Ultimate pH values in the musculature of sheep ranging from 5.6-7.0 have been obtained by using pre-slaughter injectfens of epinephrine. A high speed centrifugal method was used to measure the water-hdding capacity of raw M. semitendinosus (ST), semimembranosus (SM) and biceps femoris (BF). Results showed a high corrdation with ultimate pH. Cooking losses end the amounts of centrifugally expressed juice were determined for the JM and BF cooked for 1 hr at either 65°C or 90°C. Cooking losses et 65°C decreased linearly with increasing pH while the losses at 90°C showed little change up to o raw meat pH of CQ. 5.9, then decreased linearly with increasing pH. The amount of juice centrifugally expressed from the cooked meat, which has a high positive correlations with orgondeptic juiciness, increased linearly with pff. Tenderness of the cooked SM and BF muscles was measured using o Warner-Bratzler shearing device and cm lnstron Universal Testing Machine: both gave high objective-subjective correlations. lnstron measurements have high negative linear correlations with ultimate pH for both the 65°C and 90°C cooked samples. Hardness of these muscles, cooked at 65°C or 90°C. decreased approximately three-fold 0s ultimate pH increased from 5.649.Results obtained using the Warner-Bratzler device showed linear regressions with a significant quadratic component for one muscle at both 65°C and 90~.

The tenderness of 12 beef muscles from animals of 8 different age groups (ranging from 1 to about 60 months old) which were treated to minimize pre-rigor myofibrillar shortening, have been assessed using objective and subjective methods. The mean tenderness of these 12 muscles significantly (p

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Abstract. This paper describes the methodology used for the collection of carcass yield and meat quality data from straightbred and crossbred cattle in the Cooperative Research Centre for Cattle and Beef Quality core program. IntroductionIn order to fulfil the aims of the Cooperative Research Centre for Cattle and Beef Quality (CRC), about 10 000 cattle needed to be slaughtered, processed, sampled and measured for a range of carcass and meat quality traits. Both pre-and post-slaughter treatments were standardised, to minimise confounding of genetic comparisons and management effects by variation in environmental factors. They were also designed to result in minimal animal stress and to avoid adverse post-slaughter processing effects on meat quality. Animals were slaughtered at commercial abattoirs. Due to the geographical spread and time span of CRC activities, several abattoirs were used.In this paper, details of the methodologies used in assessing, or measuring, the carcass and meat quality traits are described. Where specific deviations from these methods occurred, they will be detailed in papers using that data.

Abstract. The potential eating quality of beef is set by the intrinsic structural and compositional characteristics of muscle. However, the extrinsic factors that prevail during the production of the animal, slaughter and processing of its carcass and finally, cooking can produce changes in these structural and compositional characteristics that ultimately manifest as large variations in beef palatability. The conditions that apply in the 24-48 h immediately before and after slaughter are recognised as having the largest influence on beef palatability. This review specifically examines the critical pre-and post-slaughter factors and discusses their putative effects on biochemical and physical changes in muscle and the consequences to beef palatability. Areas for future research within this domain are also discussed.

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The effects on carcass bruising and muscle properties of the temperament scores of 170 bullocks and 240 cows (Brahman cross and Shorthorn) from 2 properties in northern Queensland were studied. Temperaments were scored by rating their behaviours when the cattle were handled in a crush and pound. High scores indicate poor temperaments. The bullocks and cows were respectively transported 740 and 1155 km to abattoirs and slaughtered 5-7 days after mustering. In both experiments, the estimated bruise trim per carcass increased by approximately 0.3 kg per unit increase in movement score for both temperament tests. Cattle with high temperament scores had more bruising along the back and around the tuber coxae and tuber ischii. Muscle samples from cattle with higher temperament scores tended to have higher mean initial yield and peak force shear values, thus indicating that their meat may have been less tender. Neither ultimate pH nor sarcomere length was related to temperament score.

Contributions to the structural strength of meat samples by the myofibrillar and connective tissue components were altered by varying the myofibrillar contraction state, muscle type and the cooking temperature. Shear, tensile and adhesion measurements were used to evaluate quantitatively changes in the properties of the samples. Detailed examination of shear and tensile force‐deformation curves suggested that the initial effect of shear, compression or tensile force was to produce a yield in the myofibrillar structure. After the initial yield, the applied force was probably resisted mainly by the connective tissue structure. Adhesion and tensile values showed changes which indicated a probable rearrangement of the collagen fibers in the connective tissue network as it adjusted to accommodate changes in the myofibrillar contraction state.