Category: Reports

Reports

The role and fate of added phosphates in salted cod products / Role and fate of added phosphate in salted fish

Published:

01/07/2010

Authors:

Kristín Anna Þórarinsdóttir, Sigurjón Arason, Guðjón Þorkelsson

Supported by:

AGS, AVS

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

The role and fate of added phosphates in salted cod products / Role and fate of added phosphate in salted fish

The aim of the project was to evaluate the fate of added phosphate in salted fish. It is clear that its amount decreases with effect and dehydration. The same goes for phosphates that are naturally present in fish muscle. Therefore, the total amount of phosphate in dehydrated products is usually lower than in fresh fish. However, it has been shown that added phosphates (di- and triphosphates) are found in both processed and dehydrated fish. However, it depends on the amount of phosphate added to the product and the salting processes used, ie. whether phosphate was added to the fish by injection or brine. Little or nothing is detected in dehydrated products if brine is used. Differences between processes can be due to the method of salting (spraying / pickling), the type and initial amount of phosphate added and the duration of action. Further research is needed to evaluate the effect of different salting processes on the fate of phosphate in salted cod muscles.

The aim of this study was to investigate the fate of added phosphates in salted cod products. The content of both added phosphates and naturally occurring phosphates, decreases during salting and rehydration. The final content in rehydrated fish (approx. 1-2.5% NaCl) is usually below values in the raw fish. However, di- and triphosphates are present both in salted and rehydrated products. The amount depends on the quantity of added phosphates in the product and on the salting procedures applied. It seems that lower contents are present in brined products than in injected products. Differences may depend on the method used for adding phosphates (injection / brining), phosphate type and, initial content of added phosphates in the muscle after pre-salting and finally on the curing time. Further studies are needed to get accurate information on the effects of different salting procedures on the fate of phosphates in salted cod products.

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Reports

Development of Quality Index Method and shelf life of thawed mackerel (Scomber scombrus) / Development of Quality Index Method and storage life of thawed mackerel (Scomber scombrus)

Published:

01/07/2010

Authors:

Kolbrún Sveinsdóttir, Patricia Miranda Alfama, Aðalheiður Ólafsdóttir, Emilía Martinsdóttir

Supported by:

AVS Fisheries Research Fund, UNU School of Fisheries, United Nations University

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

Development of Quality Index Method and shelf life of thawed mackerel (Scomber scombrus) / Development of Quality Index Method and storage life of thawed mackerel (Scomber scombrus)

The QIM method (Quality Index Method) is an objective, fast and reliable sensory evaluation method that has been developed to assess the freshness of fish. The aim of the study was to prepare a QIM rating scale for thawed mackerel (Scomber scombrus) stored in ice at 0 ° C and to test its use in a shelf life test. The mackerel was evaluated by sensory evaluation according to QIM and DA method (generic descriptive analysis), microorganisms (TVC and H2S producing) were also counted and histamine was measured for up to 9 days after thawing. The result of the study was the QIM method for thawed mackerel which was developed and tested in a shelf life test. Quality factor - QI (total grade) increased linearly with ice shelf life. The QIM method for thawed mackerel is based on an assessment of quality factors such as the appearance of redness, texture, color and shape of the eyes, the color and odor of the gills, the appearance of mucus in the gill and gill leaf and the intestinal dissolution, and the total fish can reach a maximum of 19. The project also developed a method (general descriptive analysis-DA) for evaluating boiled mackerel. The main characteristics of the mackerel immediately after thawing were the smell and taste of fresh oil, the smell of metal and the sweet smell / taste that faded with the storage period. What limited the shelf life were sensory properties that describe the symptoms of damage, such as the stench and taste that can be noticeable in fatty fish after prolonged cold storage. According to a sensory assessment of boiled mackerel fillets, the shelf life of thawed mackerel after five months of cold storage is about 4-6 days. The total number of micro-organisms and H2S-producing micro-organisms was lower than is usually seen at the end of the shelf-life of micro-organisms. Histamine was not detected (<5 ppm) in thawed mackerel during the 9-day ice-storage period.

