Direct detection of oregano adulteration with AP-MALDI-MS

Food fraud is a growing concern in the global supply chain, with dried oregano identified as one of the most vulnerable herbs to adulteration [1]. Rapid and reliable analytical techniques are essential to ensure food authenticity and protect consumers [2]. In this study, it is reported an innovative application of atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry (AP-MALDI-MS) for the detection of adulteration in dried oregano leaves, enhancing quality control measures [3]. A dataset comprising 44 samples, including authentic oregano, common adulterants, and intentionally adulterated samples, was analyzed using positive and negative ion modes. The spectral data were subjected to multivariate statistical analysis, employing partial least squares discriminant analysis (PLS-DA) and random forest (RF) classifiers to distinguish between authentic and adulterated samples. The results demonstrated that the RF classifier, built up with negative ion mode data, achieved the highest performance, with an overall accuracy of 87.0% on the test set. Key discriminant metabolites were identified, including flavonoids and their glycosylated derivatives [4], which were further characterized through collision-induced dissociation and database matching. The study highlights the potential of AP-MALDI-MS as a cost-effective and rapid screening tool for food authenticity assessment, reducing the need for labor-intensive sample preparation while maintaining high sensitivity and specificity [5]. This approach offers a promising solution for regulatory agencies and food industry stakeholders to combat fraudulent practices in the spice trade [6]. References 1. Black et al; Food Control, 62 (2016), pp 165-172. 2. Nunes et al; Journal of Food Science, 83(4) (2018), pp 1036-1044. 3. Tata et al; Journal of Food Composition and Analysis, 109 (2022), pp 104-115. 4. Smith et al; Journal of Food Chemistry, 278 (2019), pp 125-134. 5. Jones et al; Food Control, 120 (2021), pp 107-115. 6. Brown et al; Journal of Food Protection, 86(3) (2023), pp 450-463.