Antioxidant and antimicrobial effects of dietary supplementation with rosemary diterpenes (carnosic acid and carnosol) vs vitamin E on lamb meat packed under protective atmosphere

The antioxidant and antimicrobial effects on lamb meat of the dietary use of rosemary diterpenes and vitamin E were compared. Thirty fattening lambs were assigned to three diets: (C) control; (R) C plus 600 mg kg− 1 carnosic acid and carnosol at 1:1 w:w; or (E) C plus 600 mg kg− 1 α-tocopherol. The deposition of the dietary supplements in the muscle was determined. Microbial quality (total viable counts, Lactic Acid Bacteria, Enterobacteriaceae, Escherichia coli and Salmonella spp), oxidative stability (CIELab color, malondialdehyde and total carbonyls) and sensory attributes (appearance and odor) were determined in loin stored at 2 °C under 70% O2/30% CO2 atmosphere. Microbial quality was ensured by packaging and chilling. The E-diet was more effective (P ≤ 0.05) than the R-diet in preventing meat oxidation, although the latter had antimicrobial effects on meat. The shelf life of lamb (assessed as the loss of freshness) could be increased by 5 (R-diet) or 10 (E-diet) days.