The effect of stunning method on the incidence of PSE meat and haemorrhages in pork carcasses

Two commercial Dig abattoirs (A and B) equipped with a head-only and head-t o-chest electrical stunning systems, and two (C and D) equipped with compac t carbon dioxide (CO2) stunning systems, were visited during 3 days to eval uate the effects of the stunning system on meat quality and haemorrhages. M eat quality was evaluated by measuring muscle electrical conductivity (PQM) and colour (Minolta Chromameter) at 2 and 7 h post mortem (abattoirs A and C, and B and D, respectively). PQM and colour were measured in 2486 and 23 21 loins respectively. Also ultimate pH (pHu) was measured in 2395 loins at 24 h post mortem. Haemorrhages were evaluated by recording the incidence o f petechiae, ecchymosis and haematomas, bone fractures were also recorded. A total of 1980 shoulders, 3943 loins, and 5438 hams were inspected. In the abattoirs equipped with the electrical stunning systems, a higher (P < 0.0 5) incidence of potentially PSE meat (PQM > 6) was found compared with the abattoirs equipped with CO2 stunning. Likewise, the loins From electrically stunned pigs were paler than those from CO2 stunned pigs (P < 0.05). Elect rical stunning increased the incidence of petechiae in the loin and the ham (P < 0.05). No shoulder, loin or ham with bone fractures was found in the abattoirs studied. Therefore, CO2 stunning reduces the incidence of PSE mea t and or petechiae on muscle fascia of loins and hams, compared with electr ical stunning. However, petechiae are not of great importance because they can be removed from the affected commercial cuts. (C) 2000 Elsevier Science Ltd. All rights reserved.