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Aims: Phosphorus (P), like nitrogen (N), commonly impacts the structures and functions of terrestrial ecosystems. Global changes (N deposition) and land-use intensification (mowing) may influence the components of P cycling in grassland ecosystems, especially soil organic P mineralization, which provides P for plants and microbes. It remains unclear how soil annual organic P mineralization rate responds to mowing and N addition and its potential mechanisms in the semi-natural grasslands. Methods: We conducted a five-year field experiment that included mowing (mown and unmown) and N additions (0, 2.5, 5, 10, 20, and 40 g N m−2 yr−1) to explore the responses of and main factors controlling soil organic P mineralization to these treatments in a semi-natural grassland—Songnen Meadow Steppe. Results: We found that N additions enhanced the rate of soil organic P mineralization in semi-natural grassland. The magnitude of positive effects of N additions was larger in mown plots than unmown plots. Compared with no N addition, the rates of soil annual organic P mineralization increased 39.04, 46.88, 90.57, 58.82, and 67.97% under mown as the N input increased, and 23.89, 24.13, 25.46, 33.42 and 34.81% under unmown. The alkaline phosphatase (ALP) activity was the main driver which controlled soil annual organic P mineralization rates under N additions in unmown plots, and the plant aboveground biomass, soil microbial community composition, and ALP activities were the main drivers under N additions in mown plots. Our results indicate that mowing modulated the effects of N additions on the annual organic P mineralization rate in soil. Conclusions: The soil annual organic P mineralization rate had stronger dependence on the shifts in plant-soil–microbe variables with N additions in the mown conditions than in the unmown conditions, which highlighted that P cycling may be more susceptible to future environmental changes induced by N deposition under mowing in semi-natural ecosystems. Our study provided the new insight of that plant and soil interactions have an important role in maintaining the supply of P, and they may drive soil organic P mineralization in P-deficient ecosystems as N deposition increases. [ABSTRACT FROM AUTHOR]

Farmland use challenges reflect the current complexities facing China's agricultural economic development. This study focuses on 70 counties in Hubei Province of China, with the objective of exploring the spatial relationship between green transition of farmland use and agricultural economic growth. Furthermore, it seeks to quantify their effects and assess regional heterogeneity. Here are the findings: (1) There is a notable positive spatial correlation observed between agricultural economic growth and the various subsystems as well as factor layers of the green transition of farmland use. (2) The optimization of the quantity and form of farmland has a positive promoting effect on agricultural economic growth in both the local county and adjoining counties. In contrast, the spatial pattern, ecological function, intensive use, and environmental friendliness of farmland have a negative effect. (3) The influence factors of the green transition of farmland use on agricultural economic growth show significant spatial heterogeneity, with the overall effect degree being in the following order: northern hillock, central plain, western mountain range, and eastern hills. The influence on neighboring agricultural economic growth also exhibits significant spatial differentiation, with the overall effect degree following this order: eastern hills, northern hillock, central plain, and western mountain range. Targeted suggestions are proposed to promote the green transition of farmland use and achieve sustainable agricultural economic growth. [ABSTRACT FROM AUTHOR]

The unsatisfactory cost-to-performance relationship of load-type films has promoted the utilization of bioactive materials with great film-forming properties in recent years. In this work, lily polysaccharide (LP) based edible films functionalized with sodium alginate (SA) and cold plasma (CP) were prepared. The formation of a dense filamentous structure after incorporation with SA significantly enhanced the tensile properties and the barrier properties to water and oxygen. Meanwhile, non-covalent interaction and good compatibility between LP and SA were found. On this basis, CP treatment significantly increased the tensile strength (from 13.73 to 15.82 MPa) (p < 0.05) due to the introduction of nitrogen-containing functionalities and the crosslinking of functional groups on the film surface. Moreover, the CP-modified film (CP/LPF) exhibited a significant improvement in thermal stability, antioxidant property and antibacterial activity. Finally, significant antioxidant and antibacterial effects of CP/LPF were obtained in the application of chicken breast. Based on the promising properties, CP/LPF has great potential to be utilized as eco-friendly active packaging. • Novel edible films based on lily polysaccharide were prepared and characterized. • The properties of the film improved with sodium alginate and cold plasma. • The edible film exhibited satisfactory biological activity. • The edible film had high antibacterial and antioxidant activity on chicken breast. [ABSTRACT FROM AUTHOR]