The Quality Index Method (QIM) is an objective, rapid and reliable sensory method. The aim of the present study was to develop a QIM scheme for frozenthawed Atlantic mackerel (Scomber scombrus) stored in ice at 0 ° C and evaluate the scheme in a shelf life study. The mackerel was evaluated with sensory evaluation (QIM and generic descriptive analysis (DA)), microbial counts (Total viable counts (TVC) and H2S-producing bacteria) were estimated and histamine measured for up to nine days. The main result of this study vas the QIM scheme to evaluate freshness of frozen-thawed Atlantic mackerel storage in ice which was developed and tested in a shelf life study. The quality index - QI (sum of scores) increased linearly with storage time on ice. The QIM for thawed mackerel is based on the evaluation of quality parameters dealing with the appearance on back and belly side, texture, color and shape of eyes, mucus, color and odor of gills and appearance of gill filaments and dissolution of viscera. The maximum sum of scores (QI) can be 19. A method to evaluate cooked mackerel was also developed (general descriptive analysis-DA). Newly thawed mackerel had fresh oil, metallic and sweet odors and flavors. The main limitation of shelf life in chilled storage after thawing were sensory characteristics describing spoilage such as rancid odor and flavor which can be prominent in fatty fish species after extended frozen storage. According to sensory evaluation of cooked mackerel, the shelf life of thawed mackerel after five months of frozen storage is around 4-6 days. Counts of TVC and H2S producing bacteria were relatively low at the end of shelf life. Histamine was not detected (<5 ppm) in the thawed mackerel during the storage time of nine days on ice.

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Reports

Computer controlled scraping knives for filleting machines

Published:

01/06/2010

Authors:

Jónas Rúnar Viðarsson, Ásbjörn Jónsson, Sveinn Margeirsson

Supported by:

AVS

Contact

Jónas Rúnar Viðarsson

Sviðsstjóri rannsókna

jonas@matis.is

Computer controlled scraping knives for filleting machines

This report describes the progress and results of the project "Computer-controlled scraping knives for filleting machines" which was funded by the AVS Fund. The aim of the project was to develop and build computer-controlled equipment for controlling the movements of scraper knives in a filleting machine of the type F-189-PLC from Fiskvélar. It was hoped that the computer-controlled scraper knives would improve fillet utilization and make it possible to fillet smaller fish than has previously been possible with acceptable results. Measurements of fillet utilization of the machine after changes show that utilization has increased by 0.81%, when filleting medium-sized cod (approximately 2 kg). However, due to a lack of raw materials, it was not possible to measure whether the machine performed better when filleting very small fish (<0.7 kg). The computer-controlled scraper knives seem to follow the cutting curve better than older equipment and also that they reach further into the bones. It also appears that the increased mobility of the scraper knives reduces stimuli on the fish flesh. > <0.7 kg). The computer-controlled scraper knives seem to follow the cutting curve better than older equipment and also that they reach further into the bones. It also appears that the increased mobility of the scraper knives reduces stimuli on the fish flesh.

This is a report on the progress and results of the project "Computer controlled scraping knives for filleting machines". The aim of the projects was to develop and build a computer guided device to control movements of scraping knives in the F-189-PLC filleting machine from Fiskvélar. The goal was to increase filleting yield and make it possible to fillet smaller fish than has been possible before. Measuring filleting yield of the machine after it has been fitted with the new device shows that yield has improved by 0.81%. Unfortunately the success of the machine when filling very small fish (<0.7 kg) has not yet been carried out due to lack of raw material. The new device appears to guide the knives better along the cutting curve and allow them to cut closer to the bones. Improved maneuverability of the knives is also reducing strain on the flesh of the fish. > <0.7 kg) has not yet been carried out due to lack of raw material. The new device appears to guide the knives better along the cutting curve and allow them to cut closer to the bones. Improved maneuverability of the knives is also reducing strain on the flesh of the fish.

