Multi-Element (C, N, H, O) Stable Isotope Ratio Analysis for Determining the Geographical Origin of Pure Milk from Different Regions

In order to identify the geographical origin of pure milk, different proteins and milk water were extracted from pure milk originated from Australia and New Zealand, Germany and France, the USA, and China. Then, delta C-13 and delta N-15 values of the extracted proteins and delta H-2 and delta O-18 values of milk water were determined by element analyzer-isotope ratio mass spectrometry (EA-IRMS). The results indicated that pure milk from these regions could be potentially discriminated by using analyte delta C-13, delta N-15, delta H-2, and delta O-18. The P value analysis of them was highly significant (P < 0.01) considering the origins. 3D distribution of delta C-13, delta N-15, delta H-2, and delta O-18 can also clearly present regional concentration phenomena according to the regions of pure milk. Therefore, it can be concluded that delta C-13, delta N-15, delta H-2, and delta O-18 analysis could potentially be rapid and routine for origin discrimination of pure milk.