A peristaltic pump (2) for use in a sterilisation apparatus (10) comprises: a flexible pump hose (44) having an outlet end and an inlet end, and an electrically conductive fitting (53) at each end; a motor-driven impeller (46) disposed in relation to the pump hose (44) such that when the impeller (46) is driven it will intermittently bear against the pump hose (44) so as to bring the internal walls of the pump hose together (62); a first electrode (52a) in contact with the conductive fitting (53a) at the outlet end of the pump hose (44), and a second electrode (52b) in contact with the conductive fitting (53b) at the inlet end of the pump hose (44); means (70) for applying a voltage across the first and second electrodes (52); and means (70) for measuring an electrical property between the conductive fittings (53). Other aspects of the invention provide a sterilisation apparatus including the pump, and a method of using the sterilisation apparatus.