A composition for preserving solid food products comprising a moisture-sensitive isothiocyanate compound and a hygroscopic carrier, wherein the composition is substantially free of sorbic acid, benzoic acid, and salts thereof. Also disclosed is a solid food product containing the aforementioned preservative composition and a method for preserving solid food products including the steps of adding a moisture-sensitive isothiocyanate to the solid food product and storing the resulting product at a reduced temperature.