Statistical methods for improving verification of claims of origin for Italian wines based on stable isotope ratios

Wine derives its economic value to a large extent from geographical origin, which has a significant impact on the quality of the wine. According to the food legislation, wines can be without geographical origin (table wine) and wines with origin. Wines with origin must have characteristics which are essential due to its region of production and must be produced, processed and prepared, exclusively within that region.The development of fast and reliable analytical methods for the assessment of claims of origin is very important. The current official method is based on the measurement of stable isotope ratios of water and alcohol in wine, which are influenced by climatic factors. The results in this paper are based on 5220 Italian wine samples collected in the period 2000–2010. We evaluate the univariate approach underlying the official method to assess claims of origin and propose several new methods to get better geographical discrimination between samples. It is shown that multivariate methods are superior to univariate approaches in that they show increased sensitivity and specificity. In cases where data are non-normally distributed, an approach based on mixture modelling provides additional improvements.

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► The assessment of claims of origin is of enormous economic importance for DOC and DOCG wines.
► The official method is based on univariate statistical tests of H, C and O isotopic ratios.
► We consider 5220 Italian wine samples collected in the period 2000–2010.
► Multivariate statistical analysis leads to much better specificity and easier detection of false claims of origin.
► In the case of multi-modal data, mixture modelling provides additional improvements.