Tag: Shelf life

Reports

Improved utilization of lumpfish

Published:

27/06/2013

Authors:

Gunnar Þórðarson (Matís), Skjöldur Pálmason (Fiskvinnslan Oddi), Ólafur Reykdal (Matís)

Supported by:

AVS V 11 020‐11

Contact

Gunnar Þórðarson

Regional Manager

gunnar.thordarson@matis.is

Improved utilization of lumpfish

The Ministry of Fisheries and Agriculture's regulation, No. 1083/2010, made it obligatory to bring all grayling catch ashore after 2011. It was therefore necessary to react quickly and find a market for the grayling itself, but only the roe had been harvested and the rest thrown into the sea. . A great deal of entrepreneurship had taken place for several years, and it is worth mentioning the National Association of Small Boat Owners and the export company Triton in that context, which together built up a market for grayling in the Chinese market, with a bang and all. It should be noted that the roe is about 30% by the weight of the grayling, while the whale with the head and tail is about 55%, of which the fillets are only 14% of its total weight. There was a lot of work to be done and it is clear that there is great value in this underutilized fish species and great opportunities would be created in many coastal settlements for the production and export of grayling. At the same time, increased income for fishermen and the fishing industry, as well as the fact that the grayling was now mostly brought ashore, which created a lot of work for production parties. Cutting for the Chinese market is different from the traditional method and requires more complex procedures, but it requires better working conditions that do not exist on board small fishing boats. There was little information on the chemical and nutritional content of grayling, but such information is necessary when marketing products. A detailed report was prepared on the material and raw materials are used in many parts of the country. Shelf life tests were performed on frozen grayling. A conference was held in Patreksfjörður where stakeholders in the fishing, processing and export of grayling were invited to discuss the interests of the industry.

A new regulation from Minister of Fisheries and Agriculture, No. 1083/2010, require returning all lumpfish fished in Iceland, after 2011. A quick action had to be taken to find markets for lumpfish itself, but only the roes which have been processed but the rest of the fish have been discarded into the sea. With entrepreneurial activity for some years now new markets have been developed in China, by the National Association of Small Boat Owners in Iceland in cooperation with the export company Triton. It should be noted that the roes are only about 30% of the total weight of lumpfish, with head and tail about 70% of its total weight. There was much to be done to save value in the lumpfish business and great opportunities for small communities relying on this business and find a market for the lumpfish product and create extra value for stakeholders. Furthermore, increased income for fishermen and fishing communities by creating valuable work by processing the fish at shore. Gutting and trimming the lumpfish for the China market is different from the traditional approach and calls for more sophisticated self-administration, but it requires better working conditions that do not exist on board small fishing boats. Very little information on chemical composition and nutrient value has been available for lumpfish products. An in-depth report on this subject was prepared, using samples from different regions in Iceland. Self ‐ life experiments were prepared by this project. A work shop was held in Patreksfjordur in May 2013, with stakeholders from the lumpfish business participating.

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Reports

Superchilled Round Fish - Final Report / Supercilled Whole Fish - Final Report

Published:

01/03/2013

Authors:

Björn Margeirsson, Valur Oddgeir Bjarnason, Sigurjón Arason

Supported by:

AVS Fisheries Research Fund (R 11 062‐11)

Contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Superchilled Round Fish - Final Report / Supercilled Whole Fish - Final Report

