查看文章

The food industry has been expanding globally, such that consumers can obtain various food products from all over the world. This circulation requires a valid traceability system to ensure the safety and high quality of food. In Japan, the Japanese Agricultural Standard (JAS) Law was introduced in 1950 to prevent food frauds such as mislabeling and adulteration. In accordance with this law, packaged polished rice is required to be labeled to indicate its cultivar, cultivation area, and year of production. However, it is extremely probable that packages are incorrectly labeled, either accidentally or intentionally. Thus, there is a need for a simple analytical method for checking the authenticity of food materials.

Recently, characterization of isotopic composition of food materials has been used to prevent illegal mislabeling and adulteration. 1 For example, adulterated honey and juice products2–4 and the geographical origin of meat, 5, 6 dairy products, 7, 8 wine, 9 and cereal crops10 can be traced by using natural differences in their carbon, nitrogen, and/or oxygen isotopic compositions. In our previous study, we determined the carbon and nitrogen contents (C and N contents) and the stable carbon, nitrogen, and oxygen isotopic compositions (δ13C, δ15N, and δ18O) of polished rice cultivated in Australia (New South Wales), Japan (12 different cultivation areas), and the USA (California) in order to discriminate the geographical origin of the rice. 11 We suggest that a comparison of the C and N contents