The use of hand-held infrared spectrometers combined with chemometrics to authenticate different foods has increased in popularity especially for screening samples in-situ. This study is the first interlaboratory trial to compare the performance of low-cost portable NIR devices coupled to chemometrics to detect adulterated food. In the study, there were 27 participants from 22 countries across five continents using 34 unique devices. The food chosen for this study was oregano, which already had a history of vulnerability to adulteration by different leaves of olive, myrtle, sumac, cistus and phlomis. Participants were sent authentic samples of oregano, and of olive and cistus leaves, as well as a calibration set of oregano and adulterated samples and a validation set of authentic and adulterated samples in order to build models for oregano adulteration. Participants correctly predicted >98% genuine oregano after device standardisation, and predicted 100% adulterated samples after standardisation. The devices native setup shows limited ability to perform a true screening of oregano using the setup offered. However modifications to the setup could in the future offer a solution that facilitates fit-for-purpose real time detection of adulterated samples within the supply chain.
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