The long-term effects of two salinities (15 and 27‰) on growth, feed conversion efficiency, and blood physiology of Atlantic halibut were investigated. Growth and feed conversion efficiency of juvenile Atlantic halibut was improved by 20% by rearing fish at intermediate salinities (here 15‰). Interestingly, the growth-enhancing effect of lowering the salinity seems to be independent of size and age of the halibut and is not reserved to the initial juvenile stage. A cost benefit analysis indicates that the new farming method has the potential to double the profit of a given halibut farm. Measured blood variables were lower at 15‰ compared with 27‰ while the values were within the range of that earlier described and there were no indications that reduced salinities represented a stressful environment to the fish. Overall, the results indicate that the growth rate, feed conversion, and farming economics can be improved by rearing Atlantic halibut at near intermediate salinities.
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Three feeding trials were conducted to estimate the minimum protein requirements for maximum growth of Atlantic cod (initial size 37–600 g). The diets in each trial were near iso-energetic and contained 47–64% crude protein (CP) in dry matter for small fish while diets for larger fish contained 36–57% CP. There was no significant difference in the final weight of small fish (90–130 g) fed different levels of CP. However, the specific growth rate (SGR) of fish fed 59% and 64% CP (0.9% day−1) was significantly higher than that of fish fed either 47% or 48% CP (0.5–0.7% day−1). The hepato-somatic index (HSI) increased progressively with decreased CP and the feed conversion ratio (FCR) was negatively correlated with CP of the diets. In two trials with larger fish, CP did not significantly affect mean final weight (750–900 g), SGR or FCR. As for the smaller fish, the HSI was negatively correlated with CP and in one of the experiments, the feed intake was also negatively correlated with CP. The feed efficiency tended to be reduced. The results suggest that the protein requirement for maximum growth in Atlantic cod is size dependent: for 40–107 g fish, the minimum CP is 47–52% and for larger fish (400–900 g) it is 36% or lower.
Investigation of the effect of high-pressure processing (HPP) at very short time on the inactivation of Listeria innocua was conducted as well as the effect on texture and microstructure. Lipid oxidation, colour and background bacterial flora were studied as well. HPP at 700–900 MPa for 10 s increased the inactivation of L. innocua in cold smoked salmon from 4500 cfu/g to nondetectable level (<0.3 cfu/g). L. innocua was more sensitive to HPP than the background flora tested. The product presented good microbiological quality and there was no indication of lipid oxidation. The effect of HPP on the redness of the product was not observed, however immediate effect on the lightness was noticed and the salmon becomes lighter in colour as a function of both time and pressure. The effects on the microstructure increased with both time and pressure and were most significant at 900 MPa and 60 s. The effect on microstructure coincides with the reduction of the bacteria. The knowledge from this study provides information for the industry on the development of HPP at 400–900 MPa with short pressure time of less than 60 s.
The initial handling of marine fish on board fishing vessels is crucial to retain freshness and ensure an extended shelf life of the resulting fresh products. Here the effect of onboard chitosan treatment of whole, gutted Atlantic cod (Gadus morhua) was studied by evaluating the quality and shelf life of loins processed six days post-catch and packaged in air or modified atmosphere (% CO2/O2/N2: 55/5/40) and stored superchilled for 11 and 16 days, respectively. Sensory evaluation did not reveal a clear effect of chitosan treatment on sensory characteristics, length of freshness period or shelf life of loins under either packaging conditions throughout the storage period. However, directly after loin processing, microbiological analysis of loins showed that onboard chitosan treatment led to significantly lower total viable counts as well as lower counts of specific spoilage organisms (SSO), such as H2S-producers and Pseudomonas spp., compared to the untreated group. In addition, the culture-independent approach revealed a lower bacterial diversity in the chitosan-treated groups compared to the untreated groups, independently of packaging method. Partial 16S rRNA gene sequences belonging to Photobacterium dominated all sample groups, indicating that this genus was likely the main contributor to the spoilage process.
The influence of catching and processing factors on fillet yield, gaping and number of nematodes in cod (Gadus morhua) was studied. The study was carried out in co-operation with four Icelandic fishery companies. Data on catch, condition of raw material and processing were linked together by tracing the cod from catch through primary processing. Analysis of these data show that important variables for profitability in the fish industry are strongly correlated to controllable variables, such as catch ground, catch method and age of raw material when processed. The results can aid in decision making for catching and processing cod, provided that strong relationship exist between different links in the value chain of cod.