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Reports

Population genetics of the Icelandic Nephrops norvegius stock / Stofnerfðafræði leturhumars á Íslandsmiðum

Published:

01/06/2010

Authors:

Sigurlaug Skírnisdóttir, Sigurbjörg Hauksdóttir, Kristinn Ólafsson, Christophe Pampouli, Hrafnkell Eiríksson, Steinunn Á. Magnúsdóttir, Guðmundur H. Gunnarsson, Guðmundur Ó. Hreggviðsson, Sigríður Hjörleifsdóttir

Supported by:

The Icelandic Fisheries Research Fund, the Student Innovation Fund

Contact

Sigurlaug Skírnisdóttir

Project Manager

sigurlaug.skirnisdottir@matis.is

Population genetics of the Icelandic Nephrops norvegius stock / Stofnerfðafræði leturhumars á Íslandsmiðum

As the name of the project "Stock genetics of lobster in Icelandic waters" indicates, the aim of the project was to examine the type of lobster (Nephrops norvegicus) in Icelandic waters, but stock type research is an important factor for sustainable fisheries management. The main objectives of the project were to develop new genetic boundaries to assess genetic variability within and between geographically separated hunting areas in Iceland, to define the paternity of female egg masses from separate hunting areas in order to shed light on the reproductive process of lobster breeding and to stem genetic factors. Genetic analysis involves the use of so-called genetic markers, which are based on specific DNA sequences that are somehow detectable in the genome. Genetic markers based on repeated short sequences (2-6 bases) are most commonly used, which are known to vary between individuals of the same species. These areas therefore vary in length between individuals and make them suitable options. Genetic analysis is a very powerful technology that can be used for individual analysis in a group of organisms. This method is now increasingly used for parental analysis, to assess population structure, for research traceability and to accelerate targeted breeding. Usually 5-15 different genetic markers need to be used to differentiate individuals. A large part of the development work is therefore to find the best conditions for PCR reactions, where as many genetic markers as possible can be used in one reaction (multiplex) and simultaneous runs on a sequencer. Well-made genetic analysis kits that are easy and cheap to use and provide a lot of information and good diagnostic skills are very useful for a variety of uses. They are therefore valuable products and marketers, as both genetic analysis and services based on them can be sold. The project developed eight new genetic markers for lobsters and used them to analyze samples from separate geographical fishing areas around Iceland, while Scottish lobster samples were used as a group. In addition, four previously published genetic markers were used for the analyzes. The results of analyzes with these 12 genetic markers from geographically separated regions (together with the subgroup) did not show a significant genetic difference of lobster between the regions. The results of the project have been published in articles and student projects. The student thesis is entitled "Development of microsatellite multiplex systems for Nephrops norvegicus" and is by Sóleyja Valgeirsdóttir. One article has been approved for publication in the project, which describes eight new genetic markers. The title of the article is: "Isolation and characterization of eight new microsatellite loci in the Norway lobster, Nephrops norvegicus (Linnaeus, 1758)" (approved for publication in the journal Molecular Ecology Resources, Appendix 1). Another article has been submitted for publication in the ICES Journal of Marine Science under the title "A pilot genetic study revealed the absence of spatial genetic structure of the Norway lobster (Nephrops norvegicus) at fishing grounds in Icelandic waters" but it deals with the structure of lobster in Icelandic waters where lobsters from Scotland were kept as an outing group (Appendix 2).

