Comparative physical, antioxidant, and antimicrobial properties of films prepared by dissolving chitosan in bioactive vinegar varieties.

Solvent casting following the dissolution of chitosan in aqueous acetic acid is the most widely used method for preparing chitosan films. In this study, an economical and practical way is proposed to improve the physicochemical properties of chitosan films by using vinegar varieties both as solvents and as bioactive additives to improve the properties of the films. Chitosan films were prepared by dissolving chitosan in pomegranate, grape, apple, and hawthorn vinegar. Vinegar contains bioactive phenolics and different organic acids together with acetic acid, depending on the main raw material from which it is obtained. The films' mechanical, optical properties, antioxidant and antimicrobial activities were compared with each other and with the chitosan film prepared by dissolving chitosan in acetic acid. The antioxidant and antimicrobial properties of chitosan films prepared with vinegar increased. The use of vinegar as a solvent increased the UV light barrier properties of the films. Improved antimicrobial, antioxidant, optical, and elastic properties of films prepared by dissolving chitosan in vinegar varieties are promising in applications of these films as potential and economic food packaging materials.

Antioxidant and antimicrobial chitosan films enriched with aqueous sage and rosemary extracts as food coating materials: Characterization of the films and detection of rosmarinic acid release.

Chitosan films containing aqueous extracts of sage and rosemary were prepared as a potential food coating material with antioxidant and antibacterial properties. The effect of adding extracts at different concentrations on the mechanical, physical, and optical properties of the films was investigated. The addition of the extracts significantly increased Young's modulus values of the films compared to the chitosan film, and a significant decrease was observed in the swelling percentage and water vapor permeability of the films. Since all the prepared films were ionically cross-linked, the increase in water solubility of the films with the addition of the extract was at a low level. The release of rosmarinic acid, which is found in significant amounts in both plants, from the films was monitored by the capillary electrophoresis. The antioxidant properties imparted to the films by the addition of plant extracts were determined by DPPH and FRAP methods. The addition of plant extracts increased the antimicrobial property of chitosan films against Staphylococcus aureus and Escherichia coli. Films containing sage and rosemary extracts showed potential for use as food coating materials.

A high-resolution melting assay to differentiate a peste des petits ruminants virus vaccine strain from field isolates in Turkey.

Peste des petits ruminants (PPR) mostly affects small ruminants. Vaccination with attenuated vaccines derived from PPR virus (PPRV) provides successful protection against the disease. However, current molecular methods are unable to distinguish vaccine strains from field strains. In this study, we used an EvaGreen-based high-resolution melting (HRM) assay to differentiate a PPRV vaccine strain (Nigeria 75/1) from Turkish field isolates of lineage IV based on melting peaks and melting profiles.

Preparation and characterization of antibacterial nano cerium oxide/chitosan/hydroxyethylcellulose/polyethylene glycol composite films.

Due to the rapidly increasing biological applications and antibacterial properties of versatile nano cerium oxide particles, the effects of these particles on chitosan-based films were investigated. Chitosan-based composite films with and without cerium oxide nanoparticles (NPs) were prepared by a casting method. Hydroxyethylcellulose (HEC) was used for the flexibility of films, and polyethylene glycol (PEG) was used as a plasticizer in the blending stage of film preparation. Characterizations of films were done by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TGA), and dynamic mechanical analyzer (DMA). Cerium oxide nanoparticle incorporation enhanced the antibacterial activity of chitosan-based films against Escherichia coli and Staphylococcus aureus. This composite film is proposed as packaging or coating material because of its flexibility, antibacterial efficacy, and good mechanical strength.

Synthesis of biologically active copper oxide nanoparticles as promising novel antibacterial-antibiofilm agents.

In this study, we aimed to synthesize copper oxide nanoparticles (CuONPs) mediated by plant extract in an environmentally friendly way and to reveal their potential biological activities. Here we synthesized CuONPs by using different concentrations of aqueous leaf extract of Thymbra spicata at 80 °C to obtain Ts1CuONPs and Ts2CuONPs. Biosynthesized nanoparticles were characterized by using UV-Vis, AFM, FTIR, SEM-EDS, TEM, DLS and zeta potential analysis. The antibacterial activity of the nanoparticles was determined by calculation of the inhibition zone and minimum inhibitory concentration against selected bacterial strains. Moreover, the antioxidant activity of the as-synthesized nanoparticles was evaluated based on DPPH radical scavenging activity. The results indicate that the as-synthesized NPs have an average size of 26.8 and 21 nm for Ts1CuONPs and Ts2CuONPs, respectively. The formed CuONPs have more antibacterial action on gram-positive bacteria compared to gram-negative bacteria. In addition, CuONPs demonstrated good inhibition activity against biofilm formation of Staphylococcus aureus (S. aureus). Furthermore, the results showed that the smaller size of the CuONPs caused the higher cytotoxicity on L929 mouse fibroblast cells. The as-synthesized CuONPs exhibit antibacterial and antibiofilm potential against S. aureus, indicating that they may be attractive candidates to use in future therapeutic applications.

