Development of biomaterials based on chitosan-gelatin nanofibers encapsulated with Ziziphora clinopodioides essential oil and Heracleum persicum extract for extending the shelf-life of vacuum-cooked beef sausages.

The aims of the current study were to encapsulate Ziziphora clinopodioides essential oil (ZEO, 0%, 0.15%, and 0.25%) and Heracleum persicum extract (HPE, 0%, 0.25%, and 0.5%) into the chitosan-gelatin (CH-GE) nanofibers through the electrospinning process to improve the shelf-life of vacuum-cooked beef sausages through 70 days of refrigerated storage. Scanning electron microscopy indicated that all nanofibers appeared thin, well-defined, smooth, and possessed uniform thread-like fibers without any beads or nodule formations. The Fourier transform infrared spectroscopy study confirmed the molecular interaction between encapsulated compounds and CH-GE nanofibers. The X-ray diffraction analysis of nanofibers showed an increase in crystallinity after incorporating ZEO and HPE into the polymer. Treated sausages with CH-GE-ZEO 0.25%-HPE 0.25% and CH-GE-ZEO 0.25%-HPE 0.5% showed significantly lower microbial population and lipid oxidation than the control group during the experiment period (P < 0.05). Sausages formulated with designated CH-GE nanofibers had better microbial, chemical, and sensory properties compared to sausages treated with pure ZEO/HPE during refrigerated storage. The findings also showed that treated sausages with CH-GE-ZEO 0.25%-HPE 0.5% had the highest color, odor, texture, and overall acceptability after 70 days of refrigerated storage conditions. Therefore, this treatment could be applicable for the prolonged storage conditions during cooked beef sausage production.

Intelligent double-layer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata petal anthocyanins nanofibers to monitor food freshness.

The present study was conducted with the aim of fabricating smart bilayer polymers based on carboxymethyl cellulose-cellulose nanocrystals film and poly(lactic acid)-Viola odorata extract nanofibers (CMC-CNC and PLA-VOE) for freshness monitoring of Pacific white shrimps, minced lamb meat, chicken fillets, and rainbow trout fillets, during refrigerated storage conditions. The fabricated indicators based on CMC-PLA-VOE 5%, CMC-CNC 1%-PLA-VOE 5%, and CMC-CNC 3%-PLA-VOE 5% presented remarkable color changes in pH 1-12 buffer solutions, including red at pH 1-6, violet at pH 7-8, green at pH 9-10, and brown at pH 11-12. Significantly lower water vapor permeability and oxygen transmission rate of prepared polymers were found in comparison with the control groups (P < 0.05). Regarding the monitoring of food samples in real-time, the samples spoiled after 3 days, evidenced by total viable count, psychrotrophic bacterial count, total volatile basic nitrogen, and pH values of 7.17-7.54 log CFU/g, 5.68-6.23 log CFU/g, 25.14-28.12 mg N/100 g, and 7.10-7.66, respectively. Meanwhile, the noticeable color change of prepared indicators from white to violet (day 3) and finally dark violet (day 7) was observed, indicating a potential application in intelligent packaging for real-time control of the freshness of perishable food samples.

Development and characterization of active packaging nanofiber mats based on gelatin­sodium alginate containing probiotic microorganisms to improve the shelf-life and safety quality of silver carp fillets.

