Antimicrobial Food Research Articles

Development of polylactic acid based antimicrobial food packaging films with N-halamine modified microcrystalline cellulose

Bio-based “green” films with superior antimicrobial activity were developed from polylactic acid (PLA) and cyclic N-halamine 1-chloro-2,2,5,5-tetramethyl-4-imidazolidinone (MC) grafted microcrystalline cellulose (MCC) fibers (herein referred to as g-MCC). The structure of g-MCC was characterized by Fourier Transform Infrared (FT-IR) and Nuclear Magnetic Resonance (NMR) spectroscopy. Results indicated N-halamine MC was successfully grafted onto MCC fibers, with a grafting percentage of 10.24 %. The grafting improved compatibility between g-MCC and PLA, leading to an excellent dispersion of g-MCC in the film matrix, and a superior transparency of the g-MCC/PLA compared to that of the MCC/PLA films. Additionally, the enhanced compatibility the g-MCC/PLA films produced better mechanical properties including mechanical strength, elongation at break and initial modulus than those of both MCC/PLA and MC/PLA composites. With N-halamine, g-MCC/PLA completely inactivated all the inoculated Escherichia coli and Staphylococcus aureus within 5 and 30 min of contact, respectively. More importantly, the migration test showed that the oxidative chlorine of g-MCC/PLA was highly stable than that of MC/PLA films, providing a long-term antimicrobial activity. Finally, preservation test conducted on fresh bread slices further demonstrated its promising applications in the food industry.

A novel formulation of active hexagonal‐compact nano packed composite system using emerging technology for food packaging applications

AbstractWe report the nanoformulation of the active hexagonal‐compact nano‐packed composite system with iron oxide nanoparticles and glossy glutinous chitosan‐tapioca starch biopolymer solution (CTS‐S) for improved potential benefit in food packaging applications. The high pressure processing (HPP) treatment at various pressure level ranging from 100 to 500 MPa at constant time 120 s and optimized the formation of hexagonal nano‐packed system at 500 MPa. The UV–vis spectrophotometer (UV), Fourier transform infrared spectroscopy (FTIR), x‐ray diffraction (XRD) and Zeta potential analysis suggested uniform dispersion of iron oxide nanoparticles and formulated an effective stable nano‐packed composite structure. The XRD analysis of HPP treated sample confirmed the enhancement in material properties with high degree of crystallinity nature. Further studies on antimicrobial effects for HPP treated nano‐packed composite solution exhibited an excellent antimicrobial property and examined over a period of 1 month against microbial deterioration. The study revealed that the novel nano‐packed composite solution could be used as an antimicrobial food packaging material.Practical applicationThe research focused to the development of novel formulation of active hexagonal nano‐packed composite system using non‐thermal high pressure pascalization (HPP) technology. For the first time the design of compact nano structural pattern from the composite solution was developed which expresses an anti‐microbial characteristic even after exposed to environmental condition for a month. The experimental results revealed the practical application of formulated nano‐packed composite system with improvement bio‐physical properties and material characteristics has created an interest toward the food‐borne microbial barrier coating material which can be used in food packaging applications as well as promoting longer shelf life of food products with fabrication of nano‐packaging material as a commercial beneficial aspect in food packaging industries.

Scalable production of antimicrobial food packaging films containing essential oil-loaded halloysite nanotubes

