Are Nigella sativa seeds prone to adulteration?

Nigella sativa seeds – commonly known as black cumin, black seed, and love-in-a mist, among other names – have received widespread attention in recent years, as a result of their ‘magical’ properties and distinct, savoury taste. But are these seeds susceptible to the risk of food fraud?

N. sativa is an annual-flowering plant, native to south and south-west Asia, but widely domesticated throughout Northern Africa, the Middle East, and southern Europe. The seeds exhibit strong notes of onion, oreganum and black pepper, and are typically used in curries, breads, salads, stir-fries and root-vegetable dishes. Notably, it has great medicinal value, and is in high demand; thus it is highly susceptible to commercial adulteration and substitution.

Beyond the desirable taste, Nigella seeds have significant pharmacological properties as a result of their high thymoquinone content (30-48%). Thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone) has been studied extensively, and has been found to have not only anti-cancer properties, but anti-inflammatory, anti-hypertensive, gastro-protective, anti-microbial and anti-diabetic properties as well. Thus there is increasing demand for the Nigella seed, which naturally generates the risk of adulteration and substitution of this superfood commodity with morphologically similar seeds, such as Allium cepa (Red Creole onion) seeds and Clitoria guianensis seeds.

The oils produced from these seeds are also prone to adulteration. Through incidence scanning we were able to find numerous recorded incidences of the use of adulterants such as soyabean oil (which could lead to allergen contamination), grapeseed oil, walnut oil and sunflower oil.

DNA ‘barcoding’ can be used to test for adulteration and substitution of the Nigella seed, by using small fragments of genomic DNA to distinguish between different seed species. This technique compares an individual sequence with a reference library of such DNA sequences, to uniquely identify an organism down to its species, in a similar way to how supermarket scanners use barcodes to identify an item. DNA barcoding is both accurate and efficient, and can offer consumers peace of mind that the Nigella seeds that they have purchased are in fact the magical black seeds they were promised.

For more information and assistance on this topic, or if you would like your products to be tested, please contact us.