Background and methodology:
In this study, organic and conventionally reared steers between 18 and 24 months of age were slaughtered in September 2002. Four days after slaughter, the Longissimus dorsi (lean meat) muscle was taken from the left side of each carcass and vacuum-packed and aged in chill for an additional 7 days. Steaks were cut from each sample, and from these, lean meat was removed, blended, and compositional analysis was carried out.
Organic samples were significantly higher in fat and significantly lower in moisture compared to conventional samples. No significant differences were observed for protein, ash, betacarotene, α-tocopherol or retinol. There also was no significant difference in fatty acid content.
Researchers also measured color stability and fat oxidative stability packing samples using both modified atmosphere packaging (MAP) and by over-wrapping with cling film. Samples of conventional beef with MAP packaging had the best color stability while over-wrapped conventional samples had the best lipid stability. Therefore, color and lipid stability of beef samples were influenced by sample composition and packaging used, which resulted in conventional samples outperforming organic samples with respect to shelf life stability.
Composition, sensory and shelf life stability analyses of longissimus dorsi muscle from steers reared under organic and conventional production systems. Walshe, B. E., Sheehan, E. M., Delahunty, C. M., Morrissey, P. A., & Kerry, J. P. (2006). Meat Science, 73(2), 319-325. Available on-line at: http://dx.doi.org/10.1016/j.meatsci.2005.12.008