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Identification of fish species in food using immunostaining


Key words myosin light chain, species identification, antiserum, immunodetection, fish, muscle protein, authentication, processed food, immunostaining
Latest version 2011/01/03
Completed by TTZ

How does it work?

Primary objective identification of fish species in intensively processed products
Working principle In intensively processed fish (e.g. boiled and/or dried) the majority of proteins is denatured and insoluble. Therefore, protein bands obtained from immunostaining are too ambiguous to identify species. Myosin light chains however, remain extractable and soluble due to their small size and high content of hydrophilic amino acid residues.

After separation of proteins using electrophoresis (SDS-PAGE) anti-myosin light chain antiserum is applied to detect the extracted skeletal muscle protein. To that end, the immunoblotting method is used. The characteristic fingerprints can be used to identify species present in the sample. Afterwards the protein concentration can be determined, e.g. according to Lowry.

Additional effects Myosin light chains and parvalbumin show great similarity in molecular weight, solubility and amino acid sequence. Therefore, parvalbumin may also be a possible marker protein for species identification. Additionally, due to the fact that the main fish allergens are parvalbumins, the detection of parvalbumins in food is important for people with fish allergy. But also myosin light chains are a good detector for fish allergens in food because parvalbumins are localized in the muscle, where myosin light chains are ubiquitous.
Important process parameters molecular size, solubility and amino acid sequence of protein markers
Important product parameters -

What can it be used for?

Products every product that might contain fish
Operations authentication of food labelling (quality, traceability), qualitative and quantitative analysis
Solutions for short comings identification of fish species or presence of fish in strongly processed products

What can it NOT be used for?

Products no restrictions, all products can be analyzed for traces of fish
Operations -
Other limitations protein extraction required
Risks or hazards possibility that specific fish allergens are not detected if they are not part of the muscle


Maturity lab scale, no commercial kits for fish species identification available so far
Modularity /Implementation Only standard analytical equipment for electrophoresis and western blotting is needed.
Consumer aspects Fish hypersensitivity has increased and allergy to fish is counted among the most common food allergies. Therefore a reliable method to detect fish in food is necessary.

Furthermore, it is important to verify composition of food to protect consumers and enforce food law.

Legal aspects Fish and products thereof are allergenic food and therefore have to be labeled according to Directive 2000/13/EC.
Environmental aspects

Further Information

Institutes NVI Norway, Instituto de Investigaciones Marinas, Ifremer, VTI, IPIMAR, Nofima
References 1. Etienne, M. et al. (2001). Analytical, Nutritional and Clinical Methods Section. Species identification of formed fishery products and high pressure-treated fish by electrophoresis: a collaborative study. Food Chemistry 72. 105-112.

2. Fæste, C. and Plassen, C. (2008) Quantitative sandwich ELISA for the determination of fish in foods. Journal of Immunological Methods 32, 9, 45–55.

3. Ochiai, Y., Watabe, S. (2003) Identification of fish species in dried fish products by immunostaining using anti-myosin light chain antiserum. Food Research International 36, 9-10, 1029-1035.

4. Pineiro, C., Barros-Velazquez, J., Sotelo, C.G., Perez-Martin, R.I., Gallardo, J.M. (1998) Two-dimensional electrophoretic study of the water-soluble protein fraction in white muscle of gadoid fish species. Journal of Agricultural and Food Chemistry, 46, 3991–3997

5. Van Do, T., Elsayed, S., Florvaag, E., Hordvik, I., Endresen, C. (2005) Allergy to fish parvalbumins: Studies on the cross-reactivity of allergens from 9 commonly consumed fish. Journal of Allergy and Clinical Immunology, 116, 6, 1314-1320

6. DIRECTIVE 2000/13/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 20 March 2000 on the approximation of the laws of the Member States relating to the labelling, presentation and advertising of foodstuffs. Official Journal of the European Communities

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Created by WikiSysop on 29 January 2011, at 02:48