POTENTIAL INTERACTIONS BETWEEN THE EFFECTS OF PRESLAUGHTER STRESS AND POSTMORTEM ELECTRICAL-STIMULATION OF THE CARCASSES ON MEAT QUALITY IN PIGS

The experiment examined the influence on pork quality of the electrical stimulation of carcasses from pigs subjected to different ante-mortem handling treatments. The carcasses were subjected to a slow chilling regimen to reflect less than ideal commercial practice. A total of 288 pigs (mean live weight 89 kg) of both sexes and a range of genotypes were used. They came from the Meat and Livestock Commission's Pig Development Unit at Stotfold and were processed in 12 equal batches. Prior to slaughter they were transported for 2 h (80 km) at a stocking density of 0. 5 m(2)/100 kg live weight. Preslaughter handling included being mixed or nor with unfamiliar animals and being given a 3 h rest in lairage or not. One group received handling to simulate that in stunning races immediately before slaughter. There were no material interactions between the effects of ante- and post-mortem handling. Pigs rested 3 h in lairage had lower plasma cortisol levels irrespective of whether mixed with unfamiliar animals. Plasma lactate concentrations increased with greater ante-mortem stress. Pigs subjected to the simulated stunning race treatment had elevated carcass temperature Greater ante-mortem stress progressively elevated pHu in the muscles and tended to reduce eating quality. Electrical stimulation followed by slow chilling raised initial muscle temperature, reduced pH,, and pHu, and produced meat that was paler, had higher hue and saturation values and lost move drip during storage. Neither instrumentally-determined texture nor taste panel texture was affected, but electrical stimulation decreased juiciness and increased pork flavour. Overall eating quality was not affected by stimulation.