The current study aimed to incorporate Lactobacillus acidophilus, Limosilactobacillus reuteri, Lacticaseibacillus casei, and Lacticaseibacillus rhamnosus (~10 log CFU/ml) into gelatin­sodium alginate nanofibers via electrospinning process in order to investigate the influence of fabricated mats on the growth of food-related pathogenic bacteria and shelf-life extension of refrigerated silver carp fillets in a two-week period. The strain-loaded nanofibers exhibited lower water vapor permeability, swelling index, moisture content, and tensile strength than the straight nanofibers (P < 0.05). The survival order of probiotics in nanofibers stored at 4, 25, and 37 °C for 14 days are as follows: L. acidophilus (8.15-9.35 log CFU/g) > L. reuteri (7.42-9.24 log CFU/g) > L. casei (7.41-9.13 log CFU/g) > L. rhamnosus (7.37-8.92 log CFU/g). The probiotic mats significantly delayed the growth of Vibrio parahaemolyticus, Salmonella Typhimurium, Staphylococcus aureus, and Listeria monocytogenes in silver carp fillets in comparison with the unpackaged sample (P < 0.05). Moreover, the designated nanofibers improved the bacterial, chemical, and sensory properties of treated samples in comparison with the unpackaged samples throughout the study period. Our findings indicate that gelatin­sodium alginate nanofibers are a suitable platform for the protection of living probiotics and present an alternative procedure for retarding the growth of food-borne pathogens and extending the shelf-life of fresh carp fillets under refrigerated storage conditions.

Application of active Kurdi gum and Farsi gum-based coatings in banana fruits.

This study evaluated the effects of Kurdi gum (KG) and Farsi gum (FG) based coatings with and without ethanolic Prosopis farcta extract (PFE; 0, 0.25 and 0.5%) on microbial, physicochemical, and sensory properties as well as respiration and ethylene production rates of banana fruits during storage (13 °C, 80% relative humidity (RH)) for 21 days and afterward 7 days at simulated market conditions (25 °C, 60% RH). The treatment of fruits with KG + PFE 0.5% resulted in the best bacterial, chemical, and sensory properties at the end of the storage period. It can be concluded that the application of KG and FG coatings enriched with PFE can be applied to increase the commercialization of bananas during prolonged storage.

Effect of gamma irradiation on physico-mechanical and structural properties of active Farsi gum-CMC films containing Ziziphora clinopodioides essential oil and lignocellulose nanofibers for meat packaging.

The objective of this study was to examine the effect of gamma irradiation (0, 2.5, and 5 kGy) on physico-mechanical and structural characteristics of films based on Farsi gum-carboxymethyl cellulose supplemented with Ziziphora clinopodioides essential oil (ZEO; 0%, 1%, and 2%) and lignocellulose nanofibers (LCNF; 0%, 1%, and 2%), and their application on fresh minced beef meat's shelf-life during refrigerated temperature (4 ± 1 °C) for 16 days. Gamma irradiation under the 60 Co source at 2.5 and 5 kGy doses did not have a significant effect on thickness, tensile strength, swelling index, oxygen permeability, and water vapor transmission rate of prepared films (P > 0.05). The best microbiological (total viable count, psychrotrophic bacterial count, Pseudomonas spp., Brochothrix thermosphacta, lactic acid bacteria, and Enterobacteriaceae) and chemical (thiobarbituric acid reactive substances, total volatile base nitrogen content, and peroxide value) properties were recorded for samples packaged with ZEO 2% + LCNF 2%, followed by ZEO 2% + LCNF 1%, ZEO 1% + LCNF 2%, and ZEO 1% + LCNF 1%. These results indicate acceptable extensions of hurdle technology for prolonged refrigeration of minced beef meat. PRACTICAL APPLICATION: The application of active packaging films has received considerable interest in extending the shelf-life of perishable foods during prolonged chilled storage. The effects of active Farsi gum-carboxymethyl cellulose films supplemented with Ziziphora clinopodioides essential oil 2% + lignocellulose nanofibers 2% resulted in delaying lipid oxidation and microbial spoilage growth of refrigerated minced beef meat and consequently extending the shelf-life during storage for at least 16 days.

Monitoring and risk assessment of tetracycline residues in foods of animal origin.