The main objective of the project "Super-chilled whole fish - for death solidification", which began in July 2011, was to investigate whether super-cooling of whole fish on board a fishing vessel could extend the shelf life and increase the quality of the products. Appropriate temperature and time settings for red and touch refrigerators were sought with four refrigeration experiments and the best settings were used to supercool whole fish in a shelf life experiment. The results of a shelf life test indicate that supercooled processing of whole cod can extend its shelf life by two days. According to sensory evaluation, however, there was little difference in the shelf life of different fillet groups. Shelf life was estimated at 16-18 days, which is quite a long time for cod fillets. However, the freshness period of the experimental group with super-chilled fillets of super-chilled whole fish seemed to be somewhat longer than the other groups. As with whole cod, there was little difference between the fillet groups in terms of microbial growth, chemical and physical properties. Limited differences between experimental groups can possibly be explained by stable and supercooled storage conditions. With this in mind, it is recommended to carry out another similar experiment, simulating more typical environmental temperature processes in the transport of fresh fish products (0–4 ° C) than in this experiment (–1.4 to –1.2 ° C). The results of computerized thermodynamics and hydrology modeling indicate that such models could be used for the continuous design of red and touch chillers for whole fish.

The main aim of the R&D project "Superchilled round fish - pre ‐ rigor", which was initiated in July 2011, was to investigate whether superchilled processing of whole fish on ‐ board fishing ships could increase product quality and prolong storage life. The appropriate temperature and time settings for the superchilling equipment were studied in four cooling trials and the best settings applied when preparing samples for a storage life study. The results from the storage life study indicate that superchilled processing of whole cod can extend storage life by two days. However, differences in sensory scores between the fillet groups were small. Storage life was estimated between 16 and 18 days which is quite long storage life for cod fillets. However, the group with superchilled fillets from superchilled whole fish seemed to retain freshness a little longer than other groups. As in case of the whole cod, the differences in bacterial count, chemical and physical properties between the fillet groups were small. Very similar fish temperatures between both the whole fish and the fillet groups resulting from the superchilled storage conditions applied may be the main reason for the small differences obtained. Thus, another study with more common temperature conditions during transport and storage of fresh fish (chilled but not superchilled) should be performed. The results obtained in this study show that CFD modeling of fluid flow and heat transfer is a realistic and functional tool to simulate superchilling of whole fish in a CBC ‐ cooler. In future work CFD modeling can be used to determine optimal values for parameters such as holding time, chilling temperature and air velocity. 

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Reports

Comparison of transport modes and packaging methods for fresh fish products - storage life study and life cycle assessment

Published:

01/10/2012

Authors:

Björn Margeirsson, Birgir Örn Smárason, Gunnar Þórðarson, Aðalheiður Ólafsdóttir, Eyjólfur Reynisson, Óðinn Gestsson, Emilía Martinsdóttir, Sigurjón Arason

Supported by:

AtVest (Atvinnuþróunarfélag Vestfjarði)

Contact

Birgir Örn Smárason

Research Group Leader

birgir@matis.is

Comparison of transport modes and packaging methods for fresh fish products - storage life study and life cycle assessment

There is a great benefit in improved control of the value chain of exports of fresh fish knuckles for distribution in retail chains in the UK. Improved packaging methods could increase the shelf life of a product, which is fundamental to this business. With an airtight container, it would be possible to transport the product in a sludge tank with a low temperature (down to -1 ° C), which would both reduce the transport cost significantly and could also extend the shelf life of the product. The method also provides the option of packaging with consumer information, which makes further packaging abroad unnecessary. In air transport, it would be possible to pack all goods in a 12 kg foam box instead of 3 kg, as is most common today, thus saving significant transport costs. Temperature measurements, sensory evaluation, chemical and microbial measurements and life cycle analysis were used to compare different packaging solutions for sea and air transport. Fresh haddock pieces in vacuum-packed containers in a container with slush ice, which were stored at a typical temperature in container transport, turned out to have a shelf life of 3-4 days longer than the other experimental groups, probably mainly due to better temperature control. Consistency between the results of sensory evaluation and microbiological measurements was generally good. The lowest environmental impact of all groups was the pot group with sea-transported, vacuum-packed packaging, but this design could be further improved with regard to the mixing of the ice scraper and fish temperature control and thus the shelf life.

