Quality, palatability and weight loss of pork as affected by electrical stimulation

Forty-five swine (n = 15, stress-susceptible pigs, fasted for 18 h; n = 15, normal pigs, fasted for 48, 60 or 72h; n = 15, normal pigs, fasted for 18 h) were slaughtered. One side of each pig was electrically stimulated (ES)-550 V, 2-6 A, seventeen impulses, 1·8 s on and 1·8 s off per impulse-and the opposite side was not stimulated (NS). Ham and loin temperatures were monitored at 12 and 24 hours post mortem. Carcass quality-marbling, loin eye colour, loin eye firmness, subcutaneous fat firmness and belly firmness-was evaluated at 24 hours post mortem. Sides were fabricated into four lean cuts at 48 hours; cuts were placed on open metal racks in a 2°C cooler and weight loss was measured after 24, 48 and 72 hours storage. At 120 hours post mortem, loin chops were cut, frozen (-24°C for 45 days) and subsequently used to determine thaw loss, cooking loss, Warner-Bratzler shear (WBS) force and palatability. Ham temperatures (12 h) were significantly (P < 0·05) lower for the ES sides from the stress-susceptible, short-fast (SSF) group but not for normal, long-fast (NLF) or normal, short-fast (NSF) groups. ES produced lighter coloured, softer loin eyes in the SSF group but darker coloured, firmer loin eyes and firmer subcutaneous fat in the NLF group. No significant differences (P > 0·05) were detected for thaw loss, cooking loss, palatability ratings or WBS values between ES and NS in the SSF group but chops from ES sides of NLF animals had significantly (P < 0·05) higher ratings for muscle fibre tenderness, overall tenderness and overall palatability. Weight losses of the lean cuts from the ES sides were higher (P < 0·05) than those from NS sides in only three of sixty comparisons of cuts from the three groups of swine. These data suggest that ES had very minimal effects on quality, palatability or weight loss of pork.