Use of dietary rosemary extract in ewe and lamb to extend the shelf life of raw and cooked meat

The use of a dietary rosemary extract (DRE) composed of carnosic acid and carnosol at a 2:1 (w/w) ratio is proposed to extend the shelf life of raw and cooked lamb. The sheep diet was supplemented with 600 mg DRE per kg feed during pregnancy and lactation (ewe) and/or fattening (lamb) stages. Meat quality was evaluated in packed raw fillets and cooked patties kept at retail for up to 21 and 4 days, respectively. DRE extended (P < 0.05) the shelf life of rawfillets from 9 to 11 days, delaying lipid oxidation and rancidity and, to a lesser extent, colour deterioration and microbial spoilage. By contrast, DRE did not extend the shelf life of cooked patties, because the oxidising status on lamb meat after mincing, heating and retailing exceeded the antioxidant potential of the DRE used. Taking these limitations into account, the treatment with DRE should be limited to fattening lamb alone, which reduces feeding costs, since DRE intake by pregnant and lactating ewes barely extended the shelf life of lamb fillets. Rosemary-based diets can be used as a nutritional strategy for improving lamb quality, although the extract composition should be modified to attempt to increase the degree of meat preservation, in particular, in the cooked meat.