Influence of variation in methodology on the reliability of the isoelectric focusing method of fish species identification

Abstract

The reliability of isoelectric focusing (IEF) of sarcoplasmic proteins for fish species identification was evaluated by a collaborative study among eight European laboratories. Each laboratory used its own method of IEF to identify 10 unknown samples of raw muscle by means of reference material. In 93% of cases the assignment between sample and reference was correct. In a second study, the influence of extractant (water, low ionic strength buffer, or detergent) and the position of sample application on the protein pattern was examined. Working with light muscle of rainbow trout (Oncorhynchus mykiss), it was found that the type of extractant did not influence the protein pattern. Comparison of the patterns of samples, which had been applied near the anode, in the middle, or near the cathode, revealed differences in the number and position of the protein bands under the experimental conditions applied by most laboratories. This effect was not observed with the Phast System.

Species identification of snapper: A food poisoning incident in Taiwan

“…The results revealed that species identification could be achieved by ordinary SDS-PAGE analysis. The standardized methods of species identification for raw and heat-processed fish using SDS-PAGE and urea-IEF techniques have been established via collaborative studies (Rehbein et al, 1995;Sotelo, Pineiro, Gallardo, & Perez-Martin, 1993). Many reports have also indicated that the characteristic protein bands could be extracted by SDS-containing solutions and can be used for species identification (Chen & Hwang, 2002;Rehbein et al, 1999).…”

New Fish on the German Market: Consumer Protection against Fraud by Identification of Species

“…Extraction of sarcoplasmic proteins and isoelectric focusing were performed according to Rehbein et al (1995), using Servalyt Precotes 3 -10 (SERVA, Heidelberg, Germany) of 0.3 mm gel thickness. Isoelectric points of proteins were determined by means of the broad range pI calibration kit from GE Healthcare (Freiburg, Germany).…”

A standardized method of identification of raw and heat-processed fish by urea isoelectric focusing: A collaborative study

“…The identification of species of raw fishery products by protein electrophoresis is a well-established procedure [1]. The suitability and reliability of isoelectric focusing (IEF) of sarcoplasmic proteins for fish speciation has been demonstrated in a European project entitled ªIdentification and quantition of species in marine productsº [2]. For heated fish, however, the situation is different; the conditions of processing (cooking, frying, smoking) vary considerably, resulting in more or less pronounced denaturation and degradation of muscle proteins.…”