Application of natural antimicrobial essential oils (EOs) against foodborne pathogens has been recently developed due to consumer demand. In this study, at first step, the highest concentration of Bunium persicum (Black zira) EO without any undesirable effect on sensory properties on fillet was determined, and then the antimicrobial effect of this EO at 0.05, 0.2 and 0.4% against Listeria monocytogenes was examined in fish model systems for 12 days at 4C. Fish peptone broth, kutum broth and cold smoked kutum broth were inoculated with 10 4 cfu/mL L. monocytogenes. Black zira EO demonstrated strong inhibitory activity against L. monocytogenes in fish peptone broth, this efficacy significantly decreased in kutum and cold smoked kutum broth (P < 0.05). Black zira EO performance significantly stimulated in broth with 4% NaCl. L. monocytogenes growth rate in cold smoked kutum broth was significantly lower than in kutum broth. Combination of Black zira EO, smoke component, NaCl and low temperature as a Hurdle system has noticeable inhibition on L. monocytogenes growth. PRACTICAL APPLICATIONSL. monocytogenes is one of the most important biological hazards in marine products and control of this foodborne pathogen via application of antimicrobial EOs could have a great impact on safety promotion of sea foods. This study focused on B. persicum (Black zira) because of its pleasant and proper flavor which supports the application of this EO in fish and fish products traditionally from the past times till now.The demonstrated antibacterial activity of B. persicum EO against L. monocytogenes, recommends its application as a natural food preservative. Moreover synergistic effect between NaCl, smoke compounds and the EO in a Hurdle system increased the antibacterial activity of Black zira against L. monocytogenes.

This study was conducted to evaluate the antibacterial effect of Carum copticum essential oil (Ajowan EO) against Listeria monocytogenes in fish model system. Ajowan EO chemical composition was determined by gas chromatography/mass spectral analysis and the highest concentration of Carum copticum essential oil without any significant changes on sensory properties of kutum fish (Rutilus frisii kutum) was assigned. Then the inhibitory effect of Ajowan EO at different concentrations in presence of salt and smoke component was tested on L. monocytogenes growth in fish peptone broth (FPB), kutum broth and cold smoked kutum broth at 4 °C for 12 days. Ajowan EO completely decreased the number of L. monocytogenes in FPB after 12 days of storage, however, antimicrobial effect of EO significantly reduced in kutum and cold smoked kutum broth. Addition of 4% NaCl and smoke component improved the anti-listerial activity of Ajowan EO in all fish model broths.