[en] A method has been developed to detect irradiated beef by GC analysis of differences of the types and contents of hydrocarbons between unirradiated and irradiated beef. Six hydrocarbons in irradiated beef were qualitatively and quantitively determined by procedures of extraction by hexane, separation by Florisil cloumn and GC analysis. The results shows that no 1, 7-C16: 2(1, 7-hexadecadiene) has been found in unirradiated beef, while it is significantly detectable in the irradiated sample. Therefore, 1, 7-C16: 2 is the best probe to determin whether beef is treated by irradiation or not. (authors)