The genetic structure of population and mating behavior of exploited marine species are important criteria for effective fisheries management. The distribution of Nephrops norvegicus, Norway lobster, in Icelandic waters is limited to the warmer sea of the south coast. The distribution of the Icelandic stock can be divided into ten geographical areas but the main aim of this project was to develop microsatellite markers to use for the genetics analysis and to analyze whether the lobsters in each area are a self-contained unit stock or not. The aim was furthermore to determine the paternity of egg masses from individual females, and thus elucidate the breeding structure in Icelandic waters. The final goal was to produce a plan for the conservation and management of genetic resources in the Icelandic Norway lobster stock taking into account possible natural population diversity. Microsatellites are short sequence repeats of 2-6 bases found in all prokaryotic and eukaryotic genomes analyzed to date. Microsatellites are variable, which means the number of repeats in a specific area of the DNA variants between the different members of a species. Consequently, the alleles of the microsatellites differ by the length. The different alleles and thus the different length of the microsatellites can be caused by insertion or deletion of one or more repeats during the DNA replication. These sequences are usually under a high degree of length variability and that makes them as powerful genetic markers. Therefore, microsatellites are suitable for population genetics, for family tracing in breeding programs, genetic monitoring, and kinship studies as well as tracing of origin. Usually, 5-15 microsatellites are enough to discriminate between individuals. A microsatellite multiplex system is the use of multiple, unique primer sets in a single PCR mixture to produce amplicons of varying sizes, specific to different DNA sequences. By targeting multiple loci at once, additional information may be gained from a single reaction. It is a great advantage that microsatellite markers can be run in multiplex assay systems. Larger numbers of samples and smaller DNA quantities can then be genotyped at once, saving time and money. This also minimizes the risk of handling errors. In this study we developed eight new microsatellite markers that were used to characterize the genetic diversity of Norway lobster, in and between isolated geographical areas in Icelandic waters, and an out-group sample from Scotland. In addition, four previously published microsatellite markers were used for the analysis. The microsatellites did not detect significant genetic differentiation among the location sampled, not even among Icelandic samples and the out-group collected in Scotland. The outcomes of the project are two papers and one student report. The report is titled "Development of microsatellite multiplex systems for Nephrops norvegicus" by Sóley Valgeirsdóttir. The first paper is titled; „Isolation and characterization of eight new microsatellite loci in the Norway lobster, Nephrops norvegicus (Linnaeus, 1758)“ where the eight new loci are described (Molecular Ecology Resources; Appendix 1; accepted for publication). The second paper is titled "A pilot genetic study revealed the absence of spatial genetic structure of the Norway lobster (Nephrops norvegicus) at fishing grounds in Icelandic waters" (ICES Journal of Marine Science; Appendix 2; submitted).

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Reports

Shelf life of vacuum ‐ packed smoked herring fillets

Published:

01/06/2010

Authors:

Franklín Georgsson, Margeir Gissurarson

Supported by:

AVS Fisheries Research Fund

Shelf life of vacuum ‐ packed smoked herring fillets

The aim of the study was to examine the shelf life of smoked herring fillets in vacuum-packed packaging and to examine its effect on the shelf life of the product if preservatives are not used and if sorbate is used instead of benzoate, which is used in conventional production. This study showed that the use of preservatives has a significant effect on the shelf life of smoked herring fillets. It was also stated that the sorbate treatment of herring fillets provided the best preservation against microbial growth and also the sorbate treatment of herring fillets proved to be the best in informal sensory evaluation. Whether this is due to the sorbate's inhibition of microbial growth or whether it reduces the rate of chemical and physical degradation factors compared to herring fillets with benzoate or without preservatives needs further research.

The object of this project was to evaluate the shelf life of vacuum packed smoked herring fillets and to evaluate whether the use of the preservatives benzoate or sorbate had any effect on the shelf life of the product Results showed that treatment of the smoked herring fillets with preservatives greatly affected the shelf life and that sorbate treatment of the herring fillets provided the best defense for bacteria growth and also gave best results in an informal sensory testing during the shelf life study. Whether this is due to inhibitory role of sorbate on bacteria growth or that sorbate slows down chemical and physical degradation in comparison to herring fillets with benzoate or without any preservatives needs further investigation.  

