaluer les niveaux de contamination chimique et la qualité-fraîcheur des produits de la mer est plus qu'un besoin : c'est aujourd'hui une nécéssité. C'est dans ce contexte que les travaux de cette thèse ont été menés. Deux objectifs principaux ont été visés dans la présente étude. Le premier objectif de ce travail était de faire une évaluation spatiale et saisonnière des niveaux de contamination par les polluants métalliques et organiques (HAPs et PCBs) des zones côtières du Sénégal en s'intéressant aux teneurs en contaminants dans les organismes marins. Nous avons étudié 7 espèces marines représentatives des différents maillons de la chaîne trophique (une macroalgue verte, un mollusque bivalve, un crustacé et 4 espèces de poisson) prélevées le long du littoral au niveau de 5 sites présentant des degrés d'anthropisation différents. Les résultats de cette étude montrent que les teneurs en contaminants chimiques des organismes marins sont variables selon les espèces et soulignent ainsi la nécéssité de l'approche multi-espèces pour l'étude de la contamination chimique du milieu. Des variations inter-sites de la teneur en contaminants chimiques dans les organismes ont été mis en évidence. Les sites les plus anthropisés comme Soubédioune et Rusfisque sont ceux qui présentent les teneurs les plus élevées. Les niveaux de contamination métalliques et organiques dans les organismes marins du littoral sénégalais sont inférieurs ou du même ordre de grandeur que ceux mesurés dans d'autres régions d'Afrique de l'Ouest ou dans d'autres régions du monde. L'évaluation des risques associés à l'ingestion des produits de la mer analysés montre que les teneurs en contaminants chimiques sont faibles et inférieures aux limites maximales admissibles pour la consommation humaine (norme EU). Seuls les sites de Rufisque et Soumbédioune présentent quelques dépassements chez certaines espèces (moules, sardinelles). Le deuxième objectif de cette étude était de développer des méthodes permettant d'évaluer la fraîcheur des filets de poisson et de différencier des filets frais des filets décongelés. Les méthodes retenues sont basées sur la mesure de l'augmentation de la perméabilité cellulaire du muscle de poisson. La conservation des filets de poisson à 4°C va conduire à une perméabilisation des cellules dans le temps qui peut être apréhendée par la mesure de la libération d'enzymes intracytoplasmiques ou par l'augmentation de la perméabilité des cellules à des colorants fluorescents. La mesure de l'activité LDH est intéressante à double titre : elle va permettre d'une part de mesure le niveau de lyse cellulaire, donc le niveau d'altération, des filets de poisson dans le temps. Elle va permettre d'autre part grâce à sa sensibilité à la congélation de mieux cerner les conditions qui permettraient à terme de faire la distinction entre les filets frais et des filets congelés/décongelés. / Much appreciated by consumers for its nutritional qualities, seafood plays an important role in human diet. Consumer confidence in the quality of these foodstuffs is nevertheless affected by concerns about risks associated with exposure to chemical contaminants and the freshness of these products. If the first of these is the result of pollution resulting from increasing human activities along coastlines, the second is linked to the highly perishable nature of these products. An evaluation of the levels of chemical contaminants in seafood and of its freshness is therefore a necessity. It is within this context that the work presented in this thesis was carried out. Two principal objectives were targeted in the present study. The first objective of this work was to evaluate the spatial and seasonal variability of seafood contamination by elements (including metals) and organic pollutants (PAHs and PCBs) along the Senegalese coast. We studied 7 marine species representative of different trophic level (a green macro algae, a bivalve mollusc, a crustacean and 4 species of fish) sampling them along the coastline at 5 sites representing different human activity pressur. The result of this study showed that contamination levels varied with species, underlining the importance of a multi-species approach to study contamination in the marine environment. Variations between sites were also observed. Sites with the greatest human activity, such as Soumbédioune and Rufisque, were also those where the highest levels of contaminants in seafood were found. The levels of contamination measured along the Senegalese coast, of both elements and organic pollutants, were inferior or of the same order of magnitude as those reported from other West African sites or from other regions of the globe. The risks associated with eating theseseafood products were low, with contaminant levels generally below the admissible limits (EU) for human consumption. Only a few samples of certain species (mussels, sardines) exceeded these limits at Soumbédioune and Rufisque. The second objective of this study was to develop methods to evaluate the freshness of fish fillets, and to distinguish fresh fillets from previously frozen ones. The methods developed were based upon a measure of cellular permeability within the fish muscle tissue. The conservation of fish fillets ar 4°C results in increased permeability of cells over time, measurable by studying the liberation of intra-cytoplasmic enzymes or the increasing permeability of cells to fluorescent colouring agents. The measurements of lactate dehydrogenase (LDH) is doubly interesting in this contex : on the one hand it enables a measure of cell lysis, and so the level of alteration of the fillets over time, to be established. It also, thanks to its sensitivity to freezing, to better distinguish fresh fillets from those that have been frozen then thawed.

