Changes in the concentration of biogenic amines and application of tyramine sensor during storage of beef

The vacuum-packaged beef was stored at 10, 5 and 0 °C, and biogenic amines, viable counts and tenderness with the passage of time were measured. Of the biogenic amines analyzed, only tyramine was detected in viable cell counts in the order of 105~ 106 before the appearance of a faint putrid smell (initial stage of putrefaction) at all three storage temperatures. Cadaverine was detected before the initial stage of putrefaction only at 5 °C. The changes in tenderness ceased in 5 days (10 °C), 10 days (5 °C), 28 days (0 °C), and the meat retained freshness judging from the viable counts and organoleptic evaluation. To estimate bacterial spoilage conventionally, a tyramine sensor which was composed of a tyramine oxidase-immobilized column and an oxygen electrode was applied. The sensor first detected tyramine at 5 days (10 °C), 13 days (5 °C) and 32 days (0 °C). It was confirmed that the tyramine sensor was useful for estimating the bacterial spoilage in aging beef.