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Herbs and spices are one of the food commodities most susceptible to adulteration and fraud. In this study, 5 fingerprinting techniques - Near Infrared (NIR), Mid-Infrared (MIR), Hyper Spectral Imaging (HSI), Gas Chromatography coupled to Mass Spectrometry (GC–MS), and Proton-transfer Reaction Time-of-Flight Mass spectrometry (PTR-TOF-MS), combined with chemometrics, are examined to evaluate their potential to authenticate oregano. In total, 102 oregano samples from one harvest season were analysed for origin and variety assessment, 159 samples for adulteration assessment, and 72 samples for batch-to-batch control. Different chemometric models were applied for adulteration, origin and variety assessment. The best results were for origin assessment, which gave prediction rates of more than 89%. A level of 10% adulteration of oregano with myrtle, sumac, olive and cistus could be detected using HSI, NIR and PTR-TOF-MS.

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 This paper reports the results of an international cooperative research project to address potential food fraud issues related to rice supplies in China, India, Vietnam and Ghana, and as rice fraud manifests differently in each country, tailored solutions were required. A portable NIR (Near Infra-Red) instrument with chemometrics calibrated to the authentic rice, was used as a fingerprint screening method. Non-conforming or suspicious samples were analysed in a second stage (confirmatory test) using laboratory-based gas chromatograph-mass spectrometry (GC-MS) fingerprinting methods, which were developed to differentiate between: high value Basmati rice varieties and their potential adulterants; six Geographic Indicated protected rice varieties from specific regions of China; various qualities of rice in Ghana and Vietnam; as well locally produced and imported rice in Ghana. In addition, an inductively coupled plasma-mass spectrometry (ICPMS) method was developed to support the Chinese rice varieties methods, as well as a liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOFMS) method for quality differentiation in Vietnam. This two stage approach permits a much higher level of on-site screening of rice samples followed by the laboratory corroborating mass spectrometry analysis to assist decision making in accepting rice supplies. 

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Cyclopropane fatty acids (CPFA), as lactobacillic acid and dihydrosterculic acid, are components of bacterial membranes and have been recently detected in milk and in dairy products from cows fed with maize silage. A specific quantitative gas chromatography–mass spectrometry (GC–MS) method for the detection of CPFA in cheeses has been developed. This method was applied to 304 samples of PDO cheeses of certified origin, including Parmigiano Reggiano (Italy), Grana Padano (Italy), Fontina (Italy), Comté (France), and Gruyère (Switzerland). Results showed that CPFA were absent in all of the cheeses whose Production Specification Rules expressly forbid the use of silages (Parmigiano Reggiano, Fontina, Comté, and Gruyère). CPFA were instead present in variable concentrations (300–830 mg/kg of fat) in all of the samples of Grana Padano cheese, where silage feeding is permitted.  The method was applied to a mix of grated Parmigiano Reggiano and Grana Padano, showing that the method is able to detect the counterfeiting of Parmigiano Reggiano with other cheeses up to 10–20% Grana Padano content. 

Read the full abstract:  http://pubs.acs.org/doi/abs/10.1021/acs.jafc.6b00913?journalCode=jafcau