Feasibility of lactiplantibacillus plantarum postbiotics production in challenging media by different techniques.

The postbiotic derived from Lactiplantibacillus plantarum bacteria was produced in three culture media: milk, MRS, and whey, and its antibacterial and antifungal properties were evaluated. To investigate the production efficiency of postbiotics, three methods, heating, sonication and centrifugation, were utilized to prepare postbiotics in MRS broth culture medium. The antibacterial potency of the postbiotic was evaluated using the agar well-diffusion method, and MIC and MBC tests were conducted for different treatments. The results of the study showed that the postbiotic prepared in food environments such as milk and cheese whey can have antibacterial and antifungal properties similar to the postbiotic prepared in the MRS culture medium. However, it is possible to enrich food matrices such as milk and cheese whey and make further adjustments in terms of pH settings. Additionally, the thermal process was able to create a nanoscale postbiotic, which is a significant achievement for the application of postbiotics in the food and pharmaceutical industries. The future outlook of postbiotics clearly indicates that the emergence of this generation of probiotics can have an attractive and functional position in the food and pharmaceutical industries. Therefore, future research focusing on this subject will contribute to the development of this generation of postbiotics.

Bio-nanocomposite active packaging films based on carboxymethyl cellulose, myrrh gum, TiO2 nanoparticles and dill essential oil for preserving fresh-fish (Cyprinus carpio) meat quality.

This study developed a composite film for packaging refrigerated common carp fillets using carboxymethyl cellulose (CMC) (1.5 % w/v)/Myrrh gum (MG) (0.25 % w/v) base with the addition of titanium dioxide nanoparticles (TiO2 NPs) (0.25 %, 0.5 %, and 1 %) and Dill essential oil (DEO) (1.5 %, 2.25 %, and 3 %). The film was produced using a casting method and optimized for mechanical and barrier properties. The incorporation of DEO and TiO2 NPs into CMC/MG composite films significantly reduced moisture content (MC) and water vapor permeability (WVP), improved their tensile strength (TS), and increased their antimicrobial and antioxidant properties. Moreover, MG can improve the physicomechanical properties of the CMC/MG composite films. The film components had good compatibility without significant aggregation or cracks. In conclusion, the optimized CMC/MG (1.5 %/0.25 %) film containing TiO2 NPs (0.5 %), and DEO (2.25 %) has the best overall performance and can be a good source for making edible film. Functionally, this bioactive nanocomposite film significantly increased the shelf life of refrigerated fish fillet samples for 12 days by inhibiting microbial growth and reducing the oxidation rate compared to the control sample. The knowledge obtained from this study can guide the development of bio-nanocomposite and biodegradable food packaging films based on CMC/MG to increase the shelf life of food products and environmental protection.

Optimization of Antibacterial, Physical and Mechanical Properties of Novel Chitosan/Olibanum Gum Film for Food Packaging Application.

Chitosan-based films are promising active biodegradable materials with the ability to be enhanced by different materials, including gums. This study aims to optimize the physical (transmittance, water vapor permeability and water solubility), mechanical (tensile strength and elongation at break) and antibacterial (against Staphylococcus aureus and Salmonella Typhimurium) properties of newly fabricated chitosan/olibanum gum (CH/OG) films as a function of different levels of CH (0.5, 0.75, 1, 1.25 and 1.5% w/v) and OG (0.125, 0.25, 0.375, 0.5 and 0.625% w/v), using response surface methodology (RSM). Moreover, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and differential scanning calorimetry (DSC) were used to better characterize the fabricated films. RSM analysis results showed the significant fitting of all dependent variable responses to the quadratic polynomial model. To attain the desirable physical, mechanical and antibacterial responses, the optimal concentrations were 1.31% (w/v) CH and 0.3% (w/v) OG. The encouraging antibacterial, physical and mechanical properties of the developed composites support the application of chitosan/gum blends in active food packaging, particularly for perishable foodstuffs, such as meat and horticultural products.

Sodium alginate edible coating containing Ferulago angulata (Schlecht.) Boiss essential oil, nisin, and NaCl: Its impact on microbial, chemical, and sensorial properties of refrigerated chicken breast.