Antimicrobial food packaging holds great promise in extending foods shelf-life and minimizing the risk from foodborne diseases. Specifically, essential oils (EOs) have emerged as promising natural antimicrobials to be incorporated in polymeric materials. Yet, despite the significant research in the field, commercial use of such packaging systems is still in its infancy, due to major barriers, including safety, regulation, benefit-cost ratio, and production capabilities. This work presents industrially viable scale-up production and characterization of antimicrobial low-density polyethylene (LDPE) EOs-containing films, where halloysite nanotubes (HNTs) are employed as functional nanocarriers for EOs. Carvacrol (as a model EO) was loaded into the HNTs nanocarriers and the latter were processed into a masterbatch of LDPE and ethylene vinyl-acetate. The resulting concentrated masterbatch was further diluted and processed into a multilayer film, using a semi-industrial equipment. Carvacrol content in the film was aimed to be low (0.75 wt%) and the produced films displayed a high residual carvacrol content (90 %) in spite of the multiple high-temperature processing steps. Importantly, the resulting films exhibited excellent antifungal efficacy against Penicillium commune, a major food contaminant, in in-vitro micro-atmosphere assays, even after a prolonged storage of 20 months. The film antifungal activity was further studied in two important food systems, bread and fresh cherries, and demonstrated a significant increase of > 73 % in bread shelf-life and 40 % in cherries salability. These results demonstrate that EOs can be incorporated into plastic food packaging systems via industrially viable melt-compounding and extrusion processes, without losing their antimicrobial efficacy. Moreover, we show no migration of HNTs, embedded in the film, into food simulants and address the future perspectives of use of HNTs in food contact materials.

The antimicrobial efficacy of native Australian essential oils in liquid and vapour phase against foodborne pathogens and spoilage microorganisms

Foodborne pathogens and spoilage microorganisms are a source of concern for public health and the food industry. Considering the problem of antimicrobial resistance in microbes, controlling these microorganisms using synthetic antimicrobials is challenging, thus, essential oils are a potential natural alternative. Previous studies have predominantly focussed on the antimicrobial activity of essential oils in the liquid phase. However, in this work we report on the in vitro antimicrobial activity of the liquid and vapour phases of essential oils from native Australian plants Tasmanian mountain pepper (Tasmannia lanceolata), lemon myrtle (Backhousia citriodora), as well as the common herb thyme (Thymus vulgaris) against 11 common food spoilage and pathogenic bacteria and fungi. Initial screening was conducted using the disc diffusion assay. The minimum inhibitory concentration (MIC) of the oils was determined using the broth microdilution assay. The vapour phase antimicrobial activity of the oils was assessed using an inverted petri plate assay and the vapour phase MIC (V-MIC) was quantified using a vapour diffusion assay. GC-MS was adopted to elucidate the compositional profile of the oil in liquid phase. Two extraction methods, namely solid-phase microextraction (HS-SPME) and gas tight syringe headspace sampling (HS) coupled with GC-MS were used for profiling the composition of the volatiles. The findings of this study confirmed the antimicrobial activity of the oils in both liquid and vapour phases, with lemon myrtle and thyme generally showing stronger antimicrobial activity than Tasmanian mountain pepper. The activity in liquid phase was generally higher than the volatiles. However, lemon myrtle and Tasmanian mountain pepper berry volatiles were more effective against Aspergillus niger and Saccharomyces cerevisiae, respectively, relative to the liquid phase highlighting their potential as vapour phase antifungals. In the liquid and gas phases, the major compounds in lemon myrtle were Z-citral (neral) and E-citral (geranial). Polygodial and thymol were the major compounds in Tasmanian mountain pepper and thyme in the liquid phase, respectively. However, the main compounds in their volatiles were p-cymene and γ-terpinene. In conclusion, our research indicates the essential oils' potent vapour phase activity, highlighting their potential application in gaseous diffusion-dependent food applications such as active antimicrobial food packaging.

Global gene-mining strategy for searching nonribosomal peptides as antimicrobial agents from microbial sources

Foodborne pathogenic microorganism contamination and the emergence of drug-resistant bacteria are serious threats to human public health, and cationic nonribosomal peptides (CNRPs) represent a potential solution to this threat. In this report, a global gene mining strategy was used to evaluate 6563 bacterial genomes, including Bacillus sp, Paenibacillus sp and Brevibacillus sp. Using antiSMASH with a Python script filter, we discovered that the Bacillus subtilis group, Paenibacillus polymyxa, Brevibacillus laterosporus and Brevibacillus brevis most likely produce a larger number and greater variety of CNRPs than other Bacilli bacteria. Amino acids lysine, ornithine, 2,4-diaminobutyric acid, leucine, valine, threonine and serine were incorporated in higher abundance (amino acid preference) into these antimicrobial NRPs. Furthermore, flat colony counting, acid-base titrations and Ubbelohde viscometry measurements indicated that brevilaterins from Brevibacillus laterosporus inhibited the growth of various microbes during the first four days and showed exceptional antimicrobial activity against various microbial contaminations in raw milk. Raw milk containing brevilaterins maintained its initial acidity and viscosity over two days. This study should facilitate the identification of new antimicrobial peptides derived from bacteria and their artificial design and modification, allowing those suitable microorganisms identified to be fully utilized in antimicrobial agent production and food industry applications.

