Dissertations / Theses on the topic 'Seafood'

The thesis focuses on quality and safety aspects of different types of seafood by using a multidisciplinary approach, combining different types of analyses (behavioural studies, haemolymph analyses, microbiological and chemical-physical analyses) and regulatory aspects. The thesis consists of a collection of scientific papers and laboratory activities that report the main studies of my PhD research. In the first study the evaluation of the stress level during lobster commercialization was evaluated by analysing eight different haemolymph parameters. The second study faced the potential application of a new Loop-mediated isothermal amplification (LAMP) assay for the detection of Anisakis spp. in seafood products. The third study shows the preliminary results of an ongoing investigation that aims at developing a method suitable for the extraction of microplastics from mussels. The fourth study compared the chemical composition in fish roe products from different species in order to achieve a deeper knowledge of the chemical and microbiological composition of fish roe products collected on the Italian market.

Thesis (Ph. D.)--Michigan State University. Dept. of Agricultural, Food, and Resource Economics, 2008.
Title from PDF t.p. (viewed on July 23, 2009) Includes bibliographical references. Also issued in print.

The present study quantifies the revenues generated by marine seafood in the retail and restaurant sectors. Also, since one third of total marine catch is used to produce fishmeal, revenues generated by this commodity were calculated based on the percentage of meat products that originated from fishmeal inclusion in compound-feed formulas. In total, wild seafood products generated revenues of US $318 billion in the year 2005. To arrive at this estimate I first developed a global database of seafood retail revenues, which is used to analyze fish retail values per tonne at the regional and global level. This database includes 192 maritime and non-maritime countries. The findings are that in 2005, revenues, from wild marine seafood in the retail sector alone reached US $210 billion. Revenue from seafood restaurants were calculated based on estimations of country GDP expenditures in the hotel and restaurant sector. By analyzing the data on 30 countries (US and EU countries) where primary data on restaurants and hotel were reported separately, I estimate that on average, in the US and the EU countries where data is available, 43 percent of revenues from hotels and restaurants are attributable to restaurant sales. Wild seafood restaurant sales represented 17-25% of global restaurant sales generating revenues of US $94 billion. Finally, in order to estimate the revenues from the fishmeal sector, calculations were made based on farmed fish and animal meats, which include fishmeal in their compound feed preparation. Revenues derived from animal and fish meats were calculated based on their FCR (food conversion ratios) and inclusion rates of fishmeal for each species. I estimate that US$14 billion were generated by the inclusion of fishmeal in meat products.

In this thesis, I conducted an analysis of the consumption patterns associated with demographic and socio-economic characteristics, using Tobit and double-hurdle models. Data were collected for 11,574 households from the US Bureau of Labor Statistics for the year of 2014. Specific determinants included household size, age, income, gender, education, race, region, marital status, and whether the household lived in a coastal state. The results reveal that seafood expenditures are sequential decisions. Asian racial groups, households headed by married couples, a large number of members in households, higher income households, and households residing in the Atlantic and Gulf Coasts were variables that significantly impacted seafood expenditures.

Thermal properties of ten different seafood were measured in this research. They included bluefish (Pomatomus saltatrix), croaker (Micropogonias undulatus), spanish mackerel (Scomberomorus maculatus), pink salmon (Oncorhynhus gorbuscha), black seabass (Atractoscion nobilis), spot (Leiostomus xanthurus), shrimp(Pandalus borealis), tilapia (Tilapia aurea), grey sea trout(Cynoscion regalis), and yellow fin tuna (Thunnus albacares) (Wheaton, et al. 1985). Thermal properties measured were thermal conductivity, thermal diffusivity, and specific heat from 5 to 30^oC. Enthalpy was measured from -40 to 30^oC. Moisture and fat content were measured. Thermal conductivity and thermal diffusivity were measured by a rapid transient technique using a bead thermistor probe. Specific heat and enthalpy were measured using a differential scanning calorimeter. Moisture content and fat content were measured by the AOAC specified oven dry method and ether extraction method, respectively. The measured thermal properties agreed well with the scarcely available literature values. They were then statistically correlated with moisture and fat content. Based on statistical analysis, mathematical models relating thermal properties and composition were proposed and compared with the models available in the literature. Models for thermal conductivity and specific heat were recommended to predict these properties of meats and fish with similar composition.
Master of Science

Several factors related to the proper shipping of fresh seafood by airplane were studied in this thesis. These included precooling, gel pack effectiveness, external temperatures encountered by shipping containers, and coolant placement in a shipping container. Experiments were conducted to determine cooling times of 10 and 20 pound boxes and 10 pound bags of whole fish. The ”10-pound” box was then modelled using finite element techniques. The model was found to accurately predict the temperature response of the box for a constant temperature boundary condition. Different boundary conditions were applied to the model. These were: constant temperature (such as an ice-slurry); low, medium and high velocity air (such as in a commercial refrigerator). The model was then used to predict cooling times for the other boundary conditions. The enthalpy needed to thaw the contents of different gel packs was measured and compared to that of ice. None of the gel packs had as high an enthalpy as ice. In addition, the warming characteristics of the gel packs with the highest enthalpy was compared to those of ice. It was found that the warming characteristics of the gel pack appeared to be similar to that of ice. The actual shipment of seafood to distant markets was studied by sending a data logger with several shipments to the west coast and collecting temperature data every 5 minutes during these shipments. Temperatures in 12 different locations were measured. Of particular interest were the outside temperatures which were later used in the modeling of the shipments. The shipments were sent in EQ containers. The containers experienced a wide range of temperatures. A finite element model was developed to predict the temperature of seafood under simulated transport conditions. Two boundary conditions were applied to the model; these were still air at 30°C and the approximate temperatures encountered during one of the shipments. Three different arrangements of coolant placement were studied. These were all ice on top of the product, half the ice on top and half in a layer in the middle of the product, and half of the ice on top of the product and half of the ice below the product. The latter arrangement provided the most uniform temperature distribution of the three through 18 hours of simulation. It was also found that shipments should be delivered in less than 24 hours for the amount of coolant used.
Master of Science

The aim of the thesis is to analyze the organizational culture of the company SEAFOOD Ltd. and propose a set of measures which would contribute to strengthening the organizational culture of the company. Before starting the research the theoretical materials were investigated and hypotheses were set. The main theoretical basis in this thesis is the theory of E.H. Schein. During the work there were discussed as positive impacts of the organizational culture, as well as its restrictive side. In this work was also mentioned the issue of connection between the individual characteristics and qualities of the individual and his working career. After carrying out research, which consisted of writing surveys filled by company employees, guided interviews with some managers and observations, the conclusion about the current level, the problems and the strong sides of the organizational culture SEAFOOD Ltd. was made. After the conclusion there was suggested a set of actions which should lead to the strengthening of the organizational culture of the company and contribute to a higher level of identification of the company's employees with SEAFOOD Ltd.

People derive benefits from the seafood trade including food security, work and profits. As trade increases worldwide, the impacts of seafood production increase and are known to include overfishing and labour abuses in distant source areas, including the developing countries that provide most of the world’s seafood. Over the past decade, as demand for sustainably certified wild-caught seafood has begun to increase, seafood buyers, sellers and NGOs have taken voluntary measures to encourage sustainable seafood production, but without knowledge of the effects. What kinds of effects result from voluntary industry measures for sustainable seafood? Do the effects improve the social and environmental impacts of seafood production? Drawing from quality assurance methods and sustainability theory, seven voluntary measures taken in the private sector between 2008 and 2014 were evaluated for their effects against ten qualitative attributes said by sustainable seafood scholars to be necessary conditions for stewardship of common pool natural resources. Results indicate that the seven measures led to new forms of industry self-regulation that help to control some input variables of overfishing and to some increased compliance across supply chains. New empirical information was produced by the measures to determine where change is needed to solve conflicts and to reduce risks where they occur in seafood production. Some measures made access to resources more secure for business. Others provide diagnostic tools to reduce risks for overfishing, illegal fishing and forced and trafficked labour in seafood supply chains. Overall the measures helped the private sector to see and understand what is happening in source fisheries and to agree on ways to fix unsustainable practices.
Graduate and Postdoctoral Studies
Graduate

