Fine-Scale Strontium Isotope Mapping in Eastern China (Anhui Province) and Its Application in Food Traceability

Origin traceability is critical for food safety, and the strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) has been widely used in this field due to its accuracy and stability. Establishing a regional baseline map of bioavailable ⁸⁷Sr/⁸⁶Sr is essential for precise traceability. However, the existing large-scale bioavailable Sr isotope map of China has low spatial resolution and uses water as the main sample, making it unsuitable for plant-derived food traceability. This study focused on Anhui, a major agricultural province in China. Based on geological lithology distribution, 149 plant samples were collected across Anhui to construct a fine-scale bioavailable ⁸⁷Sr/⁸⁶Sr map. The map enabled traceability of Anhui's characteristic plant-derived foods, such as Cha (Camellia sinensis), Mugua (Chaenomeles speciosa), Fengdan (Paeonia ostii), Jiegeng (Platycodon grandiflorum), and Duohua Huangjing (Polygonatum cyrtonema). It provides a basis for food origin traceability in Anhui and supports market supervision of China's geographical indication (GI) products.