If it says safe for children and animals then I would assume it is food grade, but google all you can before using!
My chickens don't sneeze with DE...I usually put a small handful into their 7 gallon feeder once or twice a week and I mix it in well before giving it to them. If I don't put it in the feed, I take defrosted frozen corn and shake it in a little DE (like shake n' bake!) and give them DE nuggets once a week or so. I've found when they eat DE regularly there are much less flies in their poop.
I also sprinkle a styrofoam cup full of DE on to the bare floor of their 4x4 foot coops, 1 cup per coop, then add another two cups of stall dry, then cover it in several inches of pine shavings.
And recently I used DE to get rid of our spring ants! I made a paste with water and used a plastic knife to put it all around the base of the house in the area they were coming in, then I dumped a little DE on their nest, and boom...no more ants. That's the easiest I have ever won the spring battle with ants.