EFFECTS OF ZIZIPHORA CLINOPODIOIDES ESSENTIAL OIL AND NISIN, BOTH SEPARATELY AND IN COMBINATION, TO EXTEND SHELF LIFE AND CONTROL ESCHERICHIA COLI O157:H7 AND STAPHYLOCOCCUS AUREUS IN RAW BEEF PATTY DURING REFRIGERATED STORAGE

The effect of Ziziphora clinopodioides (0.1 and 0.2%) and nisin (250 and 500IU/g), both separately and in combination, on mesophilic, psychrotrophic and Enterobacteriaceae microorganisms and also on Staphylococcus aureus and Escherichia coliO157:H7 in raw beef patty during storage at refrigerated temperature for 9 days were evaluated. Carvacrol (64.22%), followed by thymol (19.22%), p-cymene (4.86%) and -terpinene (4.63%) were the most abundant components of the essential oil. Both the essential oil and nisin significantly (P<0.05) affected the growth of psychrotrophic, Enterobacteriaceae and mesophilic bacteria and also S.aureus and E.coli O157:H7. Among the experimental groups, samples treated with 0.2% essential oil+500IU/g nisin showed the significant most rapid decrease (P<0.05) in the number of tested microorganisms. Our findings indicate that the essential oil of Z.clinopodioides and nisin has a potential to be applied as an antimicrobial and preservative agent in food products, especially in beef patty.