Welcome to the “rare soils” that tell us where coffee comes from

by Emanuela Pusceddu, PhD in Physics

IBIMET Institute of Biometeorology – National Research Centre (CNR)
Quality and authenticity are important aspects for the agri-food industry and consequently also for the safety of consumers and manufacturers.  A problem affecting the agri-food industry, both from the point of view of product quality and economically, lies in the issue of counterfeit origins, adulteration and labelling of products.
The scientific community has focused its attention to thwart fraud on food matrices, such as wine, oil, wheat, rice and many other products.
Several studies have addressed the issue of varietal traceability of agricultural products and allowed to develop solid analytical methodologies while to date, there are few studies on geographical traceability. Currently, several investigative techniques are able to characterise bio-matrices from a chemical, physical and biological viewpoint.
Some of these techniques take into account a family of chemical elements, the so-called "rare soils" (family of Lanthanides). These chemicals are contained in the soil and are absorbed by plants, and are also found in fruits or in food products. In particular, the analysis of chemical elements has been applied successfully in this field, such as mass spectrometry with inductively coupled plasma (ICP-MS). One study demonstrated with this technique that the composition of multiple elements in food products is strongly influenced by the solubility of inorganic compounds in the soil. This shows that there is a correlation between the chemical elements present in the soil, in the plant and in the fruit. The possible identification of trace elements, such as the lanthanides in bio-matrices may be used to identify the geographical location of the soil that produces them.
Currently, an experiment is under way to determine the traceability of coffee in collaboration with the Italian Espresso National Institute (Inei) and the International Institute of Coffee tasters (Iiac). Preliminary tests revealed a substantial difference between the quantities of Lanthanide elements contained in green coffee taken from samples from two different countries. Therefore, we have been able to observe the discrimination between two samples of coffee originated from different soils. The same type of experiment was also conducted on coffee after roasting, coming from two different countries. Even in the case of the roasted samples, it has been possible to observe the discrimination between the two agro-products from different soils.
The next steps of this study focus on the refinement of the technique used and the construction of a database of coffee with the guarantee of geographical origin. This work will allow us to achieve significant results for the agri-food sector, in the field of geographical tracking and authentication, in order to protect consumers and manufacturers.

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