Abstract of research

SCREENING OF ANTIBACTERIAL ACTIVITY OF CINNAMON, CLOVE AND ROSEMARY ESSENTIAL OILS AGAINST COMMON FOOD BORNE PATHOGENS IN MINCED BEEF

Reham, A. Amin

Abstract

Cinnamon, clove and rosemary essential oils were evaluated for their effects on the growth and survival of Staphylococcus aureus and Escherichia coli artificially inoculated into minced beef. Fresh minced beef samples were inoculated with (~ 106 CFU/ml) (6 log CFU/g) of S. aureus and (~ 104 CFU/ml) (4 log CFU/g) of E. coli and left for 30 minutes at room temperature (25οC) to allow attachment and absorption of bacteria. Initial counts of S. aureus and E. coli in minced beef samples immediately after innoculation were 10.86 and 7.91 log CFU/g, respectively. Essential oils of cinnamon (Cinnamomum zeylanicum), clove (Syzygium aromaticum) and rosemary (Rosmarinus officinalis) (%v/g) were added to the minced beef samples to achieve final concentrations of 0.5, 1 and 1.5%. Sensory (color, odor and texture) and bacteriological (S. aureus and E. coli counts) analyses were conducted after 3, 6 hrs and every day (24 hrs) during cold storage at 4°C. Initial counts in minced beef samples decreased following treatment with 1.5% of cinnamon, clove and rosemary oils for 3 hours by 5.56 log CFU/g (51.19 %), 4.01 log CFU/g (36.92 %) and 2.84 log CFU/g (26.15 %), respectively, of S. aureus and 3.58 log CFU/g (45.26 %), 2.88 log CFU/g (36.41 %) and 1.23 log CFU/g (15.55 %), respectively, for E. coli. Growth of S. aureus in minced beef samples was completely inhibited after treatment with cinnamon oil 1% after 3 days, cinnamon oil 1.5% after 2 days, clove oil 1% after 4 days and clove oil 1.5% after 3 days. As compared with several other mild preservation procedures, treatment with cinnamon, clove and rosemary essential oils is inexpensive and uncomplicated method. Results of the present study are envisaged to be useful for commercial applications of these essential oils as potential food biopreservatives and anti- E. coli and S. aureus agents in minced meat and other foods, depending upon the desired flavor of such products.