The aim of the project was to compare alternative packaging methods of fresh fish loins to the traditional packaging. Comparison was made between packages in terms of temperature control and product storage life by simulating air and sea transport from Iceland to UK in air climate chambers. The evaluation was made by the sensory panel and microbialand chemical analysis by the Matís laboratory in Reykjavík. Furthermore, the environmental impact of the aforementioned transport modes and packaging methods was assessed by means of LCA (Life Cycle Assessment). About 70–75% of Iceland's exports of fresh fillets and loins are transported by air and the rest by container ships. Increased knowledge on the advantages and disadvantages of the packages used for this fresh fish export will facilitate the selection of packages and improve the quality and storage life of the products. By using vacuum-packaging it is possible to use 12 kg packages in air freight instead of the traditional 3– 5 kg packages; but the market is increasingly demanding smaller individual packages. Sea transported larger packages use less space in shipping, lowering freight cost and environmental impact. Vacuum packed haddock loins immersed in slurry ice in a fish tub stored at sea transport temperature conditions proved to have a 3–4 day longer storage life than all the other experimental groups, probably mainly because of better temperature control. Good agreement was obtained between the sensory- and microbial evaluation. Finally, the sea transport-tub-group was found to be the most environmentally friendly and could be improved with regard to product temperature control and thereby storage life.

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Reports

Effect of superchilled processing of whole whitefish - pre ‐ rigor / Effect of supercooling on spoilage processes and shelf life of whole fish and fillets

Published:

01/05/2012

Authors:

Aðalheiður Ólafsdóttir, Björn Margeirsson, Kolbrún Sveinsdóttir, Sigurjón Arason, Eyjólfur Reynisson, Emilía Martinsdóttir

Supported by:

AVS Fund of Ministry of Fisheries in Iceland (R 062‐11)

Contact

Aðalheiður Ólafsdóttir

Sensory evaluation manager

adalheiduro@matis.is

Effect of superchilled processing of whole whitefish - pre ‐ rigor / Effect of supercooling on spoilage processes and shelf life of whole fish and fillets

The aim of the experiment was to investigate the effect of supercooling on the damage processes and shelf life of whole fish and fillets. A study was carried out on whole supercooled cod soon after fishing and also on the effect of supercooling on fillets made from supercooled cod and cod cooled in ice in the traditional way. Temperature measurements, sensory evaluation, chemical and microbial measurements were used to compare the following experimental groups, which were stored at –1.4 to –1.2 ° C average temperature:

1) NC: whole cod cooled in ice

2) SC: supercooled whole cod

3) NC-NC: traditional fillet processing from whole cod cooled in ice

4) NC ‐ SC: super-chilled fillets made from whole cod cooled in ice

5) SC-NC: traditional fillet processing from super-chilled whole cod

6) SC-SC: super-chilled fillets made from super-chilled whole cod

Sensory evaluation results suggest that supercooled processing of whole cod can extend its shelf life by two days. Supercooling of whole cod did not affect the acidity, water content, water resistance and microbial growth of whole fish compared to fish that were not supercooled during processing. According to sensory evaluation, there was little difference in the shelf life of different fillet groups. Shelf life was estimated at 16-18 days, which is quite a long time for cod fillets. However, the freshness period of the experimental group SC-SC seemed to be somewhat longer than the other groups. As with whole cod, there was little difference between the fillet groups in terms of microbial growth, chemical and physical properties. Limited differences between experimental groups can possibly be explained by stable and supercooled storage conditions. With this in mind, it is planned to carry out another similar experiment, which will simulate more typical environmental temperature processes in the transport of fresh fish products (0–4 ° C) than in this experiment (–1.4 to –1.2 ° C).

