A valve of cleanable design capable of maintaining unfavourable conditions for microbial activity on the downstream side and/or outlet of the valve, said valve comprising: A smooth and contoured body (5) with an integral upstream connector (1), downstream connector and defined fluid flow path; a flexible sealing membrane (9) being: (i) selectively moveable into contact with the valve body to close the valve; (ii) selectively moveable out of contact with the valve body to open the valve; (iii) selectively operable to a range of positions to vary the flow rate of fluid through said valve; a defined internal shape that allows the fluid to drain out of the valve body; an elongated heater (7) secured into the valve body in a location so as not to be contact with the fluid or disrupt the internal smooth and contoured body, the heater being operative to heat the valve body to a predetermined temperature.