Lutefisk is soaked in lye and still served in the basements of Lutheran churches around here. You don't have to be norwegian or swedish either. I'm german and irish and i eat it.
Lye is an old method of preserving foods as it makes it too alkaline for bacteria to grow. The opposite end of the pH spectrum from high-acid canning. It is washed out before eating. In the case of lutefisk, it is barely edible anyway.