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Reports

Better utilization of water in charr farming / Efficient rearing systems for Arctic charr

Published:

01/06/2010

Authors:

Ragnar Jóhannsson, Helgi Thorarensen, Ólafur Ögmundarson

Supported by:

Technology Development Fund

Better utilization of water in charr farming / Efficient rearing systems for Arctic charr

The need for water in aquaculture is extremely high and what ultimately limits the size and production capacity of aquaculture establishments is access to hot and cold water. The aim of the project was to test a cheap and simple way to reduce water consumption in charr farming. At the beginning of the project, it was assumed that water could be used in charr farming four times better than is currently the case. However, it turned out that the water can be used seven times better. The result of this study is that it is possible to produce around seven times more biomass in aquaculture on land with the amount of water used today. The goals of the project were therefore achieved and much better. In order for this to be possible, the following things need to be kept in mind:

• It is very important to release turbidity from the water as soon as possible. Therefore, a drum filter is a necessary equipment and all the water must be filtered with each cycle of recycling. The filter should use 100 μm cloth, which cleans all particles that can reduce the efficiency of the farming system.

• There must be sufficient current in the fish tanks and it is desirable that the water exchange rate is not less than 45 minutes to ensure self-cleaning and to satisfy the oxygen demand of fish at high concentrations.

• A bio-cleaner is a necessary equipment when the recycling is greater than 0.03-0.05 L kg ‐ 1 ∙ min ‐ 1. It releases ammonia from the broth. The biocleaner used in this study has been shown to work well and its design has been patented

Aquaculture requires large volumes of water are required for aquaculture and the size and production capacity of fish farms is in most places ultimately determined by access to water and geothermal heat. The objective of this project was to reduce water requirements in Arctic charr aquaculture. Through simple reuse of water the plan was to reduce water requirements fourfold compared with standard reference values in Arctic char fish farms in Iceland. This goal was achieved and at the end the reuse was sevenfold. The conclusions of the project are that by using the same amount of water used today and with a simple reuse of it the annual increase in production of Arctic char can be sevenfold the annual production of today. But to make that possible, the following points have to be kept in mind:

• It is necessary to minimize the turbidity in the water by all means. A drum filter of 100 μm is therefore needed in the recirculation system.

• The current in the rearing system has to be sufficient and the water change ratio should not be less than 45 minutes to secure self-cleaning and to fulfill the oxygen need of the fish reared in high density.

• A bio filter is needed if the recirculation exceeds 0.03-0.05 L kg ‐ 1 ∙ min‐ 1. It phases out the ammonia in the rearing system. The bio filter used in this project has shown that it works and the design of it has a patent

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Reports

Undesirable substances in seafood products - results from the Icelandic marine monitoring activities year 2008

Published:

01/05/2010

Authors:

Hrönn Ólína Jörundsdóttir, Katrín Hauksdóttir, Natasa Desnica, Helga Gunnlaugsdóttir

Supported by:

Ministry of Fisheries and Agriculture

Contact

Natasa Desnica

Research Group Leader

natasa@matis.is

Undesirable substances in seafood products - results from the Icelandic marine monitoring activities year 2008

In 2003, at the initiative of the Ministry of Fisheries, monitoring of undesirable substances in marine products began, both products intended for human consumption and products for the fish oil and flour industry. The purpose of the monitoring is to assess the condition of Icelandic marine products with regard to the amount of contaminants. The data collected in the monitoring project will also be used in risk assessment and to build up a database on contaminants in the Icelandic ecosystem. Coverage of contaminants in marine products, both in the mainstream media and in scientific journals, has many times demanded the response of the Icelandic government. It is necessary to have scientific results available that demonstrate the actual condition of Icelandic seafood in order to prevent damage that may result from such coverage. Furthermore, the limits of contaminants are under constant review and it is important for Icelanders to participate in such a review and support their case with scientific data. This shows the importance of regular monitoring and that Iceland conducts independent research on such an important issue as marine product pollution. This report is a summary of the results of the monitoring in 2008. Assessment of the state of Icelandic marine products with regard to contaminants is a long-term project and will only be carried out through continuous monitoring. Every year, the missing data is carefully reviewed and the aim is to fill in the blanks. In 2008, the following were measured: dioxins, dioxin-like PCBs and PCB substances, PBDEs, PAHs as well as ten different types of pesticides, in marine products intended for human consumption as well as products for the fish oil and flour industries. A special effort was made to measure PBDE and PAH substances in 2008 and very few of these substances were measured in Icelandic seafood. As before, a small amount of undesirable substances was generally measured in Icelandic seafood in 2008. Oil and flour made from blue whiting, however, tend to be close to or exceed the permitted limits for certain substances.

