Effect of Eryngium caeruleum essential oil on microbial and sensory quality of minced fish and fate of Listeria monocytogenes during the storage at 4°C

The present study investigated in vitro antimicrobial activity of Eryngium caeruleum essential oil (EEO) against five foodborne pathogenic bacteria based on microdilution and disk diffusion methods. Moreover, its effects on specific spoilage microorganisms, inoculated Listeria monocytogenes, and its sensory changes in minced fish were evaluated during 12 days of storage at refrigeration temperature. The results showed that Staphylococcus aureus and Escherichia coli were the most sensitive and the most resistant bacteria with a minimum inhibitory concentration of 0.125 and 1 mg/ml, as well as inhibition zones of 15.66 and 11.66 mm, respectively. Regarding the antimicrobial effect of EEO on the microbial profile and inoculated L. monocytogenes, treating with 0.4% EEO caused a significant decrease in the studied microorganisms when compared to the control group (p < 0.05). In addition, considering the sensory evaluation, the best scores were observed for the samples treated with 0.2% and 0.4% EEO. However, none of the groups obtained acceptable scores until the final day of storage except for the color attribute. In general, sensory evaluation and its correlation with microbial counting indicated that the treatment with 0.4% EEO was able to preserve the microbial quality of the minced fish at refrigeration temperature without any undesirable sensory effects.