How do you know the people didn't eat beans and drink milk? There is glycine in beans and milk has phosphates.
The research has got to be from a peer reviewed scientific journal, and even then I question it, unless I know the researchers.
My chemistry is a little faded but -----when I look at the low concentrations which they found----I think you would find that in any one who ate beans and drank milk. They did not specify what the residues were? It strikes me it is not great research. What makes me think it is sketchy research
is that they say "by an accepted method". In North America they would give the exact method such as ASTM ----number such.
ASTM stands for American Standards for Testing Materials. A good legitimate scientific report states exactly what they were doing.
It identifies the "accepted method".