This report is closed
Chitosan treatments for the fishery industry - Enhancing quality and safety of fishery products
This report is a summary of three shelf life experiments in which seafood was treated with different chitosan solutions, either on board a fishing vessel (with shrimp and cod) or after slaughter and pre-processing of farmed salmon. This is a continuation of Matís 'report 41-12 where chitosan solutions were developed and tested on different fish products at Matís' experimental stage. The purpose of this project was to confirm the possibility of chitosan treatment of seafood in the fishing industry. The results show that the concentration of chitosan solutions and the storage temperature of seafood affect the antimicrobial activity and the deterioration of the quality of the fish products. Solutions A and B had limited activity in whole shrimp (0-1 ° C), but slower color changes occurred as the shell took on a black color. Treatment of salmon (1.4 ° C) and cod (-0.2 ° C) with solutions C and D significantly slowed the growth of erythrocytes during the first 6 days, leading to a prolongation of the freshwater phase. The storage temperature of cod fish affected the effectiveness of the solutions. When cod (2-3 ° C) was stored in worse conditions and filleted 6 days after treatment, there was a slightly lower microbial load on the fillets at the beginning of the storage period, which resulted in a slight improvement in the quality of the products. Better storage conditions are necessary to limit the effectiveness of chitosan treatment.
This report evaluates the efficiency of different chitosan treatments (A, B, C, D) when used by fishery companies, aiming to reduce seafood surface contamination and promote enhanced quality of fishery products: whole cod, shrimp and farmed salmon. The alkaline conditions establishing in chilled raw shrimp during storage (0-1 ° C) is the probable cause for no benefits of chitosan treatments A and B used shortly after catch, except for the slower blackening of head and shell observed compared to the control group . On the other hand, salmon treatments C and D were most effective in significantly reducing skin bacterial load up to 6 days post-treatment (1.4 ° C) which inevitably contributed to the extended freshness period (by 4 days) and shelf life observed. Similarly, freshness extension and delayed bacterial growth on skin was evidenced after 6 days of storage in whole cod (-0.2 ° C) treated with solution D. For cod stored at higher temperature (2-3 ° C) and processed into loins on days 3 and 6 posttreatment, a slower microbial deterioration was observed only during early storage of loins. The contribution of chitosan treatments to sensory quality enhancement was not clearly demonstrated in these products. Based on the findings, better chilling conditions should contribute to an enhanced effect of chitosan skin treatment towards quality maintenance.
Safe Food: Increased food safety in Iceland / Örugg Matvæli: Increased food safety in Iceland
It is necessary for Iceland to have adequate capacity and infrastructure so that the government and official regulators have the capacity to monitor food safety in accordance with international standards and regulations. The project "Safe Food" was a bilateral project between Iceland and Germany and its main purpose was to increase food security in Iceland and protect consumers with regard to food safety and wholesomeness in the Icelandic market. The project was carried out in collaboration between Matís, Matvælastofnun (MAST) and the Ministry of Industry and Innovation in Iceland and the German Ministry of Food and Agriculture as well as key institutions in the field of food safety in Germany, ie the Federal Institute for Risk Assessment (BfR) and the Lower Saxony State Office for Consumer Protection. and Food Safety (LAVES). To improve the infrastructure in Iceland, specialized diagnostic equipment for food safety research was purchased through an open tender and installed in Matís' facilities in Reykjavík. A German consultant was located in Iceland for 6 months to provide professional knowledge in the field of food safety that was necessary for the progress of the project as well as to coordinate work in the project. German experts from BfR and LAVES came to Matís and Matvælastofnun to train the experts of these institutions in procedures that were defined as priorities in the field of chemical analysis and official supervision in the field of food safety. Introductory meetings were also held to inform the main stakeholders in Iceland about the progress of the project and to increase their awareness of the importance of food safety in the entire production and food chain. By the end of the project, Icelandic specialists had been trained in work processes in specific priority areas for monitoring and chemical analysis in the field of food safety. The project has therefore contributed to both improved research facilities and the capacity of both Icelandic institutions in terms of sampling and chemical analysis of important food safety aspects such as monitoring of plant pesticide residues and undesirable substances in food and feed.