Characterization of sodium alginate-based biodegradable edible film incorporated with Vitis vinifera leaf extract: Nano-scaled by ultrasound-assisted technology

Composite biodegradable edible films of sodium alginate were incorporated with Vitis vinifera (V. vinifera) leaf extract (VVLE) and quercetin to develop antioxidative and antimicrobial food packaging. Ultrasound-assisted (US) and bioactive molecule effects on the characteristics of the developed films were investigated. The films were analyzed for structural and physical properties, as well as antioxidative and antimicrobial activities. The incorporation of VVLE significantly improved the bioactive and antimicrobial activity of the developed films. Thickness, elongation at break, and moisture content of ultrasound-assisted pretreated films significantly decreased in comparison to non-treated samples. Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) indicated good compatibility of the components and well-dispersion of bioactive compounds in the alginate matrix. US pretreated film samples had smoother and more homogeneous surfaces than untreated films. The thermal stabilities of films were confirmed with thermogravimetric analysis, which suggested US significantly increased the thermal stability. The biodegradability of the films was demonstrated by soil degradation properties. In particular, the addition of VVLE and application of US pretreatment improved the structural and antimicrobial as well as the antioxidant activities of the developed alginate-based edible films. The overall findings of this study suggest that US pretreatment and VVLE incorporation have a good potential to develop biodegradable edible active films for food packaging.

Production of Silver Nano-Inks and Surface Coatings for Anti-Microbial Food Packaging and Its Ecological Impact

Food spoilage is an ongoing global issue that contributes to rising carbon dioxide emissions and increased demand for food processing. This work developed anti-bacterial coatings utilising inkjet printing of silver nano-inks onto food-grade polymer packaging, with the potential to enhance food safety and reduce food spoilage. Silver nano-inks were synthesised via laser ablation synthesis in solution (LaSiS) and ultrasound pyrolysis (USP). The silver nanoparticles (AgNPs) produced using LaSiS and USP were characterised using transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, UV-Vis spectrophotometry and dynamic light scattering (DLS) analysis. The laser ablation technique, operated under recirculation mode, produced nanoparticles with a small size distribution with an average diameter ranging from 7-30 nm. Silver nano-ink was synthesised by blending isopropanol with nanoparticles dispersed in deionised water. The silver nano-inks were printed on plasma-cleaned cyclo-olefin polymer. Irrespective of the production methods, all silver nanoparticles exhibited strong antibacterial activity against E. coli with a zone of inhibition exceeding 6 mm. Furthermore, silver nano-inks printed cyclo-olefin polymer reduced the bacterial cell population from 1235 (±45) × 106 cell/mL to 960 (±110) × 106 cell/mL. The bactericidal performance of silver-coated polymer was comparable to that of the penicillin-coated polymer, wherein a reduction in bacterial population from 1235 (±45) × 106 cell/mL to 830 (±70) × 106 cell/mL was observed. Finally, the ecotoxicity of the silver nano-ink printed cyclo-olefin polymer was tested with daphniids, a species of water flea, to simulate the release of coated packaging into a freshwater environment.

Turmeric carbon quantum dots enhanced chitosan nanocomposite films based on photodynamic inactivation technology for antibacterial food packaging

The increased demand for food quality and safety has led the food industry to pay urgent attention to new packaging materials with antimicrobial activity. In this study, we combined photodynamic inactivation of bactericidal technology in food packaging materials by incorporating fluorescent carbon quantum dots (CDs) prepared from the natural plant turmeric into a chitosan matrix to prepare a series of active composite food packaging films (CDs-CS). The chitosan film containing CDs had better mechanical properties, UV protection and hydrophobicity. Under irradiation with a 405 nm light source, the composite film was able to produce abundant reactive oxygen species, and the CDs-CS2 film exhibited reductions of approximately 3.19 and 2.05 Log10 CFU/mL for Staphylococcus aureus and Escherichia coli respectively within 40 min. In cold pork storage applications, CDs-CS2 films showed inhibition of the growth of colonization in pork and retarded the spoilage of pork within 10 days. This work will provide new insights to explore safe and efficient antimicrobial food packaging.

