I personally wouldn't worry too much about the stain being non toxic as long as it is dry and sealed. I say this because you are probably not using the handles to actually prepare or cook a pizza while using your KP. The handles don't come in contact with food. I kind of doubt the stains used on dining room tables and kitchen cabinets are non toxic, at least not when applied. Same with the sealers used. A pizza peel, bbq tool handles or the work table on a performer would be another story. What does
@zavod44 use to stain and seal the awesome kettle handles he makes?
Anyways, I used this stuff on my butcher block top kitchen island with good results:
https://www.amazon.com/gp/product/B000VITOT4/ref=pd_sim_60_6?ie=UTF8&psc=1&refRID=SZ4NXXKCCG60Z9VT5GY0It's not the same stuff you would use on a cutting board, but is food safe when dry. Also, it doesn't really "stain" the wood, just seals it.
hope this helps