Of course this approach has its limits. I thought it was clear when I said that this method is to "check if food went bad".

If something like meat has not been cooked, or a dairy product has not been properly pasteurised, or there where unsanitary food production conditions, or not canned properly etc, this method does not apply.

It is definately not a way to check if something is eadible in general. And if you are pregnant or have special diatery needs, you know the specifics of your situation.