Reconhecendo-se a susceptibilidade do camarão à autólise e à decomposição microbiana, a presente pesquisa teve como objetivo avaliar a influência de diferentes doses de radiação gama na qualidade da carne, sob os aspectos microbiológicos, físicoquímicos e sensoriais durante o armazenamento sob refrigeração do camarão-brancodo- pacífico (Litopenaeus vannamei). As amostras foram constituídas de camarões in natura, sem o cefalotórax, acondicionados em bandejas de poliestireno, embalados em filme plástico flexível e submetidos a diferentes doses de radiação gama (1,0 e 3,5 kGy), sendo que estas foram mantidas sob refrigeração (5ºC ± 1ºC) e analisadas no 1º, 7º, 14º e 21º dias de armazenamento. Foram realizadas análises microbiológicas (Staphylococcus coagulase positiva, Salmonella ssp, Coliformes totais e termotolerantes, microrganismos psicrotróficos e mesófilos), e testes físico-químicos: bases nitrogenadas voláteis totais (BNVT), pH, nitrogênio não protéico (NNP), análise de TBARS - substâncias reativas ao ácido tiobarbitúrico (TBA) e trimetilamina (TMA), além de determinações de colesterol e composição centesimal. Foram realizadas análises para cor (instrumental) e para aceitabilidade (hedônico), visando à determinação da qualidade sensorial do camarão (submetido à cocção) durante o período de armazenamento. Verificou-se que o processo de irradiação reduziu a população bacteriana inicial e após o armazenamento as amostras irradiadas apresentaram-se dentro dos padrões previstos pela legislação brasileira (BRASIL, 2005b). Já as amostras não irradiadas, após o 7º dia de armazenamento, estavam impróprias para o consumo por extrapolarem o limite estabelecido para Staphylococcus. Foram encontrados valores de 6,05 a 6,39 para pH; 19,47 a 80,84 mg/100g para BNVT; 2,61 a 12,85 mg/100g para TMA; 0,22 a 1,20 mg de malonaldeído/1000g para TBA e 53,09 a 134,81 mg/100g para colesterol. As amostras irradiadas mantiveram-se estáveis durante o período de armazenamento, o que não ocorreu nas amostras não irradiadas, quanto ao pH, índices de BNVT e TMA. A irradiação resultou na redução do teor de colesterol e valores de TBA nos diferentes tempos avaliados. Não houve diferença (p <=0,05) para cor instrumental no primeiro dia de armazenamento, em relação a amostras não irradiadas e irradiadas com 3,5 kGy. Não foram detectadas diferenças estatísticas (p <= 0,05) no aspecto sensorial entre amostras irradiadas e não irradiadas no 1º dia de armazenamento. As amostras não irradiadas foram rejeitadas sensorialmente a partir do 7º dia de armazenamento, enquanto que as amostras irradiadas com 1 kGy foram aceitas até o 14º dia. As amostras irradiadas com 3,5 kGy mantiveram-se com aroma e aparência adequados até o final do experimento. Concluiu-se que o uso da radiação gama, especialmente a dose de 3,5 kGy, proporcionou maior estabilidade físico-química e segurança microbiológica durante o armazenamento, em relação ao produto refrigerado convencional, sem ocasionar alteração na qualidade sensorial do camarão. A radiação gama assegurou maior vida útil ao camarão refrigerado, atingindo 21 dias de armazenamento, sendo, portanto, um coadjuvante recomendável. / Taking into account shrimp susceptibility to autolise and bacterial decomposition, this study aimed to evaluate the different gamma irradiation dosis influence over meat quality related to microbiological, physical-chemical, nutritional and sensorial aspects, during cold storage of the white shrimp (Litopenaeus vannamei). Samples were taken from fresh shrimps without cephalothoraxes, settled into poliestirene trays, packed with flexible plastic film and submitted to different dosis of gamma irradiation (1.0 and 3.5 kGy). Samples were kept under refrigeration (5ºC 1ºC) and analyzed at the 1st, 7th 14th and 21st day of storage. Microbiological analyzes were realized (Coagulase-positive Staphylococcus, Salmonella ssp, coliforms, psychrotrophic and mesophilic population), and physical-chemical and tests (Total volatile bases (TVNB), pH, non proteic nitrogen (NNP), TBARS analysis - reactive substances to tiobarbituric acid (TBA), trimetilamine (TMA) cholesterol teor and proximate composition). Instrumental color test were realized and hedonic test was taken to determine cooked products sensorial quality during storing period. It was noticed that the irradiation process reduced bacterial population and during storage all the irradiated samples were under