The EU Joint Research Center (JRC) has developed new methods for detecting adulteration in six popular herbs and spices, as well as new reference materials to help identify fraudulent fish products.
Addressing the Need for Sensitive Detection Techniques in Light of Pervasive Adulteration in Popular Spices and Herbs
In response to a 2021 EU-wide survey that showed the prevalence of fraudulent practices in six common herbs and spices, JRC set out to develop new laboratory techniques to meet the need for effective adulteration detection methods.
Specifically, in the 2021 survey, JRC conducted nearly 10,000 analyses on 1,885 samples of paprika, turmeric, saffron, cumin, oregano, and black pepper. The proportion of samples deemed at risk of adulteration ranged from 6 percent for paprika to 48 percent for oregano, mostly due to being adulterated with olive leaves. The proportion of suspicious samples for the four other herbs and spices were 11 percent for saffron, 11 percent for curcuma (turmeric), 14 percent for cumin, and 17 percent for pepper.
Despite the prevalence of food fraud in these popular herbs and spices, there was a lack of comprehensive adulteration detection techniques, making it difficult to enforce food authenticity. Filling this gap, JRC has developed new quantitative real-time polymerase chain reaction (qPCR) methods to identify the top five adulterants for each of the six common herbs and spices. The methods were confirmed to be specific to the adulterant for which it was intended in the relevant authentic species (e.g., wheat in turmeric).
The new qPCR methods are useful for estimating, quantifying, and confirming the presence of illegal adulterants in herbs and spices, and are sensitive enough that laboratories can even distinguish between intentional adulteration and inadvertent contamination. This identification is made possible through untargeted DNA-based techniques and chemical biomarkers analysis (e.g., an olive biomarker in an oregano sample). A total of 13 methods are undergoing laboratory exercises to ensure the methods are harmonized and validated, and to help facilitate their implementation by regulators and industry.
Catching Fish Substitutions in Processed Products
Additionally, to aid the detection of the substitution of popular fish species in processed products, JRC has produced two certified reference materials (CRMs) for pollack and saithe fish. Based on DNA barcoding, the new CRMs enable authorities to compare DNA sequences with those in processed fish products.
More specifically, the CRMs are powders processed from freeze-dried and cryogenically milled fish filets derived from a single fish—either pollack or saithe. Ensuring that tests using these CRMs will yield accurate results, JRC confirmed the authenticity of the fish filets by sequencing the species' specific DNA barcodes and comparing them to sequences in DNA databases.