SEAFOOD SAFETY: A MATTER OF ANY CONCERN ? Determination of Carbon Monoxide in Tuna by Gas Chromatography with Micro-Thermal Conductivity Detector. The suitability of a portable gas chromatograph equipped with a micro-thermal conductivity detector for the head-space determination of carbon monoxide (CO) in tuna samples is evaluated. Preliminary study on prevalence of larvae of Anisakidae family in European sea bass (Dicentrarchus labrax). A total of 561 fresh European sea bass from North-East Atlantic ocean were examined for Anisakidae larvae detection. It is the first record on the prevalence of Anisakidae larvae in this fish specie. An unexpected high prevalence was found. The results have an important consequence on epidemiology of anisakidosis and public health risk assessment. A case study: shelf-life of smoked herring fillets by volatile compounds analysis. Two different products of vacuum packed cold smoked herrings were analyzed at time intervals in order to evaluate the efficiency of the processing and product stability. Microbiological total counts, lactic acid bacteria, total coliforms, pH, water activity, water content, salt content (WPS) were determined. Shelf-life of vacuum packed cold-smoked salmon from italian market. Fourteen samples of different vacuum packed cold smoked salmon products purchased in Italian retail were analysed at about half shelf-life and at the expiry date. On the expiry date 12 samples were above the limits. Levels of Enterobacteriaceae and coagulase-positive staphylococci were very low, and no potential pathogenic bacteria were detected.

This study examined how adult guests to the California Science Center engage with a specific conservation education topic: sustainable seafood. Sustainable seafood is a common education message delivered in informal science institutions. This study also investigated whether engaging in an activity about sustainable seafood while simultaneously viewing live fish species would have a greater impact on guests than participating in the same activity while viewing a laboratory space.

The data showed that guests who participated in a hands-on activity about sustainable seafood knew more about conservation-related topics and were more likely to adopt behaviors conducive to sustainable seafood consumption than guests who participated in a different hands-on activity. The data also showed that the settings in which guests participate in this Sustainable Seafood activity do not influence their knowledge or behavior. This indicates that this Sustainable Seafood activity is effective in educating adult guests, regardless of the setting.

Sustainable development of export-orientated farmed seafood in Thailand is a major issue which can impact local stakeholders as well as global food security. The major species taken into consideration in this research were initially the Pacific white shrimp (Litopenaeus vannamei), Nile tilapia (Oreochromis niloticus), giant freshwater prawn (Macrobrachium rosenbergii), and striped catfish (Pangasianodon hypophthalmus). After which more focus was placed on Pacific white shrimp, which is Thailand’s major cultured seafood being traded for export, and tilapia, which has potential for export but also enjoying a good domestic market demand. Actors or stakeholders directly and indirectly involved in aquaculture value chains may have their own perceptions about sustainability affecting their operations, as various factors within and outside their own systems could affect these perceptions. This could lead to different efforts in responding to these factors to make their operations sustainable. Three major areas were covered in this study, namely a) describing the strengths and weaknesses of shrimp and tilapia production in Thailand in relation to their export potential, b) evaluating the status of compliance to global aquaculture standards of shrimp and tilapia farming (covering technical and labour aspects), and c) determining perceptions of sustainability across the shrimp and tilapia value chains in Thailand, with a focus on the production sector. A mixed-methods approach was employed to obtain information in the study sites in Thailand. Basic field interviews were conducted among 206 shrimp producers in 6 provinces in the east and south, and 199 tilapia producers in 4 provinces in the west and east, in terms of farm operations and perceptions of factors which will affect the sustainability of their operations, including generational aspects on future shrimp and tilapia farming. Key informant interviews were also conducted among other value chain actors (>30) such as hatchery/nursery operators, input/service providers, processors/exporters and technical/ institutional members to determine whether there are differences in their sustainability perceptions. In addition, face to face interviews with 18 shrimp farm male and female workers were conducted (Thai and migrant workers), as well as with 14 key informants involved in shrimp farm labour issues in Thailand, specifically for well-being and working conditions. Stakeholders cited environmental (technical), economic, social and institutional (equity) aspects of their operations as factors which will affect the sustainability of their operations. Disease, product price and water quality were the three most important sustainability factors among shrimp farmers, whereas water quality, disease and extreme weather conditions were for tilapia farmers. Product price was the most cited by input service providers, hatchery operators, shrimp and tilapia producers, and processors. Both Thai and migrant shrimp farm workers perceived a better or much better-off quality of life working in shrimp farms in Thailand than in their previous occupations or status. Almost all shrimp farms meet more than what are required under the Thai labour law or the global aquaculture standards for human resources. With the importance of migrant labour in Thailand, much still needs to be done in terms of assessing the impact of their working in Thailand on their families left behind in their own countries, as well as on their communities, including status of social protection to avoid exploitation. Each stakeholder group strives to achieve sustainability so they can remain in operation in the next few years, to survive on the business individually and corporately, and to be the best provider of sustainably and ethically produced seafood for the world. The compliance to aquaculture global standards and certifications may be considered to contribute to the sustainability of operations by improving farm practices thereby reducing detrimental impacts on farm and external environments, as well as strengthening human relations with in the farm and in the community. However there are some aspects of these standards which could eliminate the small players. In this study, the large scale farms were more likely to comply with all the standards, followed by medium scale, and lastly the small scale farms. The differences in perceptions which exist among these stakeholders should be understood by every sector and efforts should be made to address them so that there is cohesiveness in giving support to achieve sustainable seafood production and trade.

UK consumers bought just under 500 thousand tonnes of seafood in 2010, at a cost of £3.8bn. Despite rising prices, consumption is on a general upwards path, with the average UK adult now eating 2% more seafood than they would have eaten a generation ago, and demand predicted to grow by a further 17% by 2030. However, this demand is increasingly restricted to a narrow range of imported and wild-caught species (Cod, Haddock, Tuna) and farmed products (Salmon and Prawns) over locally-available species with the consequence that between 60% and 80% of UK domestic landings are currently exported and 80% of all the seafood eaten in the UK is one of either Cod, Haddock, Salmon, Tuna or Prawns – the so-called Big 5. The shortage of local markets for native fish species is arguably reducing the relative viability of small scale, over large-scale, fisheries in the UK. It also increases pressure upon wild stocks of commercially valuable species and is driving the rapid expansion of fish-farming operations which can have negative environmental and social implications. Considering the above, it is suggested that UK consumers could make a positive contribution to the UK economy and marine environment if they chose to buy native, locally-caught species, over farmed and exotic imports. In order to achieve this, however, significant behavioural change would need to take place; and for behavioural change initiatives to be successful, it is argued that it is first necessary to understand why these consumption patterns have developed, i.e. Why the Big 5? Accepting that no single theory has been found that can fully explain behaviours from intentions, this research used mixed methods to develop a consumer-centric view of the full range of factors that might be driving these unsustainable consumption patterns. Regular consumers of seafood from four contrasting localities in England were recruited to complete surveys, maintain shopping diaries and to take part in group and one-to-one interviews to understand their reasons for eating seafood in general and the Big 5 in particular. Drawing on the Literature on seafood consumption, demographic and geographic-induced differences in consumption were explored; and consumer understanding of, and concern for, the sustainability of their seafood was assessed. Retail behaviour was also examined by undertaking an on-line review of the seafood offered for sale by the UK’s five largest retailers. Consumers were generally ill informed and confused about the sustainability of their seafood and had little to no awareness of labelling. In their confusion/apathy, they tended to revert to habitual behaviours and safe choices tending towards the Big 5. They felt strongly that retailers should be making it easier for them to make sustainable choices. The evidence from this study is that Retail is failing in this respect. Interest in and demand for local seafood was very high, with consumers equating local with sustainable, even though the evidence to support this assertion is currently lacking. Consumer definitions of “local” and “sustainable” were found to vary from accepted policy and academic understanding, presenting the possibility of adding to consumer confusion when communicating about sustainable seafood; further, “sustainable” possessed negative connotations for these consumers who, in stark contrast to the average UK consumer, were found to score highly for Hedonism. In total, twenty eight distinct variables were identified as influencing unsustainable UK seafood consumer behaviour. Key amongst these were consumer ignorance/apathy regarding sustainability; retail behaviour; and habit – factors that are presented in the Trifold Model of Unsustainable Consumer Behaviour. This model brings much needed clarity to a complex and poorly understood area of consumer behaviour and marks a significant contribution to three areas of academic study: Sustainable Consumption; Consumer Behaviour; and Business Ethics. The Trifold Model is presented for further testing. Recommendations for policy and industry are highlighted as are areas for further research.