The main aim of the study was to study the effects of superchilled processing on storage life of both whole fish and fillets. The following experimental groups were evaluated by means of temperature monitoring, chemical and microbial measurements and sensory evaluation, which were stored at mean temperatures of –1.4 to –1.2 ° C:

1) NC: non ‐ superchilled whole cod

2) SC: superchilled whole cod

3) NC ‐ NC: non ‐ superchilled fillets from non ‐ superchilled whole cod

4) NC ‐ SC: superchilled fillets from non ‐ superchilled whole cod

5) SC ‐ NC: non ‐ superchilled fillets from superchilled whole cod

6) SC ‐ SC: superchilled fillets from superchilled whole cod

The results from the sensory evaluation indicate that superchilled processing of whole cod can extend shelf life by two days. Differences in values of pH, water content, water holding capacity and bacterial growth between the superchilled and non ‐ superchilled whole fish groups were minor. Differences in sensory scores between the fillet groups were small. Shelf life was estimated between 16 and 18 days which is quite long shelf life for cod fillets. However, the SC ‐ SC group seemed to retain freshness a little longer than other groups. As in case of the whole cod, the differences in bacterial count, chemical and physical properties between the fillet groups were small. Very similar fish temperatures between both the whole fish and the fillets groups resulting from the superchilled storage conditions applied may be the main reason for the small differences obtained. Thus, another study with more common temperature conditions during transport and storage of fresh fish (chilled but not superchilled) will be performed.  

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Reports

Development of QIM and shelf life of fresh mackerel (Scomber scombrus) / Development of QIM and shelf life of fresh mackerel (Scomber scombrus)

Published:

01/03/2012

Authors:

Aðalheiður Ólafsdóttir, Elvar Steinn Traustason, Ásbjörn Jónsson, Kolbrún Sveinsdóttir, Kristín Anna Þórarinsdóttir

Supported by:

AVS Fisheries Research Fund (R 11 037‐010)

Contact

Aðalheiður Ólafsdóttir

Sensory evaluation manager

adalheiduro@matis.is

Development of QIM and shelf life of fresh mackerel (Scomber scombrus) / Development of QIM and shelf life of fresh mackerel (Scomber scombrus)

The aim of the project was to examine changes that occur in mackerel during ice storage. Develop a QIM scale for fresh mackerel and compare it with the results of cooked fish assessments and QDA (quantitative descriptive analysis) to determine the end of shelf life. Based on QDA results, it can be concluded that mackerel stored for 9 days on ice has reached the limit of shelf life. Taste and odor symptoms (fresh oil) are then reduced and damage symptoms (cravings and bitterness) take over.

The aim of the project was to look at the changes in mackerel at storage on ice. Develop a QIM spectrum for fresh mackerel and compare with cooked fish, QDA (quantitative descriptive analysis) to decide maximum shelf life. From the QDA results, one can conclude that maximum shelf life for fresh mackerel is 9 days on ice. At that time freshness in taste and odor are decreasing and characteristic of spoilage (rancidity and bitter) dominates.

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Reports

Germicidal effects of UV light on processing line surfaces and pork shelf life / Effect of UV light on microbial contamination of processing surfaces and shelf life of pork products

Published:

01/12/2011

Authors:

Sveinn Magnússon, Eyjólfur Reynisson, Viggó Marteinsson

Supported by:

Technology Development Fund

Contact

Viggó Marteinsson

Research Group Leader

viggo@matis.is

Germicidal effects of UV light on processing line surfaces and pork shelf life / Effect of UV light on microbial contamination of processing surfaces and shelf life of pork products

The antimicrobial effect of UV radiation has been known for a long time, but UV radiation at 254nm (UV ‐ C) causes damage to the genetic material of cells and prevents microbial growth. The use of UV lighting for disinfection has increased, for example in the food industry - where UV radiation can be used to disinfect processing surfaces and food - thereby increasing safety and extending the shelf life of food. This report describes a test of the effect of UV exposure on the processing surface on the shelf life of meat products. The effect of UV exposure on the surface of meat processing - the conveyor belt and cutting board - on the shelf life of pork products was examined. The results of the study show that UV exposure has the effect of reducing the microbial content of processing surfaces. The results regarding the effect on shelf life were not decisive, but indicate that with a clean processing line and UV lighting on the processing surface, the shelf life of pork products from the processing line can be increased.

