Prevalence and molecular characterization of Listeria spp. and Listeria monocytogenes isolated from fish, shrimp, and cooked ready-to-eat (RTE) aquatic products in Iran

The prevalence of Listeria spp. and Listeria monocytogenes was investigated by biochemical and molecular methods in a total of 201 fish, shrimp, and ready-to-eat seafood samples collected from Iranian supermarkets. Thirty-six samples were also collected from a seafood processing plant. Twenty-one (8.86) of the total retail and processing plant samples (237) were positive for Listeria spp., confirmed by a simplex PCR assay for the prs gene. Seven (2.95) of the total samples were also positive for L. monocytogenes. The presence of four virulence-associated genes in the seafood isolates (inlA, inlC, inlJ, and hlyA) was examined using PCR and the results were compared with seven clinical L. monocytogenes strains. All virulence genes were detected in six fish isolates. One fish isolate did not show amplification of the inlJ and inlC genes. However, all seven clinical strains were positive for internalin genes. Furthermore, a multiplex PCR assay was employed to evaluate the major L. monocytogenes genoserogroups' distribution. The results revealed that the serotypes of lineage II are most frequently present in clinical and food isolates. In summary, PCR screening for both the major L. monocytogenes serovars and virulence genes revealed the potential public health risk posed by L. monocytogenes in aquatic products. © 2016 Elsevier Ltd

Predictive modeling of survival/death of Listeria monocytogenes in liquid media: Bacterial responses to cinnamon essential oil, ZnO nanoparticles, and strain

To predict Listeria monocytogenes population during storage (8 °C) as a function of time (1–16 days), cinnamon essential oil (EO), ZnO nanoparticles (NPs; 10–30 nm), and two different genotypes in liquid microbiological medium, an adaptive neuro fuzzy inference system (ANFIS) was developed. For this purpose, 32 modeling scenarios were investigated. The ANFIS scenarios were fed with 4 inputs of EO concentration (0, 0.8, 1.6, and 2.4), ZnO NPs (0, 5, 10, and 15 mg/ml), strain (2 strains), and storage time (1–16 days). Our findings demonstrate that the final ANFIS architecture with triangular-shaped membership function (MF) provides the best prediction accuracy (RMSE = 0.214; R2 = 0.974) over models with other MFs. Moreover, the effects of antibacterial activity of cinnamon EO were investigated in a food model system, vegetable broth. The bacterial counts decreased with increasing cinnamon oil and ZnO NPs concentrations; however, some strain variation was observed. These observations demonstrate the reliability of the ANFIS model for prediction of L. monocytogenes population and confirm its potential use as a supplemental tool in predictive microbiology. © 2016 Elsevier Lt

Characterization of gamma-irradiated rosmarinus officinalis l. (rosemary) Gama i�ınlanmı� rosmarinus officinalis l. (biberiye)

Objectives: Rosmarinus officinalis L., a member of the family Lamiaceae, is regarded as the spice with the highest antioxidant activity. Materials and Methods: In this study, the transmission electron microscopy, X-ray diffraction, and fourier transform infrared spectroscopy (FTIR) physicochemical characteristics of the nanostructure of gamma-irradiated rosemary were investigated. Results: The particle size distribution of the gamma-irradiated rosemary prepared under irradiation at 30 kGy in a Cobalt-60 irradiator exhibited a very narrow size distribution with average size of 70 nm. The results showed that irradiated (30 kGy) and crude rosemary had similar patterns of FTIR spectra, typical of phenol compound, without any notable changes in the key bands and functional groups status. Rosemary irradiated with 50 kGy and 10 kGy showed the highest and lowest crystallinity, respectively. Rosemary crystallinity of irradiated samples was lower compared with the nonirradiated sample. Conclusion: Therefore, 30 kGy can be optimum for the synthesis of nanoparticles, average size of 70 nm, with low crystallinity and without any notable change in key bands compared to nonirradiated samples. © Turk J Pharm Sci, Published by Galenos Publishing House

Effect of different concentrations of pure and mixed salt on the shelf life of salted rainbow trout (Oncorhynchus mykiss) roe during refrigerated storage

This study aimed to investigate the effects of salting of rainbow trout (Onchorhynchus mykiss) roe by pure and mixed salts (3.5, 4.5 and 5.5 %) on the quality and shelf life of the product, with respect to the contents of Total Volatile base nitrogen (TVBN), lipid oxidation (TBA), and on the proximate compositions during storage. The processing of roe leaded to changes in its chemical composition. In comparison with fresh roe, salted roe presented higher contents of TBA and lower content of TVBN. The greatest increases of TVBN were observed in the samples salted by salt without additives, in which TVBN was detected at 43.43 mg/100 g. pH value, salt absorption and TVBN and lipid oxidation had significant increase during storage (

