Quality of 'Semi-hot' and Cold Boned, Vacuum-packaged Fresh Pork as Affected By Delayed or Immediate Chilling

In 3 experiments, 53 Large White/Dutch Landrace pig carcasses with a normal rate of glycolysis, were selected from a commercial slaughterline. All carcasses were subjected to an initial 45 or 80 min period of blastchilling at -25°C. Subsequently of each carcass, one side was stored at 2±2°C to be cold boned and vacuum packaged after 24 h (n=53). The other sides were 'semi-hot' boned after a further 1 1/2-2 1/2 h equilibration period (i.e. at 4-5 h post mortem at loin-pH and -temperatures of approximately 5.9 and 14°C, respectively), and vacuum-packaged. The 'semi-hot' boned loin muscles were either conditioned for 4 h at 6-10°C before further chilling (n=27) or stored at 1 ± 1°C immediately (n=26) as were all other primals. Where assessed, total carcass yield (∑ fat, bone, meat) after 'semi-hot' boning was approximately 0.8% higher than after cold boning. After 12 days of vacuum storage major sensory quality traits of the loin and the bacteriological condition of the shoulder were assessed. Generally, neither time of boning nor delayed chilling affected sarcomere length, shear force, panel preference for tenderness, degree of sarcoplasmic protein denaturation, color (L-values) or percentage of drip in vacuum. The bacteriological quality of the 'semi-hot' boned and cold boned shoulders was similar. It is concluded that 'semi-hot' boning of pig carcasses does not appreciably affect sensory and bacteriological quality or pork. Furthermore, it appears that conditioning at high temperatures is not essential to improve tenderness of 'semi-hot' boned pork loins.