A self-contained sterilization process biological indicator is provided. The indicator includes a housing. Test microorganisms disposed in the housing are enveloped by a wax composition. The wax composition comprises a long-chain (greater than C22) linear or branched alkyl or alkenyl alcohol, wherein the alkyl or alkenyl alcohol is not linked through an ester bond or an ether bond to a short chain alkyl or aryl (C1-C6) group, wherein the alkyl or alkenyl alcohol is not linked through an ester bond or an ether bond to a long chain (C8-C36) alkyl or alkenyl group, wherein the alkyl or alkenyl alcohol is not linked through an amide bond to a linear or branched long chain (C8-C36) alkyl or alkenyl amine or acid. The wax composition has a melting point between 78° C. and 120° C. Also contained in the housing are a nutrient composition and an openable container containing a liquid medium.