Anti-bacterial effect of Rosmarinus officinalis Linn. extract and Origanum syriacum L. essential oil on survival and growth of total aerobic bacteria and Staphylococcus aureus using cooked chicken meat

The effect of oregano essential oil (OE) and rosemary extract (RE) on the survival and growth of Staphylococcus aureus, and the total aerobic bacteria (TA) in cooked ground chicken meat stored at different temperatures had been evaluated. Five treatments including i) Control (no additives); ii) 150 ppm OE; iii) 350 ppm RE; iv) 150 ppm OE + 350 ppm RE; and v) 14 ppm of butylatedhydroxyanisole and butylatedhydroxytolune mixture (BHA/BHT) were prepared. After cooking, all samples were stored (7 days) at different temperature (10, 25, 43 °C) using oxygen permeable bags and tested for TA, and total viable count of Staph. a. In addition, all additives were showed significant (P < 0.05) antimicrobial effect during storage time compared to the control. Both OE and RE showed comparable antimicrobial effect compared to the synthetic (BHA/BHT) additive at all storage temperatures. However, the combination treatment (OE + RE) was the highest among other additives suppress bacterial growth (APC & Staph. a) during storage. Based on these results, it is concluded that both OE and RE were showed significant (P < 0.05) antimicrobial activity, but this effect could be higher if meat treated by their combined mixture.