Essential Oils: Recent Advances on Their Dual Role as Food Preservatives and Nutraceuticals against the Metabolic Syndrome.

Essential oils (EO) are compounds synthesized by plants as secondary products and are a complex mixture of volatile molecules. Studies have demonstrated their pharmacological activity in the prevention and treatment of metabolic syndrome (MetS). Moreover, they have been used as antimicrobial and antioxidant food additives. The first part of this review discusses the role of EO as nutraceuticals to prevent metabolic syndrome-related disorders (i.e., obesity, diabetes, and neurodegenerative diseases), showing results from in vitro and in vivo studies. Likewise, the second part describes the bioavailability and mechanisms of action of EO in preventing chronic diseases. The third part presents the application of EO as food additives, pointing out their antimicrobial and antioxidant activity in food formulations. Finally, the last part explains the stability and methods for encapsulating EO. In conclusion, EO dual role as nutraceuticals and food additives makes them excellent candidates to formulate dietary supplements and functional foods. However, further investigation is needed to understand EO interaction mechanisms with human metabolic pathways and to develop novel technological approaches to enhance EO stability in food systems to scale up these processes and, in this way, to overcome current health problems.

Proporties and Synthesis of Biosilver Nanofilms for Antimicrobial Food Packaging.

In this original research, biodegradable corn starch (CS) and wheat gluten (wg)-based silver nanofilms were synthesized and analyzed by using goji berry extract taurine (ta), garlic extract (GC), whey powder (wh), and montmorillonite clay nanoparticles. Antibacterial-corn-starch-based nano films were analyzed by using the methods of high-performance liquid chromatography (HPLC), Fourier Transform infrared spectroscopy (FTIR-ATR), X-ray diffraction (XRD), dynamic and mechanical (DMA) analysis, and scanning electron microscopy (SEM). In addition, the antibacterial resistances of the corn starch nano films against the bacteria Salmonella and Staphylococcus aureus (S. aureus) and Listeria monocytogenes were examined and the migration assays were carried out. The migration analysis results of CS1, CS2, and CS3 nanocomposite films were found as 0.305, 0.297, and 0.297 mg/dm2, respectively. The inhibition zone of CS1, CS2, and CS3 nanocomposite films were found as 1547, 386, and 1884 mm2 against Salmonella bacteria. The results show that silver nanofilms are suitable as packaging films for the production of packaging in milk and dairy products, liquid foods, and acidic foods.

Antibacterial activity of cinnamon oil against multidrug-resistant Salmonellaserotypes and anti-quorum sensing potential

The antimicrobial resistance due to Salmonella and other foodborne pathogenic microorganisms, witnessed in recent years, has become a significant health concern. Bacteria use chemical signals to communicate each other and regulate their behavior including virulence. Depending increased antibiotic resistance, new drug development strategies being investigating and the usability of active ingredients of various medicinal and aromatic plants is especially tested as an alternative. The aim of this study was to determine the anti-quorum sensing (QS) activity of cinnamon oil (CO) on pigment production of Chromobacterium violaceum and to evaluate antibacterial activity against multidrug resistant (MDR) S. enterica serotypes. Anti QS activity was tested using biosensor strain and antibacterial activity was determined by microdilution method according to EUCAST standards. CO was found effective on QS mechanisms of Chromobacterium violaceum with pigment inhibition. Nineteen foodborne pathogens isolated from different poultry/cow sourced foods and serotyped as S. enterica serovar Infantis (15), Kentucky (1), Newport (1), Telaviv (1), and Typhimurium (1). S. enterica Infantis strains were found resistant to three or more antibiotics and categorized as MDR. The results concluded that CO has strong antibacterial activity against all S. enterica serotypes with MIC between 0.125 µg ml-1 and 1.0 µg ml-1. This research demonstrates CO is a potential candidate for developing new antimicrobial agents, antiseptic solutions or natural food preservatives against MDR Salmonella isolates also a potential as an anti-QS agent.

