Apparatus comprising a hygienic cooling system and method

A system comprising an apparatus for mixing a liquid or pasty product, the apparatus comprising a housing, said housing comprising an inlet for the liquid or pasty product to be mixed and an outlet for the mixed liquid or pasty product, and at least one set of a rotor and a stator for mixing the liquid or pasty product,

• the apparatus comprising at least a first housing part and a second housing part,
• the first housing part being assembled to the second housing part,
• the assembly of the first housing part and the second housing part forming a housing inner space between the inlet and the outlet where the liquid or pasty product flows,
• the assembly of the first housing part and the second housing part forming a cooling jacket for circulation of a coolant fluid around the housing inner space, and
• the assembly of the first housing part and the second housing part forms a buffer jacket for circulation of a clean fluid, the buffer jacket being formed between the cooling jacket and the housing inner space, wherein the system further comprises:
• a source of coolant fluid providing cooling fluid to the cooling jacket;
• and
• a source of clean fluid providing clean heat-conducting fluid to the buffer jacket.