Researchers Progress Improved Adulteration Detection Method for Dietary Supplements
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In a recent study, Chapman University researchers have demonstrated the efficacy of a novel combination of DNA testing techniques in detecting dietary supplement adulteration. Published in Food Control, the work was led by Chapman student Diane Kim as part of her M.S. degree in Food Science, and the research team was overseen by senior author Rosalee Hellberg, Ph.D., Associate Professor in Chapman University’s Food Science Program.
Ginseng products are vulnerable to fraud, with cheaper plant materials substituted for genuine ingredients, posing risks to consumer health and safety. Using a new technique combining multiplex polymerase chain reaction (PCR) and DNA barcoding, the researchers were able to detect undeclared plant species in nearly half of the 50 ginseng supplements tested.
Specifically, DNA from undeclared species were found in 48 percent of supplement samples, including rice, wheat, avocado, and pumpkin. Just one-fourth of products purely contained the expected ginseng species, while 16 percent of the samples contained both the expected ginseng species and other undeclared species, and 32 percent of the samples contained only undeclared species.
The promising testing method could help regulators and manufacturers assure authenticity and improve quality control in the dietary supplement industry.
For the study, Ms. Kim assessed a unique comparison of different genetic methods for authenticating ginseng supplements, eventually discerning an accurate method for identifying species and detecting adulterants. The researchers tested ginseng supplements for the presence of three common ginseng species used in therapeutic applications (Panax ginseng, Panax quinquefolius, and Panax notoginseng).
Authenticating herbal supplements like ginseng presents several challenges, including DNA degradation, natural variability in the amount of ginseng in the product, substitution of ginseng root with ginseng leaves or flowers, and cross-contamination during harvesting and processing. To overcome these challenges, the researchers chose to combine two distinct testing methods—DNA barcoding and multiplex PCR.
Although the new approach is a significant step forward in the field of supplement authentication, 28 percent of the samples could not be identified using either method. The failures in identification, along with the lack of ginseng species identification in numerous products, may be due to factors such as DNA degradation or interference from other compounds present in the supplements. In this context, a negative test result cannot prove the absence of a species in the product.
The researchers call for future research focused on combining DNA-based methods with chemical-based approaches to further improve ginseng detection and enable the quantification of undeclared adulterants.
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