UV radiation at 254nm (UV ‐ C) causes damage to the genetic material of cells and prevents microbial growth. The use of UV light for disinfection is increasing eg in the food production industry - where UV radiation can be used for disinfection of food production surfaces and foods - and thereby increase food safety and extend product shelf life. This report describes the testing of the effects of UV lighting on surfaces in food processing facility on product shelf life. Effects of UV lighting on process line surfaces - conveyor belt and cutting boards - on the shelf life of pork was examined. The results of the study show that UV reduces the bacterial load on process line surfaces. Regarding the effects on pork shelf life the results were not significant but suggest that cleaner process lines and UV lighting on process line surfaces can increase the shelf life of pork products.

Report closed until 01.01.2014 / Report closed until 01.01.2014

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Reports

Effect of cooling and packaging methods on the quality deterioration of redfish fillets

Published:

01/09/2011

Authors:

Hélène L. Lauzon, Aðalheiður Ólafsdóttir, Magnea G. Karlsdóttir, Eyjólfur Reynisson, Björn Margeirsson, Sigurjón Arason, Emilía Martinsdóttir

Supported by:

EU IP Chill ‐ on (contract FP6‐016333‐2)

Contact

Aðalheiður Ólafsdóttir

Sensory evaluation manager

adalheiduro@matis.is

Effect of cooling and packaging methods on the quality deterioration of redfish fillets

The aim of the experiment was to evaluate the effect of slush ice cooling after filleting and / or packing in vacuum packaging on the deterioration of the quality of fresh redfish fillets. The fillets were stored at -1 ° C for 6 days to simulate well-executed sea transport in foam plastic boxes and then at 2 ° C, as happens after delivery abroad and storage in retail. Product and ambient temperature were monitored from packaging and sensory evaluation, microbial and chemical measurements were performed. The fish was caught in the spring and processed 6 days after fishing. The results show that the quality of the raw material was not the best during packaging as the development process (PV and TBARS) was well underway. This probably explains why none of these refrigeration methods led to an increase in shelf life. It was also found that there was no benefit in cooling the fillets unprotected in slush ice as the microbial growth and formation of TVB-N and TMA in the fillets was faster with further storage. However, it seems preferable to refrigerate vacuum packed fillets in ice cream as this method has led to slower growth of pest microorganisms, lower TMA levels and a slower development process. Photobacterium phosphoreum is important in the process of damaging fresh redfish fillets, regardless of the packaging method.

The aim of this study was to evaluate the effect of slurry ice cooling in process (post ‐ filleting) and packaging method (+/‐ oxygen) on the quality deterioration of skinned redfish fillets during storage in expanded polystyrene boxes simulating well ‐ performed sea freight transportation (6 days at ‐1 ° C) followed by storage at the retailer (2 ° C). Also, to assess the use of vacuum ‐ packaging to protect the fillets from direct contact with the cooling medium (slurry ice) and to achieve superchilling following extended treatment. Temperature monitoring as well as sensory, chemical and microbial analyzes were performed. The fish was caught in the spring and processed 6 days post catch. The results show that quality of the fillets was not optimal at packaging, due to the detection of primary and secondary oxidation products. This may have been the reason why shelf life extension was not achieved by any of the methods evaluated. Further, there was no advantage of cooling the fillets unpacked since this method stimulated microbial growth and formation of basic amines. On the other hand, slurry ice cooling of vacuum ‐ packaged fillets led to a slower microbial development, the lowest TMA level and delayed autoxidation. Finally, the importance of Photobacterium phosphoreum in the spoilage process of redfish fillets, independently of the packaging method, was demonstrated.