2012/2013
The increasing distribution of marine microalgae which may produce toxins poses concern on their possible accumulation in seafood, with possible toxic effects in humans after its consumption. Also in the Mediterranean Sea, microalgae producing okadaic acid (OA) and its analogues, the main diarrheic toxins contaminating edible shellfish, were frequently detected since several years. In addition, blooms of potentially toxic microalgae belonging to Ostreopsis genus, producing palytoxins (PLTXs), were also reported in the recent years. Simultaneously, PLTX and its analogue ovatoxin-a were identified in microalgal, shellfish and echinoderm samples. This phenomenon could represent a risk for human health since food borne intoxications, including some lethal cases, attributed to the consumption of seafood contaminated by palytoxin-like compounds, were reported in tropical areas. Furthermore, co-presence of microalgae producing OA and PLTXs and the possible consequent seafood contamination lead to consider the problem of toxic effects in humans due to a simultaneous exposure to both the toxins, which could induce synergistic effects. Thus, the aim of this study was to investigate the acute and short-term oral toxicity in mice by co-exposure to palytoxin and okadaic acid, in comparison to that of each single toxin. In particular, its aim is to identify not only the main toxic effects and the target organs, but also a NOAEL (No Observed Adverse Effect Level), useful in the assessment of subchronic toxicological risk, a situation that most likely corresponds to the toxin exposure by humans. The studies were carried out using female CD-1 mice (18-20 g body weight, 4 weeks old; Harlan Laboratories; S. Pietro al Natisone, Udine, Italy). All experiments were carried out at the University of Trieste, Italy in compliance with the Italian Decree n. 116/1992 as well as the EU Directive 2010/63/EU and the European Convention ETS 123. Initially, the effects of the acute oral administration of palytoxin (30, 90 and 270 g/kg) combined to OA (370 g/kg) were studied in comparison to those of the same doses of the single toxins. After gavage administration of the toxin or vehicle (phosphate buffered saline, containing 1.8 % ethanol; controls) to groups of 8 mice, the animals were monitored for 24 h (5 mice/dose) or 14 days (3 mice/dose) for symptoms. Aftr death or sacrifice, they were submitted to necropsy, taking also blood samples for hematochemical analysis and the main organs and tissues for the histological analysis by light microscopy. Within 24 h from the administration, toxic effects and lethality were recorded only in mice administered with the higher doses of PLTX (90 or 270 g/kg), alone or in combination with OA (370 g/kg). In addition, lethality was recorded only at the highest PLTX dose alone or combined with OA. The signs and symptoms recorded in mice (scratching, piloerection, abdominal swelling, ataxia, paralysis of the hind limbs, dyspnoea) were slightly more pronounced in mice administered with both the toxins with respect to those recorded in mice administered with PLTX alone. At 24 h from PLTX administration (90 or 270 g/kg), alone or with OA, necropsy showed redness and fluid accumulation in the small intestine and an increased liver weight, whereas histological analysis showed changes at the forestomach (slight ulcers and inflammation) and liver (reduced glycogen content). During the whole observation period, mice treated with the higher doses of PLTX, also combined with OA, showed a reduced body weight and food consumption, while no toxic effects were recorded after 14 days from the administration. Thus, the study showed a slight additive effect between PLTX and OA after acute oral administration, estimating a NOAEL of 30 g/kg for PLTX and 370 g/kg for OA in combination or as single toxins. Due to the lack of toxicity data on PLTX after repeated oral administration, a toxicity study on the toxin alone after its daily administration for 7 days was carried out. The toxin was administered to groups of 6 or 8 mice at four doses (3, 30, 90 or 180 g/kg/day) and the animals were observed up to 24 h after the last treatment or, for subgroups of 3 mice, up to 14 days. The toxin induced lethal and/or toxic effects at the dose of 30 g/kg/day and above, starting from the third day of treatment; some mice died also during the recovery period after the toxin administration. At these doses, a significant reduction of body weight, abdominal swelling, chromodacryorrhea, piloerection, dyspnoea, sedation and/or paralysis of the hind limbs were recorded during the treatment period. Necropsy revealed gastrointestinal changes (gastric ulcers and intestinal fluid) in mice died during the treatment period, while histological analysis showed lung inflammation, locally associated with necrosis, hypereosinophilia and separation of myocardial fibers and liver changes (reduced glycogen content and necrosis at the highest dose). These data allowed an estimation of a provisional NOAEL corresponding to 3 g/kg/day, with the evidence of a steep dose-response relationship. The last step of the research included the study of the toxic effects in mice induced by 7days oral administration of PLTX (3 and 10 g/kg/day) and OA (185 g/kg/day) association. Both the doses of PLTX combined to OA induced lethal effects, with signs or symptoms including scratching, dyspnoea, paralysis of the hind limbs and body weight loss. At 24 h from the last treatment, necropsy showed also the presence of fluid in the small intestine of mice administered with the highest dose of PLTX combined to OA, accompanied with a decreased liver weight. An effect on the liver was also evidenced by the increased transaminases serum levels and, in one mouse, by slight foci of necrosis, associated to thymus atrophy. On the contrary, no toxic effects were recorded after 14 days from the treatment, with the exception of a decreased body weight in mice administered with both PLTX doses combined to OA. Therefore, the study showed a slight potentiation of the toxic effects by the repeated oral co-exposure to PLTX and OA, which induced lethal and/or toxic effects that were not recorded after the administration of the single toxins. The overall results highlighted that the concomitant presence of palytoxin and okadaic acid, even if chemically different, could increase their toxicity profile and latent effects. Although no clearly evident synergic or additive effects were observed, they cannot be ruled out. The next steps would include a confirmatory study in a larger group of animals followed by a 14- and 28 day repeat dose study. Additional studies which may be useful in evaluating ‘true’ and realistic conditions of intoxications which should also include animal studies aimed to investigate the impact of age and of impairment of the gastrointestinal tract on the toxicity of seafood toxins. In addition, they should consider that the amount of contaminated seafood reported in the existing guidelines does not always represent the true amount ingested by the consumers, underlining the importance of assessing the exposure to low doses of toxins as done in these studies.
La crescente frequenza di proliferazioni di microalghe marine in grado di produrre tossine, pone il problema dell’accumulo di tali composti nei prodotti ittici, con possibili effetti tossici per l’uomo in seguito al loro consumo. Anche nel mare Mediterraneo, da anni viene rilevata la presenza di microalghe produttrici di acido okadaico (AO) e suoi analoghi, tossine diarroiche che possono contaminare i molluschi destinati all’alimentazione. Recentemente, si sono anche verificate anche proliferazioni di microalghe appartenenti al genere Ostreopsis, produttrici di palitossine). Contemporaneamente, nei campioni di microalghe, di molluschi ed echinodermi sono state rilevate la palitossina (PLTX) ed un suo analogo, l’ovatossina-a. Ciò pone il problema del rischio per l’uomo, poichè in aree tropicali sono state riportate intossicazioni alimentari, anche letali, attribuite all’assunzione di prodotti ittici contaminati da composti palitossino-simili. Inoltre, La co-presenza di alghe produttrici di palitossine e acido okadaico o loro analoghi, comporta una possibile contaminazione dei prodotti ittici, con effetti tossici nell’uomo conseguenti ad una co-esposizione ad entrambe le tossine e possibili effetti sinergici. Lo scopo della mia ricerca è stato pertanto quello di studiare la tossicità nel topo, acuta e a breve termine, conseguente alla co-esposizione orale alla palitossina e acido okadaico, in confronto a quella delle singole tossine, al fine di individuare gli effetti tossici principali e gli organi bersaglio, ma anche anche un NOAEL (No Observed Adverse Effect Level), da utilizzare per la valutazione del rischio subcronico, verosimilmente lo scenario più rispondente all’esposizione umana. Gli studi sono stati condotti su topi CD-1 di sesso femminile (18-20 g di peso corporeo, 4 settimane; Harlan Laboratories; S. Pietro al Natisone, Udine, Italia). Tutti gli esperimenti sono stati condotti presso l'Università di Trieste in conformità con il Decreto Italiano n. 116/1992, nonché la Direttiva 2010/63/UE dell'UE e la Convenzione europea ETS 123. Inizialmente, sono stati studiati gli effetti indotti dalla somministrazione acuta della palitossina (30, 90 e 270 µg/kg) in associazione con l’acido okadaico (370 µg/kg), rispetto a quelli indotti dalle stesse dosi delle singole tossine. In seguito alla somministrazione intragastrica delle tossine o del veicolo (soluzione salina tamponata con fosfato contenente l’1.8 % di etanolo; controlli) a gruppi di 8 topi, gli animali sono stati monitorati per 24 ore (5 topi/dose) o 14 giorni (3 topi/dose), registrando i sintomi e la sopravvivenza. Dopo il decesso o il sacrificio, è stato effettuato l’esame necroscopico, prelevando campioni ematici per l’analisi ematochimica ed i principali organi e tessuti per l’analisi istologica al microscopio ottico. Entro 24 ore dalla somministrazione, solo nei topi trattati con PLTX alle dosi maggiori (90 o 270 g/kg), singolarmente o con AO (370 g/kg), sono stati rilevati effetti tossici anche letali (letalità: 2/5 topi, in ogni gruppo). In seguito, effetti letali si sono verificati solo alla dose più alta di PLTX, singolarmente (1/3 topi, giorno 9) o con AO (2/3 topi, giorni 4 e 5). I sintomi ed i segni di tossicità (“scratching”, piloerezione, gonfiore addominale, atassia, paralisi agli arti inferiori e dispnea) erano lievemente più intensi nei topi trattati con entrambe le tossine rispetto a quelli dei topi trattati con la sola PLTX. Entro 24 ore dalla somministrazione della PLTX (90 o 270 g/kg), da sola o con l’AO, l’esame necroscopico ha rivelato arrossamento ed accumulo di liquido nell’intestino tenue ed un aumento ponderale del fegato, mentre l’analisi istologica ha evidenziato alterazioni gastriche (lievi ulcerazioni ed infiammazione allo stomaco non ghiandolare) ed epatiche (riduzione di glicogeno negli epatociti). Durante tutto il periodo di osservazione, nei topi trattati con le dosi più alte di PLTX, anche in combinazione con l’AO, sono stati inoltre rilevati un lieve calo del peso corporeo ed una lieve riduzione del consumo di cibo. Negli animali sopravvissuti fino a 14 giorni dal trattamento non sono state invece osservate alterazioni di rilievo. Lo studio ha così evidenziato un lieve effetto additivo tra PLTX ed AO dopo somministrazione acuta per via orale, stimando dei valori di NOAEL pari a 30 g/kg per la PLTX e 370 g/kg per l’AO, singolarmente o in combinazione. Vista la mancanza di studi di tossicità della PLTX dopo ripetute somministrazioni orali, prima di valutare gli effetti della sua somministrazione ripetuta con l’AO, è stato condotto uno studio di tossicità ripetuta sulla sola PLTX. Questa è stata somministrata a gruppi di 6 o 8 topi, una volta al giorno per 7 giorni, a quattro dosi (3, 30, 90 e 180 µg/kg/die). Gli animali sono stai osservati fino a 24 ore dall’ultimo trattamento e, sottogruppi di 3 topi, fino a 14 giorni. Il trattamento ha causato effetti letali e/o tossicità a partire dalla dose di 30 μg/kg/die, dal terzo giorno e, in alcuni casi, il decesso si è verificato durante il periodo di “recovery” in assenza di trattamento, indicando che gli effetti non sono totalmente reversibili. A tali dosi, durante il trattamento sono stati rilevati un significativo calo del peso corporeo, gonfiore addominale, cromodacriorrea, piloerezione, dispnea, sedazione e/o paralisi agli arti posteriori. Alterazioni macroscopiche gastrointestinali (ulcere gastriche e presenza di fluido intestinale) sono stati osservati nei topi morti durante il periodo di trattamento, mentre l’analisi istologica ha rilevato un’infiammazione polmonare, localmente associata a necrosi, iper-eosinofilia e separazione delle fibre nel miocardio ed alterazioni epatiche (ridotto contenuto in glicogeno e necrosi alla dose maggiore). Dai dati ottenuti è stato possibile calcolare un NOAEL “provvisorio” pari a 3 μg/kg/die, indicando una relazione dose-effetto piuttosto ripida. Sono stati quindi studiati gli effetti di 7 giorni di somministrazione con PLTX (3 e 10 g/kg/die) ed AO (185 g/kg/die), osservando che entrambe le dosi di PLTX associate con l’AO hanno causato effetti letali (1/8 topi a 3 g/kg/die ed 1/8 a 10 g /kg/die di PLTX in combinazione con l’AO/kg, nei giorni 7 e 8). Negli stessi gruppi, durante il periodo di trattamento gli animali avevano manifestato “scratching”, dispnea, paralisi agli arti posteriori e calo del peso corporeo. A 24 ore dall’ultimo trattamento, l’analisi necroscopica ha inoltre rivelato un accumulo di fluido nell’intestino tenue dei topi trattati con la dose maggiore di PLTX ed AO, accompagnato da un significativo calo ponderale del fegato. Un effetto a livello epatico è stato evidenziato anche da un incremento delle transaminasi sieriche e, in un topo, da lievi focolai di necrosi epatica, accompagnata da atrofia del timo. A 14 giorni dalla fine del trattamento non sono state invece rilevate significative alterazioni, eccetto un calo del peso corporeo degli animali trattati con l’associazione di AO e PLTX ad entrambe le dosi. Lo studio ha pertanto rivelato un potenziamento della tossicità da co-esposizione orale di PLTX ed AO, in grado di determinare effetti letali ed alterazioni non rilevabili dopo somministrazione delle singole tossine. I risultati complessivi hanno evidenziato che la presenza concomitante delle due tossine, benchè chimicamente differenti, potrebbe aumentare il loro profilo di tossicità esercitanto effetti latenti; anche se non sono stati osservati chiari effetti sinergici o additivi, questi non possono essere completamente esclusi. La caratterizzazione del rischio dovrebbe progredire con studi aventi un gruppo più ampio di animali ed un trattamento prolungato a 14/28 giorni ed oltre. Questi studi, mimando le condizioni alle quali avvengono le intossicazioni umane dovranno includere specifiche valutazioni volte ad indagare l'impatto del fattore età, del deterioramento del tratto gastrointestinale, della variabilità inter-individuale nonchè la possibile attività mutagena delle tossine. Inoltre, l’attuale legislazione dovrebbe essere rivista alla luce della reale quantità ingerita di molluschi da parte dei consumatori, sottolineando l'importanza della valutazione di dosi che producano intossicazioni non clinicamente evidenziabili, come effettuato in questi studi.
XXVI Ciclo
1978

