Safety is a spectrum really. To give a very binary example we are certain that eating rotten poisonous shark (https://en.wikipedia.org/wiki/H%C3%A1karl https://

Safety is a spectrum really. To give a very binary example we are certain that eating rotten poisonous shark (https://en.wikipedia.org/wiki/H%C3%A1karl https://en.wikipedia.org/wiki/H%C3%A1karl) won't kill you because of historical record in spite of eating rotten fish and eating toxic fish separately both being known lethal things. It doesn't tell us if it is optimal health wise to do such a thing.