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Reports

Effect of temperature control on the efficiency of modified atmosphere packaging of cod loins in bulk

Published:

01/06/2011

Authors:

Hélène L. Lauzon, Kolbrún Sveinsdóttir, Magnea G. Karlsdóttir, Eyjólfur Reynisson, Björn Margeirsson, Emilia Martinsdóttir

Supported by:

EU IP Chill ‐ on (contract FP6‐016333‐2)

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

Effect of temperature control on the efficiency of modified atmosphere packaging of cod loins in bulk

The aim of the experiment was to compare the freshness, quality and shelf life of sub-chilled (CBC) cod necks in air storage and in aerated packages (MAP) at controlled temperatures to simulate temperature fluctuations during transport and distribution in the European market. Changes in the composition of the gas in the packages were monitored and sensory assessments and microbial and chemical measurements were performed. The fish was caught in bottom trawls in the spring and processed three days after fishing. There was a two-day prolongation during the freshness period and one day for the shelf life of fish in aerated packages (2.7 kg in a tray) compared to air (3.1 kg) in foam plastic, despite a 0.5 ° C difference in the average temperature of the groups and the air group was stored at lower temperatures (‐0.3 ± 0.9 ° C). The greatest temperature fluctuations led to the greatest shortening of the freshness time in air-conditioned packages. Cod saddles stored subcooled at -1.1 ± 0.1 ° C had a shelf life of 13 days. The results of microbial counts and chemical measurements showed the importance of Photobacterium phosphoreum in the formation of TMA in the process of damaging cod necks during both air and air exchange packaging. MAP and subcooling slowed down and changed the damage process. MAP increased drip by 2% in the later stages of storage.

The aim of this study was to compare freshness, quality deterioration and shelf life of CBC (combined blast and contact) ‐treated cod loins packaged in bulk under different atmospheres (air or modified atmosphere, MA) and stored under different temperature profiles to mimic temperature changes during transport and distribution to European markets. Sensory, chemical, microbial and headspace gas composition analyzes were performed regularly. The fish was caught by trawler in the spring and processed 3 days post catch. Following simulation of current sea freight conditions and distribution to European markets, a 2 ‐ day and 1 ‐ day increase in freshness period and shelf life of MA ‐ packaged fish (2.7 kg in trays), respectively, was observed compared to air ‐ stored loins (3.1 kg in EPS boxes). This is despite a mean product temperature difference of 0.5 ° C between the products, being lower (‐0.3 ± 0.9 ° C) for air ‐ stored fish. Abusive conditions had the greatest impact on the reduction of the freshness period for MAP fish. Superchilled storage of MAP loins (‐1.1 ± 0.1 ° C) resulted in a 13 ‐ day shelf life. Evaluation of microbial and chemical indicators emphasized the importance of Photobacterium phosphoreum and TMA formation in the deterioration of cod loins stored in air or MA, while superchilled MAP storage delayed as well as modified the spoilage pattern. MAP increased drip loss by about 2% at late storage.

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Reports

Overview on fish quality research - Impact of fish handling, processing, storage and logistics on fish quality deterioration

Published:

01/11/2010

Authors:

Hélène L. Lauzon, Björn Margeirsson, Kolbrún Sveinsdóttir, María Guðjónsdóttir, Magnea G. Karlsdóttir, Emilia Martinsdóttir

Supported by:

AVS R&D Fund of Ministry of Fisheries in Iceland, Technology Development Fund and EU IP Chill-on (contract FP6-016333-2)

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

Overview on fish quality research - Impact of fish handling, processing, storage and logistics on fish quality deterioration

The short shelf life of fish is a limiting factor in the export of fresh fish products from Iceland. The initial quality of raw materials, methods of cooling, processing, packaging and conditions during storage and transport are discussed, as well as the effects of all these factors on the freshness and shelf life of fish products. Temperature control is very important to maintain the quality of the fish. Pre-processed fillets have been used to lower the pre-packing temperature. However, care must be taken that the pre-cooling technology does not endanger the microbial condition of the product and thus causes it to be damaged earlier after packaging. The synergistic effects of supercooling and aerated packaging (MAP) can significantly extend the freshness period and shelf life of fish products. Furthermore, packaging methods are examined, including new, more environmentally friendly packaging. Finally, the effect of transport routes of fresh fish products on their final quality to consumers in the market is discussed. This report provides an overview of the research of the Fisheries Research Institute and Matís ohf over the past three decades on the subject. Furthermore, it is discussed how these results can benefit the fishing industry.

