Calcium Injection

It has recently been reported that inconsistency in meat tenderness is a major quality defect in our current beef production systems (Morgan et al., 1991 b). A major part of this concern is the large variation in tenderness, especially the occurrence of tough meat, in beef and beef cuts classified by the grading system as being tender (i.e. Choice). USDA quality grades were designed to segment beef carcasses based on various levels of expected meat palatability. However, the goal of the beef industry should be to produce 100% desirable meat, and not have to identify meat that has unacceptable tenderness to consumers. Experiments involving the role of the calpain proteolytic system in post-mortem tenderization (Koohmaraie et al., 1988a) led to the discovery that elevating the calcium concentration of muscle by infusing calcium chloride immediately post-mortem would result in maximizing tenderization by 24 h post-mortem (Koohmaraie et al., 1988b, 1989, 1990). The initial work involved infusing lamb carcasses immediately postmortem with 300 mM CaCI, at 10% of live weight. The utility of this process for improving meat tenderness was demonstrated in specific situations where tough meat was expected: Brahman crossbred steers (Koohmaraie et al., 1990), P-adrenergic agonist-fed sheep (Koohmaraie and Shackelford, 1991), and 12 to 17-yr old cows (Morgan et al., 1991b). Wheeler et al. (1991) have extended this work by demonstrating that the use of calcium chloride in combination with hotboning will improve tenderness of round muscles from Bos indicus cattle. This early work had clearly shown that 300 mM CaCI, infused or injected at 10% by weight into prerigor meat results in accelerated and accentuated tenderization, such that all tenderization had occurred by 24 h post-mortem. It was recognized that this process had potential for commercial application to ensure desirable tenderness in the beef industry. Subsequent studies were designed to modify the process for industry application. Carcass infusion of calcium chloride is too time-consuming and would likely create problems for USDA inspection and grading procedures. Prerigor injection of calcium chloride in meat could be used in conjunction with hot-boning or in intact carcasses, but would be difficult to implement in normal slaughtering procedures. Morgan et al. (1991a) indicated that the average length of postmortem aging before meat becomes available in a retail store