Antibacterial and Smear Layer Removal Efficacy of Er:YAG Laser Irradiation by Photon-Induced Photoacoustic Streaming in Primary Molar Root Canals: A Preliminary Study.

OBJECTIVE: The objective of this study was to compare antibacterial and smear layer removal efficacy of the erbium:yttrium-aluminium-garnet (Er:YAG) laser irradiation by photon-induced photoacoustic streaming (PIPS), neodymium:yttrium-aluminium-garnet (Nd:YAG), and diode lasers and conventional irrigation agent in primary molar root canals. BACKGROUND: The selection, application, and activation of the irrigant are important factors affecting the success of the endodontic treatment. MATERIALS AND METHODS: Distal root canals of human primary mandibular molar teeth used for antimicrobial efficacy evaluation were first inoculated with Enterococcus faecalis (n = 25). Smear layer removal efficacy was evaluated on the noninoculated specimens (n = 20). The root canals in the first treatment groups were irrigated with a conventional technique using 5% sodium hypochlorite (NaOCl). In the laser groups, the root canals were irradiated with either Nd:YAG (1064 nm) or diode lasers (940 nm) followed by NaOCl irrigation agent. In the fourth groups, the NaOCl irrigation agent was activated with an Er:YAG laser (2940 nm) by PIPS tip using nonablative settings. Antibacterial efficacy was determined by viable counts of E. faecalis after treatments. The treated root canals were examined by scanning electron microscopy to determine the smear layer removal efficacy of treatments. RESULTS: Statistically significant (p < 0.05) reductions in the number of E. faecalis were achieved in Nd:YAG and diode laser groups and Er:YAG laser by PIPS-activated irrigation groups compared to the NaOCl group. Er:YAG laser by PIPS-activated irrigation resulted in more cleaning of the root canal walls and a higher quantity of open tubules. CONCLUSIONS: These findings suggest that Er:YAG laser by PIPS-activated irrigation can be considered as an effective irrigant agitation technique in pediatric endodontics.

Disinfection of polyvinyl siloxane impression material by gaseous ozone.

STATEMENT OF PROBLEM: Impression materials must be disinfected to avoid cross-contamination before they are sent to the dental laboratory. However, whether aqueous state disinfectants affect material wettability is unclear. PURPOSE: The purpose of this in vitro study was to compare the efficacy of gaseous ozone and sodium hypochlorite (NaOCl) in disinfecting light-body consistency hydrophilized polyvinyl siloxane (PVS) impression specimens inoculated with a cocktail of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis. The effect of both disinfectants on the wettability of the material was also evaluated on uninoculated specimens. MATERIAL AND METHODS: Disk-shaped specimens (N=140) were subjected to the either gaseous ozone or NaOCl for up to 30 minutes at room temperature. In the ozone group, the specimens were ozonated under a continuous stream of gaseous ozone at a concentration of 12.8 mg/L, while the specimens in the NaOCl group were immersed into 0.5% NaOCl solution. Reductions in the size of the bacterial population at the end of the exposure times were determined by the plate count technique. The contact angle measurements on the impression surface were used to determine the wettability of the specimens. Results were analyzed with 1-way ANOVA followed by the Tukey post hoc test (α=.05). RESULTS: The material exposed to both disinfectants for 30 minutes demonstrated a reduction in the number of bacteria of up to more than 3 log. The contact angle of water on the material increased significantly (P<.001) after only 5 minutes of contact with the NaOCl solution. However, the treatment with gaseous ozone for 30 minutes resulted in a reduced contact angle (P<.001). CONCLUSIONS: Gaseous ozone treatment was identified as a promising method of disinfecting polymerized PVS impression materials because of its positive effect on the wettability of the material.

Antimicrobial cerium ion-chitosan crosslinked alginate biopolymer films: A novel and potential wound dressing.