In a world where the human population is increasing, new innovations to produce enough food are required. Aquaculture’s part of the global animal protein production has increased in recent years and could be a possible solution. However, if aquaculture is poorly managed, it can result in negative consequences and one such consequence is the development of antibiotic resistance. In this review, I examine how aquaculture affect antibiotic resistance by studying what the literature says on accumulation of antibiotics in different organisms and sediment, if antibiotics can be transferred to humans through consumption of antibiotic treated products, and if human pathogens in aquaculture farms may acquire antibiotic resistance. Furthermore, I examine what factors are contributing to irresponsible antibiotic use and how such use is managed. The result of this review indicate that antibiotics are able to accumulate in organisms and sediment. It is not clear however how consumption of these affect human microbiomes. In contrast, it is clear that antibiotic resistance can be transferred from antibiotic-resistant bacteria to human pathogens. Regarding antibiotic use, irresponsible use foremost exists in low-income countries and the main drivers behind such use are socioeconomic ones, such as lack of knowledge, poverty and food security. Finally, I propose possible solutions that might improve future management.
I en värld där den mänskliga befolkningen ökar krävs nya innovationer för att producera tillräckligt med mat. Vattenbrukets andel av den globala animaliska proteinproduktionen har ökat de senaste åren och kan ses som en potentiell lösning. Om vattenbruk dock hanteras ansvarslöst kan det uppstå negativa konsekvenser. En sådan konsekvens är utveckling av antibiotikaresistens hos skadliga bakterier. I denna litteraturstudie undersöker jag vattenbrukets påverkan på antibiotikaresistens genom att studera vad litteraturen säger om ackumulation av antibiotika i olika organismer och sediment, om antibiotika kan överföras till människor genom konsumtion av antibiotikabehandlade produkter, och om mänskliga patogener i vattenbruksodlingar kan förvärva antibiotikaresistens. Jag undersöker också vilka faktorer som bidrar till ansvarslös antibiotikaanvändning och hur den hanteras ur ett hållbarhetsperspektiv. Resultaten i denna studie tyder på att antibiotika kan ackumuleras i organismer och sediment men att det råder oklarheter huruvida konsumtion av antibiotikabehandlad mat påverkar mänskliga bakteriekulturer. Antibiotikaresistens kan dock överföras från antibiotikaresistenta bakterier till mänskliga patogener. Ansvarslös antibiotikaanvändning sker huvudsakligen i fattigare länder och det är förmodligen i stor utsträckning till följd av socioekonomiska faktorer som okunskap, fattigdom och livsmedelstrygghet. Slutligen föreslår jag lösningar som möjligen kan bidra till bättre hantering av framtida antibiotikaanvändning.

