Study of inhibition effect of Cuminum cyminum essential oil and Nisin on the growth of Streptococcus iniae in fillets of Rainbow trout using Hurdle Technology

The aquatic zoonotic bacterial Streptococcus iniae represents a threat to the worldwide aquaculture industry. This study was carried out to evaluate the antibacterial activity Cuminum cyminum essential oil and nisin for control of S.iniae in fillets of Rainbow trout (Oncorhynchus mykiss) in 4 Cº on basis hurdle technology between 2012 and 2013.The effect of different concentrations of nisin (0, 0.25 and 0.75 µg/ml) and Cuminum cyminum (0, 0.005, 0.135 and 0.405 %) were conducted on growth of S.iniae GQ850377 for 15 days. The results showed that growth of bacterial delayed in samples treated with nisin and essential oil singly to 9 days and together to 3 days. Samples treated with essential oil showed a significant decrease on the growth of the bacteria compared with nisin and control sample (P<0.05). No significant different was observed on the growth of S.iniae in samples treated with higher concentrations of C.cyminum (0.135 and 0.405 %) (p>0.05), but different concentrations of nisin was statistically significant (p<0.05). Synergistic effects were observed at concentration of 0.405% C.cyminum and 0.75 µg/mL nisin.