Monitoring Quality Loss of Pasteurized Skim Milk Using Visible and Short Wavelength Near-Infrared Spectroscopy and Multivariate Analysis

Representative visible and short wavelength near-infrared spectral patterns (600 to 1,100nm) of control (t=0h) and milk samples stored at 6, 21, and 37°C for t=3 (A), 8 (B), and 30h (C).

Representative second-derivative transformation of spectral patterns for control (t=0h) and milk samples stored at 6 (A), 21 (B), and 37°C (C) for t=3, 8, and 30h.

Principal components analysis for control (t=0h) and pasteurized milk samples stored at 6 (A), 21 (B), and 37°C (C) for t=3, 8, and 30h.

Soft independent modeling of class analogy classification of control (t=0h; A) compared with milk samples stored at 6 (B), 21 (C), and 37°C (D) at t=30h.

Comparison of the measured with predicted bacterial count (log₁₀ aerobic plate count cfu/mL) for a partial least squares model (5 latent variables): control (t=0h; A) and milk samples stored at 6 (B), 21 (C), and 37°C (D) for t=30h.

Comparison of the measured and predicted pH for a partial least squares model (5 latent variables): control (t=0h; A) and milk samples stored at 6 (B), 21 (C), and 37°C (D) for t=30h.