Evaluation of ED-XRF for the detection of inorganic adulterants in turmeric, paprika and oregano

Herbs and spices are known to be prone to food fraud and accurate analytical tools are needed to detect adulterants. Amongst the potential adulteration, dilution with bulking agents has regularly been reported, especially with inorganic materials such as talc or brick powder. Energy Dispersive X-Ray Fluorescence (ED-XRF) spectrometry is a well-established non-destructive analytical technique for qualitative and quantitative elemental analysis of a wide variety of samples. ED-XRF was here evaluated for the detection of inorganic adulterants in turmeric, paprika and oregano, which were selected as representative for the herbs & spices food category. Magnesium, silicon, and calcium were identified as elements to detect talc, soapstone, brick/clay powder, and chalk inorganic adulterants. ED-XRF successfully detected adulterated samples when spiked down to 5% (w/w) in the selected herbs and spices. With its ease-of-use and speed, ED-XRF is well adapted for the monitoring of inorganic adulteration of herbs and spices along the supply chain.