International audienceIn dairy industry, the mastering of membrane fouling and cleaning remains a bottleneck of membrane processes especially for aged and degraded membranes. This paper reports an in-depth study of the impact of membrane chemical ageing due to NaOCl disinfection on the fouling and cleaning of PES/PVP membranes.Fouling by skim milk was performed at critical and limiting flux found to have an impact on the initial irreversible fouling, i.e. the one remaining after water rinsing. Furthermore, for filtrations performed with pristine membranes, the fouling removal by formulated alkaline detergents was also affected by the filtration conditions.On the contrary, aged membranes were highly irreversibly fouled whatever the operating...