CO2 stunning procedure on Manchego light lambs: Effect on meat quality

This study examined the effect of different gas stunning methods (concentration of CO2/time of exposure (G1: 80%90s; G2: 90%90s; G3: 90%60s; G4: 80%60s) on the initial meat quality of Manchego breed light lambs (25 kg live weight) and at 7 days post-mortem, assessed by pH, colour coordinates, water holding capacity (WHC), cooking loss (CL), drip loss (DL) shear force (SF) and lipid oxidation. An electrically stunned control group (G5) was used. Stunning method had a significant effect on pH values (P < 0.001) as well as on pH decline (P < 0.01). The lowest pH was found at 24 h post-slaughter in G1 and the highest one on G5. The greatest drop in pH (pH0–pH24) was found in G1 and G5 while the smallest in G3. In general values of colour coordinates, WHC and DL were similar in all groups. Stunning method affected CL (P < 0.001) at 7 days post-slaughter, with the lowest values being found in G1. Significant differences among groups were found (P < 0.05) in SF values at both post-mortem times, with less tender meat in groups stunned with 80% CO2, especially in G1. A significant effect (P < 0.001) due to the type of stunning was found at 24 h on lipid oxidation, with the highest value in G5. After ageing this parameter was lowest (P < 0.05) in G1 and G4.