This study aimed to investigate the effects of sodium alginate (ALG) coating incorporated with Ferulago angulata (Schlecht.) Boiss essential oil (FAEO, 10 and 20 mg/mL), nisin (N, 500 and 1000 IU/mL), and NaCl (2 %) on microbial (lactic acid bacteria, LAB; total viable bacteria, TVC; psychrotrophic bacteria; Pseudomonas; Enterobacteriaceae, and yeast and mold), chemical (pH, PV, TVB-N, and TBARS), sensory (color, odor, texture, and overall acceptance), and antioxidant properties of refrigerated (4 °C) chicken breasts. GC-MS analysis revealed that trans-ß-ocimene (45.36 %) and α-pinene (18.01 %) constituted most of the components in FAEO. The antioxidant properties of FAEO were evaluated via the DPPH method. The IC50 value of FAEO was 562 mg/mL. The results of antimicrobial evaluations indicated that there was no significant difference between control and ALG treatments (p > 0.05). The highest antimicrobial effect was associated with ALG + FAEO2 + N2 + NaCl treatment. The logarithmic reduction of the TVC, psychrotrophic count, Pseudomonas count, Enterobacteriaceae, LAB, as well as yeast and mold count in the ALG + FAEO2 + N2 + NaCl treatment were 1.40, 0.92, 1.20, 1.02, 0.88, and 1 log CFU/g, respectively compared to the control treatment. The initial level of TVB-N in the control treatment was 8.26 mg/100 g, which reached 42.84 mg/100 g at the end of the storage period. In ALG+ FAEO2 + N2 + NaCl treatment, the lowest TVB-N was observed, being 36.37 mg/100 g at the end of the storage period. The initial level of PV in the control treatment was 0.14 meq/kg, which reached 3.04 meq/kg at the end of the storage period. In the treatments containing FAEO, PV was lower than in other treatments, indicating the antioxidant properties of FAEO. There was a significant difference between control and other treatments in pH and TBARS evaluation (p < 0.05). The samples treated with FAEO had a lower pH than control. At the end of the storage period, the TBARS level in the control treatment reached 1.20 mg MDA/kg, while in the treatment of ALG+ FAEO2 + N2 + NaCl treatment, its level was 0.36 mg MDA/kg. The results of sensory properties indicated that in evaluating the color, odor, texture, and overall acceptance on the final days, treatments containing FAEO, nisin, and NaCl had higher scores due to their antimicrobial and antioxidant properties. In conclusion, this study indicated that adding FAEO, nisin, and NaCl to ALG coating would enhance the shelf-life of chicken meat.

Histological and stereological approaches for detection of tissues and fraud in some meat products.

Meat and meat products are highly important sources of protein in the diet. Nowadays, the consumption of meat and meat products has increased owing to modern manufacturing techniques. Due to the economic value of meat, the use of unauthorized tissue is possible in meat products. In some cases, there is fraud in the percentage of meat in meat products to reduce prices. In this study, 34 samples of minced meat, hamburger and sausage were randomly collected from the markets in the northeast of Iran. Then, sections were stained using Hematoxylin and Eosin (H & E), Verhoeff-van-Gieson, Masson's trichrome and periodic acid-Schiff-Alcian blue stains. In this regard, for the first time, the efficacy of stereological technique to determine the percentage of meat listed in sausages and the possible existence of fraud was evaluated. The results showed that, due to the presence of some unusual tissues, histological technique could determine different tissues in meat products. The stereological results of control samples showed a very slight difference; whereas, the results for the samples collected from the city stores showed a distinctive difference regarding the percentage of meat compared to the percentage of label. Skeletal and smooth muscles, blood vessels, nerve, gizzard, adipose tissue, glandular tissue, cartilage, bone, tendon, skin, lymphatic tissues and plant materials were observed. It was confirmed that stereology was a reliable method to determine and confirm the percentage of meat used in meat products.

Physicochemical, antioxidant, antibacterial and antibiofilm activity of Carum copticum essential oil nanoemulsion on Escherichia coli O157:H7 and Listeria monocytogenes.