A total of 450 samples consisting of red meat, poultry meat, aquatic product and raw milk were collected during winter 2016 and summer 2017. 22.2% (100/450) of collected meat and raw milk samples were found to be contaminated with antibiotic residues in the initial screening using Premi®test. According to the enzyme linked immunosorbent assay (ELISA) results, the mean tetracyclines (TCs) concentration of meat samples determined as follows: chicken (155.41 µg/kg) > turkey (138.68 µg/kg) > quail (130.7 µg/kg) > cow (108.92 µg/kg) > calf (105.18 µg/kg) > goat (99.4 µg/kg) > sheep (95.22 µg/kg) > rainbow trout (35.62 µg/kg) > shrimp (31.80 µg/kg). The content of TCs in cow, goat and sheep milk samples were found to be ranged 45.6-163.5 µg/L, 72.4-101.1 µg/L and 65.5-98.9 µg/L, respectively. 5.7% (26/450) of samples had TCs confirmed the ELISA results using high performance liquid chromatography coupled with ultra-violet detection, although the concentration of TCs residues in samples was higher than that of ELISA.

Shelf-Life Enhancement in Fresh and Frozen Rainbow Trout Fillets by the Employment of a Novel Active Coating Design.

The goal of this study was to determine the effect of incorporating ethanolic Prosopis farcta extract (PFE, 0 and 0.5%) and curcumin nanoparticles (CCM, 0, 0.1 and 0.2%) into sodium alginate (SA) coating on shelf-life of refrigerated and frozen rainbow trout fillets during storage lasting for 12 days and 6 months, respectively. Antioxidant and antibacterial properties of designated coatings were examined using 2, 2-diphenyl-1-picrylhydrazyl hydrate free radical scavenging activity and broth microdilution methods, respectively. The highest antioxidant and antibacterial activities were found in CCM 0.2% + PFE 0.5% and CCM 0.1% + PFE 0.5%. The CCM 0.2% + PFE 0.5% and CCM 0.1% + PFE 0.5% treatments could significantly extend the shelf-life of fresh trout fillets for 12 days during refrigerated storage evidenced by the 3.6 to 4.3 and 3 to 3.7 log CFU/g decrease in the microbial population in comparison with the untreated group, respectively. At the end of refrigerated storage time, the chemical change in all treated fillets was significantly lower than the untreated group (P < 0.05). The treatments of frozen trout fillets with SA + different concentrations of PFE and CCM resulted in better microbial and chemical properties than of the untreated group at the end of storage period (P < 0.05). PRACTICAL APPLICATION: Antimicrobial edible coatings from natural renewable resources have been found to be very useful in the food preservation field owing to the increasing consumer interest for the improvement of shelf-life property and appearance of fresh foodstuffs. Rainbow trout fillets without chemical preservatives have a limited shelf-life due to its biological properties. This study indicates the possibility of application of sodium alginate coatings containing Prosopis farcta extract and curcumin nanoparticles to increase shelf-life and maintain the quality of refrigerated trout fillets.

Effects of sodium alginate coating containing Mentha spicata essential oil and cellulose nanoparticles on extending the shelf life of raw silver carp (Hypophthalmichthys molitrix) fillets.

The aim of the present study was to evaluate the effects of sodium alginate (SA) coatings containing Mentha spicata essential oil (MSO; 0.5 and 1%) and cellulose nanoparticles (CN; 0.25 and 0.5%) on chemical (total volatile base nitrogen content and peroxide value), microbial (total viable count, psychrotrophic count, Pseudomonas spp., and Enterobacteriaceae), and sensory (odor, color, and overall acceptability) properties of raw silver carp fillets during 14 days of refrigerated storage. The MSO was mostly comprised of carvone (78.76%) and limonene (11.50%). SA + MSO 1% + CN 0.5% was most effective in extending the shelf life of silver carp fillets, followed by SA + MSO 1% + CN 0.25%, SA + MSO 1%, SA + MSO 0.5% + CN 0.5%, SA + MSO 0.5% + CN 0.25%, SA + MSO 0.5%, SA + CN 0.5%, SA +CN 0.25%, and SA. Incorporation of MSO 0.5% didn't have any adverse effect on odor, color, and overall acceptability of treated samples.

Effect of methanolic Prosopis farcta extract on storage stabilization of canola oil.