Wound dressings require good antiseptic properties, mechanical strength and, more trustably, natural material ingredients. Antimicrobial properties of cerium ions and chitosan are known and alginate based wound dressings are commercially available. In this study, the advantages of these materials were combined and alginate films were crosslinked with cerium(III) solution and chitosan added cerium(III) solution. Films were characterized by Fourier transform infrared spectroscopy (FTIR), light transmittance, scanning electron microscopy (SEM), swelling experiments, water vapor transmittance tests, and mechanical stretching tests. The antibacterial and physical properties of the films were compared with those of conventional calcium alginate films. Both cerium ion crosslinked and cerium ion-chitosan crosslinked alginate films gained antibacterial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. Cerium alginate-chitosan films showed high resistance to being deformed elastically. Results show that cerium alginate-chitosan films can be flexible, ultraviolet-protecting, and antibacterial wound dressings.

Antimicrobial and physical properties of chitosan films incorporated with turmeric extract.

In this study, the effects of turmeric extract incorporation on the antibacterial and physical properties of the chitosan films were evaluated. Turmeric containing chitosan-based film was produced with casting procedure and cross-linked with sodium sulfate. Mechanical, optical, thermal properties, and water vapor permeability of the films were studied. The addition of turmeric to chitosan film significantly increased the tensile strength of the film and improved the ultraviolet-visible light barrier of the film. Infrared spectroscopy analysis suggested an interaction between the phenolic compounds of the extract and amin group of chitosan. Antimicrobial activity of the chitosan films was studied against Salmonella and Staphylococcus aureus by plate count agar technique and a better antimicrobial activity was observed with turmeric incorporation. Turmeric incorporated chitosan films with enhanced antimicrobial activity and film stiffness can be suggested as a promising application for food packaging.

Biofilm formation by Staphylococcus aureus isolates from a dental clinic in Konya, Turkey.

The ability of Staphylococcus aureus to form biofilm is considered to be a major virulence factor influencing its survival and persistence in both the environment and the host. Biofilm formation in S. aureus is most frequently associated with production of polysaccharide intercellular adhesion by ica operon-encoded enzymes. The present work aimed at evaluating the in vitro biofilm production and presence of the icaA and icaD genes in S. aureus isolates from a dental clinic in Konya, Turkey. The surfaces of inanimate objects were sampled over a period of six months. S. aureus isolates were subjected to Congo Red Agar (CRA) and crystal violet (CV) staining assays to evaluate their ability of biofilm production, while the presence of the icaA and icaD genes was determined by polymerase chain reaction. S. aureus contamination was detected in 13.2% of the environmental samples. All the 32 isolates were observed to be positive for both the icaA and icaD genes. Phenotypic evaluations revealed that CV staining assay is a more reliable alternative to CRA assay to determine biofilm formation ability. A high percentage of agreement (91%) was observed between the results from CV staining and ica genes' detection assays. Phenotypic and genotypic evaluations should be combined to detect biofilm formation in S. aureus. Our findings indicate that dental clinic environments should be considered as potential reservoir for biofilm-producing S. aureus and thus cross contamination.

Antimicrobial and mechanical properties of dental resin composite containing bioactive glass.

BACKGROUND: The aim of this study was to evaluate the antimicrobial efficacy and mechanical properties of dental resin composites containing different amounts of microparticulate bioactive glass (BAG). METHODS: Experimental resin composites were prepared by mixing resin matrix (70% BisGMA and 30% TEGDMA) and inorganic filler with various fractions of BAG to achieve final BAG concentrations of 5, 10 and 30 wt%. Antimicrobial efficacy was assessed in aqueous suspension against Escherichia coli, Staphylococcus aureus and Streptococcus mutans and in biofilm against S. mutans. The effect of incorporation of BAG on the mechanical properties of resin composite was evaluated by measuring the surface roughness, compressive strength and flexural strength. RESULTS: Under the dynamic contact condition, viable counts of E. coli, S. aureus and S. mutans in suspensions were reduced up to 78%, 57% and 50%, respectively, after 90 minutes of exposure to disc-shaped composite specimens, depending on the BAG contents. In 2-day-old S. mutans biofilm, incorporation of BAG into composite at ratios of 10% and 30% resulted in 0.8 and 1.4 log reductions in the viable cell counts compared with the BAG-free composite, respectively. The surface roughness values of composite specimens did not show any significant difference (p>0.05) at any concentration of BAG. However, compressive and flexural strengths of composite were decreased significantly with addition of 30% BAG (p<0.05). CONCLUSIONS: The results demonstrated the successful utilization of BAG as a promising biomaterial in resin composites to provide antimicrobial function.

Inactivation of Alicyclobacillus acidoterrestris spores in aqueous suspension and on apples by neutral electrolyzed water.

