One of the reviews that I linked to talked about this. According to them, they talked to several suppliers who said the food-grade difference was make by turnin

One of the reviews that I linked to talked about this. According to them, they talked to several suppliers who said the food-grade difference was make by turning the (source! I think) canister over and running it for a couple seconds. Take that with a big grain of salt. I'd certainly look into it more before I used it. :)