The aim of the present study was to evaluate the effect of methanolic Prosopis farcta extract (PFE; 0, 200, 400, 600, 800 and 1000 ppm) on storage stabilization of canola oil during 24 days of accelerated storage. The canola oil was mainly comprised of oleic acid (65.01%), linoleic acid (19.56%), linolenic acid (8.11%) and palmitic acid (4.48%). The 1, 1-diphenyl-2-picrylhydrazyl radical scavenging activity and ß-carotene bleaching ability of the PFE were 1.16 µg/ml and 0.09 mg/ml, respectively. Our study showed that total phenolic content of PFE was 365.72 ± 6.21 mg gallic acid/g of dried fruit quantified by Folin-Ciocalteu's method. Peroxide value, p-anisidine value and thiobarbituric acid value exhibited that PFE at concentration levels of 400, 600, 800 and 1000 ppm in canola oil had good antioxidant effect. According to the results of the present study. The induction periods of treated samples were significantly increased with increasing of PFE concentration. Indeed, the induction periods of oil were improved from 1.99 (control) to 3.32, 4.56, 8.32, 9.89 and 13.34 h by addition of 200, 400, 600, 800 and 1000 ppm of PFE, respectively.

Application of carboxymethyl cellulose and chitosan coatings containing Mentha spicata essential oil in fresh strawberries.

The aim of the present study was to investigate the effects of carboxymethyl cellulose (CMC) and chitosan (CH) coatings containing Mentha spicata essential oil (MSO 0.1 and 0.2%) on survival of Listeria monocytogenes, and physicochemical (weight loss, titratable acidity and pH), microbial (total viable count, psychrotrophic bacteria as well as yeasts and molds) and sensory (appearance, color, texture and overall acceptability) properties of fresh strawberries during refrigerated storage. The treatments of fruits with CH+MSO 0.2% and CMC+MSO 0.2% resulted in the best microbial, physicochemical and organoleptic properties after 12days storage. The final population of L. monocytogenes in treated samples was decreased by 3.92-3.69 compared to control groups. It can be concluded that CH and CMC coatings enriched with MSO can be used as appropriate active packaging materials to preserve fresh strawberries in the food industry.

Application of nanocompostie chitosan and carboxymethyl cellulose films containing natural preservative compounds in minced camel's meat.

In the present study, novel films based on nanomontmorillonite-chitosan (MMT-Ch) and nanomontmorillonite-carboxymethyl cellulose (MMT-CMC) incorporated with different concentrations of Ziziphora clinopodioides essential oil (ZEO; 0.5, 1 and 2%) alone and in combination with Ficus carica extract (FCH; 1%) were investigated as active packaging materials for minced camel's meat to increase the shelf life (microbial, chemical and sensory properties) and inhibit the growth of Listeria monocytogenes and Escherichia coli O157:H7 during storage at refrigerated condition. Final microbial populations of meat samples packed in CMC-MMT+ZEO 2%+FCH 1% and Ch-MMT+ZEO 2%+FCH 1% were decreased approximately 1-4 log CFU/g compared to control (P<0.05). Packed meats with nanocomposite films tended to retard the increases in total volatile base nitrogen (TVB-N), pH, peroxide value (PV), protein carbonyl content and thiobarbituric acid reactive substances (TBARS). Sensory attributes (odor, color and overall acceptability) were significantly enhanced in treated meat samples (P<0.05). The results indicated that CMC-MMT+ZEO 2%+FCH 1% and Ch-MMT+ZEO 2%+FCH 1% films could be considered as promising packaging materials for minced camel's meat.

Chemical compositions, antioxidant and antimicrobial properties of Ziziphora clinopodioides Lam. essential oils collected from different parts of Iran.

