Multi stable isotope ratio analysis for the traceability of northern Italian apples

Isotope ratio mass spectrometry is a well-known technique used to trace the origin of agri-food products from different countries. Here this method was tested to trace the exact orchard of provenance of Italian apples harvested at sites close to each other. We measured the δ(13)C, δ(15)N, and δ(34)S values of apple subfractions (peel, petiole, pulp, seed) from two orchards in Ferrara and one orchard in Trento. Sulfur represents the best marker for tracing the regions of provenance of samples because it is linked to the presence of sulfate (Ferrara1: +9.0 ‰; Ferrara 2: +7.3 ‰) and sulfide (Trento: −1.3 ‰) minerals in soils. However, the δ(13)C of apple subfractions combined with the δ(34)S of seed in a linear discrimination analysis better discriminated the three orchards. The isotopic fingerprint of apples is thus significantly affected by the relative terroir, and it can be used as “isotopic identity card” to certify “protected designations of origin”.