Mcmaster says viton is good to about 400F.
This site: (third google result for 'viton food safe')
Materials: Viton, Nitrile, Silicone, Polyurethane, EPDM, Fluorosilicone, Teflon, PTFE filled, PEEK, Nylon, Acetal
does NOT say viton is food safe, but more importantly it says it is NOT recommended...