Methods of determining the quality of milk due to the presence of
mastitis, by monitoring the concentration of various ions, and ratios of
those ions, in the milk. As the level of mastitic infection progresses,
the concentrations of sodium and chloride ions increase and the
concentrations of potassium and calcium ions decrease. A ratio of sodium
to potassium is more sensitive to infection detection than either ion
concentration alone. Similarly, sodium to calcium, chloride to potassium
and chloride to calcium is more sensitive than any of the ions alone.