Abstract: An apparatus and related methods using photographic imaging and the interactions between light beams and dairy milk to provide in-line monitoring, analysis, and display of the quality of milk collected from dairy animals. The apparatus is robust in that it is reliable, simple to install, relatively small in size, cost effective, easily cleaned, and low maintenance. The apparatus can be installed directly in-line with the milk collection apparatus for each animal so as to measure the entire milk yield produced by that animal at flow rates typically used in milking parlours without requiring any unusual tube fittings or non-standard equipment. The apparatus is capable of handling analysis of a flow having mixed densities, air/liquid ratios, temperature variations, or any other similar variation of physical characteristics.