An item packing system configured to sort and/or pack items into item containers, the system comprising a robotic arm. At least one end effector for holding and manipulating an item to be sorted and/or packed, wherein at least one end effector comprises a pressure sensing assembly. A controller configured to receive sensor signals from the pressure sensing assembly to obtain an indication of a magnitude of contact pressure for contact between the end effector and the item held by the end effector. A direction of contact pressure for contact between the end effector and the item held by the end effector, wherein the controller is configured to determine whether the end effector is correctly holding the item based on the indication of the magnitude of the contact pressure and the indication of the direction of contact pressure.