Preparation of amino cellulose nanofiber via ε-poly-L-lysine grafting with enhanced mechanical, anti-microbial and food preservation performance

A green and effective method was proposed for producing amino cellulose nanofibers (ε-PL-TOCNs) with a yield of > 60%, which was obtained via ε-poly-L-lysine-grafting of 2, 2, 6, 6-tetramethylpiperidine-N-oxyl (TEMPO)-oxidized cellulose (TOC). The different carboxyl group content of TOC, EDC/NHS molar ratio and their adding ways, ε-poly-L-lysine concentration on the yield, amino content and physicochemical properties of ε-PL-TOCNs were systematically investigated and optimized. The ε-PL-TOCNs with the characteristics of enhanced thermal stability, improved mechanical strength, and fluorescence properties was successfully produced. Moreover, the ε-PL-TOCNs was zwitterionic with both anionic and cationic charges due to the co-existence of carboxyl and amino groups, thus showed excellent dispersion stability in a wide pH range except for the isoelectric point around pH 9. Notably, the ε-PL-TOCNs possessed an excellent anti-microbial effect (>99%) against Escherichia coli and Saccharomyces cerevisiae at 200 μg/mL loading dosage because of the positive role of amino groups, which made it applicable to extend the freshness of fruits. This preparation approach of amino cellulose nanofibers was advantageous over traditional methods owing to green and efficient methods, which expanded the application of cellulose nanofibers in anti-microbial agent and food preservation.

Effect of plasma‐activated water treatment on physicochemical and functional properties of whey protein isolate

SummaryPlasma‐activated water (PAW) is an emerging nonthermal processing method explored for its food disinfection properties. However, the effect of reactive species in PAW on the food composition has not yet been studied. In this study, a simple protein, whey protein isolate (WPI) was used to understand the effect of PAW reactive species on its physicochemical and functional properties. The results showed mild oxidation of WPI evidenced from the decrease in the sulfhydryl group content and increase in the surface hydrophobicity. Increase in the soluble protein content was observed with PAW 45 min treatment. Foam stability of the PAW‐treated samples increased significantly following PAW treatment. However, no linear change in WPI properties was observed with PAW treatment time. Reduction in the thermal stability of samples was observed in 10 and 50 mg mL−1 concentrations with PAW treatment. The SDS‐PAGE analysis revealed that PAW treatment did not form in‐soluble protein aggregation in WPI samples. FTIR spectrum of the treated WPI samples showed that there were no new functional groups formed by the PAW treatment. Increase in β‐sheet, random coil percentage and reduction in α‐helix percentage was observed in 5 mg mL−1 concentration. The results suggest that the reactive oxygen species in the PAW lead to mild oxidation and unfolding of the WPI samples and improved its foam stability.

Optimizing dissolved gas composition in a double-bath-type sonoreactor for efficient production of ultrasonic-activated water with stable oxygen and nitrogen reactive species

Plasma-activated water (PAW), which mainly contains reactive oxygen and nitrogen species, has recently gained considerable attention due to its potential applications in disinfection of food and sustainable agriculture.

A scoping review of factors associated with antimicrobial-resistant Campylobacter species infections in humans.

Human infection with antimicrobial-resistant Campylobacter species is an important public health concern due to the potentially increased severity of illness and risk of death. Our objective was to synthesise the knowledge of factors associated with human infections with antimicrobial-resistant strains of Campylobacter. This scoping review followed systematic methods, including a protocol developed a priori. Comprehensive literature searches were developed in consultation with a research librarian and performed in five primary and three grey literature databases. Criteria for inclusion were analytical and English-language publications investigating human infections with an antimicrobial-resistant (macrolides, tetracyclines, fluoroquinolones, and/or quinolones) Campylobacter that reported factors potentially linked with the infection. The primary and secondary screening were completed by two independent reviewers using Distiller SR®. The search identified 8,527 unique articles and included 27 articles in the review. Factors were broadly categorised into animal contact, prior antimicrobial use, participant characteristics, food consumption and handling, travel, underlying health conditions, and water consumption/exposure. Important factors linked to an increased risk of infection with a fluoroquinolone-resistant strain included foreign travel and prior antimicrobial use. Identifying consistent risk factors was challenging due to the heterogeneity of results, inconsistent analysis, and the lack of data in low- and middle-income countries, highlighting the need for future research.

