This study attempts to identify whether Phenethylamine (PTA), having a similar smell to fish malodor, is appropriate as a replacement of Trimethylamine (TMA). In a continuous measurement test, the odor intensity of both reagents TMA and PTA measured within 5 minutes showed between 0.4~0.7, indicating a dramatic reduction in olfactory sense, while the measurement test conducted after olfactory recovery did not represent much decrease. The result shows that both TMA and PTA have odors that stay long, but are judged to be inappropriate as a replacement as they stimulate the olfactory sense of the panel and give direct impact on the panel"s next judgement.