A Novel Approach to Detecting Adulteration in Ginseng Supplements

Rosalee Hellberg, an associate professor in Chapman University's Food Science Program, and her research team have made a significant breakthrough in the fight against adulteration in dietary supplements. Effective methods for identifying adulteration and fraud have remained elusive. Now, a new study of 50 commercially available ginseng products has found surprising results. 

Ginseng products are vulnerable to fraud, with cheaper plant materials substituted for genuine ingredients, posing risks to consumer health and safety. Using a novel combination of DNA testing techniques, the researchers detected undeclared plant species in nearly half of the 50 ginseng supplements tested.

The Chapman University research team detected DNA from undeclared species in 48% of samples, including rice, wheat, avocado and pumpkin. One in four products contained only the expected ginseng species, 16% of the samples contained both the expected ginseng species and other undeclared species, and another 32% of the samples contained only undeclared species. The detection method used could help regulatory bodies and manufacturers improve quality control in the dietary supplement industry. The global market for ginseng supplements is projected to reach $17.9 billion by 2030.

The study, entitled "Use of a Novel Combination of Multiplex PCR and DNA Barcoding in Assessing Authenticity of Ginseng Products," is published online in the journal Food Control.

Diane Kim, who led the study as part of her master's degree in food science, assessed a unique comparison of different genetic methods for authenticating ginseng supplements, ultimately pointing the way towards a more accurate method for identifying species and detecting adulterants in this rapidly growing market. Kim and her colleagues 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.

While the new approach is a significant step forward in the field of supplement authentication, 28% 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. Because of this, a negative test result does not prove the absence of a species in the product. The team suggests that future research should focus on combining DNA-based methods with chemical-based approaches to further improve ginseng detection and enable the quantification of undeclared adulterants.

We found that the use of a combination of genetic methods was more powerful than using either method alone, allowing us to detect plant species in the majority of products. While the detection of undeclared species is concerning, additional testing is needed to quantify the level of these potential adulterants."

Rosalee Hellberg, Associate Professor, Food Sciences, Chapman University