The size and shape of a piece of beef, its colour, the amount of fat visible and the fineness of its texture are the principal criteria which, together with the purchase price, condition consumer choice.  However, these characteristics do not inform as to the sensory qualities of the meat (tenderness, juiciness, flavour) after cooking.  Indeed, meat quality depends on technological factors (conditions of animal slaughter, ageing, processing and cooking of the meat).  But this quality also varies as a function of how the animal was reared, its genetic nature and the part of the body used which influence the biological characteristics of muscles (content in collagen, intramuscular lipids, enzymes and enzyme inhibitors, size and type of muscle fibres). 
However, only 30% of the variability of meat tenderness can be explained by differences in the muscle characteristics of animals.  Identifying new biological characteristics of muscle with a marked influence on meat quality is thus a major challenge for the butchery industry.  Particularly since these criteria could be integrated in breeding schemes for cattle.

^{1This work was carried out in partnership with professionals in the cattle industry (APIS-GENE), in the context of Carine Bernard's thesis project and the MUGENE research programme under AGENAE (Analyse du GEnome des Animaux d’Elevage, or Analysis of the Genome of Livestock) funded as a result of the GENANIMAL call for tenders by the ANR.}

References:
Bernard C., Cassar-Malek I., Hocquette J.F., 2006. Genomic marker for meat tenderness. Patent 06 300943.5. 12 September 2006.
Bernard C., Cassar-Malek I., Le Cunff M., Dubroeucq H., Renand G., Hocquette J.F., 2007. New indicators of beef sensory quality revealed by expression of specific genes. Journal of Agricultural and Food Chemistry. 55. 5229-5237.