In general the way **** works in the US is once it's proven to be dangerous they'll do something, so...So did the F.D.A. not catch this, or......?
In reality to be able to market something as food that has been through the process to be "generally regarded as safe" there's a pretty lengthy process that includes toxicity testing. But once you get through that it's pretty much up to the producer to maintain processes and variation. For something like this I don't think there's any sort of periodic approval.