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Quality of lamb meat from the Information Nucleus Flock

Warner, R.D., Jacob, R.H., Hocking-Edwards, J.E., McDonagh, M., Pearce, K.L., Geesink, G.H., Kearney, G.A., Allingham, P., Hopkins, D.L. and Pethick, D.W.ORCID: 0000-0002-3255-7677 (2010) Quality of lamb meat from the Information Nucleus Flock. Animal Production Science, 50 (12). pp. 1123-1134.

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The effects of production and processing factors on tenderness, and colour of lamb meat produced from 7 locations as part of the Australian Sheep Industry CRC's Information Nucleus flock were investigated, using data from 2052 lambs slaughtered in 2007. At 24 h post-slaughter, samples of m. longissimus lumborum(LL) and m. semimembranosus (SM) were collected for measurement of intramuscular fat (IMF), myoglobin, iron and copper and fresh meat colour (L*, a*, b*) and pH at 24 h measured on the LL. pH and temperature measurements made pre-rigor were used to calculate the pH at 18 degrees C. Tenderness was measured by LL shear force at days 1 (SF1) and 5 (SF5) post-slaughter, the shear force difference (SF-diff) and SM compression and collagen concentration were determined. Retail colour stability was assessed using over-wrapped LL under simulated retail display for 3 days, according to the change in the oxymyoglobin/metmyoglobin ratio. All traits were affected by flock and date of slaughter (P < 0.001). After 4 days of ageing, 70-95% of the LL samples from all flocks, except for one, had acceptable tenderness for consumers based on their shear force. Low IMF, high LL pH at 18 degrees C and high pH at 24 h increased SF1 and SF5 and also had an effect on SF-diff (P<0.001). The retail colour of 44.8% of the samples on day 3 of retail display were lower than acceptable. Retail colour was influenced by IMF, pH18 and the concentration of iron and copper (P < 0.001). In conclusion, breeding and management practices that increase muscle IMF levels and reduce ultimate pH values and processing practices that result in moderate rates of pH fall post-slaughter, improve the tenderness of lamb. Extension of retail colour stability may be antagonistic to traits associated with tenderness and nutritional traits, particularly IMF and mineral levels.

Item Type: Journal Article
Murdoch Affiliation(s): School of Veterinary and Biomedical Sciences
Publisher: CSIRO Publishing
Copyright: (c) CSIRO
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