Effect of indigenous slaughter methods on post-mortem gycolytic potential and shelf-life of goat meat

Abstract

The objectives of the study were to determine the effect of Transverse neck incision (TNI), Suprasternal notch piercing (SNP), and the under shoulder blade piercing at the chest floor point of the elbow (CFP) to the direction of the heart methods of slaughter treatments on post-mortem glycolytic metabolites and shelf-life properties of muscle tissue. A total of 18 non-descript male castrate goats which are a common type of goat found in villages across South Africa (averaging 16.8 ± 1.84 kg) with live weights ranging between 18 and 21 kg, and sixteen months of age, were stratified based on live weight and randomly assigned into the TNI, SNP, and CFP slaughter treatments (6 goats/treatment). Goats were slaughtered with TNI, SNP, and CFP based on their treatment group and the Musculus longissimus thoracis et lumborum (LTL) was sampled at post-mortem for muscle tissue glycolytic potential, glycogen, lactate levels, ultimate pH, and colour measurements. Overall, the TNI, and CFP slaughter treatment had lower muscle tissue ultimate pH in addition to higher glycolytic potential, glycogen, lactate levels, redness (a*), yellowness (b*), and chroma (C*) values. The TNI and CFP slaughter treatments had higher glycolytic potential, glycogen, and lactate levels, consequently, improving the physicochemical properties of muscle tissue. Overall, the slaughter technique did not influence (P ≥ 0.05) muscle tissue pH. Muscle tissue redness (a*) decreased over time, being highest (P ≤ 0.05) at day 0, followed by day 7 (P ≤ 0.05), and 14, respectively. Muscle tissue yellowness (b*) decreased (P ≤ 0.05) over time being highest for the CFP (P ≤ 0.05) on day 3, followed by the TNI and SNP (P ≤ 0.05) at day 7, and CFP (P ≤ 0.05) on day 11, respectively. Muscle tissue lightness (L*) decreased over time, being highest at day 0, followed by day 11, and day 3 being the lowest, respectively. The shelf-life of muscle tissue from goats slaughtered with TNI was longer compared to the SNP and CFP slaughter treatment.