the patterns established by the Brazilian legislation (BRAZIL, 2005a). Non-irradiated samples were inappropriate for consumption after one week of storage, since they were over Staphylococcus established limits. The pH values ranged from 6.05 to 6.39; 19.47 to 80.84 mg.100g-1 for TVNB; 2.61 to 12.85 mg.100g-1 for TMA-N; 0.22 a 1.20 mg of malonaldeide.1000g-1 for TBA and 53.09 to 134.81 mg.100g-1 for cholesterol concentrations. Irradiated samples kept more stability during storage period when compared to non-irradiated samples, regarding to pH, TVNB and TMA levels. Samples irradiation resulted into cholesterol and TBA values reduction at different evaluated moments. No significant differences (p <= 0.05) were found in terms of instrumental color during the first day of storing when compared to the non-irradiated samples and to the 3.5 kGy irradiated ones. Statistical differences were not found (p <= 0.05) between non-irradiated and irradiated samples within the first day of sensorial analysis. Non-irradiated samples were rejected on the sensorial test after the 7th day of storage, while the 1kGy irradiated samples were accepted until the 14th day. Samples irirradiated with 3.5 kGy kept viability in terms off flavour and aspect until the end of the experiment. When compared to conventional refrigerated product, the gamma-irradiation technique, (especially the 3.5 kGy dosis) provided a higher stability related to physicalchemical properties and microbiological safety during storage. No differences on the sensorial shrimp quality were found. Through gamma irradiation, we obtained a product with minimal procedure modifications, with enhanced shelf life under refrigeration.

A hipersensibilidade a alimentos é comum em crianças e adultos. O camarão, apesar de muito apreciado, é um alimento potencialmente capaz de desencadear reações alérgicas em indivíduos geneticamente predispostos. O principal alérgeno em camarão é a tropomiosina. O objetivo desse experimento foi avaliar os efeitos da radiação gama na reatividade IgE a tropomiosina de camarão da espécie Litopenaeus vannamei e avaliar as modificações físico-químicas e sensoriais no produto, induzidas por esse processo. As amostras foram constituídas de camarões sem o cefalotórax, descongelados e liofilizados, submetidos a diferentes doses de radiação gama: 0 (test.), 5, 10 e 15 kGy. Utilizou-se para a irradiação um irradiador multipropósito, semi-industrial de 60 Co. A taxa de dose empregada foi de 7,5 kGy/hora. Determinou-se a reatividade IgE utilizando as técnicas: ELISA e \"Imunobloting\". Foram realizados testes físico-químicos e sensoriais, para verificar a viabilidade do produto após a irradiação. Os dados obtidos foram submetidos à análise de variância (ANOVA) e teste de Tukey (p<=0,05). As doses de radiação gama aplicadas nesse experimento não alteraram de forma significativa a reatividade IgE, a cor, o colesterol, teor de ácidos graxos e a aceitação dos camarões. Concluiu-se que a radiação gama nessas doses, apesar de não causar modificações que comprometam a qualidade do produto, não pode ser indicada para o controle de alérgenos em camarões, por ter apresentado baixo impacto na modificação da estrutura protéica alergênica / The hypersensitivity to foods is common in children and adults. The shrimp in spite of very appreciated is a food potentially capable to unchain allergic reactions genetically in individuals per disposed. The major allergen in shrimp is the tropomiosin. The aim of this study was to evaluate the effects of gamma irradiation on IgE reactivity to shrimp tropomyosin (Litopenaeus vannamei) and evaluate the physical and chemical changes and sensory product, induced by this process. The samples will be constituted of thawed and freeze-dried shrimp submitted to different radiation doses: 0 (test.), 5, 10 and 15 kGy. Was used for irradiating an irradiation multipurpose semi-industrial sector. 60 Co. The dose rate used was 7.5 kGy / hr. The samples, later to the irradiation, they will go by analyses for allergens determination using the techniques: ELISA and Imunobloting. Acceptance test will be done to verify physic-chemical and sensorial attributes after irradiation. Datas will be evaluated by ANOVA and Tukey test (p<=0.05). The gamma radiation doses applied in this experiment did not change significantly IgE reactivity, color, cholesterol, fatty acid content and the acceptance of shrimp studied. It was concluded that the gamma radiation in these doses, although not causing changes that compromise the quality of the product cannot be indicated for control of allergens in shrimp because it presented a low impact on allergenic protein structure modification

