Early on-line classification of beef carcasses based on ultimate pH by near infrared spectroscopy

Prediction of ultimate pH (measured 48 h post mortem; pHu) in beef from Visible–near infrared (VIS–NIR) spectra collected 20 to 40 min post mortem was assessed. Spectra were collected from carcasses (cows: n = 86, bulls: n = 170, steers: n = 363, and heifers: n = 38) in a commercial hot boning abattoir under routine conditions. Partial Least Squares (PLS) models showed limited accuracy with RMSE for validation equal to 0.26, 0.20 and 0.36 for the All-animals, Non-bulls and Bulls models, respectively. The pHu–PLS-predicted values were used to segregate carcasses as normal (pHu < 5.8) or high (pHu ≥ 5.8) showing better performance, by correctly classifying at least 90% of high pHu carcasses. The Non-bulls model was equivalent to the current technology used in the abattoir to classify carcasses based on pHu. Thus near infrared spectroscopy (NIRS) could be used for on-line classification of beef carcasses based on pHu.