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 regionâ s lightness factor, which a consumer may consider as opaqueness, more accurately represented the thermal doneness than the external qualities. The FDAâ 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

This thesis is intended to improve the understanding of China’s evolving export-oriented farmed seafood systems, and in particularly, shrimp and tilapia farming value chains in Southern China. An integrated, systems thinking and interdisciplinary approach in which both top–down and bottom–up approaches were combined. The research moved from system reviews, to field surveys and workshops, and then to improving sustainability by Action Research (AR), in order to form a holistic understanding of sustainability at both national and local scales. In the new millennium, the aquaculture sector has matured, and many factors now slow the growth rate of Chinese aquaculture production, such as increasing culture of high-value species and an emerging trend of extensification. There are been some strategy shifts in the aquaculture industry such as changing from a high production to high profit orientation and from causing environmental damage to ecological remediation. A key conclusion is that high growth rates, regularly used in policy dialogues, are misleading indicators and do not reflect, realistic or sustainable, growth profiles. Although overall Chinese aquaculture production is likely to further increase to meet an increasing and changing market demand, growth rates will decrease further. China already is and will continue to be a fisheries products net importer, however, if fishmeal excluded China will remain as a seafood net exporter. The status and development of four internationally-traded farmed seafood, tilapia, penaeid shrimp, macrobrachium prawns and striped catfish in China were reviewed. China is the largest producer of tilapia, penaeid shrimp and macrobrachium prawns, and striped catfish is not produced in significant quantities due to climate limitations. Meanwhile, China is the largest exporter of tilapia, the second largest exporter in the volume and third in value of shrimp in the world, while macrobrachium prawns mainly support domestic markets. Tilapia and penaeid shrimp were selected for further research. An analysis of tilapia and shrimp farm scale indicators and their relationship to farming system and market orientation, farm intensification and performance was made. Farm area, both land and water area, labour, including paid and unpaid were effective indicators to distinguish farm scale. Small-scale farms had higher land productivity in production terms but no difference in value output term, and they had much lower labour productivity than medium and large-scale farms. Farming systems were also correlated with land and labour productivities. Market orientation was closely linked to farm scale as most farms with an export orientation required registration with CIQ (China Entry-Exit Inspection and Quarantine) and were mainly large-scale. An assessment of local stakeholder sustainability perspectives along value chains revealed that more than 80% shrimp and tilapia farmers didn’t want their children to continue basing their living on aquaculture; because they considered it hard work, high risk and poorly remunerated. Farming was comparative stable with few changes in the five years prior to the survey. Major sustainability factors identified by stakeholders included input costs, profit, water availability & quality and the weather, most of which were outside their control. The measurement of these sustainability factors was firstly proposed by stakeholders and then developed to a set of sustainability indicators (SIs). Life cycle assessment (LCA) was used as evaluate the environmental performance of tilapia, pig and integrated tilapia-pig farming systems in China. Pig farming had higher environment impacts based on most impact categories than tilapia, and integrated farming systems. Sensitivity analysis showed that improvements of 5% and 10% higher feed efficiency, reduction of fishmeal in feed to 1% level and use of EU electricity could significant reduce overall environmental impacts. An action research (AR) approach was used to assess the practice of farm record keeping with farmers which were found to be generally low and a major constraint to improving product traceability increasingly demanded by consumers. Large scale and CIQ farms were more likely to keep records and for them to be detailed and analysed to inform improved management. Farmers’ motivation, ability and capability and background had significant correlation with record keeping practice. Two major dilemmas were identified by the analysis. Easy-to-use farm record-keeping system more suitable for less formally educated farmers was a clear requirement but useful storage and analysis of farm data capacity requires sophisticated management tools such as a computer system. Another dilemma is the need for coercion by regulatory authorities or encouragement through provision of education and training in increasing on-farm record-keeping to a level required for international trade and, increasingly, domestic markets. “Precision aquaculture”, value chain integrated solution, and further social-economic reforms were discussed. Finally, sustainable intensification, diversification, and extensification were proposed as strategies for China to meet the challenges of globalization and the growing demands of export and domestic value chains. In order to enhance sustainability of the sector and provide opportunities for small-scale farmers, the current status and changes of the Chinese social, economic context, food safety and environments issues were discussed. Farmers’ organizations, future consolidation, and land reforms were identified as key to the required changes of farmed seafood value chains.

Shellfish and fish are sources of potent allergens in sensitised individuals. In view of the limited information available from published studies, especially on mollusc allergens, more detailed characterisation of the major allergens from different shellfish and fish is necessary to accurately predict cross-allergenicity. The need for a detailed characterisation of the immune response and the allergens in an indigenous mollusc species, followed a recent increase in patients presenting in the Cape Town area, with TY.pe I allergic reactions after ingestion of abalone (Haliotis midae). The first objective of this study was to determine the frequency and spectrum of reported hypersensitivity to abalone and other related seafood species in the Western Cape of South Africa. 105 volunteer subjects with suspected seafood allergy were recruited by means of a detailed seafood allergy questionnaire, advertised in the local press. The analysis of the questionnaire demonstrated clearly the importance of abalone, which was the third most frequently reported species (35%), after rock lobster and shrimp, of the 26 seafood species implicated in allergic reactions. Allergy to seafood was confirmed by the presence of specific IgE using in-house and commercial radioimmunoassays (RASTs). A novel Abalone-RAST identified specific IgE to abalone in 17/38 subjects who reported adverse reaction following the ingestion of abalone. The novel Abalone-RAST correlated positively not only with the phylogenetic closely related Snail-RAST (p<0.01) but also with squid and several indigenous crustacean species. Among subjects with multiple seafood allergies, the immune responses to molluscs species were found to be diverse. The presence of species specific allergens in the mollusc group was supported by the very low frequency of concurrent sensitivity to all mollusc species (13%) compared to concurrent sensitivity between mollusc and among the crustacea and fish group (42% and 56% respectively). The persistence of specific IgE, following a period of more than three years of seafood avoidance, was demonstrated in the mollusc species studied. The second objective was to investigate the specific immune responses to local seafood in more detail using RAST-inhibition experiments, skin prick tests (SPTs) and Western blots to demonstrate the presence of species-specific allergens. Sensitivity for the detection of abalone allergy was improved using an additional in-house SPT in six RAST negative subjects (23/38, 61 %). RAST-inhibition experiments with abalone extract demonstrated the highest degree of cross-reactivity with the Snail-RAST. In addition, a strong inhibition was achieved using commercial crustacean RASTs, confirming the presence of cross-reacting allergens in species of the same and other seafood groups. However, the low inhibitions achieved with the indigenous black mussel and squid extracts indicated that their allergen compositions differ from the species utilised in the commercial RASTs. Unique species-specific protein bands could be detected by SDS-gel electrophoresis, which clearly distinguished related mollusc species. These have not been demonstrated previously. Western blot analysis of different mollusc species identified several prominent allergens. An unexpected finding was the appearance of novel specific IgE binding reactivity after cooking the abalone. Several IgE binding proteins with similar molecular weights could be detected in immuno blots of indigenous crustacean and fish species. The next objective was to characterise the hypersensitive reactions to the local abalone species (H midae) in detail and identify the allergens found in this mollusc species. The questionnaire on abalone sensitive subjects revealed that asthma-like symptoms and the delayed onset of symptoms were frequent in sensitised individuals (42% and 34% respectively). This has previously only been reported for snail and in one case report on abalone. Surprisingly, the five abalone sensitive subjects who were studied in more detail had concurrent sensitivity to HDM and, analysed by RAST-inhibition, demonstrated two distinct types of responses. One set of subjects demonstrated a strong inhibition by HDM, indicating clearly for the first time that cross-reacting allergens or epitopes must exist between the food allergens from abalone and the air borne allergens found in HDM. SDS-gel electrophoresis demonstrated common but in addition species-specific protein bands even between very closely related abalone species from South Africa, Australia and Japan. Western blot analysis revealed two major allergens with molecular weights of about 38 and 45 kDa. Their remarkable thermal stability was demonstrated by various in-vitro and in-vivo assays. These two allergens were also present in extracts of other indigenous mollusc species, and surprisingly in some local crustacean and fish species. The individual immune responses to mollusc species were very heterogeneous for each analysed individual. The 38 kDa allergen is believed to belong to the protein family of tropomyosins, as was supported by specific IgE binding to recombinant tropomyosin of shrimp. This novel 45 kDa allergen of the South African abalone (H midae), was registered with the WHO International Union of Immunological Societies (IUIS) as Hal m 1. It is only the second allergen recognised for a mollusc species after Tod p 1 from squid. A further aim of these studies was to generate monoclonal antibodies (MoAbs) to the mollusc allergens using the hybridoma technology. The MoAbs were used, due to their consistent specific binding, to identify cross-reacting allergens among species of different seafood groups. In addition, I attempted to develop an immunologic test to distinguish between abalone species from different parts of the world. This test is of importance for the South African police to identify for forensic purposes unequivocally, fresh or processed abalone tissue exported illegally from South Africa to the Far East. Three ELISA- and Western blot assay positive clones were analysed. They demonstrated highly individual binding profiles when binding to fresh and cooked mollusc species was analysed. MoAb clones 2.11 and 2.12 (generated to the same protein of abalone) lacked complete binding to four and two of the ten abalone species respectively, allowing for very distinct species identification. Furthermore, antibody binding to cross-reacting proteins in crustacea and fish was also detected. Western blot results demonstrated clearly that these two antibodies bind to different epitopes on the same protein, making them very useful as tool for allergen and species identification. Finally, an amino acid analysis of the 3 purified antibody binding fractions of abalone was conducted. These proteins were rich in glutamine and asparagine, like tropomyosin, but differed significantly from tropomyosin with respect to serine content. The immunological findings using different patient specific sera and the monoclonal antibodies generated, provide important new information and insights into the concordant and multiple positive sensitivity to molluscs, crustacea and fish, and new information about the complexity and stability of immune responses to seafood and mollusc allergens observed in allergic subjects.