This project was started in 2003 at the request of the Icelandic Ministry of Fisheries and Agriculture. Until then, monitoring of undesirable substances in the edible portion of marine catches had been rather limited in Iceland. The purpose of the project is to gather information and evaluate the status of Icelandic seafood products in terms of undesirable substances. The information will also be utilized for a risk assessment and gathering of reference data. This report summarizes the results obtained in 2008 for the monitoring of various undesirable substances in the edible part of marine catches, fish meal and fish oil for feed. The monitoring began in 2003 and has now been carried out for five consecutive years. The evaluation of the status of the Icelandic seafood products in terms of undesirable substances is a long term project which can only be reached through continuous monitoring. For this reason, we carefully select which undesirable substances are measured in the various seafood samples each year with the aim to fill in the gaps in the available data over couple of year time. In 2008, data was collected on dioxins, dioxin-like PCBs, marker PCBs, ten different types of pesticides, PBDEs and PAHs in the edible part of fish, fish liver, fish oil and meal for feed. Samples collected in 2008 generally contained low concentrations of undesirable substances. These results are in agreement with our previous results obtained in monitoring programs 2003-2007. This year (2008) special emphasis was placed on gathering information on PBDE and PAHs and the results reveal that these compounds are in very low amounts in fish and fish products and most PAHs are actually below detection limits. Blue whiting meal and oil can contain undesirable substances in concentration close to or exceeding the maximum level set by the EU.

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Reports

Improved fertilization of halibut eggs

Published:

01/05/2010

Authors:

Jónína Þ. Jóhannsdóttir, Heiðdís Smáradóttir, María Pétursdóttir, Rannveig Björnsdóttir

Supported by:

AVS

Improved fertilization of halibut eggs

The main bottlenecks in sea fish farming are the early stages of development and the supply of quality eggs, larvae and juveniles. The egg quality of fish varies greatly and is mainly assessed by the fertilization rate and performance of eggs and larvae, but is controlled by various factors. It is very important for the management and performance of companies to be able to assess roe quality as soon as possible. The aim of this project was to define factors that affect the fertilization rate of halibut eggs and that can possibly be controlled. At the same time, experiments were carried out with different methods of fertilization where the amount of seaweed was changed or substances were added to the environment during fertilization. Fish in two spawning groups were followed up and extensive research was carried out on the characteristics and bacterial flora of roe doses. The results show that there is not much variability in the measures examined and there is no significant correlation with the fertilization rate, which indicates that they are unlikely to have a decisive effect on egg quality. However, the results indicate that the composition of the total bacterial flora and the composition of essential fatty acids are different in eggs with a higher fertilization rate and can therefore affect the quality of eggs. The main results of fertilization experiments indicate that the addition of glucose at a certain concentration in the roe environment can lead to a 10% increase in the fertilization rate of roe, which offers the possibility of a large increase in income for aquaculture companies. Extensive research is planned on the further effects of glucose admixture on roe performance as well as larval performance and quality.

