['Microbial transglutaminase (MTGase) is an enzyme utilized in the food industry in many areas. In this study, the suppression effect of MTGase at various levels (0, 2, 5, 10\u2009g\u2009kg(-1)) on the formation of biogenic amines in mackerel was determined during refrigerated storage of 8 days.', 'Mince added with 2\u2009g\u2009kg(-1) MTGase showed the lowest formation of putrescine, cadaverine and tyramine throughout the storage. Histamine exceeded the consumable limit (500\u2009mg\u2009kg(-1) ) after the 4th day, except for that containing 2\u2009g\u2009kg(-1) MTGase. The formation of total volatile basic nitrogen and total free amino acid content were retarded and the pH value was unaltered by addition of MTGase. With increasing MTGase levels, the growth of total psychrophilic bacteria, mould, yeast and coliform bacteria was retarded. The sensory scores of mackerel mince increased as MTGase concentrations increased.'] Do suppression of the formation of biogenic amines in mackerel mince by microbial transglutaminase?