The Impact of Diets Supplemented with Different Forms of Rosemary and BHA on Chemical, Microbial and Sensory Properties of Rainbow Trout Fillet

The objective of this study was to evaluate the effect of different forms and doses of rosemary on chemical, microbial, and sensory properties of rainbow trout fed nine different diets: control (C), 20 g.kg �1 rosemary powder (20RP), 40 g.kg �1 rosemary powder (40RP), 0.3 g.kg �1 rosemary extract (0.3RE), 0.6 g.kg �1 rosemary extract (0.6RE), 0.15 g.kg �1 rosemary nanopowder (0.15RNP), 0.3 g.kg �1 rosemary nanopowder (0.3RNP), 0.15 g.kg �1 butylated hydroxyanisole (BHA) (0.15BHA), and 0.3 g.kg �1 BHA (0.3BHA). After 8 weeks� feeding, the fish fillets were sampled on the 1st, 4th, 8th, 12th, and 16th days and then stored on 4°C. Lower value of pH, peroxide value (PV), total volatile base nitrogen (TVB-N), free fatty acids (FFA), and thiobarbituric acid (TBA) were reported in fish fed with RP, RE, RNP, and BHA; among them, RNP groups had the lowest properties (p < 0.05). Furthermore, lower total viable aerobic bacterial counts (TVC) and psychotropic counts (PTC) were observed in the fillets of the fish fed with rosemary treatments, especially in RNP treatments (7.52�9.41 log 10 CFU.g �1 ), along with a slower spoilage in terms of sensory factors (texture, color, odor, and overall) on the 16th day. Finally, use of natural antioxidant nanorosemary in the diet may positively affect fish fillet quality and delay post-mortem deterioration. © 2019, © 2019 Taylor & Francis Group, LLC

Values of antioxidant activities (ABTS and DPPH) and ferric reducing and chelating powers of gamma-irradiated rosemary extract

This study was carried out to evaluate the effect of the various gamma dose irradiations on the antioxidant activity of rosemary PBS (phosphate-buffered saline) extract. The PBS extract of rosemary was irradiated with gamma rays at the doses of 10, 20, 30, 40 and 50 kGy, and their antioxidant activities were investigated by DPPH (1,1-diphenyl-2-picrylhydrazyl), radical cation ABTS�+ (2,2-Azino-Bis (3-Ethylbenzthiazoline-6-Sulfonic Acid), Diammonium Salt), ferric reducing antioxidant power assay (FRAP) and ferric chelating capacity using ferrozine. The scavenging activities of gamma irradiated rosemary were observed to be significantly higher at 30 and 40 kGy using both methods, DPPH and ABST. Also, the reducing power values of 30 kGy gamma irradiated rosemary were higher than that of non-irradiated (P < 0.05) and the other doses of irradiation could not make any significant difference in reducing power of non-irradiated rosemary. The gamma irradiation of rosemary (at 10-50 kGy), significantly increased the Fe2+ chelating activity compared to non-irradiated rosemary while increasing the absorbed doses reduced Fe2+ chelating activity in rosemary (P < 0.05). There is no significant difference in the rosemary irradiated with 10 kGy and 30 kGy. The gamma irradiated rosemary showed higher antioxidant activities at doses of 30 kGy (79.5 ) and 40 kGy (80 ) with DPPH method, while slightly lower activities were recorded at doses of 30 kGy (34.8 ) and 40 kGy (34.2 ) with ABTS test. Also, results indicate that the 30 kGy might be an effective dose with maximum enhancement in the antioxidant properties of the gamma irradiated rosemary. © 2020 Walter de Gruyter GmbH, Berlin/Boston 2020

Antimicrobial resistance of Listeria monocytogenes isolated from seafood and humans in Iran

Fourteen Listeria monocytogenes isolates previously collected from seafood (n = 7) and human patients (n = 7) were studied for their antimicrobial susceptibility against eight common antimicrobials (ampicillin, penicillin, gentamicin, streptomycin, tetracycline, trimethoprim-sulfamethoxazole, chloramphenicol, and cefotaxime). A high resistance level to ampicillin, cefotaxime (100), and pencillin (57 in seafood isolates and 71.4 in clinical isolates) was observed in this study. However, all of the isolates were susceptible to trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline. Simultaneous resistance was identified in 4 clinical isolates (57.1). Genotypic characterization of fish isolates (isolated from three fish species) was performed by pulsed-field gel electrophoresis (PFGE). A high diversity among fish isolates was observed. PFGE analyses distinguished the 4 isolates into 4 reproducible pulsotypes. There was no correlation between the antibiograms with pulsotypes. In conclusion, the resistance of seafood isolates to the antibiotics commonly used to treat listeriosis could be a potential health hazard for consumers. © 2016 Elsevier Lt

