W. 2012. Effects of low-voltage electrical stimulation and aging on lamb meat quality. Can. J. Anim. Sci. 92: 59Á66. The aim of this study was to evaluate the effect of electrical stimulation (ES) and aging time on meat quality of heavy lamb as produced in Quebec. Seventy-six Suffolk-sired crossbred male lambs were slaughtered at a target weight of 5092 kg. Half of them were electrically stimulated (ES vs. control) at 5Á10 min postmortem (21 V; 0.25 A; 60 s). Postmortem pH decline and temperature were monitored. After carcass cutting, longissimus dorsi sections were assigned to aging periods of 1, 3 or 8 d. Temperature decline was the same for both treatments (P00.749). However, ES carcasses always had a lower pH value than controls during the first 24 h (P B0.001) while the ultimate pH was equivalent (P 00.803). Tenderness, as assessed by either Warner-Bratzler shear force (39 carcasses) or sensory evaluation (35 carcasses) was enhanced by both ES (P B0.001) and aging (PB0.001). At each aging time, tenderness was greater for ES meat. In addition, only 3 d of aging were necessary for ES meat to achieve the tenderness level attained by the controls after 8 d. Sarcomeres were longer (PB0.001) in ES meat than in controls while myofibrillar fragmentation index was not affected by ES treatment (P 0 0.743). Electrical stimulation also had small effects on color parameters (a*, b* and L*; PB0.01) and flavor (P00.04). These results provide the first evidence that tenderness of the meat from heavy lambs produced and processed in Quebec could be enhanced by ES, mostly through cold shortening reduction.

W. 2014. Use of electrical stimulation and chilling to enhance meat tenderness of heavy lambs. Can. J. Anim. Sci. 94: xxxÁxxx. The aim of this study was to determine if electrical stimulation and chilling can modulate pre-rigor pHÁtemperature dynamics in order to enhance meat tenderness of heavy lambs produced in Quebec and determine if there is an optimum carcass temperature window to reach pH 6.0. A total of 128 heavy lambs (fasted body weight between 38 and 52 kg) were selected at the abattoir over 8 slaughter days (16 lambs d Á1 ) and assigned to four processing treatments in a 2 )2 factorial design: electrical stimulation (ES) or not (NES) and normal (NC) or slow (SC) chilling. Slow-chilled carcasses stayed warmer during the first 12 h postmortem (PB0.001), but reached the same temperature as NC ones thereafter. They also had a lower pH between 2 and 12 h (PB0.05). Stimulated carcasses had a lower pH than NES throughout the first 24 h postmortem (PB0.001), while ultimate pH was similar (P00.738). Shear force values were improved (PB0.001) by both ES and aging as expected, although chilling had no effect (P 00.400). Stimulation )aging interactions for shear force values (P 00.019) and myofibrillar fragmentation index (P 00.097) indicate that aging began earlier following ES. Sarcomeres were longer for ES compared with NES carcasses (P B0.001) indicating that the latter were subject to cold shortening. Meat from NES carcasses was more prone to be tough, although an important part of NES carcasses provided tender meat. This illustrates the importance of individual variations on tenderness and the multiplicity of factors involved in its development. No optimal window was observed for temperature at pH 6.0.