The aims of the present study were to investigate chemical compositions, antioxidant and antimicrobial properties of Ziziphora clinopodioides essential oils (ZEOs) collected from four provinces in western Iran (Ilam, Lorestan, Kermanshah and Kurdestan). Carvacrol was the most abundant constituent in the flower, stem and leaf oil samples of Ilam, Lorestan and Kermanshah regions by 73.12-74.29%, 66.47-66.89% and 65.11-65.32%, respectively. The most abundant components in Kurdestan sample were thymol (55.32-55.60%), followed by γ-terpinene (24.45-24.56%), p-cymene (10.21-10.25%) and α-terpinene (2.75-2.77%). The ZEO inhibited the growth of Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Bacillus subtilis, Bacillus cereus and Staphylococcus aureus at MIC values between 0.03 and 0.04%. Kermanshah oil sample had a higher 1,1-diphenyl-2-picrylhydrazyl radical scavenging (0.30-0.31 mg/ml), ability to prevent the bleaching of ß-carotene (0.09-0.1 mg/ml), ferric reducing power (0.40-0.42 mg/ml) and thiobarbituric acid (0.004-0.006 Meq of malondialdehyde/g) values than that of ZEOs from Ilam, Kurdestan and Lorestan. The strong in vitro antimicrobial and antioxidant activities supports the traditional use of ZEO in the treatments of gastrointestinal diseases.

The properties of chitosan and gelatin films incorporated with ethanolic red grape seed extract and Ziziphora clinopodioides essential oil as biodegradable materials for active food packaging.

The aim of this study was to improve different characteristics including antibacterial, antioxidant, physical and mechanical properties of chitosan (Ch) and gelatin (Ge) films by incorporating Ziziphora clinopodioides essential oil (ZEO; 0 and 1% v/w) and ethanolic grape seed extract (GSE; 0 and 1% v/w). The main compounds of the ZEO were carvacrol (65.22%) and thymol (19.51%). According to our findings, addition of aforementioned materials could improve total phenolic content, antibacterial and antioxidant activities, thickness and also water vapor barrier property. ZEO and GSE reduces swelling index, tensile strength, puncture force and puncture deformation of Ch and Ge films. Pure Ch and Ge films had slightly yellow and white appearances, respectively, while films incorporated with GSE in combination with ZEO had grey appearances. This study indicated the some benefits of addition of ZEO and GSE into Ch and Ge films and their potentials for application as biodegradable active packaging.

Effect of PLA films containing propolis ethanolic extract, cellulose nanoparticle and Ziziphora clinopodioides essential oil on chemical, microbial and sensory properties of minced beef.

This study was conducted to examine the effects of polylactic acid (PLA) film containing propolis ethanolic extract (PE), cellulose nanoparticle (CN) and Ziziphora clinopodioides essential oil (ZEO) on chemical, microbial and sensory properties of minced beef during storage at refrigerated temperature for 11days. The initial total volatile base nitrogen (TVB-N) was 8.2mg/100g and after 7days reached to 29.1mg/100g in control, while it was lower than 25mg/100g for treated samples. At the end of storage time in control samples peroxide value (PV) reached to 2.01meqperoxide/1000g lipid, while the values for the treated samples remained lower than 2meqperoxide/1000g lipid. Final microbial population decreased approximately 1-3logCFU/g in treated samples compared to control (P<0.05). Films containing 2% ZEO alone and in combination with different concentrations of PE and CN extended the shelf life of minced beef during storage in refrigerated condition for at least 11days without any unfavorable organoleptic properties.

Prevalence and pathological lesions of ovine cysticercosis in slaughtered sheep in western Iran.