Nutritional composition and antioxidant activity of vobla roach (Rutilus rutilus caspicus) muscle tissue exposed to heavy metals

The present study was carried out to study the toxic effects of different sublethal concentrations of cadmium chloride and lead salts [CdCl2 and Pb(NO3)2] on lipid, carbohydrate, protein contents and antioxidant enzymes of vobla-roach (Rutilus rutilus caspicus), a common Caspian fish species, in laboratory bioassays. R. rutilus caspicus was exposed to various sublethal concentrations of CdCl2 and Pb(NO3)2, i.e. 0.75, 1.5 and 2.25 mg L-1 for 24, 48, 72 and 96 hr. Then, the fishes were sacrificed and muscle was collected for the determination of carbohydrates, lipids, proteins, lipid peroxidation (LPO), catalase (CAT) and superoxide dismutase (SOD) activities. The results showed that the maximum decrease in lipid, carbohydrate and protein contents were observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (55.76%, 46.25% and 48.81%, respectively). Furthermore, antioxidant enzyme activities increased when fishes were exposed to cadmium and lead. The maximum increase in the lipid peroxidation and superoxide dismutase was recorded at 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (184.47 % and 110.52 %, respectively). According to the results, catalase activity decreased with increasing concentration of heavy metals and exposure duration. The maximum decrease in catalase activity was observed 96 hr after treatment with 2.25 mg L-1 of Pb(NO3)2 (81.21 %). In general, both heavy metals were highly toxic in muscle of R. rutilus caspicus, with lead showing higher toxicity then cadmium in terms of nutritional parameters and antioxidant enzyme activity

GAMMA-IRRADIATED ROSEMARY (ROSMARINUS OFFICINALIS) DIPS TREATMENT EFFECT ON QUALITY OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) FILLETS DURING REFRIGERATED STORAGE

The effect of the gamma-irradiated extract of rosemary and butylated hydroxyanisole (BHA) antioxidant on sensory, chemical and microbiological changes of rainbow trout fillets stored at 4 ± 1°C was investigated for 16 days. The fillets were divided into: control (C), 750 and 1500 rosemary extract (RE) (immersed in 750 and 1500 ppm rosemary extract); 250 and 500 gamma-irradiated rosemary (GIR), (immersed in 250 and 500 ppm gamma-irradiated rosemary) and 250 and 500 BHA (immersed in 250 and 500 ppm BHA). The shelf life of fillets was reported to be 8 days for C, and 12 days for 500 GIR group according sensory, microbiological and chemical parameters. The pH, peroxide value (PV), total volatile basic nitrogen (TVB-N), free fatty acid (FFA), thiobarbituric acid (TBA), psychrotrophic counts (PTC), and total viable aerobic bacterial counts (TVC) values were 7.62 ± 0.21, 17.17 ± 1.6, 51.07 ± 1.1, 6.05 ± 0.13, 3.42 ± 0.18, 12.03 ± 0.19, and 13.16 ± 0.16 respectively for C group and also, 7.42 ± 0.16, 15.2 ± 1.7, 42.5 ± 1.5, 4.48 ± 0.39, 2.59 ± 0.15, 9.98 ± 0.15, and 10.5 ± 0.15 respectively for 500 GIR group. Finally, the following trend in effectiveness was reported: gamma-irradiated rosemary PBS extract > BHA > rosemary PBS extract. © 2022, Trakia University. All rights reserved

Efecto del almacenamiento sobre las propiedades físicas de las películas de quitosano con inclusión de aceites esenciales de tomillo y romero

Se estudió el efecto de factores como humedad, temperatura y tiempo de almacenamiento sobre las propiedades físicas de las películas de quitosano con y sin inclusión de aceites. Se incluyeron aceites de tomillo (TEO) y de romero (REO) en proporciones de 0,5:1 y 1:1 v/p (EOs: CH), así como su combinación 50:50 (TEO:REO). Las películas formadas se almacenaron a temperaturas de 5, 20, 33°C y humedades relativas de 60 y 93% durante cuatro semanas. Las condiciones de almacenamiento alteraron las propiedades mecánicas y físicas de las películas, tales como humedad y capacidad de retención de agua debido a la hidrofícidad del polímero, al efecto plastificante de las moléculas de agua y a fenómenos de retrogradación influenciados por la temperatura y el tiempo de almacenamiento