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Food safety and added value of Icelandic fishmeal – Determination of toxic and non‐toxic arsenic species in fish meal / Verðmæti og öryggi íslensks fiskimjöls – Greining eitraðra og hættulausra efnaforma arsens í fiskimjöli

Author(s):

Ásta Heiðrún E. Pétursdóttir, Hrönn Ólína Jörundsdóttir, Helga Gunnlaugsdóttir

Funded by:

AVS Rannsóknasjóður í sjávarútvegi

Contact

Ásta Heiðrún E. Pétursdóttir

Project Manager

asta.h.petursdottir@matis.is

Food safety and added value of Icelandic fishmeal – Determination of toxic and non‐toxic arsenic species in fish meal / Verðmæti og öryggi íslensks fiskimjöls – Greining eitraðra og hættulausra efnaforma arsens í fiskimjöli

Í lífríkinu er mikið til af arseni í lífrænum efnasamböndum sem og á ólífrænu formi og hafa fundist meira en 50 náttúruleg efnaform af arseni. Sjávarfang inniheldur frá náttúrunnar hendi háan styrk heildararsens miðað við t.d. landbúnaðarafurðir. Stærsti hluti arsens í sjávarfangi er hins vegar bundið á lífrænu formi sem kallast arsenóbetaníð, sem er talið hættulaust. Önnur form arsens í sjávarafurðum eru að jafnaði til staðar í lægri styrk, m.a. ólífrænt arsen (arsenít og arsenat) sem er eitrað og fer sjaldan yfir 3% af heildarstyrk arsens í fiski og krabbadýrum. Formgreining arsens í sjávarfangi er mikilvæg vegna þess að upptaka (bioavailability) og eiturvirkni arsens er háð því á hvaða efnaformi það er. Nýlega kallaði EFSA (European Food Safety Authority) eftir upplýsingum um ólífræn og lífræn efnaform arsens í fæðu og eftir efnagreiningaraðferðum til að greina ólífrænt arsen. Í þessari ritgerð koma fram niðurstöður og mat á mælingum á heildarstyrk í yfir 100 sýnum af íslensku fiskimjöli. Meðal annars var skoðað hvort árstíðamunur á heildarstyrk arsens væri til staðar. Sýnin voru fyrst brotin niður með örbylgjun og því næst mæld á ICP massagreini, ICP‐MS (Inductively coupled plasma mass spectrometry). Til að meta hvaða efnaform arsens eru til staðar í mjölinu var fyrst þróuð þrískipt úrhlutunaraðferð. Síðan var áhersla lögð á greiningu eitraðs ólífræns arsens. Áður birt alkalí‐alkóhól úrhlutunaraðferð, til að greina ólífrænt arsen, var aðlöguð og sýnin mæld með HPLC búnaði tengdum við ICP‐MS. Í ljós kom að arsenóbetaníð var í öllum tilfellum ríkjandi efnaform arsens. Ólífrænt arsen reyndist vera undir fjórum prósentum af heildarstyrk í tólf mældum fiskimjölssýnum. Aftur á móti kom í ljós, þegar annarri efnagreiningartækni (HPLC‐HGAFS) var beitt á sýni af stöðluðu viðmiðunarefni (certified reference material), að styrkur ólífræns arsens mældist þrisvar sinnum lægri. Reyndist alkalí‐alkóhól úrhlutunaraðferðin gefa sannfærandi efri mörk á styrk ólífræns arsens. Niðurstöðurnar sýna ennfremur að ekki er nóg að reiða sig á eina aðferð þegar efnaform arsens eru greind og magngreind. Aukinheldur sýna þær nauðsyn á vottuðum styrk ólífræns arsens í stöðluðu viðmunarefni til að kanna áreiðanleika efnagreiningaraðferða. Þörfin fyrir frekari þróun efnagreiningaaðferða á þessu sviði er brýn.

Arsenic is found in the biosphere both in 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 e.g. 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 found not 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 furthermore stresses the need for a certified value of inorganic arsenic in a certified material to check the robustness of developed methods.

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Categories
Reports

SSS PREDICTION Námskeið / SSS PREDICTION WORKSHOP

Author(s):

Paw Dalgaard, Anna Kristín Daníelsdóttir, Steinar B. Aðalbjörnsson

Contact

Anna Kristín Daníelsdóttir

Deputy CEO / Director of Research & Innovation

annak@matis.is

SSS PREDICTION Námskeið / SSS PREDICTION WORKSHOP

Námskeið í notkun á spáforritum í sjávarútvegi: SSS (Seafood Spoilage and Safety) Prediction version 3.1 2009 (http://sssp.dtuaqua.dk/), Combase (www.combase.cc) and Pathogen Modeling forrit (http://pmp.arserrc.gov/PMPOnline.aspx). Kennari er Dr. Paw Dalgaard frá Tækniháskólanum í Danmörku (DTU) og fer kennslan fram á ensku. Forritið nýtist vísindamönnum, yfirvöldum og iðnaði í sjávarútvegi.

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.

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