Novel active edible food packaging films based entirely on citrus peel wastes

This is the first report on mobilizing three value-added compounds from citrus peel wastes to fabricate novel/cost-effective active edible films with multiple functionalities. Pectin extracted from grapefruit peels (GFP) with improved recovery yields (48.35%), displayed better thermal stability and superior physico-chemical properties to commercial citrus pectin ( CPec ) with regard to methoxylation degree, anhydrouronic acid and moisture contents. Active films plasticized with PEG 400 (25% w/w of polymer) were prepared by solution casting upon incorporating 0.04% (w/v) of grapefruit peel methanolic extract (GFPE) and maltodextrin-encapsulated lemon peel extract (MD-LPE) into grapefruit pectin ( GFPec ; 3% w/v) matrix. The bioactive ingredients and the optimally active ( GFPec -GFPE/MD-LPE) film-forming solutions exhibited strong radical scavenging and antimicrobial activities against foodborne pathogens. SEM micrographs of the optimal active film revealed good dispersion and compatibility of ingredients in agreement with the FTIR data that confirmed no modifications in the film's functional groups. GFPE and MD-LPE capsules synergistically enhanced the tensile strength, thermal, water vapor/UV barrier properties and soil biodegradability of the elaborated transparent flexible films compared to CPec -based films. Wrapping of artificially contaminated cherry tomatoes with optimal active films inhibited the growth of a four-strain cocktail suspension of E. coli O157:H7 by ∼1.6 log units after 6 days of chilled storage. Overall, the study highlights the benefits of citrus wastes valorization, provides evidence of potential applicability of the fabricated novel edible GFPec -based films as candidates for antimicrobial food packaging, shelf life extension of fresh-cut produce, and supports their consideration as promising eco-friendly alternatives to synthetic food packaging materials. • Three value-added compounds were mobilized from citrus peels for film fabrication. • High methoxyl grapefruit pectin showed superiority to commercial citrus pectin. • Free and encapsulated extracts had remarkable antioxidant and cytotoxic activities. • Incorporating both ingredients enhanced thermal and barrier properties of films. • The novel active film inhibited E. coli O157:H7 growth on wrapped cherry tomatoes.

Improving barrier and antibacterial properties of chitosan composite films by incorporating lignin nanoparticles and acylated soy protein isolate nanogel

Chitosan (CS) films have demonstrated strong antibacterial properties, excellent biocompatibility and biodegradability, but poor UV blocking, oxygen and water barrier and mechanical properties limit their application in antimicrobial food packaging. In this study, CS films were incorporated with nanofillers, including lignin nanoparticles (LNP, 1–5 wt %) and acylated soy protein isolate nanogel (ASPNG, 3–7 wt %) to improve their tensile strength, oxygen and water barrier, UV blocking and antibacterial properties. SEM images illustrated that the addition of LNP and ASPNG significantly affected the surface morphology of the CS film. Meanwhile, LNP incorporation improved UV blocking property of composite film, while an improved sustained antibacterial property was achieved with ASPNG incorporation. Interestingly, CS composite film incorporated with 3% LNP and 5% ASPNG showed a remarkable increase in tensile strength (37.29–54.29 MPa) and decreased oxygen barrier property (5.73–2.83 cm 3 /m 2 ·24h MPa) relative to pure CS film. It is worth mentioning that the bacterial counts in samples treated by 3% LNP/5% ASPNG-CS composite film decreased approximately 2.37 log CFU/mL, which exhibited higher antibacterial activity than other composite films. However, this study also demonstrated that incorporation of LNP and ASPNG slightly decreased the light transmission and increased surface roughness of CS film. All in all, the CS composite film with enhanced mechanical, barriers, antibacterial properties were obtained by incorporating an appropriate proportion of LNP and ASPNG and could further be utilized as a promising antibacterial food packaging material. • Lignin nanoparticles (LNP) and acylated soy protein isolate nanogel (ASPNG) were fabricated. • LNP and ASPNG incorporation improved tensile strength and elongation at break of the film. • LNP and ASPNG incorporation improved oxygen and water vapor barrier properties of the film. • 3% LNP/5% ASPNG enhanced CS film's potassium sorbate sustained release ability. • 3% LNP/5% ASPNG-CS film had higher antibacterial activity than pure chitosan film.

