Abstract: A system for continuous pasteurizing of liquid foods is provided which includes the ability to clean the pasteurizing system in place without the need for manual connection and disconnection of piping. The system includes a supply of liquid food product, a source of water, a heat exchanger section for heating the liquid food product, a balance tank for maintaining desired flow to the heat exchanger during fluctuations in demand, and at least one mixproof valve connected to the water source and liquid food supply for delivering one or the other, without risk of intermixing, upstream of the balance tank. The system also discloses the use of a mixproof valve for delivering clean in place solution to the balance tank while preventing the flow of liquid food into the clean in place solution source.