Assembly for treating food products with conditioned treatment fluids, comprising a first treatment device and a second treatment device, in which the first treatment device comprises: - a first housing which defines a first treatment space and is provided with a first inlet for introducing products to be treated into the first treatment space, and a first outlet for discharging treated products from the first treatment space, with the first treatment space being in open communication with the environment, - a first conveying means (16, 20) for conveying the food products from the first inlet through the first treatment space to the first outlet, the first conveying means (16, 20) between the first inlet and first outlet following a first helical conveying path comprising several turns one above the other, - first circulation means for circulating a first treatment fluid through the first treatment space, - first conditioning means (56, 57) for conditioning the first treatment fluid, wherein the second treatment device comprises: - a second housing which defines a second treatment space and is provided with a second inlet for introducing products to be treated into the second treatment space, and a second outlet for discharging treated products from the second treatment space, with the second treatment space being in open communication with the environment, - a second conveying means (26,120) for conveying the food products from the second inlet through the second treatment space to the second outlet, the second conveying means, between the second inlet and second outlet following a second helical conveying path with several turns one above the other, - second circulation means for circulating a second treatment fluid through the second treatment space, - second conditioning means (156, 157) for conditioning the second treatment fluid, with the first outlet of the first treatment device and the second inlet of the second treatment device being connected to one another by a connecting duct through which a conveying means for conveying the food products travels, characterized in that the connecting duct extends through the first housing and through the second housing with the ends (64, 66) of the connecting duct being positioned in the first and second treatment space (18, 118), respectively, at a position where the pressure, during operation, is always substantially identical when circulating the treatment fluid in the treatment space, irrespective of any difference in circulation speed of said treatment fluid, and in that said ends (64, 66) of the connecting duct are positioned in the first and second treatment space (18, 118), respectively, in such a manner that there is essentially no pressure difference between the end of the connecting duct in the first treatment space and the end of the connecting duct in the second treatment space during operation and thus little flow of treatment fluid through the duct. - a first housing which defines a first treatment space and is provided with a first inlet for introducing products to be treated into the first treatment space, and a first outlet for discharging treated products from the first treatment space, with the first treatment space being in open communication with the environment, - a first conveying means (16, 20) for conveying the food products from the first inlet through the first treatment space to the first outlet, the first conveying means (16, 20) between the first inlet and first outlet following a first helical conveying path comprising several turns one above the other, - first circulation means for circulating a first treatment fluid through the first treatment space, - first conditioning means (56, 57) for conditioning the first treatment fluid, - a second housing which defines a second treatment space and is provided with a second inlet for introducing products to be treated into the second treatment space, and a second outlet for discharging treated products from the second treatment space, with the second treatment space being in open communication with the environment, - a second conveying means (26,120) for conveying the food products from the second inlet through the second treatment space to the second outlet, the second conveying means, between the second inlet and second outlet following a second helical conveying path with several turns one above the other, - second circulation means for circulating a second treatment fluid through the second treatment space, - second conditioning means (156, 157) for conditioning the second treatment fluid, with the first outlet of the first treatment device and the second inlet of the second treatment device being connected to one another by a connecting duct through which a conveying means for conveying the food products travels, characterized in that the connecting duct extends through the first housing and through the second housing with the ends (64, 66) of the connecting duct being positioned in the first and second treatment space (18, 118), respectively, at a position where the pressure, during operation, is always substantially identical when circulating the treatment fluid in the treatment space, irrespective of any difference in circulation speed of said treatment fluid, and in that said ends (64, 66) of the connecting duct are positioned in the first and second treatment space (18, 118), respectively, in such a manner that there is essentially no pressure difference between the end of the connecting duct in the first treatment space and the end of the connecting duct in the second treatment space during operation and thus little flow of treatment fluid through the duct.