Alicyclobacillus acidoterrestris can be difficult to control in fruit juices as their spores survive juice pasteurization temperatures and may subsequently germinate and grow. Contaminated fruits can be regarded as a major source of spoilage caused by A. acidoterrestris in fruit juices. The objective of this study was to evaluate the efficacy of neutral electrolyzed water (NEW) in reducing the number of A. acidoterrestris spores in aqueous suspension and on surface-inoculated apples. Its effectiveness was compared with that of sodium hypochlorite (SH) solutions at free chlorine concentrations of 50 and 200mg/L. Viable spore counts in test suspensions were significantly (P<0.05) reduced after exposure to NEW (200mg/L free chlorine) for 1 min. However, NEW (50mg/L free chlorine) and SH solutions were unable to significantly (P>0.05) reduce the number of viable spore during the same exposure period. More than 5 log reduction in spore counts was achieved by NEW solution containing 200mg/L free chlorine after 5 min of exposure. Exposure to NEW solutions for 3 min yielded more than 4 log reductions in the number of viable spores on apple surfaces. At the same concentrations of free chlorine, NEW was three to more than ten-fold effective than SH in reducing viability of A. acidoterrestris spores in aqueous suspension and on apple surfaces. This finding suggests that NEW can be considered as an effective disinfectant for the control of A. acidoterrestris on fruits.

Efficacy of ozone against Alicyclobacillus acidoterrestris spores in apple juice.

Alicyclobacillus acidoterrestris survives during the typical pasteurization process and can cause the spoilage of fruit juices thanks to its spore forming and thermo-acidophilic nature. In recent years, A. acidoterrestris has become a major concern to the fruit juices industry worldwide. This study was undertaken to evaluate ozone for the reducing number of A. acidoterrestris spores in apple juice. Apple juice inoculated with A. acidoterrestris spores was bubbled with continuous stream of two different constant concentrations (2.8 and 5.3mg/L) of ozone at 4 and 22 °C up to 40 min. Level of A. acidoterrestris spores in juice decreased by 2.2 and 2.8 log after 40 min of ozonation at 4 °C with concentrations of 2.8 and 5.3mg/L, respectively. Treatments at 22 °C for 40 min with 2.8 and 5.3 mg/L ozone resulted in 1.8 and 2.4 log reductions of spore viability, respectively. At the ozone concentration of 5.3 mg/L, significant (P<0.05) reductions were observed in total phenolic content of juice at both temperature levels. However, treatments performed at 2.8 mg/L were observed to have no significant (P>0.05) effect on total phenolic content. The results presented in this study indicate that over the 2 log reduction in the count of A. acidoterrestris spores in apple juice can be achieved by bubbling ozonation at 4 °C without causing a significant decrease in total phenolic content of product. Therefore, it can be suggested that bubbling ozonation is a promising method for the control of A. acidoterrestris in fruit juices.

Efficacy of gaseous ozone against Salmonella and microbial population on dried oregano.

Interest in potential food applications of ozone has expanded in recent years in response to consumer demands for green technologies. This study was conducted to evaluate the efficacy of gaseous ozone for the microbial reduction and elimination of Salmonella on dried oregano. Ozone treatment was performed up to 120min under continuous stream of two different constant ozone concentrations (2.8 and 5.3mg/L). Significant (P<0.05) reductions of 2.7 and 1.8 log were observed in aerobic plate counts and yeast and mold counts after ozonation at 2.8mg/L for 120min, respectively. Ozonation performed at 5.3mg/L for 90min yielded a reduction of over 3.2 log in the aerobic plate counts. Initial population of a cocktail of Salmonella serotypes (S. Typhimurium, S. Newport and S. Montevideo) on inoculated oregano determined as 5.8logCFU/g decreased significantly by 2.8 and 3.7 log after ozonation at 2.8 and 5.3mg/L for 120min, respectively. Sensory evaluation results suggested that over the 2 log reduction in the microbial population can be obtained on dried oregano by gaseous ozone treatments with an acceptable taste, flavor and appearance. The results demonstrated that the gaseous ozone treatment is an effective alternative microbial reduction technique for dried oregano.

Antibacterial effectiveness of chitosan-propolis coated polypropylene films against foodborne pathogens.

Antibacterial properties of chitosan are well documented in the literature. However its antibacterial effectiveness in the film form is controversial due to the methodological differences in test methods used. In this study, antibacterial effectiveness of chitosan-coated polypropylene films alone and incorporating ethanolic extract of propolis (EEP) were evaluated against six foodborne pathogens (Bacillus cereus, Cronobacter sakazakii, Escherichia coli O157:H7, Listeria monocytogenes, Salmonella typhimurium and Staphylococcus aureus) using the ISO 22196 method designed for the antibacterial treated plastic products. The results demonstrated that chitosan coated film exhibited the broad-spectrum antibacterial activity. Incorporation of EPP to coating at 10% (propolis resin/chitosan) enhanced antibacterial activity against all pathogens tested. Results of this study revealed that chitosan has antibacterial activity in the film form and that propolis is a promising antimicrobial for the food packaging applications.