Cysticercusovis, the intermediate stage of a canine tapeworm, Taenia ovis, produces cystic lesions in the skeletal and cardiac muscle of sheep which, if numerous, will result in the condemnation of an entire carcass. This study was carried out between March 2013 and March 2014 to estimate the prevalence of Taenia oviscysticercosis in sheep slaughtered at the Kermanshah municipal abattoir, in western Iran. Of 69,198 sheep examined, 833 (1.27 %) were infected with cysticerci of Taenia ovis. The prevalence of C. ovis was significantly higher in males than females (P < 0.05). Seasonal analysis revealed significantly higher prevalence in spring (1.8 %) than other seasons (P < 0.005). The heart muscles (29.7 %), diaphragm (18.8 %), masseter muscles (18.2 %) and tongue (15.5 %) were the main predilection sites of the cysts. The cysts of ovinecysticercosis were also identified on the triceps, intercostal muscles, thigh muscles, intestinal mucosa, liver and Spleen. This parasite caused extensive damage resulting in infiltrative, degenerative changes, necrosis and exudation mainly in the vicinity of cysts. The results indicate that the prevalence of C. ovis in this area is high. Therefore improving the standard of disease prevention and control on farms is necessary.

The antibacterial effect of Ziziphora clinopodioides essential oil and nisinagainst Salmonella typhimurium and Staphylococcus aureus in doogh, a yoghurt-based Iranian drink.

Doogh is the most popular and commonly consumed yoghurt-based Iranian drink. The aim of this study was to investigate the antibacterial effects of Ziziphora clinopodioides essential oil (ZEO) at 0.10 and 0.20% concentrations, nisin at 250 and 500 IU mL-1, and their combination against Salmonella typhimurium and Staphylococcusaureus in doogh during storage at 4 ˚C for  9 days. Nine batches were studied as follows: control: no ZEO or nisin added, A: 0.10% ZEO, B: 0.20% ZEO, C: 250 IU mL-1 nisin, D: 500 IU mL-1 nisin, E: 0.10% ZEO + 250 IU mL-1 nisin, F: 0.10% ZEO + 500 IU mL-1 nisin, G: 0.20% ZEO + 250 IU mL-1 nisin and H: 0.20% ZEO + 500 IU mL-1 nisin. Based on gas-chromatography and mass spectrometry, carvacrol (65.22%), thymol (19.51%), p-cymene (4.86%) and É£-terpinene (4.63%) were the major components of ZEO. The populations of S. typhimurium and S.aureus in samples treated with all concentrations of the ZEO and nisin were kept below 1 log CFU mL-1 on day 5 of storage, while the count of S. typhimurium and S.aureus was found as 2.72 ± 0.02 and 2.21 ± 0.00 log CFU mL-1 on day 5 for untreated samples, respectively. The ZEO separately and in combination with nisin, was very effective against these two common food-borne pathogens. The ZEO alone and in combination with nisin could be considered as a potential strong antimicrobial agent that can be used for the growth inhibition of aforementioned bacteria in food products especially doogh.

A retrospective survey of liver flukes in livestock based on abattoir data in Kermanshah, west of Iran.

A retrospective study was carried from 2008 to 2013 to estimate the prevalence of liver flukes in ruminants slaughtered at the abattoir of Kermanshah province, west of Iran. A total of 663,633 animals slaughtered in the 5-year period and totally 1.95 % of livers were condemned due to liver flukes. Fasciolosis were responsible for 0.8, 0.7 and 1.5 % of liver condemnations, whereas 1, 0.8 and 1 % of liver were condemned because of Dicrocoelium dendriticum infection in the sheep, goats and cattle, respectively. A significant difference in the prevalence of liver flukes were observed among studied animals (p < 0.001) and the highest and lowest prevalence were detected in cattle and goats, respectively. Data showed significant seasonal pattern for distomatosis in sheep and goat (p < 0.001). Liver condemnations due to fasciolosis were prevalent in sheep and goats and cattle slaughtered during winter, summer and autumn, respectively, whereas dicrocoeliosis were common in autumn season for sheep and cattle and in winter for goats. This survey provides baseline data for the future monitoring of these potentially important parasitic infections in the region.

A retrospective survey of hydatidosis based on abattoir data in Kermanshah, Iran from 2008 to 2013.

