Stable isotopes verify geographical origin of yak meat from Qinghai-Tibet plateau

Abstract

High-value yak meat from Qinghai-Tibet Plateau was investigated using stable isotopes (δ13C, δ2H, δ18O, δ15N and δ34S) to identify attributes which could verify and protect its geographical origin. Supervised PLS-DA was applied to the isotope data to discriminate four geographical locations. δ13C, δ2H, and δ18O values showed significant differences according to origin while δ15N and δ34S values did not show any change across the different regions. Isotope values of different body tissues from the same animal showed no statistical difference for the five stable isotopes. In addition, the δ2H and δ18O values of defatted yak meat was highly correlated to farm altitude and associated drinking water. This yak meat traceability method is particularly useful to protect the Product of Geographical Indication (PGI) status of Gannan yak meat and verify the farming origin of yak meat sold in markets for food safety purposes, especially when excessive hormones, pesticides or heavy metals are found.