<p>Bakgrund: Historiskt har företag haft stora lager för att kunna möta kundernas efterfrågan. I takt med att kundanpassning och flexibilitet har ökat har det blivit allt dyrare och näst intill omöjligt att hålla lager som kan tillgodose kundernas behov. Att styra sitt lager så att det motsvarar efterfrågan har nästan varit en omöjlighet. En lösning på lagerstyrningsproblematiken är Vendor Managed Inventory (VMI) som innebär ett tätare samarbete mellan kund och leverantör. Kunden tillhandahåller information om lager och efterfrågan och leverantören tar över ansvaret för att varorna i kundens lager inte ska ta slut. Litteraturen kring VMI tar upp många positiva effekter som kommer att inträffa vid ett VMI-samarbete. Dock är det skralt med empiriska undersökningar beträffande effekterna av införandet av ett VMI-samarbete.</p><p> Syfte: Syftet med uppsatsen är att undersöka ett VMI-samarbete mellan en leverantör och en kund för att se om det finns empiriskt stöd för de kostnads- och leveransserviceeffekter som teorierna kring VMI tar upp. </p><p>Genomförande: Vi har undersökt samarbetet mellan Abba Seafood och ICA Handlarna. Vi intervjuade personer på båda företagen. Respondenterna hade antingen ett övergripande ansvar för VMI-samarbetet eller kom i kontakt med VMI i det dagliga arbetet. </p><p>Resultat: Efter att ha analyserat samarbetet mellan Abba och ICA så kan vi konstatera att många av de positiva effekter som kan förväntas av ett VMI- koncept har infriats och några inte. Vad vi inte kan fastställa i alla lägen, är om det är just VMI som är bakgrunden till förbättringarna, eller om det helt enkelt är den förbättrade informationsspridningen. En stor fråga har varit om det verkligen är nödvändigt för leverantören att ta över styrningen av kundens lager för att förbättringarna ska vara tydliga.</p>

Vibrio parahaemolyticus is a Gram-negative, halophilic pathogen that occurs naturally in coastal and estuarine environments. This human pathogen is frequently isolated from a variety of seafood, particular oysters, and is the leading cause of gastroenteritis associated with seafood consumption. Several outbreaks of V. parahaemolyticus infections linked to consumption of raw oysters have been documented. Contamination of oysters with V. parahaemolyticus is a concern for public health. This study investigated the efficacy of high pressure processing (HPP) in inactivating V. parahaemolyticus in raw Pacific oysters (Crassostrea gigas) and identified a process condition capable of achieving greater than 3.52-log reductions of V. parahaemolyticus in raw oysters for commercial application. Raw Pacific oysters were inoculated with a clinical strain of V. parahaemolyticus 10293 (O1:K56) to levels of 10⁴⁻⁵ cells per gram and processed at 293 MPa (43K PSI) for 90, 120, 150, 180 and 210 s. Populations of V. parahaemolyticus in oysters after processes were analyzed with the 5-tube most probable number (MPN) method. A minimum HPP of 293 MPa for 120 s at groundwater temperature (8±1 °C) was identified capable of achieving greater than 3.52-log reductions of V. parahaemolyticus in Pacific oysters. The HPP (293 MPa for 120 s at 8±1 °C) was validated at a commercial scale according to the FDA's National Shellfish Sanitation Program Post Harvest Processing (PHP) Validation/Verification Interim Guidance for Vibrio vulnificus and Vibrio parahaemolyticus. Negative results obtained by the MPN method were confirmed with a multiplex PCR detecting genes encoding thermolabile hemolysin (tl), thermostable direct hemolysin (tdh) and TDH-related hemolysin (trh). Oysters processed at 293 MPa for 120 sec had a shelf life of 6-8 days when stored at 5 °C or 16-18 days when stored in ice. This validated HPP was accepted by the FDA as a post harvest process to eliminate V. parahaemolyticus in raw oysters. / Graduation date: 2012

