A model based on enzyme kinetics was developed to predict differences in postmortem pH change in beef muscles as affected by cooling rate. For the calibration and validation of the model, pH and temperature measurements were conducted at different positions in following conventional carcass cooling or faster cooling of the muscle after hot boning. The glycogen conversion, and, hence, the pH fall, was observed to significantly vary with position and cooling regime but only during the initial hours of cooling. Comparison of the cooling regimes indicated that fast cooling following hot boning avoids heat shortening induced by the combined effect of high temperature and low pH.

The objective of this study was to evaluate the influence of two different vacuum ageing times (7 and 14days) and the impact of the modified atmosphere packaging (MAP) configuration (gas/product ratios: 0.5 and 1 and gas composition: 70% O-2 + 30% CO2 and 40% O-2 + 30% CO2 + 30% N-2) on the quality of fresh beef during subsequent storage at 4 degrees C. For this purpose, three separate experiments were performed. For each experiment, two different muscles (Longissimus dorsi and Biceps femoris) were sampled from four double-muscled Belgian Blue beef carcasses. Next to colour, also the evolution in microbial load, pH, O-2 and CO2 in the headspace and lipid oxidation at the meat surface were evaluated. A vacuum ageing for 14days compared with 7days resulted in a higher initial microbial load on the day of MAP packaging, which resulted finally in a significantly shorter shelf life. This ageing effect was less pronounced on the colour stability and lipid oxidation of the meat samples. No significant influence of the packaging configuration on any of the analysed parameters (colour, microbial load, pH and lipid oxidation at the meat surface) was observed

Destructured zones in the core of cooked ham are associated with PSE in terms of biochemical characteristics. In this study, the potential of near-infrared spectroscopy (NIRS) to predict the suitability of fresh pork for the production of cooked ham was investigated. Using NIR spectra obtained in a first trial (inducing PSE characteristics in Longissimus thoracis et lumborum (LTL) muscles) and in a second trial (collecting Semimembranosus (SM) samples either with or without presence of visual PSE characteristics) resulted in 93.3 and 90.0 % correct classification after crossvalidation for respectively the LTL and SM samples. In a third experiment, 48 fresh hams were processed to highquality cooked hams, sliced, and visually classified as inferior or normal quality (i.e., presence or absence of destructured zones, respectively). Measuring NIR spectra on the Biceps femoris (BF) muscle after deboning resulted in a 56.5 % correct classification after cross-validation for inferior-quality hams. It can be concluded that NIRS has potential to discriminate PSE from normal pork.

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