Tag: Cod fillets

Reports

The effect of different precooling media during processing and cooling techniques during packaging of cod (Gadus morhua) fillets

Published:

01/04/2010

Authors:

Björn Margeirsson, Hannes Magnússon, Kolbrún Sveinsdóttir, Kristín Líf Valtýsdóttir, Eyjólfur Reynisson, Sigurjón Arason

Supported by:

AVS Fund of Ministry of Fisheries in Iceland, The Technology Development Fund at the Icelandic Center for Research, University of Iceland Research Fund

Contact

Kolbrún Sveinsdóttir

Project Manager

kolbrun.sveinsdottir@matis.is

The effect of different precooling media during processing and cooling techniques during packaging of cod (Gadus morhua) fillets

The purpose of the experiments was to investigate the effect of different refrigerants in pre-cooling before packaging on temperature control, quality and shelf life of cod fillets. The following refrigerants were examined and compared with no special pre-packing pre-packing:

  1. brine with a low salt content, 2) ice cream with a low salt content.

In addition, the effects of using ice mats and dry ice on the storage of the wrecks were investigated. Temperature changes were monitored by temperature sensors at all levels. Samples were quality assessed by sensory evaluation, microbial and chemical measurements for up to 13 days from processing and packaging (16 days from fishing). The fillets were stored in supercooled conditions (below 0 ° C) for most of the storage time. Lower temperatures of slurry ice than brine led to lower fillet temperatures during packing, and the temperature of the liquid brine was found to rise rapidly during processing. Different treatment resulted in a comparable freshness period according to sensory evaluation. However, the use of a liquid brine during pre-packaging pre-packing proved to lead to a shorter shelf life of 1-2 days compared to no pre-cooling or pre-cooling with slush ice. The reasons for this can be traced to the fact that the brine contained a considerable amount of microorganisms, including H2S-producing bacteria which are active producers of trimethylamine (TMA). Comparison of liquid-cooled fillets showed that the use of dry ice prolonged shelf life by 1 day compared to ice mats. The results of microbial and chemical measurements were consistent with these results.

The aim of the experiment was to investigate effects of two cooling media during precooling at processing on temperature control, quality and storage life of cod fillets. The two cooling media compared to no special precooling during processing (NC) were: 1) liquid brine (LC) and 2) slurry ice (SIC). In addition, the influence of using either dry ice or ice packs during storage was studied. The samples were kept at superchilled conditions during most of the trial. The environmental and product temperature history of each group was studied using temperature monitors. The samples were analyzed with sensory evaluation, microbial and chemical methods for up to sixteen days from catch (thirteen days from processing). Lower temperature of the slurry ice than the liquid brine resulted in lower fillet temperature at packaging and the liquid brine temperature increased rapidly during a processing break, which seems to be a weakness of the liquid brine tank. Results from sensory, microbial and chemical analysis all showed that immersing the skinless cod fillets in liquid cooling brine prior to packaging resulted in one to two days reduction of shelf life in comparison with fillets that were not immersed in liquid brine (no cooling) or in slurry ice. This could be attributed to the fact that the cooling brine carried considerable amounts of microbes including H2Sproducing bacteria which are active producers of trimethylamine (TMA). Comparison of the groups receiving liquid cooling showed that dry ice appeared to extend the shelf life of one day as compared to ice packs. The length of the freshness period was, however, similar in all experimental groups according to sensory evaluation. These results were confirmed by total volatile bases (TVB-N) and TMA analysis and microbial counts.

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Reports

The effect of liquid cooling at processing and different cooling techniques during transport of cod (Gadus morhua) fillets

Published:

01/11/2009

Authors:

Hannes Magnússon, Lárus Þorvaldsson, Kolbrún Sveinsdóttir, Hélène L. Lauzon, Kristín Anna Þórarinsdóttir, 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 liquid cooling at processing and different cooling techniques during transport of cod (Gadus morhua) fillets

The purpose of the experiments was to investigate the effect of different refrigeration techniques and the effect of temperature fluctuations on the quality and shelf life of cod fillets. The following cooling technology was investigated: Liquid cooling in brine during processing based on no cooling and the effect of temperature fluctuations during storage compared to a constant temperature (-1 ° C). In addition, the effects of using ice mats and dry ice on the storage of the wrecks were investigated. Temperature changes were monitored by temperature sensors at all levels. Samples were quality assessed by sensory evaluation, microbial and chemical measurements for up to 14 days from fishing (11 days from processing and packaging). Different treatment resulted in different freshness times and shelf life according to sensory evaluation. Groups that were liquid-cooled during processing had a shelf life of about 2-3 days shorter than fillets that were not cooled in this way. The reasons for this can be traced to the fact that the cooling brine contained a considerable amount of microorganisms, including the destructive bacterium Photobacterium phosphoreum, which is a very active producer of trimethylamine (TMA). Comparison of liquid-cooled fillets showed that the use of dry ice prolonged shelf life by 1-2 days compared to ice mats. Storage at -1 ° C did not have a significant effect on freshness time and shelf life compared to fillets where temperature fluctuations were applied according to sensory evaluation. The results of microbial and chemical measurements were consistent with these results.

