Oxidative stability and microbial growth of turkey breast fillets during refrigerated storage as influenced by feed supplementation with olive leaves, oregano and/or alpha-tocopheryl acetate

Abstract

1. The aim of this study was to evaluate the inhibitory potential of feed supplementation with olive leaves, oregano and/or alpha-tocopheryl acetate on microbial growth and lipid oxidation of turkey breast fillets during refrigerated storage. 2. A total of 40 turkeys, allocated to 5 groups of 8 birds each, were fed on diets supplemented with olive leaves at 10 g/kg, oregano at 10 g/kg or alpha-tocopheryl acetate at 150 or 300 mg/kg. Following slaughter, fillets from breast were stored at 4 degrees C in the dark for 12 d, and lipid oxidation and microbial growth were assessed. 3. Results showed that dietary olive leaves were more effective than oregano at inhibiting lipid oxidation, but were inferior to dietary supplementation of 300 mg alpha-tocopheryl acetate/kg. In turn, -tocopheryl acetate supplementation at 150 mg/kg was effective at inhibiting lipid oxidation compared to the control but inferior to oregano supplementation. 4. Total viable counts, lactic acid bacteria, Enterobacteriaceae and psychrotrophic bacteria counts were all increased in breast fillets of all groups throughout the refrigerated storage. Diet supplementation with alpha-tocopheryl acetate had no effect on the bacterial counts recorded in the control group, but diet supplementation with olive leaves or oregano resulted in a decrease of all bacterial counts at d 2 of storage and thereafter; during this period, oregano was more effective at inhibiting bacterial growth compared with olive leaves. 5. Therefore, if shown clinically to be safe and having beneficial effects invivo, olive leaves and oregano might be utilised in novel applications as nutritional supplements or functional food components.