Persistent organic pollutants (POPs) are readily detected in biological samples at remote sites in the Arctic and sub-Arctic due to long-range transport from source areas. The aim of this study was to investigate the presence of POPs, polybrominated contaminants and their metabolites in guillemot (Uria algae) eggs from Iceland, the Faroe Islands, Norway and Sweden to assess spatial trends of these compounds in the Arctic and sub-Arctic areas of Europe. Egg samples were extracted, and cleaned for chemical analysis. Concentrations of PCBs, 4,4′-DDE and β-HCH were an order of magnitude higher in eggs from the Baltic Proper compared to eggs from the North Atlantic. Concentrations of HCB were of the same magnitude at all sites, ranging from 160 to 520 ng / g fat. Concentration of BCPS was 100 times higher in eggs from the Baltic compared to eggs from the North Atlantic and therefore seems to be special regional problem. Concentrations of PBDEs were lower in eggs from the North Atlantic compared to eggs from the Baltic Proper but the difference was not as large as for PCBs and 4,4′-DDE. HBCDD showed the same spatial trend as PCBs, where the concentrations in eggs from the Baltic Proper were an order of magnitude higher than in eggs from the North Atlantic. OH-PCB and MeSO2-PCB metabolites of PCBs, showed the same trend as the parent compounds while spatial trends of MeSO2-DDE and OH-PBDEs, metabolites of 4,4′-DDE and PBDEs, respectively, differed from the trend of the parent compounds. This may be due to two factors; firstly, the limited ability of birds to metabolize DDT, and secondly, to natural production of OH-PBDE, respectively. Guillemot is suggested as a monitoring species for circumpolar monitoring.
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Applications of Decision Support Systems (DSSs) in the food industry, and in particular the seafood industry, are discussed. The amount of data recorded in the food industry has increased greatly in the last decade, parallel to descending cost of data recording through automation and computer systems. The data can be used to fulfill the demands of consumers that want information on their food products, such as origin, impact on the environment and more. By using traceability this flow of data can be used for decision support. Many fields within food processing can gain from using DSS. Such fields include for example lowering environmental impact of food processing, safety management, processing management and stock management. Research and development projects that the authors have taken part in and the following implementations of software solutions are discussed and some examples given of practical usage of DSS in the food industry as a result of such work.
This chapter discusses the potential of fish protein hydrolysates (FPH) as a food antioxidant and bioactive ingredient to combat oxidative processes in living systems. The effect of hydrolysis and enzymes on flavor of FPH and the processing techniques to reduce off-flavors and odors of FPH are described. The antiproliferative and immunomodulatory activities of FPH are also discussed.
Aims: To assess the effects of bacterial treatment at the earliest stages of cod rearing on the microbial load, larval development and performance, testing three bacterial strains (Carnobacterium divergens V41, Arthrobacter sp. and Enterococcus sp.) in vivo that were previously shown to have inhibitory potential towards fish pathogens in vitro.
Methods and Results: A bacterial mixture was added eight times to the rearing water from the prehatch to the mid-larval stage (a 38-day period). Microbiological analysis of ova, larvae and rearing water was performed regularly. Larval performance and development were evaluated by survival rate, hypersalinity tolerance and physiological measurements. Different larval survival rates were observed within and between treatments, and possibly explained by variations in larval microflora and established probionts. Larvae from one silo, which had been bathed in the bacterial suspension, showed the highest survival rate (42 · 1%), lowest Vibrio levels, and were significantly heavier (19 · 3%) and more stress tolerant than control larvae (P<0 · 01). This coincided with the intestinal establishment of two of the tested bacteria.
Conclusions: Arthrobacter and Enterococcus strains added regularly to the rearing water from the postfertilized egg stage can be established in larval gastrointestinal tract. The Enterococcus strain was associated with increased larval growth, performance and microflora control, indicating its probiotic nature.
Significance and Impact of the Study: Regular application of autochthonous probionts may promote larval welfare, development and stress tolerance at early stages, hence increasing production yield in intensive cod larviculture.
In order to study the possible interactive effects of salinity and photoperiod on growth, feed conversion, and blood chemistry in juvenile halibut, 2,604 (initial mean weight 26.8 g ± 0.2 SEM) juvenile halibut were exposed to six different combinations of salinities (13, 21 , or 27 ‰) and photoperiods [continuous light, C and simulated natural photoperiod (65 ° N), SNP] for 129 days. Improved (10–20%) growth and 10–24% higher feed conversion efficiency were observed at low and intermediate salinities compared to the high salinity groups. Improved feed conversion efficiency (20%) and temporary growth enhancing effects (10%) of continuous light were observed, but effects faded out as day length in the simulated natural photoperiod group increased. No interactive effects of photoperiod and salinity on growth feed conversion or measured blood chemistry variables (blood sodium, pH level, haematocrit, bicarbonate content, and total carbon dioxide). It is suggested that juvenile Atlantic halibut should be reared at low and intermediate salinities and at continuous light, as this will improve growth and increase feed conversion efficiency.
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 previously 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.
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, color 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 color 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 exists between different links in the value chain of cod.