The main bottle necks in intensive marine aquaculture are the first stages and the supply of high quality eggs, larvae and juveniles. Egg quality is highly variable and has been defined in many ways mainly the fertilization rate and the viability of fertilized eggs and larvae. Multiple factors affect egg quality and an early assessment of egg quality is of great importance for hatchery management. The objective of this work was to define indicators for halibut egg quality that could possibly be regulated. Furthermore, the effects of variable fertilization methods have been tested, that is, variable amounts of seawater and addition of various chemicals during fertilization. Batches of eggs were collected from two spawning groups and extensive examination carried out on their characteristics and bacterial composition. The results show very little variability in the factors examined and no correlation with the fertilization rate that indicates insignificant importance for egg quality. However, the bacterial composition and the fatty acid composition were different in the batches of eggs with higher fertilization rate compared to lower indicating its importance for egg quality. The fertilization experiments indicate that the use of a certain concentration of glucose during fertilization could result in 10% increase in the fertilization rate which could bring about an increased operation success for the aquaculture companies. Comprehensive studies are scheduled to further investigate the effect of additional glucose on egg viability and larval survival as well as quality.

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Reports

The effect of cooling methods at processing and use of gel-packs on storage life of cod (Gadus morhua) loins - Effect of transport via air and sea on temperature control and retail-packaging on cod deterioration

Published:

01/05/2010

Authors:

Emilia Martinsdóttir, Hélène L. Lauzon, Björn Margeirsson, Kolbrún Sveinsdóttir, Lárus Þorvaldsson, Hannes Magnússon, Eyjólfur Reynisson, Arna Vigdís Jónsdóttir, Sigurjón Arason, Maria Eden

Supported by:

EU (contract FP6-016333-2) Chill-on, AVS, R&D Fund of Ministry of Fisheries in Iceland, the Technology Development Fund at the Icelandic Center for Research

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

The effect of cooling methods at processing and use of gel-packs on storage life of cod (Gadus morhua) loins - Effect of transport via air and sea on temperature control and retail-packaging on cod deterioration

The purpose of the experiments was to investigate the effect of different cooling during processing and temperature fluctuations in transport with and without a cooling mat on the shelf life of cod necks. In processing, it was compared to use no pre-cooling for filleting, liquid cooling and skin cooling (CBC) which is always liquid-cooled. The effect of simulated temperature fluctuations in transport temperature changes (RTS) was compared with storage at a constant temperature (-1 ° C). The effects of using a cooling mat in storage and transport were also assessed. Samples were quality assessed by sensory evaluation, microbial and chemical measurements. Temperature was monitored with thermometers. Skimmed cod fillets in foam plastic boxes were transported to Bremerhaven by air and ship, where they were repackaged in air and aerated packages (MAP) and stored at 1 ° C. Chemical and microbiological measurements were performed to monitor quality changes. The temperature of the erythema necrosis was lower than in the first 2 days of the experiment. The cooling mats had a certain effect of lowering the temperature when temperature fluctuations were in the process and lower temperatures were maintained throughout the storage period. However, the use did not affect the duration of freshness or shelf life according to sensory evaluation. The number of microorganisms was somewhat lower if temperature fluctuations occurred in the process, but there was little difference at a constant temperature. Storage at a constant, low temperature (-1 ° C) prolonged shelf life by approx. 3 days according to sensory evaluation and it was in accordance with microbial counts and measurements of TVB-N and TMA. Experiments in Bremerhaven showed that the number of microorganisms was generally lower when using aerated packaging compared to airborne fish. This was especially noticeable in the flying fish. The fish transported by ship was still stored for as long as the fish transported by air. This is due to the fact that the flying fish experienced greater temperature fluctuations during transport and its surface temperature measured 4 ° C on arrival in Bremerhaven. The transport time by ship was much longer (+48 hours) but the surface temperature was below 2 ° C on receipt. The use of cooling mats had little effect on the temperature during transport, but nevertheless the surface temperature was slightly lower in fish with cooling mats on arrival in Bremerhaven both by air and by ship.

