The invention provides a method for the continuous, microbe-reduced production and/or processing of a biopharmaceutical, biological macromolecular product from a heterogeneous cell culture-fluid mixture, comprising the steps of: (a) providing a particle-free fluid from a heterogeneous cell culture-fluid mixture containing the product, in the form of a product stream, (b) at least one filtration, providing a filtrate, (c) at least two chromatography steps for purifying the product, (d) at least one virus depletion, (e) at least one ultrafiltration and/or at least one diafiltration of the product stream of steps (b), (c) and/or (d), characterized in that the at least two chromatography steps from (c) comprise a purification via at least two chromatography columns and/or membrane adsorbers in each case and that the process is carried out in a closed and modular manner The invention further provides a corresponding modular system for carrying out said method.