Effect of dietary supplementation of vitamin E on characteristics of lamb meat packed under modified atmosphere.

The effect of dietary vitamin E supplementation on modified-atmosphere packed lamb meat during storage was studied. Thirty-six weaned male Manchego breed lambs were fed diets supplemented with three different vitamin E concentrations (0, 250, 500 and 1000mg/kg feed) for an average of 37 days, in the 13-26kg live weight growth range. Slices of m. longissimus dorsi were packaged under modified atmosphere (70% O(2) and 30% CO(2)), stored at 2±1°C in darkness for 14 and 28 days. Meat quality parameters after both storage periods were assessed. Dietary vitamin E supplementation significantly increased α-tocopherol concentration in muscle. Initially, lipid oxidation (TBARS), meat colour and bacterial load were similar in all groups. Lipid and colour oxidation of meat increased significantly (P<0.001) throughout storage. The increase was greater in non-supplemented lambs than in supplemented ones. The bacterial counts after 28 days of storage reached the limit for microbiological shelf life (7log(10)cfu/cm(2)). Dietary vitamin E supplementation increased the shelf life of meat packaged under modified atmosphere to 14 days. TBARS, pigment oxidation and bacterial load were inside the acceptable limit. The meat maintained its quality for 28 days of storage only when lambs were fed with the 1000mg/kg dietary supplement, though the bacterial load was at the limit of acceptability.