To ensure a high level of protection for human health and consumers' interest in relation to food safety, it is essential that Iceland has the appropriate infrastructures to carry out inspections and official controls of food products in line with the requirements of European food legislation. A bilateral project between Iceland and Germany was established and carried out in 2014 to assist Iceland to achieve this goal. The objective of the project was to strengthen Iceland's ability to ensure food safety and protect consumer interests in relation to food safety. The bilateral project was carried out in collaboration between Matís, Icelandic Food and Veterinary Authority (MAST) and the Ministry of Industries and Innovations in Iceland from the Icelandic side and the German Federal Ministry of Food and Agriculture, Federal Institute for Risk Assessment (BfR) and Lower Saxony State Office for Consumer Protection and Food Safety (LAVES) from the German side. The laboratory infrastructure for food safety analysis in Iceland wasimproved by procuring new laboratory equipment through an open tender process and installing them at Matísfacilities in Reykjavík. A German Resident Advisor resided in Iceland for 6 months to provide the necessary professional experience in areas of food safety covered by the project and coordinate the project activities. German experts from BfR and LAVES came to Matís and MAST to train experts of these institutes in procedures identified as priority analytical and official control proceduresto ensure food safety in Iceland. A number of stakeholder events were also carried out to inform key stakeholders of project activities and increase their awareness of importance of food safety in the entire food chain. At the end of the project the majority of the priority procedures were implemented at the Icelandic institutes and the Icelandic experts that participated in the project were well informed and trained. The project has therefore contributed significantly to the improvement of both institutional and laboratory capacity in Iceland concerning sampling and analysis in important areas such as monitoring for residues of plant protection products, contaminants in food and feed as well as genetically modified food and feed.
Evaluation of antibacterial and antioxidant properties of different chitosan products
In this study, the bactericidal and antioxidant properties of twelve different chitosan substances from Primex ehf. The effect of viscosity / molecular weight (150-360 KDa) and the degree of deacetylation (A = 77‐78%; B = 83‐88%; C = 96‐100%) on the activity of the substances were assessed. The effect of pH (6 and 6.5) and temperature (7 and 17 ° C) on bactericidal activity was also examined. Antioxidant activity was assessed by four methods: oxygen radical absorbance capacity (ORAC), ferrous ion chelating ability, reducing power and DPPH radical scavenging ability. Variable antioxidant activity was found in different chitosan substances. A1 had the highest but actually slight reducing and binding properties, while B3 and B4 had the highest ORAC values. Chitosans with 96-100% deacetylation had the highest in vitro antioxidant activity, regardless of their molecular weight. Similarly, the bactericidal activity of the chitosan substances varied among the bacterial species studied, in addition to which the pH and temperature effects were different. However, some chitosan substances were found to work well on all bacterial species, eg A3 ‐ B2 ‐ B3 ‐ C1.
This report evaluates twelve different types of chitosan products manufactured by Primex ehf and tested for their antibacterial and antioxidant properties in a suitable carrier solution. This study examined the effect of viscosity / molecular weight (150‐360 KDa) and degree of deacetylation (A = 77‐78%; B = 83‐88%; C = 96‐100%) on the properties evaluated, as well as the influence of pH (6 and 6.5) and temperature (7 and 17 ° C) on the antibacterial activity of the chitosan products. The antioxidant activity was evaluated using four assays: oxygen radical absorbance capacity (ORAC), ferrous ion chelating ability, reducing power and DPPH radical scavenging ability. The different chitosan products had different antioxidant properties. A1 had both some reducing and chelating ability, while B3 and B4 had some oxygen radical absorbance capacity. The radical scavenging ability of high DDA (96‐100%) chitosan products was emphasized. Similarly, the antibacterial activity of the different chitosan solutions differed among the bacterial species evaluated as well as pH and temperature conditions. Nevertheless, some products demonstrated antibacterial activity towards all strains tested: mainly A3 ‐ B2 ‐ B3 ‐ C1.
Report closed until 01.01.2014
Ásta Heiðrún E. Pétursdóttir
Head of Public Health and Food Safety
Food safety and added value of Icelandic fishmeal - Determination of toxic and non ‐ toxic arsenic species in fish meal / Verðmæti og tryggi íslensks fiskimjöls - Kaupthing
There is a lot of arsenic in the ecosystem in organic compounds as well as in inorganic form and more than 50 natural chemical forms of arsenic have been found. Seafood naturally contains a high concentration of the total arsenic compared to, for example, agricultural products. However, most arsenic in seafood is bound in an organic form called arsenobetanide, which is considered safe. Other forms of arsenic in marine products are generally present in lower concentrations, including inorganic arsenic (arsenite and arsenate) which is toxic and rarely exceeds 3% of the total concentration of arsenic in fish and crustaceans. The morphology of arsenic in seafood is important because the bioavailability and toxicity of arsenic depend on its chemical form. Recently, the EFSA (European Food Safety Authority) called for information on inorganic and organic forms of arsenic in food and for chemical analysis methods to detect inorganic arsenic. This dissertation presents the results and evaluation of measurements of the total concentration in over 100 samples of Icelandic fishmeal. Among other things, it was examined whether there was a seasonal difference in the total concentration of arsenic. The samples were first decomposed by microwave and then measured on an ICP mass spectrometry (ICP-MS). To evaluate the chemical forms of arsenic present in the flour, a three-part distribution method was first developed. Emphasis was then placed on the analysis of toxic inorganic arsenic. The previously published alkali-alcohol extraction method, for the detection of inorganic arsenic, was adapted and the samples were measured by HPLC equipment connected to ICP-MS. Arsenobetanide was found to be the predominant form of arsenic in all cases. Inorganic arsenic was found to be less than four percent of the total concentration in twelve measured fishmeal samples. On the other hand, when another chemical analysis technique (HPLC-HGAFS) was applied to a sample of certified reference material, the concentration of inorganic arsenic was three times lower. The alkali-alcohol distribution method proved to give a convincing upper limit on the concentration of inorganic arsenic. The results also show that it is not enough to rely on one method when analyzing and quantifying arsenic forms. In addition, they demonstrate the need for a certified concentration of inorganic arsenic in standard materials to test the reliability of chemical analysis methods. The need for further development of chemical analysis methods in this field is urgent.
