I get my sprayers from a local Restaurant Supply house. Don't know if they're "food grade" but as long as they're clean, and used only for this, I think they're fine.
You name it, someone has probably added it to a spray
Bourbon
Tequila
Juices of all types (grape, cherry, pineapple)
Lots of options.
For me, spraying will not keep the food moist, that's a function of the meat itself and cooking. It WILL help with outer color, layering of flavors on the outside.