Bakgrund: Historiskt har företag haft stora lager för att kunna möta kundernas efterfrågan. I takt med att kundanpassning och flexibilitet har ökat har det blivit allt dyrare och näst intill omöjligt att hålla lager som kan tillgodose kundernas behov. Att styra sitt lager så att det motsvarar efterfrågan har nästan varit en omöjlighet. En lösning på lagerstyrningsproblematiken är Vendor Managed Inventory (VMI) som innebär ett tätare samarbete mellan kund och leverantör. Kunden tillhandahåller information om lager och efterfrågan och leverantören tar över ansvaret för att varorna i kundens lager inte ska ta slut. Litteraturen kring VMI tar upp många positiva effekter som kommer att inträffa vid ett VMI-samarbete. Dock är det skralt med empiriska undersökningar beträffande effekterna av införandet av ett VMI-samarbete. Syfte: Syftet med uppsatsen är att undersöka ett VMI-samarbete mellan en leverantör och en kund för att se om det finns empiriskt stöd för de kostnads- och leveransserviceeffekter som teorierna kring VMI tar upp. Genomförande: Vi har undersökt samarbetet mellan Abba Seafood och ICA Handlarna. Vi intervjuade personer på båda företagen. Respondenterna hade antingen ett övergripande ansvar för VMI-samarbetet eller kom i kontakt med VMI i det dagliga arbetet. Resultat: Efter att ha analyserat samarbetet mellan Abba och ICA så kan vi konstatera att många av de positiva effekter som kan förväntas av ett VMI- koncept har infriats och några inte. Vad vi inte kan fastställa i alla lägen, är om det är just VMI som är bakgrunden till förbättringarna, eller om det helt enkelt är den förbättrade informationsspridningen. En stor fråga har varit om det verkligen är nödvändigt för leverantören att ta över styrningen av kundens lager för att förbättringarna ska vara tydliga.

The consumption of seafood in the United States has increased rapidly in recent years due to high quality protein and health benefits of seafood. Seafood can be a carrier for bacteria normally distributed in the marine environment and, in some cases, can be contaminated by human pathogens. Therefore, there is a potential health risk if seafood is consumed raw or undercooked. However, information regarding prevalence of foodborne pathogens in retail seafood products and the ability of pathogens to survive in the products during refrigerated and frozen storage is limited. The objective of this study was to generate such information for a better understanding of distribution of foodborne pathogens in seafood products and provide data which might be used for risk assessment of foodborne infection associated with seafood consumption. A total of 45 seafood products were collected from local retail stores and analyzed for aerobic plate counts (APC) and psychrotrophic bacterial counts (PBC) as well as presence of foodborne pathogens, including Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, Staphylococcus aureus, Vibrio parahaemolyticus, and Vibrio vulnificus according to procedures described in the U.S. Food and Drug and Administration Bacteriological Analytical Manual (BAM). Presumptive isolates for each foodborne pathogen were further characterized by biochemical reactions using commercial identification kits and confirmed with polymerase chain reaction (PCR) assay. The samples had bacterial populations ranging from 1.90 to 6.11 CFU/g for APC and from 2.00 to 6.78 CFU/g for PBC. According to the microbiological criteria of International Commission on Microbiological Specifications for Foods (ICMSF), all 45 samples were considered acceptable quality (APC < 10⁷ CFU/g, E. coli < 3 MPN/g) with most samples (93.3%) being good quality (APC < 5 × 10⁵ CFU/g, E. coli < 3 MPN/g). No E. coli O157:H7, Salmonella, S. aureus, V. parahaemolyticus, and V. vulnificus was detected in any samples. Two previously frozen shrimp products (4.4%) were confirmed to carry L. monocytogenes. Studies of growth and survival of L. monocytogenes (3 strains), S. aureus (2 strains), and Salmonella (2 serovars) in raw yellowfin tuna meat stored at 5 - 7 °C for 14 days revealed that L. monocytogenes had the ability to multiply in the tuna meat during refrigerated storage while populations of S. aureus and Salmonella were reduced by 1 to 2 log CFU/g after 14 days at 5 - 7 °C. Studies of holding raw yellowfin tuna meat contaminated with L. monocytogenes, S. aureus, and Salmonella at -18 ± 2 °C for 12 weeks observed that all three pathogens, except Salmonella Newport, in tuna samples survived the frozen storage with less than 2- log of reductions in the populations over 12 weeks of storage. No viable cell of Salmonella Newport was detected in samples after 42 days storage at -18 °C. Raw seafood can be a carrier of foodborne pathogens, particularly L. monocytogenes, and