The US Food and Drug Administration (FDA) has established a defect action level of 50 ppm for histamine in tuna, mahi-mahi (dolphin), and other fish species as an indication of potential health risk (FOOD…, 1996). The European Community has fixed 100 ppm for fish and fish products as a maximum average value in a group of 9 samples (VECIANA-NOGUES et al., 1995). Mexico has a maximum limit of 200 ppm of histamine for tuna and tuna products.