Carum copticum essential oil (CEO) is used to prevent the growth of food-borne pathogens. The Carum copticum essential oil nanoemulsion (CEON) was prepared using low energy sonication at 0, 2.50, 5.00 and 10 min based on surfactant to-oil ratio (SOR=1). Chemical composition, antimicrobial and antibiofilm properties of CEON were examined. Our data showed that the average diameter of the droplets of CEON was between 46.89 and 120.90 nm. The MICs of CEON and CEO against E. coli O157:H7 and L. monocytogenes were tested. L. monocytogenes was more sensitive than E. coli O157:H7. The sonication time and the total viable bacteria (TVC) in the study were inversely related to each other. Furthermore, CEON at the 4.00 × MIC concentration and contact time of 20 min caused 77.14% and 67.03% reduction of E. coli O157:H7 and L. monocytogenes biofilms, respectively. The antibiofilm activity of CEO was significantly lower than CEON and caused a 62.60% and 43.86% reduction of E. coli O157: H7 and L. monocytogenes biofilms, respectively. The results showed that CEON produced by low energy sonication would have a higher antibacterial efficiency than non-encapsulted essential oil.

Ribose-induced Maillard Reaction as an Analytical Method for Detection of Adulteration and Differentiation of Chilled and Frozen-thawed Minced Veal.

Quality control of meat products is one of the main concerns of consumers, governmental control authorities, and retailers. The purpose of this study was to employ ribose-induced Maillard reaction in detection of meat adulteration and differentiation of fresh-chilled from frozen-thawed minced veal. The browning intensity was assessed through measuring the absorbance at 420 nm with a spectrophotometer as well as the direct analysis of the color and pH. The results showed that CIE b*, CIE a*, and A420* values in the extract of fresh-chilled veal were significantly (p<0.05) higher than frozen-thawed samples. The extract of frozen meat samples stored at -18°C became significantly darker and more yellowish compared to -4°C. The results showed that the A420* value in the frozen-thawed veal stored at -4°C and -18°C was reduced by approximately 17.22±3.53% and 11.68±2.49%, respectively, compared with fresh-chilled veal. The findings also showed that the storage temperature of minced veal and the heating time in this reaction had a significant effect on all tested variables (p<0.0001). The proposed method can be considered as an easy, quick, and inexpensive test for differentiating between the fresh-chilled and frozen-thawed minced veal.

Chemical composition, antioxidative , antibacterial , and time-kill activities of some selected plant essential oils against foodborne pathogenic and spoilage organisms.

Essential oils (EOs) have been utilized as a growth inhibitor of microorganisms. This study was aimed to recognize the composition, antioxidative , antibacterial , and time-kill activities of Origanum vulgare, Zataria multiflora, Syzygium aromaticum; and Cinnamomum verum EOs against Listeria monocytogenes, Escherichia coli O157:H7, Shewanella putrefaciens and Pseudomonas fluorescens. Gas chromatography-mass spectrometry was used to determine the chemical composition of EOs. Disc diffusion, minimum inhibitory concentration, minimum bactericidal concentration, and time-kill methods were used to determine the antibacterial activity of EOs. The antioxidative activity of EOs were determined by 2, 20-diphenyl-1-picrylhydrazyl radical scavenging and ferric reducing antioxidative power methods. All EOs exhibited antibacterial activity, however, Z. multiflora EO was the most effective followed by O. vulgare EO. The lowest antibacterial activity was observed in C. verum EO. The most sensitive among tested bacteria to Z. multiflora and O. vulgare EOs was E. coli O157:H7 and to S. aromaticum; and C. verum EOs were S. putrefaciens and P. fluorescens, respectively. Z. multiflora and O. vulgare EOs were able to kill 85.00% and 80.00% of the E. coli O157: H7 and S. putrefaciens cells in 4 hr, respectively. The highest antioxidative activity was observed in Z. multiflora EO. The tested EOs showed the highest antioxidative activity at a concentration of 2.00 g L-1. Ferric reducing antioxidant power value of Z. multiflora, O. vulgare, S. aromaticum and C. verum was 2.01 ± 0.03, 1.47 ± 0.04, 1.01 ± 0.03, and 0.66 ± 0.34, respectively. High concentrations of tested EOs showed a decrease in antioxidative activity.

