Post-mortem processing of export beef in Costa Rica

Eighteen intact male beef animals of 2 1 2 to 3 years of age, weighing 400-425 kg and fed entirely on rangelands grass, were slaughtered in a Costa Rican export plant. Six animals each were assigned to: low-voltage stimulation (75V), high-voltage stimulation (350V) and control. Hot-boning coupled with various chilling rates was also investigated. Mean muscle pH values for all treatment groups were above 6·4 at 1 1 2 h after slaughter, which may be related to the fact the animals were intact males which had been exposed to stressful conditions prior to slaughter. Palatability traits measured were tenderness, juiciness, flavor and overall desirability. With the exception of tenderness, there were no significant differences among electrical stimulation or chill treatments, and there were no interactions. The low-voltage electrical-stimulation treatment produced less tender meat (P<0·05) than the high-voltage treatment, but there was no significant difference compared to the control. In an attempt to explain the finding that electrical stimulation had little or no effect on tenderness, the data were inspected in regard to ultimate pH. The panel score for samples with an ultimate pH less than 6 was 3·27, and for samples with a pH higher than 6 it was 5·70. A possible explanation is to suggest that the high-pH group underwent appreciable neutral proteolytic enzyme activity compared to the low-pH group.