I made some reusable snack bags for my son using a nylon inner and cotton/poly exterior. I use them for carrying dry snacks in the car or to the grocery store etc. I don't store things in the bags overnight. I was told the other day that nylon is not food-safe unless labeled as such. I have been reading and bags sold commercially say they are food grade nylon or vinyl. My questions are : is there a honestly a different process for making food grade fabric or is it just that one company is investing in getting the FDA label? Is there any difference in allowing his pretzels and nuts to touch nylon or touch a plastic sandwich bag?