The notion that DNA barcoding could have been used to identify supplement ingredients at scale was always very unlikely. To make 1kg of a common type of gingko

The notion that DNA barcoding could have been used to identify supplement ingredients at scale was always very unlikely. To make 1kg of a common type of gingko extract, you take 20kg of dry plant matter, grind it all to a very fine powder, extract it in a boiling solvent (often hexane or methanol), filter it under pressure, boil off as much of the solvent as you can, and then you spray-dry or freeze-dry it. This process would leave essentially no intact DNA. I think that the "DNA barcoding" notion was formulated by somebody who didn't understand how extracts are made, and the media just ran with it. What's funny is that rice flour is used as a common filler ingredient in supplements. Imagine barcoding a gingko product and getting "100% Rice" in your DNA report. And yet that would have been possible with even the most scrupulously honest products.