The limited shelf life of fresh fish products is a large hurdle for the export of fresh products from Iceland. The influence of raw material quality, cooling methods, processing, packaging and storage conditions on freshness and shelf life extension is discussed. Temperature control is important to maintain fish quality. Pre-cooling of fillets in process has been used to lower the temperature prior to packaging. However, the cooling technique applied should not compromise the microbiological quality of the product and render it vulnerable to faster spoilage postpackaging. Synergism of combined superchilling and modified atmosphere packaging (MAP) can lead to a considerable extension of the freshness period and shelf life of fish products. Further, alternative and environmentally-friendly packaging methods are considered. Finally, the impact of transportation mode of fresh fish products on their resulting quality is examined. This report provides an overview of the findings on fish research carried out at Matís (Icelandic Fisheries Laboratories) over the last three decades and further discusses their practicality for the fish processing industry.

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Reports

The effect of different cooling techniques on the quality changes and shelf life of whole cod (Gadus morhua)

Published:

01/08/2010

Authors:

Hannes Magnússon, Kolbrún Sveinsdóttir, Lárus Þorvaldsson, María Guðjónsdóttir, Hélène L. Lauzon, Eyjólfur Reynisson, Árni R. Rúnarsson, Sveinn H. Magnússon, Jónas R. Viðarsson, Sigurjón Arason, Emilia Martinsdóttir

Supported by:

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

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

The effect of different cooling techniques on the quality changes and shelf life of whole cod (Gadus morhua)

The purpose of the experiment was to investigate the effect of three different cooling methods on the shelf life of whole, gutted cod: (i) Cooling with crushed plate ice, (ii) cooling with liquid ice, (iii) pre-cooling with liquid ice and then cooling with crushed plate ice. Temperature processes were monitored with temperature sensors in all groups during the storage period. Samples were assessed by sensory evaluation, microbial and chemical measurements during the 10 days the fish was stored. The results of microbial and chemical measurements were generally in good agreement with the results of sensory evaluation. Comparison of experimental groups revealed that cod chilled with liquid ice had a shelf life of about two to three days shorter than the other two groups. The shelf life of the cod was considerably shorter than various previous studies have shown, especially in the group that was cooled with liquid ice (only 9-10 days). It is now clear that the cod that was cooled with liquid ice was vanished on board the fishing vessel compared to the other two groups. In addition, refrigerated storage after landing was not as good as might be considered, but the temperature fluctuated between 2-5 ° C. This could possibly explain the shorter shelf life of all groups compared to previous studies.

The aim of this experiment was to investigate the effect of three different cooling methods on the storage quality of whole, bled gutted cod: (i) Cooled with crushed plate ice, (ii) cooled with liquid ice, (iii) pre-cooled in liquid ice and then cooled with crushed plate ice. The temperature history of each group was studied using temperature loggers. The samples were analyzed with sensory, microbiological and chemical methods for up to 10 days from catch. The results from microbial and chemical measurements were generally in good agreement with the results from sensory evaluation. Comparison of the groups showed that the use of liquid ice instead of plate ice resulted in two to three days shorter shelf life than in the other two groups. The shelf life in this study was considerably shorter compared to previous studies with whole cod, especially in the experimental group where liquid ice was used for cooling (only 9-10 days). It is now known that the liquid iced group in this experiment was insufficiently iced on board the fishing vessel compared to the other two groups. Additionally, the ambient temperature in the cold room of the fish plant was relatively high and fluctuated between 2 - 5 ° C during the storage period. This could possibly explain the shorter shelf life of all groups compared to some earlier studies.

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