Abstract: A method for detecting and localizing bacterial growth on a surface comprising the steps of:(a) applying a solid substrate to the surface;(b) removing said substrate from said surface and incubating said substrate for purposes of facilitating ultimate visualization of selective bacterial growth; and(c) observing the locus of bacterial growth on the substrate.The method is particularly effective in detecting and localizing cariogenic activity in the mouth.

Abstract: A method for the separation or purification of biopolymers comprises adsorbing the biopolymer on the surface of liquid oil droplets; and separating the adsorbed biopolymer from the oil droplets. The adsorbed biopolymer is separated from the oil droplets by mixing the droplets in an aqueous liquid, removing the lower aqueous phase and adding a fresh aqueous phase to the droplets, cooling the mixture to solidify and coalesce the oil and to cause it to release the adsorbed biopolymer to the fresh liquid, separating the fresh liquid and the biopolymer from the coalesced oil, separating the biopolymer from the fresh liquid.