Effect of carcass electrical stimulation on sheep and goat meat quality: a meta-analysis study

Abstract

Context The utilization of electrical stimulation (ES) in small ruminant carcasses is less common than in beef processing facilities. Nevertheless, ES shows promise in mitigating cold shortening and improving meat quality traits in small ruminants. Aim This meta-analysis assessed how ES applied to carcasses influences meat quality parameters in sheep and goats. Methods To evaluate the effect of ES on small ruminant carcasses, two datasets were created: sheep (21 peer-reviewed publications, 53 treatment means) and goats (8 publications, 27 treatment means). The effects of ES were assessed using weighted mean differences (WMD) between stimulated and control carcasses. Heterogeneity was examined through meta-regression and subgroup analysis considering animal age, slaughter method, stimulation timing, ES duration, and ES system. Key results In goats, ES enhanced proteolysis, increasing the myofibrillar fragmentation index (5.74%; P < 0.0001) and sarcomere length (9.32%; P < 0.0001). Low-voltage ES (50–150 V) reduced pH (WMD = −0.16; P < 0.0001) and shear force (WMD = −2.29 kgf/cm2; P < 0.0001), while increasing L* (WMD = 3.02; P = 0.001) and tending to reduce a* (WMD = −1.24; P = 0.055). In sheep, medium-voltage ES (150–500 V) reduced pH (WMD = −0.06; P = 0.041) and shear force (WMD = −0.51 kgf/cm2; P = 0.046), while improving color traits: L* (WMD = 1.27; P < 0.0001), a* (WMD = 1.18; P = 0.002) and b* (WMD = 0.75; P = 0.002). Conclusion Overall, reductions in pH and shear force in both species suggest improvements in instrumental tenderness, a key determinant of sensory quality and consumer acceptance. Sheep also showed enhanced color parameters, which may increase visual appeal and marketability. Notably, ultralow-voltage ES (<50 V) applied to goat carcasses reduced pH and shear force while increasing sarcomere length, without compromising color, suggesting potential benefits at minimal energy input. Implications ES affects goat and sheep meat quality differently, indicating that species-specific stimulation protocols may be needed to optimize its benefits.