Disclosed is a process for releasing ATP from living cells in aqueous mixtures of polymers or pigments. The aqueous mixture of a polymer or pigment is agitated in the presence of a particulate disruption agent to cause rupturing of the living cells and release of the ATP contained therein. Also disclosed is a process for detecting living cells in a aqueous mixtures of polymer or pigments by detecting the ATP released by the disruption process by a luciferin/luciferase assay. A kit for the detection of living cells in aqueous mixtures of polymers or pigments also is described.