Arsenic is found in the biosphere in both organic and inorganic forms, and there have been recognized more than 50 naturally occurring arsenic species. Seafood products have naturally high concentration of total arsenic compared to eg agricultural produce. Arsenic is toxic to humans and animals and is known to be carcinogenic. The toxicity of the arsenic species varies severely and a large portion of the arsenic in seafood is present in the form of the organic compound arsenobetaine, which is considered non ‐ toxic. Other arsenic species are generally present in lower concentrations, including the most toxic inorganic arsenic species, arsenite, As (III) and arsenate, As (V), which usually do not exceed 3% of the total arsenic in fish and crustaceans. Existent European regulations on limits of arsenic in foodstuff and feed only take into account total arsenic concentration, not the toxic arsenic species. Recently the EFSA (European Food Safety Authority) stressed the need for more data on levels of organic and inorganic arsenic in different foodstuffs and the need for robust validated analytical methods for the determination of inorganic arsenic. In this thesis results from total arsenic concentration from over 100 samples of Icelandic fish meal are presented and evaluated. The samples were microwave digested and measured with inductively coupled plasma mass spectrometry (ICP ‐ MS). The samples were screened for a seasonal difference in the total arsenic concentration. To evaluate the arsenic species present in the meal a sequential method of extraction was developed. In addition, a special focus was on the determination of inorganic arsenic and a previously published method for an alkaline ‐ alcoholic extraction of the inorganic arsenic was modified and applied. For determination of arsenic species high pressure liquid chromatography (HPLC) was coupled to the ICP ‐ MS. The predominant arsenic species found in all samples was the non ‐ toxic arsenobetaine. Inorganic arsenic was not found to exceed 4% of total arsenic concentration in 12 samples of fish meal. However, a suspicion of co ‐ elution arose, and when another analytical instrument technique (Hydride generation atomic fluorescence spectroscopy (HPLC ‐ HG ‐ AFS)) was applied, concentration of inorganic arsenic was approximately three times lower in a certified reference material, TORT‐ 2. The alkaline ‐ alcoholic extraction method was found to give convincing upper limits of the inorganic arsenic concentration in fish meal samples. These results show the necessity of further method development and separate methods when identifying and quantifying species. This further stresses the need for a certified value of inorganic arsenic in a certified material to check the robustness of developed methods.
SSS PREDICTION WORKSHOP
Courses in the use of forecasting programs in the fisheries sector: SSS (Seafood Spoilage and Safety) Prediction version 3.1 2009 (http://sssp.dtuaqua.dk/), Combase (www.combase.cc) and Pathogen Modeling programs (http: // pmp .arserrc.gov/PMPOnline.aspx). The teacher is Dr. Paw Dalgaard from the Technical University of Denmark (DTU) and the teaching is in English. The program is useful for scientists, authorities and industry in the fisheries sector.
Workshop on the practical use of computer software to manage seafood quality and safety. It includes presentations and hands-on computer exercises to demonstrate how available software can be used by industry, authorities and scientists within the seafood sector. Examples with fresh fish, shellfish and ready-to-eat seafood (smoked and marinated products) are included in the workshop. Special attention is given to: (i) the effect of storage temperature and modified atmosphere packing on shelf-life and (ii) management of Listeria monocytogens according to existing EU regulations (EC 2073/2005 and EC 1441/2007) and new guidelines from the Codex Alimentarius Commission. The presentations included in the workshop are given in English by Paw Dalgaard from the Technical University of Denmark. Participants will use their own laptop computers for the PC-exercises included in the workshop. Instruction for download of freeware will be mailed to the participants prior to the start of the workshop.
