Use of chemical fingerprints to differentiate foods from diverse origin. The case of argentinean foods.

WUNDERLIN D.A.

Wellington

Simposio; Go Trace Symposium; 2011

University of Otago + Oritain.

The main goal of our research group is assessing food provenance considering several endpoints. Among possible hypothesis, we evaluated the follow up of several metals from farm soil to food products, changes in stable isotopic composition in foods, production of specific proteins or secondary metabolites. Thus, we sampled and analyzed food commodities produced at five different areas of Argentina (AR). Then, we analyzed such foods constructing a chemical fingerprint, pointing out differences among studied areas as well as with similar products produced in other latitudes, like EU. So far, we tested the concept of chemical traceability of foods, which could be a valuable complement for other traceability techniques, reinforcing the confidence of consumers in such foods that can be traced ¡°from farm to fork¡±. Studied Areas in AR include the provinces of Buenos Aires, Entre R¨ªos, C¨®rdoba, San Juan and Mendoza, covering wet-templates areas (pampas) and semi-arid regions with different geology. Studied Areas in EU correspond to those covered by TRACE project (Austria, Germany, Denmark, France, Greece, Ireland, Italy, Poland, Portugal, Spain and UK). Analyzed elements include 31 trace elements (TE) and stable isotopic pattern (¦Ä 13C, ¦Ä 15N, ¦Ä 18O, the ratio 86Sr/87Sr, etc.). Thus, we constructed a fingerprint characteristic for a particular product, arising from a particular country, or a single area within a country. Food commodities included in our study were: Honey, Beef, Wheat and Wine. We also analyzed the composition of agricultural soils and irrigation water. A brief presentation of each product will be performed during the conference. We found good differentiation between commodities produced at different areas of AR. Differences can be evidenced by the chemical profile (trace elements + isotopic pattern) and are quite similar to honey, wheat, beef and wine, even when each product have different attributes. Thus, both animal and vegetal products retain certain characteristics, associated with the provenance soil, linked to the irrigation water. Furthermore, differentiation with similar commodities produced in EU was also possible at a global scale, and even possible at regional scale considering areas with similar geology in EU and AR. For instance, AR wheat samples from three different provinces can be clearly differentiated by TE analysis. This analysis can be extended to differentiate wheat grew in similar geologies at both EU and AR, reaching 98% average certainty in the prediction of wheat provenance considering the chemical profile. Similar results are obtained with honey from AR and EU. Additionally, AR meat (beef) from three different areas can be clearly differentiated by both TE and isotopic pattern, evidencing association with different soils but also the use of diverse feed. Particularly, meat from the province of C¨®rdoba reveals feeding with maize, while meat from Buenos Aires and Entre R¨ªos present a typical profile of grass feeding. Finally, the provenance of Argentinean wine samples can be differentiated considering TE, stable isotopes and secondary metabolites, matching those elements present in cultivation soil. We conclude that it is possible to differentiate the geographical origin of Argentinean foods, not solely from similar inland products but also from European foods. This task can be achieved after considering several parameters that include chemical elements and stable isotopic patterns, constructing a fingerprint accounting for different species and production practices in addition to environmental factors. These results point out the need of constructing extensive databases, including chemical and isotopic composition of food in association to soil characteristic, geology, pollution degree, etc. Such databases should be used in the future to support claims for the origin of foods, helping the international trade and increasing consumer¡¯s confidence by avoiding frauds.