Meat color is important for consumer acceptability, with excessively dark meat often associated with consumer rejection. It is determined chromatically by pigment content (measured by hue and chroma) and achromatically by scattering of light by the microstructure (measured by lightness), the latter of which has received minimal research focus. This review discusses the individual components of the meat microstructure that cause differences in achromatic contributions to color. Differences in achromatic light scattering between light and dark extremes of meat color are most likely explained by structural attributes within the muscle cell. These differences are proposed to arise from variations in (a) transverse shrinkage of the structural lattice of the myofilaments, myofibrils, and muscles fibers, (b) longitudinal shrinkage of the sarcomere, and (c) different protein composition of the surrounding medium (sarcoplasm and extracellular space). These are discussed at a mechanistic level, in relation to six parameters of the muscle cell: (a) protein surface charge altering the myofilament spacing, (b) protein solubility, (c) sarcoplasmic protein binding to myofilaments and myofibrils, (d) integrity of the cytoskeleton and cell adhesion proteins, (e) sarcomere integrity and myofibrillar proteins, and (f) myosin denaturation and rigor bond modification. New data are presented to support the proposed role of structural elements in muscle causing achromatic light scattering and their contribution to the surface color of meat. In addition, the relationships between lightness and water holding capacity and pH are explored and the economic impact of dark meat for the meat industry is discussed.

Optimal beef meat colour is associated with increased consumer acceptance, whereas dark or pale meat has a reduced desirability. Dark beef also has a variable eating quality and reduced shelf-life. We hypothesised that a poor meat colour at carcass grading would generate an unacceptable eating quality after vacuum-packed chilled storage for up to 20 weeks, due to the unfavourable pH conditions commonly associated with light and dark muscles. At three beef processing plants, beef longissimus muscles from 81 pasture- and grain-fed cattle (mix of Bos taurus and Bos indicus × Bos taurus) were graded at ~24 h post-slaughter for meat colour. The carcasses were allocated to light, medium and dark colour groups, with n = 27 carcasses per colour group. From the 81 carcasses, a total of 162 longissimus lumborum (LL) muscles was collected and half LLs were randomly allocated to three ageing times (2, 12, 20 weeks) within colour group and six half LLs were used per colour group within storage period and plant. Vacuum-packed muscles were stored at –1.0 ± 0.5°C for the designated period and sampled for biochemical and sensory assessments. The effects of colour group, storage week and carcass traits were analysed. Dark muscles had higher pH than the lighter ones (P < 0.05). The carcass trait dentition, feed type and fat depth did not influence the eating quality (P > 0.05). After 2, 12 and 20 weeks of vacuum-packed chilled storage; eating quality was similar for all 3 meat-colour groups (P > 0.05). With increasing storage time, all eating-quality attributes improved (P < 0.001 for all). Lipid oxidation increased with storage time and although values at 20 weeks were slightly above accepted levels for rancidity detection, MQ4 scores indicated that the meat would still be categorised as a three-star product, indicative of the opportunity to store the longissimus lumborum (LL) for this length of time, while maintaining an acceptable eating quality, regardless of meat colour at carcass grading.

Unacceptable meat colour scores at the time of carcass grading are associated with reduced meat quality and consumer rejection. We hypothesised that the meat colour at carcass grading would be influenced by the pH and temperature decline post slaughter, as these would be determined by animal and processing factors. Beef carcasses (n = 1512) at seven Australian processing plants were assessed, at grading, for the meat colour of the M. longissimus thoracis. Statistical modelling determined the animal, carcass and processing factors contributing to the meat colour score at carcass grading. The occurrence of unacceptably dark meat dropped from 8 to 3% when the time of grading was increased from 14 to 31 h post slaughter (P < 0.01). A high temperature at pH 6 (rigor temperature), high final pH (pHF), pasture feeding and older animals were associated with dark M. longissimus thoracis at carcass grading (P < 0.05 for all). Less than 30% of carcasses with non-compliant pHF displayed a dark non-compliant meat colour >3, indicative of an opportunity to determine the mechanism behind this pH-induced colour development and thus reduce the incidence of non-compliance. It is recommended that when there is a high occurrence of carcasses with a dark meat colour >3 that the time from slaughter to grading is checked to ensure carcasses are in full rigor at the grading point. This will assist in minimising economic penalties due to dark-coloured carcasses. Finally, animal factors, such as maturity and feeding regime also had a considerable impact on the meat colour at carcass grading.

In Northern Ireland, where the majority of children are educated at schools attended mainly by coreligionists, the debate concerning the role of schools in perpetuating intergroup hostilities has recently been reignited. Against questions regarding the efficacy of community relations policy in education, the research reported in this paper employs qualitative methods to examine social identity and intergroup attitudes amongst children attending a state controlled Protestant school and the school's response to dealing with issues of diversity and difference. Findings suggest a relationship between ethnic isolation experienced by children and negative intergroup social attitudes and the discussion focuses on issues germane to the separateness of the school that are likely to contribute to strong ‘own’ group bias, stereotyping and prejudice. The implication of the school's separate status for its engagement with a policy framework for relationship building is also considered. The paper concludes with some policy reflections that are likely to have resonance beyond Northern Ireland.