many foodborne pathogens can survive in frozen products for several months. Consumption of raw or undercooked seafood products may lead to human infection if the products are contaminated with pathogens. Therefore, sanitation standard operating procedure (SSOP), good manufacturing practice (GMP) and hazards analysis and critical control points (HACCPs) programs shall all be implemented in the seafood industry to prevent seafood products from being contaminated with foodborne pathogens during handling and processing. Moreover, proper storage of raw seafood products and avoiding cross-contamination during handling at the retail levels also helps to minimize risk of human infection associated with ready-to-eat products. / Graduation date: 2013

Innovative ways to conduct disease surveillance are required to address the complexity of Ciguatera Fish Poisoning (CFP). Mixed methods were employed to explore CFP epidemiology and interdisciplinary approaches to its surveillance in the Turks and Caicos Islands (TCI). Quantitative analyses of cross-sectional data collected by the TCI’s National Epidemiology and Research Unit in 2010 demonstrated that a low percentage of residents reported lifetime histories of illness following fish consumption (3.9%). Furthermore, gender, age, island, and home remedy use were significantly associated with reported clinic visitation by ill individuals. Next, a multisectoral CFP surveillance model was conceptualized. A qualitative exploration of the model’s hypothetical integration into TCI’s health system revealed that several systemic and contextual factors could influence the future uptake of interdisciplinary CFP surveillance. Targeted interventions are recommended to improve national CFP surveillance and to facilitate the growth of interdisciplinary networks between stakeholders from TCI’s health, fisheries and environment sectors. / Canadian Institutes of Health Research, Ontario Veterinary College, University of Guelph, Ministry of Health and Human Resources of the Turks and Caicos

Planar electromagnetic sensing system has been used as one of the NDT methods to evaluate the material properties i.e., to evaluate near-surface properties such as conductivity, permeability and dielectric properties. The applications of planar electromagnetic sensors will depend on both the characteristic of the sensor type chosen and also the characteristic of material under test. Conventional planar interdigital sensors and novel planar interdigital sensors have been designed, fabricated and tested for detection of dangerous marine biotoxins in seafood. Our main objective is to sense the presence of dangerous contaminated acid in mussels and other seafoods. Initial studies were conducted with three peptide derivatives namely Sarcosine, Proline and Hydroxylproline. These three chemicals are structurally closely related to our target molecule (domoic acid). The initial results have shown that all sensors respond very well to the chemicals and it is possible to discriminate the different chemicals from the output of the sensor. Novel interdigital sensors have shown better sensitivity measurement compared to conventional interdigital sensors. The novel interdigital sensors were then being tested with three seafood products. Results from the analysis have shown that novel interdigital sensor with configuration #1 (Sensor_1) has better sensitivity compared to other sensors. Sensor_1 has been chosen for experiment using proline and mussels. The changes in sensor sensitivity were analysed with mussels before and after adding the proline. The presence of proline on the mussel surface and also injected proline to the mussel samples were clearly detected by Sensor_1. Further experiment was conducted with small amount of domoic acid (0.5 µg to 5.0 µg) injected to a mussel and it was found that Sensor_1 was able to detect small amount of domoic acid (1.0 µg) injected into the mussel sample. Sensor_1 was able to detect approximately 12.6 µg/g of domoic acid in mussel meat. Three threshold levels of particular sample thickness have been established for detection of domoic acid. The first prototype of a low cost sensing system known as SIT (Seafood Inspection Tool) has been developed. The outcomes from the experiments provide chances of opportunity for further research in developing a low cost miniature type of sensors for reliable sensing system for commercial use.