Effect of stun duration and current level applied during head to back and head only electrical stunning of pigs on pork quality compared with pigs stunned with CO2

The effect of current, duration and method of application of manual electrical stunning on pork carcass and meat quality attributes in comparison with stunning pigs with CO2 was investigated. Two experiments were conducted using a total of 96 Large White×Landrace boars (homozygous dominant for the halothane gene). In Experiment 1, 48 pigs were allocated to one of six stunning treatments: CO2 (90% in air), electrical stunning (ES) using head only (HO) tongs delivering current at a frequency of 50 Hz at 1.3 or 2.0 A for 4 s and 0.9, 1.3 or 2.0 A for 19 s. Higher drip loss occurred in M. longissimus thoracis et lumborum (LTL) muscles from ES pigs, except those stunned with 0.9 A for 19 s, compared with pigs stunned with CO2. The incidence of pale, soft exudative (PSE) meat was higher in ES pigs, except those stunned at 1.3 A for 4 s, compared with CO2 stunned pigs. In Experiment 2, 48 pigs were allocated to one of six stunning treatments: ES using a head to back (HB) handpiece delivering current at 1.3 or 2.0 A for 4 s and 0.9 or 1.3 A for 10 s; HO 1.3 A for 4 s or CO2. Although stunning treatment did not influence ultimate pH, muscle lightness, tenderness or cooking loss, drip loss and PSE incidence in LTL muscles from CO2 stunned pigs were lower compared with ES pigs. Overall, ecchymosis and bone fractures were more prevalent in ES pigs compared with CO2 stunned pigs. This research identified that stunning pigs with CO2 compared with manual ES lowered the incidence of bone fractures, ecchymosis, PSE and drip loss of pork.