The present invention relates to a fluid cooling system (1), for use in dispensing or distributing a chilled or cooled fluid, comprising a primary heat exchanger system (2), a secondary heat exchanger system (3), a first conduit (9) through which fluid to be cooled or chilled is circulated, and a heat transfer agent (8) for transferring cooling energy to the fluid to be chilled circulating in the first conduit (9), wherein the primary and secondary heat exchanger systems (2, 3) are arranged at least partially one inside of another The invention also relates to cooled fluid dispensers incorporating the fluid cooling system and a methods for sterilization thereof.