[Effect of zataria multiflora boiss essential oil and nisin on shelf life in light salted fish fillet of silver carp [hypophthalmichthys molitrix]]

Zataria multiflora is medical plants in Traditional Medicine of Iran. It is necessary to study on antimicrobial effects of essential oil on foodborne pathogens. Nisin is bacteriocin, antimicrobial food preservative. It is regarded as natural because it is a polypeptide produced by certain strains of Lactococcus lactis subsp. lactis [hereafter referred to as L. lactis], during fermentation. This study was performed to evaluate the antimicrobial effects of Zataria multiflora Boiss essential oil and Nisin on the shelflife of light salted fish fillet, silver carp. Effects of different concentrations, Zataria multiflora Boiss essential oil [0, 0.045, 0.135, 0.405 and 0.810%] and Nisin [0, 0.25 microg/ml] were studied on shelf life in light salted fish fillets of silver carp at unfavourable refrigeration storage temperature [10 C] by measuring of microbial flora and chemical values such as pH, thiobarbituric acid [TBA] and total volatile basic nitrogen [TVB-N] and perioxide compared with control group. The results showed that higher used concentrations of Zataria multiflora essential oil [0.135, 0.405 and 0.810%] and Nisin [0.25%] had a significant effect on the shelf life of fish fillets [p> 0.05]. The results showed that Z. multiflora essential oil and nisin have antimicrobial effects and are as a food natural preservative in fish fillet. Also, Total volatile basic nitrogen [TVB-N] increased with growth of microbial flora and TVN in the study was best factor for shelf life changes

[Effect of Zataria multiflora Boiss. essential oil on the behavior of Vibrio parahaemolyticus in salted fish]

Thyme [Zataria multiflora Boiss.] is one of the Iranian traditional spices and it has antimicrobial effect on the pathogenic bacteria which are agents for some current food borne intoxications. The aim of this study was to evaluate the antimicrobial activity of Zataria multiflora Boiss. essential oil on V. parahaemolyticus in salted [8% Nacl in tissue] silver carp. Effect of different concentrations of this Essential oil [0.0%, 0.045%, 0.135%, 0.405%, 0.810%] on behavior of V. parahaemolyticus in two temperatures [15, 25 C] was determined by evaluation of the bacterial growth in salted fish fillets. The essential oil in used concentrations had significant inhibitory effect on the growth of V. parahaemolyticus in salted fish compare with control treatment during the storage time [p<0.05]. There was no significant difference between all treatments. The results showed that Zataria multiflora Boiss. Essential oil had inhibitory effect on V. parahaemolyticus, therefore it can be considered as a natural preservative in salted fish

[Study on the growth of Staphylococcus aureus in processed fillets of silver carp with salt and nisin]

There is increasing demand for use of natural preservatives such as bacteriocins to control foodborne pathogens in seafoods. This study was performed to evaluate the antimicrobial effects of Nisin on Staphylococcus aureus in light and heavy salted silver carp fillets [4 and 8% NaCl]. Effect of different concentrations of Nisin [0, 0.15, 0.25, 0.75, 1.5 micro g/ml] on behavior of S.aureurs at unfavourable refrigeration storage temperature [10 [degree sign]C] was determined by evaluation of the bacterial growth in salted fish fillets. The results showed that used concentrations of Nisin had inhibitory effect on the growth of S.aureus in light and heavy salted fish fillets compared to the control [p<0.05]. This study showed inhibitory effect of Nisin on the growth of S.aureus. Therefore it can be considered as a natural preservative in light and heavy salted fish