THE USE OF A HIGH-PRESSURE WATERJET COMBINED WITH ELECTROIMMOBILIZATION FOR THE STUNNING OF SLAUGHTER PIGS - SOME ASPECTS OF MEAT QUALITY

It is considered that waterjet stunning may be a humane stunning metho d to apply in slaughter facilities. An experiment was conducted in a s laughter-house to examine the effects of waterjet stunning combined wi th electroimmobilization during exsanguination on the occurrence of ha emorrhages in the muscles and on meat quality. Slaughter pigs (n = 31) were stunned by waterjet (3900 bar) in a V-type restrainer and immobi lized electrically (40 V) during exsanguination. Control animals (n = 39) were stunned automatically and electrically (600 V) using the same restraint device. At 45 min post mortem the pH in the semimembranosus (SM) and longissimus dorsi (LD) muscles was significantly lower (p < 0.01), while rigor mortis and temperature in the SM and LD were signif icantly higher (p < 0.05 and p < 0-01, respectively) in the carcasses of pigs stunned with the waterjet as compared to control pigs. At 18 h post mortem the ultimate pH of the LD was lower (p < 0-05), while sca tter (fibre optic probe) and filter paper test values of the LD were h igher (p < 0.01) in carcasses of pigs stunned with the waterjet. Fewer haemorrhages were observed in the shoulders of pigs stunned with the waterjet. The results of this experiment suggest that waterjet stunnin g, when combined with electroimmobilization, may be a suitable method to stun pigs in a slaughterhouse. However, further studies are require d to improve the meat quality.