Copper, Iron, Manganese, Zinc, Cobalt, Arsenic, Cadmium, Chrome, and Lead Concentrations in Liver and Muscle in Iranian Camel (Camelus dromedarius).

Camel meat as healthy food has received much attention for human consumption. In the present study, liver and muscle from 60 camels (Camelus dromedarius) including 26 males and 34 females were sampled to determine the concentration of As, Cd, Pb, Cr, Cu, Fe, Mn, Zn, and Co using the inductively coupled plasma-optical emission spectrometry (ICP-OES). Based on the obtained results, the average content of essential or toxic elements in the liver and muscle was as follows: 111.2 ± 26.51, 38.57 ± 7.97 (Zn), 3.28 ± 0.79, 2.12 ± 0.49 (Cu), 76.98 ± 14.20, 59.34 ± 11.81 (Fe), 0.87 ± 0.22, 0.48 ± 0.12 (Mn), 0.52 ± 0.27, 0.03 ± 0.01 (Co), ND ± 0.008, 0.012 ± 0.008 (Cd), 7.06 ± 1.58, 3.90 ± 0.86 (Cr), 0.85 ± 0.043, and 0.18 ± 0.02, and 1.12 ± 0.21 (As) mg kg-1. Pb concentration was lower than the detection limit (ND). The results showed that the liver concentrations of Cu, Zn, Fe, Mn, Co, and Cr were significantly higher than those in the muscle. The association of sex, age, region, and sampling period, with a concentration of these elements, revealed that concentration of zinc in the liver and cobalt in the muscle were significantly higher in the male. Also, significantly higher cobalt and zinc concentrations in muscle were seen in the first 6 months of the year. Age-related differences in muscle concentrations were observed for cobalt. The concentration of trace elements and heavy metals in the liver and muscle samples were not correlated. Comparison of heavy metals concentration in both tissues with European Commission regulation showed that except Cd, the other heavy metals had a higher level than the EU standard. The results of this study showed that camel meat can be contaminated with heavy metals, but more investigations are needed.

Optical and electrochemical aptasensors for the detection of amphenicols.

Various methods have been introduced to detect amphenicols in biological samples. However, because of some problems involved in conventional methods, such as time-consuming processes, expensive equipment, and high consumption of reagents, novel strategies for the detection and quantitative determination of amphenicols are required. Aptamer-based biosensors with unique recognition features have gained much attention because of their rapid response, high specificity, and simple fabrication. In this study, we summarized the optical and electrochemical amphenicol aptasensors with a focus on the recent advancements and modern approaches in amphenicol aptasensors to provide readers with an inclusive understanding of their improvement.

Development and characterization of DNA aptamers against florfenicol: Fabrication of a sensitive fluorescent aptasensor for specific detection of florfenicol in milk.

Specific ssDNA aptamers for the antibiotic florfenicol (FF) were developed from an enriched nucleotide library using magnetic beads-based SELEX (Systematic Evolution of Ligands by EXponential enrichment) technique with high-binding affinity. After 12 rounds of selection, thirty-six sequences were obtained that were then divided into five major families, according to the primary sequence similarity. Binding affinity analyses of three fluorescently tagged aptamers belonging to different families demonstrated that the dissociation constants (Kd) were in the low nanomolar range (Kd = 52.78-211.4 nmol L-1). Furthermore, to verify the potential application of the aptamers, a fluorescent aptasensor was fabricated for detecting the FF residue in raw milk samples based on the energy transfer between graphene oxide as the acceptor and fluorescently tagged FF-specific aptamer as the donor. Under optimal conditions, the aptasensor displayed a wide linear range from 5 to 1200 nmol L-1 and a detection limit of 5.75 nmol L-1 with excellent selectivity in milk. The recovery rate in the milk was between 101% ± 0.14% and 110% ± 2.8%, indicating high accuracy. This fluorescent aptasensor possessed considerable potential for rapid analysis of FF in raw milk because of its simplicity of detection. Moreover, the interaction between the aptamer and FF was studied using molecular modeling.

Characterization of a novel biodegradable edible film obtained from Dracocephalum moldavica seed mucilage.

