Causes for variation in pork quality

Research was carried out on 260 pigs that were slaughtered in 12 batches in the slaughter facilities of ID-DLO at Zeist. The practical circumstances were highly standardized. The 'animals' meat quality was good with only little variation; 46 animals showed a 'slightly' aberrant quality and 6 'slight' DFD. Carcasses within the quality categories 'PSE' and 'slight' PSE did not occur. Statistically significant effects on meat quality could be shown for the duration of the resting period before slaughter and the muscular contractions occurring while stunning, shackling and exsanguination, despite the minor variation in pork quality under standardization. A longer resting period before slaughter induced significantly lower temperatures in the m.semimembranosus and the loin at 45 min post mortem and a slightly higher ultimate pH, accompanied by a somewhat darker colour (24hr post mortem). A connection between the animal's behaviour at the fattening station and ultimate pork quality could not be shown. The same counts for fighting in the resting pen of the slaughter house and the pig's behaviour in the stunning area. Muscular contractions during and after stunning had a negative effect on pork quality, causing a more rapid drop in pH, a faster development of rigor mortis and a reduced water holding capacity. An imperfect electrical stunning procedure caused an increase in muscular contractions.