Food-grade additives are about avoiding adulterants, etc. I can't imagine people are going to that kind of effort for cheap hygroscopics. Also, and here's what

Food-grade additives are about avoiding adulterants, etc. I can't imagine people are going to that kind of effort for cheap hygroscopics. Also, and here's what I suspect the real reason is; silica gel sold as a dessicant is hard (not quite as hard as silica glass, but hard), in relatively large particles, and indigestible. That's mechanically bad news for your intestines.