Food Grade Poison

Ok, so can you tell me what's wrong in that statement?

Yesterday I was making soap and was running low on lye. I ran over to my friends house to grab a container from her, and noticed this odd labeling:

"Food Grade Sodium Hydroxide" For those of you who don't know, sodium hydroxide is a poison. So, how can a poison be food grade? Don't ask me. I'm still trying to figure it out. I did get a bit of it in my mouth and I can tell you it's not pleasant.I guess if you kill yourself with it, at least you know it was food grade and I can now officially say that my soap is made with ONLY food grade ingredients. Even the poison!!

Mickey