Rather than dealing with substances that are prohibited, FDA Regulation 21 CFR 177.2600 specially addresses the use of silicones intended for use in food operations. Under paragraph (c) of this section Silicone Si, Psi, Vsi, Fsi, and PVsi are identified as silicones that can be used in food operations.
Silicone provides several useful properties as a food sealant. Silicone provides good thermal stability in both low and high temperature ranges. It acts to repel water forming watertight seals. It provides excellent resistance to oxygen with low toxicity, while not supporting microbiological growth. If you have further questions or concerns regarding a specific silicone sealer you can always contact your local FDA, or USDA, representative for assistance.