A method is disclosed for generating data relating to the quality of product in a bulk stream product during its passage through a monitoring station. An inspection of at least a portion of product in the monitoring station is conducted at intervals while the stream is owing. The inspectors identities individual product pieces in the portion being inspected by using one or more of various techniques. Those individual pieces are then examined according to chosen criteria, and a measure is established of the quantity or proportion of such individual product pieces that fail to meet those criteria. The data generated by these inspections can be analysed to provide an indication of the quality of the bulk stream.