You test at least moderately close to the actual target and you punish those who are breaking the rules brutally (it is actually food safety!). Instead we allow Olive oil that isn't and Fish that aren't because, nobody has died yet? Allergies are possible even at very low levels.
My real point wasn't the simplicity or cheapness, but often the biproduct of those is that it's a test you already have that doesn't measure what you want (nitrogen rather than protein). In the case of Olive oil, if what we cared about was it's fluoresced color rather than the material in it, that would be great.
If what we care about is components, random GC/IR spectroscopy (perhaps after centrifuging) to see the actual compounds with consequences would be a better choice than the cheapest thing they can just add another weird chemical to defeat.
A funny version of this is Manuka honey. It's not easy to define and it's slowly turned into an NZ versus Australia thing. There have been examples where bees that only gave Manuka to feed on are making honey that doesn't meet the standard, and bees that weren't thought to be feeding on Manuka have been making Manuka honey.
I have seen recipes for making non compliant honey into compliant honey (to be clear, the input honey is Manuka, but the lab test wasn't being being passed). It's about blending various types of honey.
It's a bit dumb in my view and needs a better test. As you say, it's meeting the test, not the objective of the test.
My real point wasn't the simplicity or cheapness, but often the biproduct of those is that it's a test you already have that doesn't measure what you want (nitrogen rather than protein). In the case of Olive oil, if what we cared about was it's fluoresced color rather than the material in it, that would be great.
If what we care about is components, random GC/IR spectroscopy (perhaps after centrifuging) to see the actual compounds with consequences would be a better choice than the cheapest thing they can just add another weird chemical to defeat.