What do you expect them to do? Evidence at the time suggested food X was bad. Should they spend another fifty years running trials to make sure, discover it was indeed killing people, and yes we knew about this fifty years ago sorry we didn't say anything sooner?
It's a tough position and I sympathize with them. I suspect no matter how soon they do or don't pull the trigger, hordes of people will wind up incensed.
I expect them to tell people about it, continue studying the matter, and ultimately let people make their own decisions.
Or as an intermediate step: require warning labels or warning signs. If we let companies sell cigarettes with warnings, we should let companies sell donuts and movie popcorn with similar warnings.
The problem with going from no information to full ban is that sometimes (quite often) the health authorities are wrong. Let us make our own decisions about what tiny statistical risks we want to take in exchange for what marginal improvement in cost and/or tastiness some ingredient enables. If everybody agrees it's not worth the cost, the outcome will be the same as a ban. If only some people think it isn't, labels will let those people avoid that risk without inflicting their standards on the rest of us.
It's a tough position and I sympathize with them. I suspect no matter how soon they do or don't pull the trigger, hordes of people will wind up incensed.