We have determined the isotopic composition and the carotenoid contents of 38 extra-virgin olive oils (EVOOs) from seven regions along the Italian coasts, by means of isotope ratio mass spectrometry (IRMS) and resonant Raman spectroscopy (RRS), respectively. The application of linear discriminant analysis to our overall results demonstrated the combination of isotope and carotenoid data is a promising method to discriminate EVOOs from production sites that are impacted by similar geographical and climatic parameters. In particular, this dual approach allowed correct classification of 82% EVOO samples, while separate IRMS and RRS investigations were able to discriminate only samples from Sicily and Latium, respectively.

The main elemental constituents (H, C, N, O, and S) of bio-organic material have different stable isotopes (2H, 1H; 13C,12C; 15N,14N; 18O,17O,16O; 36S, 34S, 33S, and 32S). Isotopic ratios can be measured precisely and accurately using dedicated analytical techniques such as isotope ratio mass spectrometry (IRMS). Analysis of these ratios shows potential for assessing the authenticity of food of animal origin. In this review, IRMS analysis of food of animal origin and variability factors related to stable isotope ratios in animals are described. The study also lists examples of application of stable isotope ratio analysis to meat, dairy products, fish, and shellfish and emphasizes the strengths and weaknesses of the technique. Geographical, climatic, pedological, geological, botanical, and agricultural factors affect the stable isotope ratios (SIR) of bio-elements, and SIR variations are ultimately incorporated into animal tissue through eating, drinking, breathing, and exchange with the environment, being recorded in the resulting foods. SIR analysis was capable of determining geographical origin, animal diet, and the production system (such as organic/conventional or wild/farmed) for pork, beef, lamb, poultry, milk, butter, cheese, fish, and shellfish. In the case of the hard PDO (protected designations of origin) cheeses Grana Padano and Parmigiano Reggiano it is also used in real-life situations to assess the authenticity of grated and shredded cheese on the market.

Stable (H,O,N,C) and radiogenic isotope (Sr) data for cheese, milk, animal feed and soil from six artisanal cheese producers in Quebec, Canada, demonstrated the potential of isotope geochemistry in linking land/terroir to agricultural produce. The hydrogen and oxygen isotope compositions of the water, milk and cheese samples showed good general alignment with the Global Meteoric Water Line, with small off-sets in the milk and cheese samples related to cheese production. Carbon and nitrogen isotope data for the cheese and milk reflect the diet of the cattle and fertilization of the cattle grazing pastures. The strontium isotope compositions of the soils, milk and cheese are similar for a given farm/cheese producer, but vary widely between producers due to differences in geology. Combining the climate-sensitive δ18O and geology-sensitive 87Sr/86Sr proxies shows potential for discriminating between Quebec artisanal cheeses, commercial Canadian cheeses and European cheeses.

The aim of this study was to investigate the effects of the geographic location and climatic characteristics of the sesame-producing sites on the carbon, hydrogen, and oxygen stable isotope ratios of Korean sesame oil. In addition, the study aimed to differentiate Korean sesame oil from Chinese and Indian sesame oils using isotopic data in combination with canonical discriminant analysis. The isotopic data were obtained from 84 roasted oil samples that were prepared from 51 Korean, 19 Chinese, and 14 Indian sesame seeds harvested during 2010-2011 and distributed in Korea during the same period. The δ(13)C, δD, and δ(18)O values of Korean sesame oil were negatively correlated with latitude, distance from the sea, and precipitation (May-September), respectively. By applying two canonical discriminant functions, 89.3% of the sesame oil samples were correctly classified by their geographic origin, indicating that the triple-isotope approach is a useful tool for the traceability of the oils.