Composition, sensory and shelf life stability analyses of Longissimus dorsi muscle from steers reared under organic and conventional production systems

In recent years the demand for organically grown food has increased. In this study, organic (O, n = 6) and conventionally (C, n = 6) reared steers aged between 18 and 24 months were slaughtered during the month of September 2002. Four days post-slaughter, the Longissimus dorsi (LD) muscle was excised from the left side of each carcass. All muscles were vacuum packed and aged in a chill for a further seven days. Steaks were cut from each sample, and from these, lean meat was removed, blended and compositional analysis was carried out. O samples were significantly higher (P > 0.05) in fat content and therefore were significantly (P > 0.05) lower in moisture content than C samples. No significant differences were observed between C and O samples for protein, ash, β-carotene, α-tocopherol or retinol. There was also no significant difference in fatty acid content between C and O samples. Colour stability and fat oxidative stability of samples were also measured, while stored under retail conditions. Samples were packed using both modified atmosphere packaging (MAP) and by overwrapping with cling film. MAP C samples had the best colour stability while overwrapped C samples had the best lipid stability. Therefore, colour and lipid stability of beef samples were influenced by sample composition and packaging format used, which resulted in C samples outperforming O samples with respect to shelf life stability.