New EU legislation (EU Regulation 1924/2006) will allow a number of nutrition and health claims in food products. The objective of this research was to study how health claims affect consumers’ perception of other product attributes. A survey with a total of 4612 respondents from the Nordic countries explored consumers’ perceptions of attractiveness, healthiness, naturalness, tastiness and ability to reduce risk of disease by comparing ratings of products with and without health claims. Used claims varied in their benefit, active ingredient, claim structure and framing. The results showed that health claims had a moderate but mostly negative impact on the perception of other product attributes; the most significant impact was decrease in perceived naturalness. Consumers could also interpret the benefits in claims as intended. The wording of the claim had only small impact on the perception of the products, whereas earlier market presence of the ingredient had a large impact: differences among the Nordic countries reflected the previous exposure to health claims. The findings from this study suggest that consumers do not imply other health benefits from health claims and the health claim per se is not likely to cause any unrealistic positive inferences in perceived product quality.
We report the development of new PCR assays and loading panels for the Atlantic salmon using 15 microsatellite loci. A total of 8, 3 and 4 loci were coamplified in three separate PCRs using labelled primers and loaded on the ABI DNA analyzer in two separate panels. Amplified alleles were clearly typed, and easily interpretable results were obtained. The method was successfully applied in different laboratories, even when different types of DNA polymerase were employed. The method is useful for analysing paternity, population genetics and conservation as well as for selective breeding programmes.
The aerobic respiratory chain of the thermohalophilic bacterium Rhodothermus marinus, a nonphotosynthetic organism from the Bacteroidetes/Chlorobi group, contains a high-potential iron–sulfur protein (HiPIP) that transfers electrons from a bc1 analog complex to a caa3 oxygen reductase. Here, we describe the crystal structure of the reduced form of R. marinus HiPIP, solved by the single-wavelength anomalous diffraction method, based on the anomalous scattering of the iron atoms from the [4Fe–4S]3+/2+ cluster and refined to 1.0 Å resolution. This is the first structure of a HiPIP isolated from a nonphotosynthetic bacterium involved in an aerobic respiratory chain. The structure shows a similar environment around the cluster as the other HiPIPs from phototrophic bacteria, but reveals several features distinct from those of the other HiPIPs of phototrophic bacteria, such as a different fold of the N-terminal region of the polypeptide due to a disulfide bridge and a ten-residue-long insertion.
The purpose of this work was to develop a conceptual framework that can be used to evaluate the effectiveness of traceability systems at food producers based on information from process mapping. The framework was based on a broad literature review from the food processing industry. The proposed framework was then applied to evaluate the traceability system at a Vietnamese fresh farmed Pangasius catfish producer and validated by evaluating the ability to track and trace through the company. In addition, the studied traceability system was analyzed on its compliance with regulation on traceability of importing countries such as EU regulation No. 178/2002, as well as with the TraceFish standard. The paper also aimed to propose how to use recorded data more efficiently to improve quality management and supply chain management. The results show that the framework works well in the specified case, but further investigation for other cases is desirable. The company traceability system meets with EU regulation No. 178/2002, but not with the TraceFish standard as global trade item numbers (GTIN) are not used for dispatched products. It is suggested that the company also stores recorded data in electronic form in parallel with paper form to facilitate data access. It is proposed that the temperature data during storage and transportation are used to estimate the warm up time and the remaining shelf life (RSL) of the products.
Purpose
The aim of this study is to explore potential barriers to seafood consumption by young adults and the parents of young children. Knowledge of these barriers will be used to assist the development of new seafood product concepts that fulfil the needs of consumers.
Design/methodology/approach
To gather this information, 28 infrequent consumers of seafood participated in three semi‐structured two‐hour focus group discussions in Denmark, Norway, and Iceland. The results were then linked to the Stage‐Gate model for consumer‐based new product development (NPD).
Findings
The participants thought of seafood as either healthy or convenient, although there were concerns about the amount of effort required to prepare it. These concerns resulted in an expression of their need for products that are attractive, healthy, palatable, and convenient. In particular, the newly developed products should be accompanied by clear advice on preparation methods and materials. An increase in seafood availability coupled with lower prices would encourage these consumers to add seafood to their diet.
Research limitations/implications
Purchase‐point‐marketing and habitual behaviour were found to implicitly skew planned behaviour.
Practical implications
Inputs for NPD related to convenience, attractiveness, quality, trustworthiness, knowledge and requirements about seafood preparation are discussed.
Originality/value
The present study combines qualitative methods to lead to practical input for NPD focusing on overcoming the barriers that keep consumers from choosing existing healthy seafood products. The importance of the consumers’ confidence in their ability to successfully prepare a seafood meal was revealed and can be used in Stage‐Gate based NPD.