Mercury and other undesirable trace elements in brown trout (Salmo trutta trutta L.) from Lake Thingvallavatn
The aim of the project was to obtain information on the amount of mercury and other undesirable trace elements in Þingvallaurrið, taking into account their size and prehistory with human nutrition in mind. That goal also meant that the results should be communicated to the public as well as stakeholders in the Þingvellir area. The study was conducted in collaboration with Matís and Laxfiskar. A total of 43 trout in the size range of 23-98 cm and 0.13‐14 kg were studied. The trout covered by the study were caught in the years 2002-2008. For some of them, information from traditional labels was available. In addition, samples were taken from several fish that had a prehistory that was recorded in detail with measuring instruments in terms of their behavior and environment. The results of these studies on the behavioral ecology of the fish showed that some of them sought to stay by hot springs that flow into Þingvallavatn below Nesjahraun. Biological factors of the fish such as size, age, sex, sexual maturity, etc. were recorded for each individual and samples taken from the flesh and trace elements analyzed. The results of trace element analyzes of the fish's flesh show that there is a considerable probability that fish longer than 60 cm will contain more mercury than is permitted by Icelandic and European regulations (0.5 mg / kg mercury). According to the recommendations of the Food Administration (MAST), which is an official regulator of food in Iceland, it is not permitted to sell fish that contain more than 0.5 mg / kg of mercury. The results of the study showed that there was a strong correlation between the length of the trout and the amount of mercury in it. Biomagnification is the most likely reason for the high concentration of mercury in trout from Þingvallavatn, which usually become rather large and old, as the concentration of mercury increases as it moves up the food chain. Þingvellir trout is at the top of the food chain, where it eats most of its age, mainly char, primarily the brown variety. It is desirable that further research be carried out in this field to get a picture of the origin of mercury in the Þingvellir landslide and the process of its accumulation.
The aim of the project was to study the occurrence and quantity of mercury as well as other undesirable trace elements in brown trout from Lake Thingvallavatn in relation to the fish size and their life history. Public health was the main issue of this study. The aim was also to disseminate the results to the public and all stakeholders. The study was carried out in co ‐ operation of Matis and Salmon and Trout Research (Laxfiskar). In total, 3 brown trout individuals, 23‐98 cm long and weighing 0.13‐14 kg, were examined. The trout were caught during the years 2002 to 2008. Information from conventional tagging studies were available for some of the individuals. For six fish additional detailed results from studies on their behavior and corresponding environment was available, due to use of electronic tags (data storage tags and ultrasonic tags). These studies on the behavioral ecology of the trout showed that some of the individuals preferred areas where hot spring water runs into Lake Thingvallavatn at the Nesjahraun area. Individuals were measured and examined in order to get information on their size, condition and life history. Flesh samples were taken from the fish for trace element analyzes. The results of the study show that there is a positive linear relationship between the mercury concentration and the fish length. These analytical results showed that there is significant probability that fish that is 60 cm in length or larger, can contain mercury in quantity that exceeds the maximum allowed limit according to Icelandic and European regulations (0,5 mg / kg mercury). According to the Icelandic Food and Veterinary Authority (MAST), food products containing mercury in higher concentration than 0,5 mg / kg should not be sold or distributed. Biomagnification is presumed to be the cause for high concentration of mercury in the bigger and older brown trout from Lake Thingvallavatn as the results show that brown trout is a top predator in Lake Thingvallavatn and feeds mainly on charr (Salvelinus alpinus L.), especially the pelagic morph murta. Further research is needed on the origin of mercury in brown trout in Lake Thingvallavatn and on the route of the corresponding biomagnifications in the food chain of the lake.
Fungicides and the MYCONET project / Mycotoxins and the MYCONET project
Mycotoxins are many substances that can be formed in some types of fungi. Fungicides can have a variety of harmful effects on humans and animals. All available information on fungal toxins in food on the Icelandic market was compiled. Research lacks the formation of fungal toxins in the Icelandic environment, but it is likely that some of the substances are not formed in fields in this country due to low ambient temperatures. The MYCONET project was a European network project on fungal toxins in wheat for food and feed production. A system was developed to assess the emerging risk of fungal toxins, in particular the substances formed in Fusarium fungi. A special survey was conducted on the needs of regulators, companies and farmers for information on fungal toxins. Evidence of antifungal risk was examined and ranked by importance. The so-called Delphi method was used for this. Detailed information was then obtained on the most important clues. Models were developed to predict the presence of fungal toxins based on evidence of emerging risks.
Mycotoxins are a varied group of contaminants that can be formed in molds. They can be harmful to humans and animals. Information about mycotoxins in foods on the Icelandic market was collected. Research on mycotoxins in Iceland have been limited but it is likely that some of the mycotoxins do not form in open fields because of low temperature. The MYCONET project was a European network of information sources for the identification of emerging mycotoxins in wheat-based supply chains. Main emphasis was on mycotoxins produced by Fusarium spp. The needs of stakeholders and other end users (risk managers) were investigated. The most important indicators for emerging mycotoxins were identified together with evaluation of their relative importance by the Delphi method. Information sources on these key indicators were evaluated. Finally, an information model was developed to predict emerging mycotoxin risk from indicators and information sources.