A retrospective study was carried out from 2008 to 2013 to estimate the prevalence of hydatidosis in ruminants slaughtered at the Kermanshah municipal abattoir, in western Iran. A total number of 663,633 livestock (393,585 sheep, 81,080 goats and 188,968 cattle) slaughtered in the 5-year period and overall 9,524 (1.43 %) livers and 13,147 (1.98 %) lungs were condemned. The lungs were more frequently infected with hydatid cysts than the livers in all animal species. The average prevalence of hydatidosis was 2.7 % in this area. The prevalence of Echinococcus granulosus infection recorded in the present study was generally lower than those reported from other regions of Iran. Greater awareness among farmers, destruction of organs containing hydatid cysts, prevention of access of dogs to raw offals and implementation of national rabies control program could be responsible factors. The results showed a significant difference (p < 0.001) in the prevalence of hydatidosis among studied animals with higher prevalence in cattle than sheep, with the lowest prevalence recorded in goats. However the annual prevalence of liver and lung condemnations due to hydatidosis was decreased in some years, but the overall trend had a variable pattern in the prevalence of hydatidosis over the study period. Data showed a significant seasonal pattern for hydatidosis in all studied animals. Liver and lung condemnations due to hydatidosis were higher in the fall for sheep and cattle, whereas in goats were higher in summer. This could be attributed to various factors such as sources of slaughtered animals, changes in management practice and ecological factors. The current results suggest that a systematic investigation that lead to a disease control strategy is required to reduce the economic and public health consequences of hydatidosis. In addition, the present survey provides baseline data for the future monitoring of this potentially important parasitic disease in the region.

Determination of naturally occurring estrogenic hormones in cow's and river buffalo's meat by HPLC-FLD method.

This study was performed to measure and compare the levels of steroid hormones [estrone (E1), 17ß-estradiol (E2), and estriol (E3)] and their conjugated metabolites in cow's and river buffalo's meat in two distinct follicular and luteal phases. Moreover, the possible effect of a heating process on steroid hormone concentration was also investigated. The collected meat (biceps femoris muscle) samples were subjected to liquid extraction, enzymatical deconjugation, and C18 solid-phase extraction. Estrogens were analyzed using high performance liquid chromatography equipped with a fluorescence detector. In the follicular phase the levels of steroid hormones (E1 and E2) in either tested species were higher than the luteal phase. Moreover, in the present study, E1 concentration (free and deconjugated value, 16.2 ± 1.1 ng/L) was found to be the highest phenolic estrogen in beef, while the dominant estrogen in muscle of river buffalo was E2 (free and deconjucated value, 23.3 ± 1.3 ng/L). The study revealed that animal species influenced the concentration of hormones (E1 and E2) in the samples. The heating process did not significantly change (p > 0.05) the levels of estrogens. The further findings of the present study showed that E3 (deconjugated form) was only detected in the buffalo's meat (15.8 ± 1.9 ng/L). These data suggest that although meat is one of the valuable nutrient sources for humans, there are, however, increasing concerns about the safety of meat due to the excessive presence of steroid hormones.

Voltammetric determination of Pb, Cd, Zn, Cu and Se in milk and dairy products collected from Iran: An emphasis on permissible limits and risk assessment of exposure to heavy metals.

This study was carried out to determine the concentrations of some heavy metals in dairy products, collected from five industrial regions in Iran (n = 250 samples) during winter and summer in 2013. The samples were analyzed using the differential pulse anodic and cathodic stripping voltammetry technique. The obtained ranges of mean Pb, Cd, Cu, Zn and Se were as follow: in raw milk 14.0, 1.11, 427, 571, 2.19 µg kg(-1), in pasteurized milk 9.59, 1.0, 378, 447, 1.78 µg kg(-1), in cheese 14.5, 1.25, 428, 586, 1.68 µg kg(-1), in yoghurt 7.54, 0.99, 399, 431, 1.23 µg kg(-1) and in doogh 7.2, 0.84, 320, 369, 0.99 µg kg(-1), respectively. In nearly all cases the concentrations of the metals were below the international permissible limits and do not pose a health concern for the consumption of milk and dairy products in Iran.