Species substitution of restaurant fish entrees

Fish species substitution has been a common problem in the retail markets, However, this problem has not been documented in restaurant-cooked fish entrees. This study investigated fish substitution in restaurant-cooked snapper and swordfish entrees from four major cities in the U.S. The species of 16 snappers including 13 red snapper and 21 swordfish samples were verified as presented on the menu using isoelectric focusing (IEF). Fish samples were cleaned and desalted by rinsing with distilled water before protein extraction. Protein separation war; carried out in a polyacrylamide gel with a wide pH gradient range of 3.5-9.5, Distinctive IEF protein band patterns of unknown samples were compared with the authentic standards. Six out of 13 (46%) red snapper samples and two out of 21 (10%) swordfish samples were misrepresented. The method used in this study adequately and efficiently verified the species of restaurant-cooked snapper and swordfish samples.