Effect of antibacterial activity of different concentrations Cuminum cyminum essential oil (0, 0.005, 0.015, 0.045, 0.135, 0.405%) and nisin (0, 0.125, 0.25, 0.75 ?g/ml) was carried out to evaluate in lab and food model (fillets of Rainbow trout) on control Streptococcus iniae for 15 days at 8?C in 2013. In lab, micro-dilution method was used for determine MIC and MBC of nisin and essential oil, so used for food model. Results showed that MIC and MBC essential oil and nisin were 0.015, 0.005% and 0.25, 0.125?g/ml, respectively. Since 15 days, according to the results, statistical significant showed between concentrations of nisin and essential oil with control treatment (P<0.05). Results showed growth of bacterial delayed in different samples treated with nisin and essential oil singly to 3 and 6 days and in combination 6 days. The highest synergistic effect of nisin with essential oil in 0.135 and 0.405% concentration of essential oil and 0.75 ?g/ml nisin in 8?C.