Differentiated Study of Constituents between Organic Milk and Ordinary Milk by Stable Isotope Ratio and UPLC-Q-Orbitrap

Objective: To prevent some illegal companies driven by interests from arbitrarily labeling "organic" to deceive consumers using ways such as counterfeiting, forgery, and shoddy food. Methods: This study investigated differential components between organic and regular milk by stable isotope ratio and UPLC-Q-Orbitrap-based metabolomics. Organic milk with different lactation stages was also analyzed. Results: There was a significant difference between organic and ordinary milk for single factor ANOVA P<0.01. The carbon stable isotope and nitrogen stable isotope ratios could be used to distinguish organic and ordinary milk. Based on the data from UPLC-Q-Orbitrap, differential metabolites were screened by the OPLS-DA method, five different constituents were obtained, and there was a big difference between different lactation stages of organic milk such as histidine etc. Conclusion: Although the data of this study was obtained from limited samples, the different constituents between organic and ordinary milk were confirmed. Organic milk could be preliminarily determined by the data of carbon isotope ratio, nitrogen isotope ratio, and five different constituents screened by the UPLC-Q-Orbitrap method. This study could provide a scientific basis for the identification of organic and ordinary milk.