Antioxidant Activities of Natural Polysaccharides and Their Derivatives for Biomedical and Medicinal Applications.

Many chronic diseases such as Alzheimer's disease, diabetes, and cardiovascular diseases are closely related to in vivo oxidative stress caused by excessive reactive oxygen species (ROS). Natural polysaccharides, as a kind of biomacromolecule with good biocompatibility, have been widely used in biomedical and medicinal applications due to their superior antioxidant properties. In this review, scientometric analysis of the highly cited papers in the Web of Science (WOS) database finds that antioxidant activity is the most widely studied and popular among pharmacological effects of natural polysaccharides. The antioxidant mechanisms of natural polysaccharides mainly contain the regulation of signal transduction pathways, the activation of enzymes, and the scavenging of free radicals. We continuously discuss the antioxidant activities of natural polysaccharides and their derivatives. At the same time, we summarize their applications in the field of pharmaceutics/drug delivery, tissue engineering, and antimicrobial food additives/packaging materials. Overall, this review provides up-to-date information for the further development and application of natural polysaccharides with antioxidant activities.

Plasma-treated LDPE film incorporated with onion and potato peel extract – A food packaging for shelf life extension on chicken thigh

This study aimed to develop a new antimicrobial food packaging from low-density polyethylene (LDPE) film containing the natural extract. In this regard, onion and potato peel extract were obtained using the ultrasound-assisted method. The polyethylene film surface was exposed to atmospheric plasma treatment to improve the wettability properties and subsequently increase the attachment of the extract on the film surface. Results showed significant changes in surface hydrophilicity; the contact angle reduced from 89° to 42° after 45 s treatment (350 W). The 10 % and 20 % concentrations of extracts were coated on the plasma-treated film’s surface, separately and in their combinations, by immersing the film into the extract solutions. The absorption and release rate of the film samples containing potato peel extract (PPE) was considerably higher than the other samples. However, the film containing onion peel extract (OPE) showed the highest phenolic content and antioxidant activity. The antibacterial activity of film samples demonstrated the significantly higher antibacterial activity of OPE than PPE. Results introduced the plasma-treated film containing 20 % OPE as the most effective antimicrobial film used for packaging chicken thighs. The chicken thigh samples packaged by antimicrobial film showed a lower value of thiobarbituric acid (0.09 mg MDA/kg sample), total volatile nitrogen (14.27 mg/100 g), and total viable count (4.05 log CFU/g) compared to the control sample (pristine film) during 6 days’ storage period. Our results suggest that plasma-treated film containing 20 % OPE has potential application as a functional food packaging film in food antimicrobial packaging.

Combining analytical epidemiology and genomic surveillance to identify risk factors associated with the spread of antimicrobial resistance in Salmonella enterica subsp. enterica serovar Heidelberg.

Antimicrobial resistance (AMR) has become a critical threat to public health worldwide. The use of antimicrobials in food and livestock agriculture, including the production of poultry, is thought to contribute to the dissemination of antibiotic resistant bacteria (ARB) and the genes and plasmids that confer the resistant phenotype (ARG). However, the relative contribution of each of these processes to the emergence of resistant pathogens in poultry production and their potential role in the transmission of resistant pathogens in human infections, requires a deeper understanding of the dynamics of ARB and ARG in food production and the factors involved in the increased risk of transmission.