Isoscapes of carbon and oxygen stable isotope compositions in tracing authenticity and geographical origin of Italian extra-virgin olive oils

The authentication and verification of the geographical origin of food commodities are important topics
in the food sector. This study shows the spatial variability in d13C and d18O of 387 samples of Italian extravirgin
olive oil (EVOO) collected from 2009 to 2011. EVOOs' d13C and d18O values were related to GIS
(Geographic Information System) layers of source water d18O and climate data (mean monthly temperature
and precipitation, altitude, xerothermic index) to evaluate the impact of the most significant largescale
drivers for the isotopic composition of Italian EVOOs. A geospatial model of d18O and d13C was
developed for the authentication and verification of the geographical origin of EVOOs. The geospatial
model identified EVOOs from four distinct areas: north, south-central Tyrrhenian, central Adriatic and
islands, highlighting the zonation of the expected isotopic signatures. This geospatial approach can be
used to define a protocol for analyzing the isotopic composition of EVOOs in order to certify their origin
and prevent food fraud. Limits and perspectives of the model are discussed.