A sterilization apparatus for use with a cardioplegia heat exchanger device includes an enclosure having an internal volume defined between two ends and a wall. The first end includes a bulb access port, an inlet port formed proximate to or in the first end, a biofilm sterilizing port, and an outlet port formed proximate to or in the second end. A quartz sleeve and an ultraviolet bulb project inwardly into the internal volume from proximate the bulb access port. The ultraviolet bulb illuminates to radiate water entering the inlet port and flowing towards the outlet port between the cylindrical wall and the quartz sleeve. A wiper ring may be slidably fixed around the quartz sleeve for cleaning. In an alternate embodiment, the bulb access port is formed through a water tank of the cardioplegia heat exchanger device with the quartz sleeve and bulb projecting inwardly into the water tank.