Over the past 60 years, the world’s marine fisheries have more than quadrupled their total output from 20 million t to around 80 million t. Yet, a closer examination of the catch statistics, as conducted in this thesis, reveals that this increase was achieved by geographical expansion of the global fisheries from the coastal waters off North Atlantic and Northwest Pacific to the waters in the Southern Hemisphere and into the high seas. The globalization of fisheries coincides with the globalization of seafood markets and an analysis of trade statistics carried out in this dissertation indicates net flows of marine fisheries resources into the markets of the EU, Japan and USA with their “consumption footprints” covering most of the world’s ocean. Recognizing the global limit to growth, various international initiatives have been launched in recent years to improve the state of world’s marine fisheries. This thesis examines fisheries subsidies negotiations at the World Trade Organization and its failure to reach an agreement, despite a general consensus that some forms of fisheries subsidies contribute to overcapacity and overfishing. The failure of the WTO negotiations exposes the difficulties of overcoming the status quo in fisheries. This thesis argues that improvements in our understanding of the states of world fisheries and their values and economic contributions are critical to achieving meaningful political actions. As such, the thesis explores two approaches for enhancing existing fisheries statistics. First, a new methodology for predicting the values of seafood across various national markets was developed, allowing improved economic evaluations of fisheries resources and the fisheries industry. Second, a recently developed catch-reconstruction method was applied to the fisheries of Japan to examine the scale of previously ignored components of marine fisheries catch even in countries where fisheries are generally considered to be data-rich. The two approaches presented, jointly, should enable the development of a more comprehensive picture of the state of marine fisheries which can then be presented to the public; a picture that, combined with other efforts by fisheries scholars around the world, I hope, will speak loud enough to initiate the transition to sustainable fishing.

Responsible Sourcing is gaining growing importance for companies willing to demonstrate responsibility and commitment to sustainable practices. Sourcing is a key element of supply chain management and by adopting responsible sourcing practices, companies can greatly contribute to the sustainability of their entire supply chains. Being close to both customers and suppliers, retailers hold a particularly influential position in the supply chain and their sourcing choices can play a key role for sustainability improvements. This paper investigates the different strategies that can be adopted to guarantee responsible sourcing in the retail sector, through the specific case study of two UK retailers, Sainsbury´s and Tesco, and their offer of sustainable seafood. Specifically, the relation between the offer of MSC certified products and the retailers´ commitment to source responsibly is here analysed. The main source of data collection is a content analysis of retailers´ CSR online reports and web pages. Additional information is obtained through reports and web pages’ analysis of four UK organizations dealing with sustainable seafood issues. The findings of the study suggest that the offer of MSC certified products is positively correlated with the adoption of responsible sourcing practices; different strategies are available to retailers to guarantee responsible sourcing and that retailers´ sourcing policies can be influenced by other stakeholders´ guidelines for responsible sourcing.

Aquaculture and fisheries hold promise for supplying a growing world population with healthy food produced without undermining the earth’s carrying capacity. However, just as livestock production and agriculture, seafood production can have negative environmental impacts and if a continuous or even increased supply is to be guaranteed, the pressure on affected ecosystems needs to be limited. Due in part to a perceived failure of other governance mechanisms in improving the environmental performance of the sector, a large number of voluntary market based standards for farmed and wild caught seafood have been developed. Nonetheless, the knowledge base on the extent to which implementation leads to environmental improvements remains limited. Moreover, the role of consumers in driving demand for eco-labeled seafood is presently an under-researched area. This thesis aims at reducing this knowledge gap through an examination of the potential environmental effectiveness of aquaculture eco-certification and internal, psychological variables predicted to be of importance for sustainable seafood consumption. Put differently, what is the potential of eco-certification in greening the blue revolution and fuel ‘turquoise growth’, and how can consumer demand be spurred? In Paper I, the role of eco-certification in improving the growing aquaculture sector at large was explored. Results showed that environmental effects at global scale likely will be limited due to e.g. partial coverage of species groups and environmental impacts, and a lack of focus on Asian markets and consumers. In Paper II the environmental performance of eco-certified and non-certified mangrove-integrated shrimp farms in Vietnam was compared by using Life Cycle Assessment and put in relation to conventional, more intensive farms. While there was no substantial difference between certified and non-certified farms in terms of environmental impacts, emissions of greenhouse gasses were higher for mangrove-integrated than conventional farms due to mangrove land use change. The results from Paper III demonstrated that the body of literature investigating ecological effects of seafood eco-certification is limited. ‘Spatially explicit ecosystem service information’ (ES-information) on e.g. key ecosystem services and biodiversity in a given area is suggested to have potential to improve sustainability standards. Taking guidance from the pro-environmental behavior literature, consumers in Stockholm, Sweden were consulted on awareness of and attitudes towards eco-labeled seafood (Paper IV-V). Two variables, concern for environmental impacts and knowledge about seafood eco-labels were the best predictors for stated eco-labeled seafood purchasing. Moreover, there seemed to be a misalignment between consumers’ expectations on eco-labeled food in general and certification requirements for eco-labeled seafood. From this set of findings, a number of improvements of current seafood eco-certification are suggested. First, include an LCA-perspective in standards to a higher degree than presently done and provide readily available ES-information in the implementation and evaluation phase of certification. Second, introduce standardized mechanisms for capturing potential environmental improvements over time. And finally, stimulate demand by targeting Asian consumers and markets as well as strengthen consumer eco-label awareness and emotional involvement.

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.