This study investigated the feasibility of using Dracocephalum moldavica seed mucilage (DMSM) as a novel film-forming material. The chemical composition and functional group of the dried DMSM were determined. The DMSM films were prepared using three levels of glycerol (10-40%, w/w). The thermal, micro-structural, barrier, physical, and mechanical properties of the films and their antioxidant activity were examined as a function of the glycerol concentration. As the concentration increased, the films' water vapour permeability, elongation at break (%EB), water solubility, and moisture content significantly increased. But the tensile strength, surface hydrophobicity, melting point, and glass transition point (Tg) decreased significantly. The films became slightly greenish or yellowish in colour but still looked transparent All the DMSM films displayed remarkable antioxidant activities. The electron micrographs showed that the plasticized films had a uniform surface without any obvious cracks or pores. The results of the present study suggest that DMSM as a novel antioxidant edible film with interesting specifications can be used to package several food products.

Frequency of specific agr groups and antibiotic resistance in Staphylococcus aureus isolated from bovine mastitis in the northeast of Iran.

Staphylococcus aureus is generally regarded as a leading cause of mastitis in dairy cattle. The aim of this study was to investigate the pattern of agr groups and any possible relationship between agr groups and antibiotic resistance among S. aureus strains isolated from bovine mastitis in Northeast of Iran. For this purpose, a total of 300 bovine mastitic milk samples were taken from dairy industry farms of Khorasan Razavi Province, Iran. S. aureus were isolated and identified according to the standard methods. Antibiotic susceptibility testing was conducted by disk diffusion method. In this study a total of 31 isolates of S. aureus were evaluated for agrD gene polymorphism by specific primers. Most of the isolates belonged to agr group I (54.8%), followed by agr group III (25.8%) and agr group II (19.4%). There was not any isolates belonging to group IV. Resistance to methicillin in agr group I isolates was more than other groups. Agr groups II and III were quite susceptible to methicillin. Due to high prevalent of S. aureus isolates and high antibiotic resistance rate in bovine mastitic isolates, it is important to verify the characteristics of S. aureus strains in Iran.

Evaluation of antibacterial activity of selected Iranian essential oils against Staphylococcus aureus and Escherichia coli in nutrient broth medium.

The antibacterial effect of different concentrations (0.01 to 15%) of thyme (Thymus vulgaris), peppermint (Mentha piperita L.) caraway seed (Carum carvi), fennel (Foeniculum vulgar), tarragon (Artmesia dracunculus) and pennyroyal (Mentha pullegium) essential oils on the Staphylococcus aureus and Escherichia coli was studied in nutrient broth medium. The MIC values of peppermint, fennel, thyme, pennyroyal and caraway essential oils against Escherichia coli were 0.5 +/- 0.03, 1 +/- 0.03, 0.3 +/- 0.01, 0.7 +/- 0.03 and 0.6 +/- 0.02% and in contrast, for Staphylococcus aureus were 0.4 +/- 0.01, 2 +/- 0.13, 0.1 +/- 0.01, 0.5 +/- 0.02 and 0.5 +/- 0.02%, respectively. The MBC values of peppermint, fennel, thyme, pennyroyal and caraway essential oils for Escherichia coli were 0.7 +/- 0.02, 2 +/- 0.05, 0.5 +/- 0.02, 1 +/- 0.02 and 0.8 +/- 0.02 and for Staphylococcus aureus were 0.5 +/- 0.02, 4 +/- 0.26, 0.3 +/- 0.02, 0.7 +/- 0.02 and 0.6 +/- 0.01, respectively. Statistical evaluation of the results indicated that the essential oils of thyme (Thymus vulgaris) showed the broadest spectrum of action (p < 0.05). Essential oils of peppermint (Mentha piperita), caraway seed (Carum carvi), pennyroyal (Menthae pullegium) and fennel (Foeniculum vulgar) had moderate effect against tested microorganisms and in contrast, tarragon essential oil were less effective against tested microorganisms. In conclusion, essential oils of edible plants could be a potential source for inhibitory substances for some foodborne pathogens. Natural substances that extracted from plants have applications in controlling pathogens in foods.