The aim of the experiment was to investigate the effects of different cooling techniques and temperature fluctuations on the storage life of cod fillets. The following cooling techniques were studied: liquid cooling in brine at plant as compared to no special cooling at processing. The effect of real temperature (RTS) simulation during storage was compared to a steady storage temperature at -1 ° C. Additionally, the influence of using either dry ice or ice packs during storage was studied. The temperature history of each group was studied using temperature loggings. The samples were analyzed with sensory evaluation, microbial and chemical methods for up to 14 days from catch (11 days from packaging). The different treatments of the groups resulted in different lengths of freshness period and maximum shelf life according to sensory evaluation. Liquid cooling resulted in a 2-3 days shorter maximum shelf life than the group that was not receiving liquid cooling. This could be attributed to the fact that the cooling brine carried considerable amounts of microbes including the spoilage bacterium Photobacterium phosphoreum which is an active producer of trimethylamine (TMA). Comparison of the groups receiving liquid cooling showed that dry ice appeared to extend the shelf life of 1-2 days as compared to ice packs. Storage at -1 ° C did not have much influence on the freshness period or maximum shelf life. These results were confirmed by total volatile bases (TVB-N) and TMA analysis and microbial counts.

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Reports

The effect of different cooling techniques and temperature fluctuations on the storage life of cod fillets (Gadus morhua)

Published:

01/08/2009

Authors:

Hannes Magnússon, Hélène L. Lauzon, Kolbrún Sveinsdóttir, Björn Margeirsson, Eyjólfur Reynisson, Árni Rafn Rúnarsson, María Guðjónsdóttir, Kristín Anna Þórarinsdóttir, Sigurjón Arason, Emilía 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 and temperature fluctuations on the storage life of cod fillets (Gadus morhua)

The purpose of the experiments was to examine two refrigerants on board a fishing vessel, to use different refrigeration techniques during processing, including so-called CBC (combined blast and contact) refrigeration and to examine the effect of temperature fluctuations during storage compared to continuous storage at -1 ° C. There was little difference in microbial and chemical measurements, whether plate ice or liquid ice was used for processing, but according to sensory evaluation, the group that was cooled with liquid ice had one day longer freshness and shelf life. The temperature was usually slightly higher in the group as plate ice was used for processing during the storage period. According to sensory evaluation, microbial counts and chemical measurements, CBC cooling proved to be the best for prolonging freshness and shelf life. Temperatures were found to be lower in the groups where CBC cooling was used. The number of microorganisms was similar in the two groups where CBC cooling was not used in the processing (liquid cooling and no cooling). These results were consistent with the results of sensory evaluation. TMA levels were slightly higher on storage days 12-19 in the liquid-cooled group. The results of temperature measurements during the storage period were similar. A similar number of microorganisms were found to be in groups stored at a constant temperature (about -1 ° C) on the one hand and in groups where temperature fluctuations were applied during the first part of the storage period on the other hand. During the first 15 days of storage, TVB-N and TMA values were found to be similar in the groups. The groups stored at a constant temperature did not undergo sensory evaluation. Microbial assays performed by the fast-acting method qPCR were in good agreement with culture methods for Pseudomonas spp. and Photobacterium phosphoreum.

The purpose of this experiment was to examine two different cooling methods on board fishing vessel, to apply different cooling techniques during processing at fish plant including the CBC (combined blast and contact) cooling and to compare storage of packed cod fillets kept either at steady temperature (-1 ° C) or below temperature fluctuations. No marked difference was seen in microbial and chemical measurements whether plate ice or liquid ice was used prior to filleting but according to sensory analysis, the experimental group where liquid ice was used had one day extension in freshness and shelf life compared to the group with plate ice. Temperature was usually slightly higher in the plate ice group than the liquid ice group during storage. According to sensory, microbiological and chemical analysis, the CBC cooling clearly resulted in longer freshness period and shelf life extension in comparison to the two groups where this technique was not applied during processing. Temperature was lower in these groups during the storage period. Similar microbial counts were found between the two experimental groups where CBC was not applied during processing (liquid cooling and no cooling). These results were in agreement with results from sensory analysis. TMA values were however higher on storage days 12 to 19 in the group with liquid cooling. Temperature measurements during storage of these two groups were very similar. No marked difference was seen in microbial counts between groups that were stored at a constant temperature around -1 ° C compared to groups where temperature fluctuations were used during early phases of storage. During the first 15 days of storage, TVB-N and TMA values were very similar for these groups. Sensory analysis was not done on the two groups kept at -1 ° C. The rapid qPCR analysis was generally in good agreement with the cultivation methods for Pseudomonas spp. and Photobacterium phosphoreum.

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