On the traceability of truffles by means of the lanthanides distribution

Truffles are among the most requested and expensive foods. In particular, the Tuber magnatum Pico from Piemonte (Italy) is considered to be among the five most prised food in the world. Therefore, it is important to have at disposal analytical methods to verify the geographic provenance of truffles sold on the market. In this work we studied the passage of microelements from soil to truffle, aiming at finding chemical markers useful for the traceability of truffles. We found that the distribution of lanthanides, determined by means of ICP-MS analysis, is apparently a fingerprint of the soil in which the truffles are collected. A parameter called L-value has been introduced to evaluate how the distributions of lanthanides are maintained between samples. Therefore, if each truffle has the original fingerprint of the pertinent soil, this can be used for the purpose of authentication. It is demonstrated that the features of the soil are more relevant than the species of truffle in the permanence of the fingerprint, even if truffles are compared with fungi collected in the same soil. Of course, there is a possibility that, for pedological reasons, similar soils, located in areas far from each other, have the same fingerprint: in that case it will not be possible to distinguish the truffles collected in those soils. The similarity between soil and truffle, expressed through the distribution of the lanthanides, is therefore a condition necessary but not sufficient. It can, however, help in the authentication of a truffle provided the pertaining soil is available. In fact, it must be remembered that truffles grow on specific soils: this is particularly true for the Tuber magnatum Pico, the only species impossible to cultivate.