The nutritional quality of milk lipids is determined by a method for predicting percentages of minor fatty acids in milk. A database is created by correlating known fatty acid profiles of reference milk samples obtained by gas phase chromatography to mid-infrared spectra to obtain calibrations, wherein the calibrations vary in accuracy from one fatty acid to another. The determination of a milk fatty acid profile to be analyzed through infrared treatment is limited to some fatty acids with a satisfactory calibration. Equations to predict the percentages of minor fatty acids are developed using correlations of fatty acids with satisfactory calibrations.