Antioxidant and antibacterial effects of Lavandula and Mentha essential oils in minced beef inoculated with E. coli O157:H7 and S. aureus during storage at abuse refrigeration temperature

The essential oils (EOs) of Lavandula angustifolia L. and Mentha piperita L were analyzed by gas chromatography mass spectrometry (GC/MS). The major constituents were linalool (22.35%), linalyl acetate (21.80%), trans-ocimene (6.16%) and 4-terpineol (5.19%) for L. angusnfolia and menthol (33.28%), menthone (22.03%), and menthyl acetate (6.40%) for M. piperita. In vitro antibacterial activity of both EOs against Escherichia call 0157:H7 and Staphylococcus aureus CECT 4459 showed high inhibition against S. aureus. The lowest minimal inhibitory concentrations (MIC) were obtained with L. angustifolla (0.25 mu L/mL) against S. aureus: M. piperita exhibited a MIC of 0.50 mu L/mL against both microorganisms. Both EOs caused a significant decrease of bacterial growth in minced beef (p < 0.05) stored at 9 +/- 1 degrees C. Minced beef treated with EOs showed the lowest TBARS values (lipid oxidation). Moreover, the results showed that the addition of EOs significantly extended fresh meat odor even at abuse temperature. (C) 2012 Elsevier Ltd. All rights reserved.