Detecting seafood off-flavors: Limitations of sensory evaluation

Off-flavors in seafood can occur as a result of many factors. The farm-raised catfish industry considers environmental off-flavors associated with blooms of blue-green algae and other microbes to be its most significant problem (Tucker and Martin, 1991). Algal blooms can produce geosmin and 2-methylisoborneol (MIB), which impart a muddy, musty flavor in seafood (Johnsen, 1991). Other environmental taints occur in seafood from exposure to wood processing effluents, odorants of detergents, spilled petroleum products (ASTM, 1996a), and chemical tanker washings and spills (Peels et al., 1988), Postharvest conditions can contribute to the development of fishy and sour flavors if products are exposed to temperatures above 4 degrees C after collection; this is due primarily to the breakdown of amino acids by bacterial enzymes (Gorga and Ronsivalli, 1982; Hebard et al., 1982). Freezer storage of seafood can contribute to development of cardboardy and painty flavors which are typically associated with lipid oxidation products (Johnsen and Kelly, 1990; Johnsen et al., 1987).