Using visible or near infrared spectroscopy (NIRS) on cheese to authenticate cow feeding regimes

An experiment was conducted to evaluate the ability of two spectroscopy methods to distinguish between pasture and preserved-forage cheeses. The reflectance spectra of 308 fresh and freeze-dried samples of cow's milk cheeses were recorded at wavelengths in the range of the visible, using a portable MINOLTA CM-2002 spectrophotometer. The reflectance spectra of the same samples were also measured in near infrared range using a non-portable laboratory monochromator NIRSystem 6500. The proportion of cheeses correctly classified by NIRS and visible spectra was respectively 0.96 and 0.91 for pasture samples, and 0.96 and 0.79 for preserved-forage samples. No significant differences were found when fresh and freeze-dried cheeses were compared. We conclude that NIRS is able to classify cheese samples from different regimes (here, pasture vs. preserved-forage).