The sterilisation capacity of H2O2 was determined by investigating the variations of total bacterial and coliform counts with respect to time in raw milk samples containing various amounts of H2O2 at different temperatures. The removal of H2O2 used in milk sterilisation was accomplished by catalase immobilised on DEAE-cellulose, modified initially with 2-amino-4,6-dichloro-s-triazin and then with hexamethylenediamine and glutaraldehyde. To investigate the applicability of immobilised catalase in discontinuous batch and fluidised bed reactor systems, some kinetic parameters were examined and reaction rate constants determined.