電子線照射牛挽肉の炭化水素法による検知

Abstract

Hydrocarbons produced from two main fatty acids (oleic acid and palmitic acid) are useful marker for detection of irradiation treatment. The main products, 1-C14: 1, 1, 7-C16: 2, C15: 0 and 8-C17: 1 were measured and their ratios were calculated to identify irradiated meat. As the value of 1-C14: 1/1, 7-C16: 2 was nearly equal to ratio of original fatty acids, the sample was easily detected as irradiated meat. The value of C15: 0/8-C17: 1 can be also used for identification, when the background in nonirradiated meats are low and dose is high enough to be detected hydrocarbon.As range of electron beam is shorter than that of gamma-ray, distribution of hydrocarbons in sample irradiated with electron beam was examined.Cylindrically trimmed ground beef meat with the sizes of 70 mm in diameter and 30 mm in height was irradiated with 5 MeV electron beam at surface doses of 5 and 10 kGy. After irradiation, the cylinder was sliced, and hydrocarbon contents were measured in each slice. Amount of hydrocarbon was maximum in the slice obtained at 7-10 mm depth from the surface. Hydrocarbon formation was very few in the slice obtained at 25-30 mm depth of the central part. The study shows depth profile of hydrocarbon formation with 5 MeV electron beam agreed to theoretical depth-dose curve. On the other hand, profound effect of irradiation was observed in peripheral part of the slice of 20-30 mm depth.