The main aim of the experiment was to investigate the effects of different cooling techniques during processing and temperature fluctuations during transport on the storage life of cod loins with and without gel packs. The following cooling techniques were studied: combined blast and contact (CBC) cooling (with liquid cooling prior to the CBC cooling), only liquid cooling and where no special cooling was used prior to deskinning and trimming. The effect of real temperature simulation (RTS) during storage was compared to a steady storage temperature of -1 ° C. The samples were analyzed with sensory, microbial and chemical methods. The temperature was monitored from packaging using temperature loggers. CBC cooled loins were transported to Bremerhaven via air and ship freight after packaging in EPS boxes. The fish was repacked in air and modified atmosphere and stored at 1 ° C. Deteriorative changes were evaluated by microbial and chemical indicators. CBC cooling resulted in a lower temperature profile the first two days of the experiment. The use of gel packs lowered somewhat the temperature increase in the products when RTS was applied and lower temperature was maintained during the entire storage period. According to sensory evaluation, the use of gel packs did not result in prolonged freshness period or shelf life. According to microbial and chemical analysis no marked difference was seen whether gel packs were used or not in groups stored at a steady temperature. However, microbial counts were somewhat lower and slower formation of TVB-N and TMA occurred in RTS groups where gel packs were used compared to no gel packs. Storage at a steady -1 ° C resulted in extended shelf life of three days according to sensory evaluation. This was confirmed by microbial and chemical analysis as lower microbial counts, TVB-N and TMA values were generally obtained in the steady temperature group than in the group receiving the RTS treatment. The storage studies carried out at Bremerhaven on modified atmosphere vs. air packed loins showed generally lower microbial counts, especially in the air transported fish. Deterioration process of air and sea freight fish was however similar. Re-packaging of sea freight fish at a later stage did not significantly affect its deteriorative process compared to re-packed air freight fish. This might be due to the fact, that the air freight fish was subject to high temperatures during transport and surface temperature reached over 4 ° C. The sea freight fish had a much longer transport phase, but arrived with surface temperatures below 2 ° C. This shows that not only the time of re-packaging but also the temperature profile during transport are important factors influencing the deteriorative process and shelf life. Gel packs did not have significant cooling effect in this experiment. However the surface temperature in boxes with a gel pack was slightly lower than in boxes without a gel pack independently of transport mode used.

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Reports

Air-dried lamb. Final report / Air dried lamb meat. Final report

Published:

01/05/2010

Authors:

Þóra Valsdóttir, Óli Þór Hilmarsson, Guðjón Þorkelsson

Supported by:

Productivity Fund, Professional Council for Sheep Breeding / BÍ Board

Contact

Þóra Valsdóttir

Project Manager

thora.valsdottir@matis.is

Air-dried lamb. Final report / Air dried lamb meat. Final report

The aim of the project was to develop products from air-dried lamb in collaboration with farmers. The project was also about increasing farmers' skills in processing and processing lamb into air-dried products, ie. make them suitable for the manufacture of such products. A co-operation group of 5 farmers was formed who were interested and have facilities for home processing of such products. The aim was to develop one product with each farmer, and the product must meet all the requirements for safety, quality, finish and presentation that are relevant for products in the consumer market. In the main, it went well. Farmers were able to adopt the production methods necessary for dry processing and they developed new production processes and products, each different from what is on the market today. The results therefore strengthen the farm in question for the development of new products from its own raw materials and thus their working basis.

The aim of the project was to develop products from air dried lamb in cooperation with farmers. The project centered as well on extending farmers' knowledge on processing and curing methods for these products. Group of five farmers was selected to participate in the project. All farmers had an interest and facilities for this kind of processing. The products should fulfill all requirements regarding safety, quality and presentation of consumer products. This succeeded in most cases. The farmers adopted practices needed in producing dry aired products, new processing methods and products were developed. The results will thus strengthen each producer in development of new products from their own raw material, thus boosting their own operation.

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