A preliminary study using Fourier transform near infrared spectroscopy to monitor the shelf-life of packed industrial ricotta cheese

Ricotta cheese is a dairy product characterised by a short shelf life. The aim of this study was to monitor changes occurring during storage of packed industrial ricotta cheese using a simple and fast method. Several samples of manufactured ricotta cheese were monitored during storage at three different temperatures (3, 10 and 20 degrees C). Spectral data were collected over the range 12000 to 4400 cm(-1) using a Fourier transform near infrared (FT-NIR) spectrometer fitted with an optic fibre working in diffuse reflectance. Some chemical and rheological parameters were also measured. Principal component analysis (PCA) was applied as an exploratory chemometric technique to each one of the three sets of data (FT-NIR, chemical and rheological data) and a calibration model between the NIR data set and chemical and rheological indices was developed by means of partial least squares regression. The PCA results showed in all cases the influence of the storage temperature on the shelf life trend and were able to identify a critical day of shelf life for each storage temperature.