Methods of gadoid fish species identification in food and their economic impact in the Czech Republic: a review

Abstract

ABSTRACT:The purpose of the present study was to give an overview of imported and traded gadoid fish species (Gadiformes) in the Czech Republic and to describe available methods for their authentication. Due to the increasing interest of customers in the purchase of buy fish meat and other seafood animals, it is necessary to have available analytical methods with discriminating power of respective fish species. With regard to different values and prices of various fish species, these may be adultered. Until recently, electrophoretic, chromatographic and immunological methods based on the analysis of proteins extracted from fish musculature seemed to be promising. Using these methods, various fish species can be identified in fresh, chilled and frozen products. However, they often fail in heat treated products. Molecular biology methods based on DNA analysis are more reliable and suitable for the analysis of fish products that have been heat treated during the production process.Keywords: cod fish; fish species identification; electrophoresis; PCR-RFLP; cytochrome b gene; food adulteration List of abbreviations AK = adenylate kinase; ARGK = arginine kinase; ATP = adenosine triphosphate; CE = capillary electrophoresis; CK = creatine kinase; CR = Czech Republic; DGGE = denaturating gradient gel electrophoresis; DHA = docosahexaen acid; DNA = deoxyribonucleotide acid; EPA = eicosapentaen acid; EU = European Union; FINS = forensically informative nucleotide sequencing; G 3-PD = glycerol 3-phosphate dehydrogenase; HPLC = high performance liquid chromatography; IEF = isoelectric focusing; LDH = lactate dehydrogenase; MDH = malate dehydrogenase; MS = mass spectrometry; mt cyt b = mitochondrial cytochrome b gene; Mw = molecular weight; NDKA = nucleoside diphosphate kinase A; NTSs = nontranscribed spacers; PCR = polymerase chain reaction; PCR-RAPD = polymerase chain reaction -random amplified polymorphic DNA; PCR-RFLP = polymerase chain reaction -restriction fragment length polymorphism; PCR-SSCP = polymerase chain reaction -single strand conformation polymorphism; pI = isoelectric point; RP-HPLC = reversed phased -high performance liquid chromatography; SDS-PAGE = sodium dodecyl sulphate -polyacrylamide gel electrophoresis; urea-IEF = urea isoelectric focusing; 2DE = two dimensional electrophoresis

Molecular identification methods of fish species: reassessment and possible applications

“…Traditional and official methods used in species identification, including fish, are based chiefly on the separation and characterization of specific proteins using electrophoretic techniques, such as isoelectric focusing: IEF (Rehbein 1990) and capillary electrophoresis: CE (Kvasnička 2005), high performance liquid chromatography: HPLC (Hubalkova et al 2007), or immunoassay systems, such as EnzymeLinked ImmunoSorbent Assay: ELISA ) (for a complete review see e.g., Mackie et al 1999;Civera 2003; Moretti et al 2003;Hubalkova et al 2007). Nowadays, different companies commercialize ELISA diagnostic kits for various applications, such as the authentication of species in milk and cheese ).…”

Evaluation of the 16S and 12S rRNA genes as universal markers for the identification of commercial fish species in South Africa

“…Although protein-based methods (particularly electrophoretic, chromatographic and immunological methods) have traditionally been employed for fish species authentication, DNA-based methods offer a number of advantages for such purposes over their proteinbased counterparts (Hubalkova et al, 2007;Lockley and Bardsley, 2000;Sotelo et al, 1993). Unlike proteins which lose their biological activity soon after animal death and which are mostly heat labile, DNA is a relatively long-lived molecule and is comparatively more stable during processing and with the application of high temperatures.…”

Establishment of a mitochondrial DNA sequence database for the identification of fish species commercially available in South Africa

“…The sequencing of specific DNA fragments amplified by the polymerase chain reaction (PCR) is considered to be the most accurate and informative method for the identification of fresh, frozen and processed fish species (Lockley & Bardsley 2000; Gil 2007; Hubalkova et al. 2007).…”

“…The sequencing of specific DNA fragments amplified by the polymerase chain reaction (PCR) is considered to be the most accurate and informative method for the identification of fresh, frozen and processed fish species (Lockley & Bardsley 2000;Gil 2007;Hubalkova et al 2007). Nonetheless, the success of such authentication techniques relies on the establishment of databases containing reference DNA sequences from a large variety of expertly identified fish specimens (Martinez et al 2005;Steinke et al 2009a;Ward et al 2009).…”