 

Thesis (Ph. D.)--University of Oregon, 2001.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 143-163). Also available for download via the World Wide Web; free to University of Oregon users.

Aquaculture is playing an important role in the development of fisheries in Vietnam, a role which has accelerated since 2000. Sustainability in aquaculture is receiving increasing attention, and this issue is not only the concern of government, but also stakeholders participating in the value chain. Therefore, this study aims to identify sustainability issues of farmed seafood by assessing the main sustainability issues raising concern. The Global Value Chain framework described by Gereffi et al. (2005) is applied for this study to explore the business relationships in supply chain and the perceptions of sustainability concerned by the value chain actors. A combination of qualitative and quantitative methods was used to collect data. An assessment of four species cultured on the Mekong Delta, the countries farmed seafood ‘hub’, found a clear distinction between species cultured with a local domestic market orientation (Giant Freshwater Prawn Macrobrachium rosenbergii; and Tilapia Oreochromis niloticus) and the two key export commodities - Striped catfish (Pangasianodon hypophthalmus) and Penaeid shrimp (Penaeus monodon & Litopenaeus vannamei). These orientations were based on a range of factors including the development of effective seed supplies and the cultural value of marketing in the live format. This study, conducted in ten provinces in the Mekong Delta from 2009 to 2013 had a focus on understanding the export-orientated commodities, striped catfish and shrimp through collection of baseline information on the value chain of farmed seafood, focusing on the farming sector, the actors and institutions involved and beneficiaries. Sustainability issues and perceptions of experts (top-down) and primary stakeholders (bottom-up) opinions were assessed through participatory workshops. Shrimp and striped catfish production are mainly farmed for export, with 83% and 95% of its production, respectively, leaving the country mainly after processing. Currently, mainly families operate small-/medium-scale farms; while large-farms are integrated within seafood processors. Production efficiency of large-farms tends to be better than small-/medium farms. Many striped catfish and shrimp farms are likely to reach several standard criteria such as economic feed conversion ratio (eFCR), stocking density, no banned chemical/drug and wild-seed use, and land property rights; however, there were still many standard criteria that existing farms could not meet such as effluent management, farm registration, fishmeal control, farm hygiene and record-keeping requirement. Hence, current farming practices, especially small-/medium farms have a long way to go to meet emergent international food standards. Recently, many small-/medium catfish farms faced problems with low fish prices, so they have had to cease catfish farming activities and temporarily stop farming; while some larger farms also had to temporarily stop farming. Therefore, fish price has tended to be a main driving force for catfish farm changes. In the shrimp industry, there were technical changes occurring in the high intensity level of shrimp farms (HiLI); whereas, the remaining shrimp farms had fewer changes in farm management. Most HiLI shrimp farms were affected by AHPNS disease, which was a main factor driving their farm changes. Many perceptions of sustainability were identified by stakeholder groups, however seven sustainability issues had a high level of agreement among stakeholders including input cost, capital & credit costs, unstable markets, government regulation & policy, disease, seed quality, water quality and water availability factors. Hatcheries, farmers and manager groups were more concerned about environmental issues; while for the input suppliers and processors, economics was the main issue. Farmers and processors were two main actors that played an important role in the production process of the value chain. Small-/medium farms dominated the number of farms overall and still played an important role in primary production. However, small-scale farms were considered as more vulnerable actors in the value chain, and they faced more difficulties in meeting increasing requirements on food quality/safety. To maintain the position in the value chain, the solutions could be horizontal and vertical coordination. Thus policy makers will need to find ways to include them in the planning processes. To reach sustainability will require the efforts of direct stakeholders, the role of the state agencies is essential in negotiation and diplomacy to create partnerships with the seafood importing countries. However, efforts to develop sustainable production become impossible without participation from importers, retailers and consumers.

This thesis explores the sexual division of labour in three worksites associated with the Western Australian Fishing industry: fishers' households, a seafood processing company and fishing vessels. There has been no previous substantial study of the labour of women in Australian fishing industries. My research has been primarily undertaken by interviewing women and men who work in the Western Australian fishing industry, and my findings are presented through a comparison with overseas literature relative to each site. As I found, in the households of fishermen, women do unpaid and undervalued labour which includes servicing men and children; managing household finances and operating fishing enterprises. In seafood processing companies women are allocated the lowest paid and least rewarding work which is regarded as women's work. On-the factory floor issues of class, race/ ethnicity and gender intersect so that the majority of women employed in hands-on processing work are migrant women from a non-English speaking background. The majority of women who work at sea are cook/ deckhands who are confronted by a rigid sexual division of labour, and work in a hyper-masculine workplace. The few other women who have found a niche which enables them to enjoy an outdoor lifestyle while they earn their own living, are those who work as autonomous independent small boat fishers. In each site there is evidence that women, individually and collectively, exercise some power in determining how and where they work, but they remain marginalised from the more lucrative sites of the industry, and have limited access to economic and social power.

This thesis explores the sexual division of labour in three worksites associated with the Western Australian Fishing industry: fishers' households, a seafood processing company and fishing vessels. There has been no previous substantial study of the labour of women in Australian fishing industries. My research has been primarily undertaken by interviewing women and men who work in the Western Australian fishing industry, and my findings are presented through a comparison with overseas literature relative to each site. As I found, in the households of fishermen, women do unpaid and undervalued labour which includes servicing men and children; managing household finances and operating fishing enterprises. In seafood processing companies women are allocated the lowest paid and least rewarding work which is regarded as "women's work". On-the factory floor issues of class, race/ ethnicity and gender intersect so that the majority of women employed in hands-on processing work are migrant women froma non-English speaking background. The majority of women who work at sea are cook/ deckhands who are confronted by a rigid sexual division of labour, and work in a hyper-masculine workplace. The few other women who have found a niche which enables them to enjoy an outdoor lifestyle while they earn their own living, are those who work as autonomous independent small boat fishers. In each site there is evidence that women, individually and collectively, exercise some power in determining how and where they work, but they remain marginalised from the more lucrative sites of the industry, and have limited access to economic and social power.

