Multielemental + Isotopic Fingerprint Enables Linking Soil, Water, Forage and Milk Composition, Assessing the Geographical Origin of Argentinean Milk.

GRIBOFF, JULIETA; BARONI, M.V.; HORACEK, MICHA; WUNDERLIN, D. A.; MONFERRÁN, M. V.

Ljubljana

Workshop; 5th IAEA Meeting: CRP 5293: Accessible Technologies for the Verification of Origin of Dairy Products as an Example Control System to Enhance Global Trade and Food Safety.; 2018

IAEA & Jozef Stefan Institute.

Milk can be consumed directly, transformed to several dairy products such as cream, butter, cheese, etc., or incorporated in the production of a variety of foods, such as cakes, biscuits, cookies, ice-cream, chocolates, etc. In the last few years, with the development of a globalized food market and the increased interest of consumers to know the characteristics, quality and geographical origin of foods, many countries have adopted/introduced regulations to guarantee the traceability of food. The Protected Denomination of Origin (PDO) and Controlled Denomination of Origin (DOC) systems have been promoted, and applied to control and, ultimately, ensure the origin and quality of food as well as to prevent fraud (Kelly et al., 2005). One of the requirements to achieve PDO or DOC certifications is to obtain a chemical characterization of the food. The inorganic pattern of a food reflects the local geochemistry of both soil and water, which is influenced by geology, temperature, climate, distance from the sea, elevation, latitude, food processing, etc. (Goitom Asfaha et al., 2011; Di Paola Naranjo et al., 2011, Baroni et al., 2011). Thus, the inorganic composition of foods can be assumed to be more stable in time, compared to the organic constituents, which are subject to change by microbial action, biochemical reactions, oxidation-reduction, hydrolisis, etc.Trace element content and isotopic ratios of plants that can be used as forage are assumed to be related to the chemistry of the local water and soil layers in which they grow, although anthropogenic practices could have some influence. So far, as the soil layer reflects the underground rock, the isotopic and elemental composition of a crop should be correlated with the geological characteristics of producing areas (Branch et al., 2003). The analysis of elemental composition is considered an effective primary tool. In addition to the essential elements that plants need for growing (B, N, Mg, P, S, Cl, K, Ca, Mn, Fe, Ni, Cu, Zn, and Mo) (Laursen et al., 2011), plants can uptake other bio-available elements from soil and water. Thus, non-essential elements, such as alkaline metals, especially rubidium (Rb) and cesium (Cs), can be easily mobilized in the soil and transported into plants, becoming good indicators of geographical identity (Kelly et al., 2005). However, the availability of soil elements depends on several factors, such as soil pH, humidity, porosity, clay and presence of humic complexes, etc. Consequently, the range of soils present, in addition to different agricultural practices (organic, traditional, etc.), and the bioavailability of soil constituents may supply unique fingerprints in the final food product that characterize its geographical origin (Kelly et al., 2005). Food authentication studies have shown that one single method, or one single parameter, is generally insufficient to indicate the origin, and to enable the traceability of food (García-Ruiz et al., 2007). Thus, our current knowledge indicates that it is necessary to evaluate at least two different groups of parameters (e.g. trace elements and isotopes), combining them by using multivariate statistics, to achieve a good differentiation of food from various geographic origins (Di Paola Naranjo et al., 2011, Baroni et al., 2011, 2015; Podio et al., 2013). Therefore, we propose to assess the provenance of dried milk, measuring inorganic elements and isotopes in soil, water, forage (silage or natural grass) and milk from different farms, distributed in the main production area of Argentina (Provinces of Córdoba and Santa Fe) as well as in samples from a reference zone (Province of Catamarca). Samples will be taken considering spatial and temporal changes in the environment (rain and drought periods, different water sources, different vegetation, etc.). Thus, we expect to provide scientific evidence on the differences between milk produced in different areas of Argentina that can be compared with similar results evaluated in other countries participating in this CRP. Additionally, we propose the use of multivariate statistics to enable classification rules that help verify different geographic origins (spatial differences), temporal differences (wet vs. dry season), different feeding, etc. The sum of all these results could provide the scientific basis for PDO/ DOC regulations in member states.In previous reports we present the results of inorganic elements and isotopes in soil, water, forage and milk from different farms in rain period (summer) and in the dry season (winter), in this report we present results of inorganic elements in water, soil, milk and we add cheese samples. We propose the use of multivariate statistics (correlations, multivariate statistics, etc.) to enable classification rules that help verify different geographic origins (spatial differences). The sum of all these results could provide the scientific basis for PDO/ DOC regulations in member states.