Fate of Salmonella during sesame seeds roasting and storage of tahini.

Tahini is usually consumed without further heat treatment, and roasting of sesame seeds is the only Salmonella inactivation step in its traditional production process. This study examined the efficiency of the roasting process in the elimination of Salmonella from sesame seeds and the survival of Salmonella in tahini during storage. Sesame seed and tahini samples were inoculated with a cocktail of three serotypes of Salmonella (S. Typhimurium, S. Newport and S. Montevideo). Complete inactivation of Salmonella in sesame seeds, inoculated with 5.9 log cfu/g, was achieved by roasting at 110 °C for 60 min, 130 °C for 50 min, or 150 °C for 30 min. Salmonella levels in tahini (aw=0.17) inoculated with 5.6 log cfu/g and stored for 16 weeks at 22 or 4 °C decreased by 4.5 and 3.3 log, respectively. Results of this study demonstrated that the standard roasting process is sufficient to inactivate Salmonella in sesame seeds and low water activity of tahini prevents microbial growth, but its composition allows Salmonella to survive for at least 16 weeks. Therefore, prevention of cross-contamination after roasting is crucial for food safety.

Effect of ultrasonic treatment on reduction of Esherichia coli ATCC 25922 and egg quality parameters in experimentally contaminated hens' shell eggs.

BACKGROUND: In this study, hen eggs which were experimentally contaminated with Esherichia coli ATCC 25922 were used. Contaminated eggs were washed statically (S5 to S30; 0 kHz) and by ultrasonic waves (U5 to U30; 35 kHz) for given applications of time (5, 15 and 30 min), then the eggs were stored at 22°C for 14 days. RESULTS: Depending on the time of ultrasonic application, a significant increase in egg shell strength (P < 0.01) was recorded. The highest value of the Haugh unit (67.93, 1 day) was observed on the eggs which were washed by ultrasonic waves. Yolk width values of ultrasonic washed eggs diminished. E. coli was completely removed by 30 min of ultrasonic application. During storage E. coli growth was not detected on the eggs which were washed by ultrasonic waves except the eggs in U5 group (2.04 log CFU eggshell⁻¹) on the first day of storage. CONCLUSION: Depending on the time of ultrasonic application a significant increase in egg quality parameters (shell strength, albumen height, Haugh units, and yolk height) were observed. The application of ultrasound led to a significant reduction in E. coli numbers on egg shells.

Evaluation of RapidChek Select for the screening of Salmonella in meat and meat products.

The efficacy of the RapidChek Select, an alternative rapid method based on lateral flow technology, for the screening of Salmonella in meat and meat products, was compared with the current ISO reference culture-based method. Of the 265 routine samples examined, 61 were found to be positive for Salmonella by both methods. The percentage of agreement between the results of two methods was determined as 98%. All presumptive positive results obtained by the RapidCheck Select were confirmed to be positive by ISO method. For five samples ISO method gave positive result, while RapidChek Select gave negative result. The limit of detection (LOD(50)) of RapidChek Select and ISO methods for minced beef meat samples were 1.00 cfu/25 g and 0.63 cfu/25 g, respectively. For sausage samples, LOD(50) of both methods were 2.00 cfu/25 g. As a result, the high agreement between two methods and the comparable detection limits of two methods showed that the RapidChek Select is an efficient alternative method for the screening of Salmonella in meat and meat products.

Synthesis of novel tripodal-benzimidazole from 2,4,6-tris(p-formylphenoxy)-1,3,5-triazine: structural, electrochemical and antimicrobial studies.

Four new tripodal-benzimidazole derivatives were synthesized by Schiff base reaction between 2,4,6-tris(p-formylphenoxy)-1,3,5-triazine (TRIPOD) and different diamine derivatives. The structures of the obtained compounds were identified by FT-IR, (1)H NMR, (13)C NMR and UV-vis spectral data, thermal analysis and elemental analysis. Electrochemical behaviors of the compounds were studied by cyclic voltammetry in DMF including 0.1 M [NBu(4)] [PF(6)]. The voltammograms showed peaks having similar characteristics except tripodal-benzimidazole including -NO(2) derivative. In addition, their antimicrobial activities were evaluated by using the standard disk diffusion method in dimethylformamide media. The activities were determined against 4 bacteria cultures by comparing to those of gentamycin.