本文以有机奶粉和非有机奶粉为研究对象，以有机奶粉和非有机奶粉的碳稳定同位素比值和氮稳定同位素比值为研究目标，探索有机奶粉和非有机奶粉的碳、氮稳定同位素组成的差异性。研究结果显示，有机奶粉的碳稳定同位素比值（δ13C）整体趋势更负于非有机奶粉的δ13C值，有机奶粉的氮稳定同位素比值（δ15N）稍低于非有机奶粉的δ15N值。尽管两种样品的δ13C值和δ15N值的数据范围有交叉，但是根据统计分析，有机奶粉的δ13C值和δ15N值与非有机奶粉的δ13C值和δ15N值具有差异性（p<0.05）。有机奶粉与非有机奶粉δ13C值和δ15N值的差异性主要受牛奶来源的影响，主要与动物的饲料、牧场土壤及肥料等有关。研究结果虽然经有限的样本获得，但是该方法对监管有机食品的真实性具有一定的参考价值。

In this study, the research objects were organic milk powder and convention milk powder. The carbon stable isotope ratio and nitrogen stable isotope ratio of organic milk powder and convention milk powder were studied. Stable isotopes of carbon and nitrogen were analyzed to record the difference between convention milk powder and organic milk powder. The results showed that the overall trend of the mean δ13C value of organic milk powder was more negative than that of conventional milk powder, and the mean δ15N value of organic milk powder was lower than that of conventional milk powder. Although the data range of δ13C and δ15N values of samples were crossed, both δ13C and δ15N values were statistically different for the organic milk powder and conventional milk powder (p<0.05). The different in δ13C and δ15N values between organic milk powder and convention milk powder could be caused by the dairy cow’s diet, fertilizer types and soil characteristics used for milk production. The results of the present study, which is based on preliminary data from a limited sample size, could be highly valuable and helpful for monitoring the authenticity of organic milk powder.

国家重点研发计划项目（2017YFF0211303）；国家质检总局科技计划项目（2016IK220）；中央引导地方科技发展专项（YDZX20173100004528）；长三角科技合作项目（17395810102）；上海市科委科研项目(17DZ2293700）