Effect of Rosmarinus officinalis essential oil on the quality of Hypophthalmichthys molitrix surimi inoculated with Escherichia coli during refrigerated storage

This study aimed to investigate the effect of essential oil inhibition on Escherichia coli inoculated in surimi of Hypophthalmichthys molitrix during refrigerated storage (4˚C). Surimi inoculated (103 CFU/g) with E. coli and treated by concentrations of 1, 2 and 3 µL/g of Rosemary leaf essential oil and after packing stored in refrogerator (4˚C). Chemical (PV, TBA and TVB-N) and microbial parameters (Escherichia coli count, TVC and PTC) were measured at 24, 72, 144, 216 and 288 hours. The PV, TBA and TVB-N values of treatment containing E. coli without essential oil was more than other treatments. The values of these indicators increased during storage in all treatments, but this increase was lower in treatments containing Rosemary leaf essential oil. The treatments containing Rosemary leaf essential oil had lower TVC and PTC. The number of E. coli in Rosemary leaf essential oil treatments increased until 144 hours and then decreased, but it increased during storage in E. coli without essential oil treatment. All concentrations of Rosemary leaf essential oil inhibited the growth of E. coli during storage, but the concentration of 3 µL/ghad greatest effect on inhibiting the growth of E. coli. The results of this research showed that the Rosemary leaf essential oil has antibacterial and antioxidant properties and it can be use as a natural preservative in fisheries products.