There is an FDA approved dust available, I don't know why nobody ever mentions it, was called platinum dust, I get it from CK who for some unknown reason just changed the name.
I looks and acts just the same as pear dust, but has a slightly higher pricepoint. So if you use the recipe on the home page and use the above dust, it's food safe. I am fairly sure you can buy it on Amazon or GSA if you can't buy wholesale.
This debate always makes me laugh a bit though because there is so much stuff that bakers - heck, ALL people that make edibles including chefs, that use totally inedible stuff in their food but we seem to focus on this one thing. I am very glad disco dust is no longer accepted for use in cake competitions but we have so much more to go - like ribbon direct on cakes. At least disco dust is made and packaged under some guidelines that it's going on an edible. Ribbon is just flat disgusting, made packaged and shipped with all kinds of poisonous dyes and chemicals with no intention of going on something being eaten, but it's used all the time on 99% of the cakes on here. But hey, I'm a huge hypocrite now, I spent the first 3 years of my bakery business having a "no ribbon" policy for my cakes and spent countless hours perfecting an invisible seam technique that makes the tiers blend into each other without having to use ribbon or anything else to cover it up but I've caved now because every pretty fake styled cake on Pinterest that brides bring in have pretty ribbon all over it (if the cake isn't covered in ruffles). It sucks but it is what it is! So guess who has 2 thumbs and is using ribbon now if a client wants it? This gal. Sigh. Whatever. Saves me a ton of time I guess instead of trying to blend the seams on my tiered cakes but I'd really rather NOT use ribbon -pretty much ever.