2010/2011
The present thesis was developed for the characterization of the risk associated to palytoxins as seafood contaminants. To this aim, an integrated approach between in vitro and in vivo studies was chosen. Palytoxin and its analogues are known seafood contaminants that can accumulate in several edible species of shellfish, fish, crustaceans and echinoderms. Generally, primary symptoms associated to the ingestion of contaminated food involve the gastro-intestinal apparatus and later develop with the involvement of the muscular tissue. For a better comprehension of the mechanism of action of this family of biotoxins, the effects of PLTX have been studied on primary culture of mouse skeletal muscle cells. The myotoxic insult triggered by PLTX was described in detail with the definition of the cytotoxicity together with the description of the morphologic alterations and functional impairment caused by the toxin. Moreover, the influence of the ionic composition of the extracellular medium on the effects of the toxin was elucidated. Primary cultures of skeletal muscle cells, that presents in vitro many of the peculiarities of the adult muscle fiber, allowed the investigation of the membrane mechanisms that regulate the intracellular calcium increase triggered by the toxin. It was possible to discriminate the difference between calcium release from intracellular stores and the calcium entrance from extracellular compartment both elicited by the toxin, and to understand the importance of the latter in relation to the toxic event. Moreover, the involvement of the main membrane channels and transporters that may be related to the entrance of calcium was investigated and the crucial role of stretch-activated channels in the mechanism of toxicity was demonstrated. Once defined the crucial molecular mechanisms of action of PLTX, experiments were also performed with two of its analogue: the 42-hydroxyl-palytoxin and the ostreocin-D. In parallel to in vitro studies, the effects of repeated oral administration of PLTX in mice were also investigated. In fact, in vitro studies are not sufficient for the complete comprehension of the real hazard associated to a food contaminant, since molecules once in contact with the body may undergo adsorption, distribution and metabolism before reaching the target tissue. Short-term (7 days) administration of the toxin revealed toxicity at all the doses tested and lethality was recorded in the treated animals already from the dose of 30 µg/kg. Histological analysis highlighted alterations in several tissues: severe inflammatory processes and even foci of necrosis were observed in lungs. Alteration of the muscular tissues was visible as fiber separation and degeneration in the heart and increased cellularity between fibers in skeletal muscle. Moreover, depletion of glycogen content of hepatocytes and moderate alterations of the spleen were also observed. Data collected in the present project revealed, for the first time, toxicity of PLTX at doses much lower than that currently used by European Food Safety Authority (EFSA) for the estimation of limit values for presence of these compounds in seafood. For this reason, these results are likely to have a considerable impact at regulatory level and to have crucial importance for the protection of the consumers.
Il presente lavoro di tesi è stato sviluppato con lo scopo di caratterizzare il rischio associato alla presenza delle palitossine quali contaminanti dei prodotti ittici destinati ad uso alimentare. A tal fine, è stato scelto un approccio integrato tra studi in vitro e in vivo. La palitossina e i suoi analoghi sono noti contaminanti dei prodotti ittici e possono accumularsi in diverse specie edibili di molluschi, pesci, crostacei ed echinodermi. Generalmente, i primi sintomi associati all’ingestione di cibo contaminato coinvolgono l’apparato gastro-intestinale e poi si sviluppano con l’interessamento del tessuto muscolare. Per una migliore comprensione del meccanismo d’azione di questa famiglia di biotossine, gli effetti della PLTX sono stati studiati mediante colture primarie murine di cellule muscolari scheletriche. L’insulto miotossico indotto dalla PLTX è stato descritto nel dettaglio con la definizione della citotossicità assieme alla descrizione delle modifiche morfologiche e delle alterazioni funzionali causate dalla tossina. Inoltre, è stata caratterizzata l’influenza della composizione ionica dell’ambiente extracellulare negli effetti della tossina. Le colture primarie di cellule muscolari scheletriche, che presentano molte delle caratteristiche peculiari della fibra muscolare adulta, hanno permesso l’indagine dei meccanismi che regolano l’aumento intracellulare di calcio indotto dalla tossina. E’ stato possibile discriminare la differenza tra il rilascio di calcio dai depositi intracellulari e l’entrata di calcio dai compartimenti extracellulari, entrambi effetti indotti dalla tossina, e comprendere l’importanza del secondo meccanismo in relazione agli eventi tossici. E’ stato indagato il coinvolgimento dei canali e trasportatori di membrana in relazione all’ingresso di calcio ed è stato dimostrato il ruolo cruciale dei canali attivati da stiramento nel meccanismo di tossicità. Una volta definiti i meccanismi d’azione cruciali per la PLTX, esperimenti sono stati condotti anche con due dei suoi analoghi, la 42-idrossi-palitossina e l’ostreocina-D. Parallelamente agli studi in vitro, sono stati studiati gli effetti della somministrazione orale ripetuta della PLTX nel topo. Infatti, gli studi in vitro non sono sufficienti alla comprensione del reale pericolo associato ad un contaminate alimentare, dal momento che, le molecole, una volta a contatto con l’organismo, possono subire assorbimento, distribuzione e metabolismo prima di raggiungere il tessuto bersaglio. La somministrazione a breve termine della tossina (7 giorni) ha rivelato tossicità a tutte le dosi somministrate, e letalità è stata registrata negli animali trattati già alla dose di 30 µg/kg. Le analisi istologiche hanno evidenziato alterazioni a carico di diversi tessuti: a livello polmonare sono stati osservati severi processi infiammatori associati anche a focolai di necrosi. Le alterazioni del tessuto muscolare erano visibili come degenerazione e separazione delle fibre nel cuore e aumento degli elementi cellulari tra le fibre del muscolo scheletrico. Inoltre sono stai osservati, deplezione del contenuto di glicogeno negli epatociti e moderate alterazioni della milza. I dati raccolti nel presente elaborato hanno rivelato, per la prima volta, la tossicità della palitossina a dosi molto inferiori rispetto a quelle correntemente utilizzate della European Food Safety Authority (EFSA) per la stima di valori limite per la presenza di questi composti nei prodotti ittici destinati ad uso alimentare. Per questo motivo, i risultati avranno probabilmente un considerevole impatto a livello legislativo e un’importanza cruciale per la protezione dei consumatori.
XXIV Ciclo
1984

The development of emerging technologies in seafood processing can contribute significantly to meet consumer needs toward safe, healthy, and minimally processed foods. This PhD thesis is focused on the qualitative and quantitative evaluation of the effects of emerging treatments applied to extend shelf-life of seafood processing and to preserve the qualitative characteristics of raw materials. The application of innovative non-thermal technologies to recover bioactive substances from crustacean by-products were also studied. Several experimental procedures were evaluated individually by the following studies: i) study of the effect of modified atmosphere packaging (MAP) with unconventional gas mixtures on the modification of the main qualitative parameters of sardine fillets during refrigerated storage; ii) valorization of an underutilized crustaceans by the application of mechanical flesh separation and freezing iii) application and evaluation of the main effects of high pressure processing (HPP) treatments on the quality and stability of different seafood products; iv) study and application of innovative non-thermal technologies, such as accelerated solvent extraction (ASE) and pulsed electric fields (PEF) for the recovery and valorization of value-added products from crustacean processing by-products. Based on the obtained results, the use of argon for MAP of sardine fillets showed an inhibitory effect on bacterial spoilage increasing their shelf-life. The effect of HPP treatment on the different types of considered seafood products, intended for raw consumption, highlighted a significant microbiological shelf-life increase at the highest applied pressure levels for all the considered species. The application of ASE and PEF showed high yield of astaxanthin and seemed to be an effective tool to recover high antioxidant compounds from crustacean by-products. The overall results of this PhD thesis highlighted the great advantages in the application of emerging technologies for both seafood products and crustacean by-product valorization, therefore contributing to the potential increase of the sustainability of the seafood sector.

碩士
國立臺灣海洋大學
應用經濟研究所
95
This investigation into the traceability baseline in Taiwan finds that private sector seafood firms have developed a substantial capacity to trace. Traceability systems are a tool to help firms manage the flow of inputs and products to improve efficiency, product differentiation, food safety, and products quality. Firms balance the private costs and benefits of traceability to determine the efficient level of traceability. It has developed a number of mechanisms to correct the problem, including contracting, third-party safety/quality audits, and good practices. The best targeted government polices for strengthening firms’ incentives to invest in traceability are aimed at ensuring that unsafe or falsely advertised foods are quickly removed form the system, while allowing firms the flexibility to determine the manner. Possible policy tools include timed recall standards, increased penalties for distribution of unsafe seafoods and increased foodborne-illness surveillance. The cost of implementation of traceability systems is likely to vary enormously between business and sectors depending on the type of technology adopted, the amount of information required to be stored and the complexity of the seafood chain. It is clear that traceability comes at a cost. But the costs of not having it, or having inefficient systems in pace may be severe both for governments, consumers, individual companies and the food industry as a whole.

碩士
國立臺灣海洋大學
食品科學系
105
Glazing, as a quality protecting tool, has a long history and a common practice in frozen seafood processing. The aim of this study is to investigate “can this procedure re-define and extend shelf-life for seafood food which has limited shelf-life, e.g. within 3 months?” Criteria for glazing practice include surface/weight ratio, dipping time, and dipping cycle. Three species and processing types, salmon fillet, halibut fillet, and capelin whole fish, varied mainly by their lipid contents, were selected and quality index, TRARS, TVB-N, and drip-loss were used to evaluate their quality changes during normal, -25℃, and accelerated storage test, at -15℃ and -5℃ up to 12 weeks. Results indicated, the highest glazing pick-up rate can be achieved at smaller surface area, thinner, and longer dipping time. However, there are no significant difference in pick-up rate between second and third glazing cycles. Hence, a reference glazing table was developed indicating the suitable practice to achieve the target glazing pick-up ratio. Glazing pick-up ratio were set at 0% (control),15% and 30% for fish samples. During 12 weeks’ storage period, gradually but significantly increased TBARS and TVB-N were observed for all treatments, while there was no significant difference among drip-loss changes. Arrhenius equation was used to calculate the activation energy (Ea) for TBARS and TVB-N of the tested samples which were then used to predict the expected shelf-life of these short shelf-life products. Results suggested that TBARS is a better quality index for high-fat fish, such as salmon in this study, while TVB-N is a more suitable index for low-fat or smaller whole fish. Results showed that smaller area-weight ratio, the more glaze uptake. 15% glazed is adequate and effective to guarantee the final quality of higher fat fish samples (>20%) during frozen storage. Excessive glazing (>15%) will have the adverse effect on the quality changes due to longer time exposure to higher environmental temperature.