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A key advantage of the Direct Analysis in Real Time (DART) mass spectrometry (MS) ion source is its ability to ionise the sample without the need for extraction.  In this study (open access), the authors compared DART with a previously-published extraction-based MS method to analyse key components in olive oil.

Having optimised and validated DART-MS, they then used it to build a discrimination model between different classes of edible oils.  They analysed a reference set of 80 samples from different regions of Greece (Crete, Peloponnese, Central Greece, and the North Aegean) to discriminate authentic extra virgin olive oil (EVOO).  These were from 10 oil categories including 35 EVOOs, 15 lower-quality olive oils (five of each category: refined, olive pomace, and ordinary), and 30 vegetable oils (five of each type: sunflower, corn, soybean, canola, sesame, and linseed).

They report that multivariate statistical analysis revealed clear discrimination of EVOO from other oils and enabled detection of EVOO adulteration down to 1 % with vegetable oils and 5 % with lower-quality olive oils. Key authenticity markers, including phenols, squalene, and triacylglycerols (TAGs), were identified.

They conclude that the proposed method demonstrates high potential for rapid, reliable EVOO authentication in routine quality control.

In this study (open access) the researchers used a panel of three different DNA test protocols to verify the labelled species in dairy products sampled from Greek supermarkets over the winter of 2024.  They tested 74 samples in total encompassing cow, sheep and goat products. This included 15 different commercial brands of goat yoghurt, 7 brands of sheep yoghurts, 3 brands of goat kefir, and, samples of feta cheese and sheep-goat cheese from 16 to 11 different geographical origins and 7 brands of goat cheese were analysed.  The brands are anonymised within the publication.

They report widespread adulteration, particularly in goat yogurts (40 %) and cheeses (40 %), as well as in three kefirs and several mixed and whey-based cheeses. Notably, only 7 out of 17 - nominally goat - feta samples contained detectable goat DNA..

Image from the publication

In this paper (open access) two optical spectroscopic techniques,  Laser-Induced Breakdown Spectroscopy (LIBS) and UV-Vis-NIR absorption spectroscopy, are assessed for EVOO adulteration detection, using the same reference database of olive oil samples. In total, 184 samples were studied, including 40 EVOOs and 144 binary mixtures with pomace, soybean, corn, and sunflower oils, at various concentrations (ranging from 10 to 90% w/w). The reference class of “pure” EVOOs were limited to oils from a specific geographic region (either Crete, Lesvos, Kalamata or Achaia, with a different model built for each case).

The emission data from LIBS, related to the elemental composition of the samples, and the UV-Vis-NIR absorption spectra, related to the organic ingredients content, were analyzed, both separately and combined (i.e., fused), by Linear Discriminant Analysis (LDA), Support Vector Machines (SVMs), and Logistic Regression (LR). In all cases, very highly predictive accuracies were achieved, attaining, in some cases, 100%.

The authors conclude that both techniques have the potential for efficient and accurate olive oil verification test protocols, with the LIBS technique being better suited as it can operate much faster.