Analysis of cheese using step-scan Fourier transform infrared photoacoustic spectroscopy

The potential of Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) for examination of food and the package was demonstrated. Full-fat cheddar cheese slices wrapped in polymer package were chosen as the food sample for analysis. Photoacoustic spectroscopy (PAS) in conjunction with the step-scan and digital signal processing (DSP) function was used to perform depth-profiling studies of the intact sample and package. Well-separated PAS bands of fat and protein were obtained in the spectra of cheddar cheese samples with minimum sample preparation. Cheese samples were kept in a dessicator overnight to minimize the effect of moisture on the PAS spectra. Depth profiling study of the cheese polymer package indicated that there is a diffusion of cheese components into the package during storage.