Aim: Nitrogen (N) and phosphorus (P) are two major limiting factors in terrestrial ecosystems. Excessive N applications alter ecosystem functions by causing nutrient imbalances with P. Yet, little is known about why and how the balance between N and P regulates soil multifunctionality –the simultaneous provision of multiple soil functions–. Methods: We explored how P additions regulated the responses of soil multifunctionality to different levels of N fertilization (10, 20, 40 g N m−2 yr−1) using a mesocosm experiment in a temperate grassland in China. Results: Nitrogen alone and P addition increased multifunctionality at rate of ≤10 and 20 g N m−2 yr−1, respectively. However, the magnitude of positive effects decreased with N additions over this level. P additions increased multifunctionality resistance to N at low rate of ≤10 g m−2 yr−1 compared to higher N levels. Soil N:P stoichiometry and plant diversity played dominant roles in regulating soil multifunctionality. Conclusions: We found that a balanced combination of N and P additions (20:10) can help maintain the highest multifunctionality in this temperate grassland. The results provide new insights that through P addition, we could better manage soil multifunctionality and increase its resistance to expected fertilization scenarios (≤ 10 g m−2 yr−1). [ABSTRACT FROM AUTHOR]

Growing consumer concern about foodborne disease outbreaks and health risks associated with chemical additives has propelled the usage of essential oils (EOs) as novel food additives, but are limited by instability. In this regard, a series of EOs nano/micro-capsules have been widely used to enhance their stability and improve food quality. However, classical food quality assessment methods are insufficient to fully characterize the effects of encapsulated EOs on food properties, including physical, biochemical, organoleptic, and microbial changes. Recently, the rapid development of high-throughput sequencing is accelerating the application of metabolomics in food safety and quality analysis. This review seeks to present the most recent achievements in the application of non-targeted metabolomics to identify and quantify the overall metabolite profile associated with food quality, which can guide the development of emerging food preservation technologies. The scientific findings confirm that metabolomics opens up exciting prospects for biomarker screening in food preservation and contributes to an in-depth understanding of the mechanisms of action (MoA) of EOs. Future research should focus on constructing food quality assessment criteria based on multi-omics technologies, which will drive the standardization and commercialization of EOs for food industry applications. [ABSTRACT FROM AUTHOR]

Nitrogen (N) fertilization due to N deposition, N in manure from grazing livestock and direct input to soil by humans are impacting our terrestrial ecosystems globally. However, to date, our understanding of how artificial gradients of N fertilization indirectly affect phosphorus (P) availability by altering the rates and interrelationships of multiple structural and functional attributes of terrestrial ecosystems is still limited.Here, we conducted a 3‐year field experiment to evaluate the direct and indirect effects of multiple level of N addition on a wide range of ecosystem structural and functional attributes associated with >20 plant, soil and microbial variables in a semi‐arid grassland.We found that N fertilization can have multiple cascading effects on ecosystem structures and functions. These cascading events ultimately result in the activation of multiple biologically driven mechanisms to promote P availability (e.g. increased soil organic P mineralization, plant phosphorus resorption, enzymatic and genetic processes of phosphatase). The increasing phosphatase production and its functional gene expression, and decreasing plant and microbial biomass might imply important shifts in the carbon‐use strategies of plants and microbes allocating more resources to high‐C consuming enzymatic and genetic processes and less in plant and microbial biomass. Nitrogen addition decreases fungal community biomass which suggests the decoupling of key symbiotic plant–fungal relationships for nutrient acquirement.Overall, our study advances our understanding of how and why N fertilization simultaneously influences multiple structural and functional attributes, ultimately accelerating phosphorus cycle in terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

• Solid cuminaldehyde/HPβCD-IC was prepared with the aid of ultrasound technique. • IC formation altered the physicochemical properties of free essential oil component. • The antibacterial activity of solid IC against E. coli and S. aureus was tested. Ultrasound is an energy saving, simple, high efficiency and eco-friend physical technology. In this study, the inclusion complex of cuminaldehyde (CUM), a major constituent of cumin essential oil, with 2-hydroxypropyl- β -cyclodextrin (HP β CD) was synthesised with the aid of ultrasound. The solid CUM/HP β CD-IC was characterized using Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. The stability constants were evaluated by phase solubility, absorption and fluorimetry methods, and were found to be 168, 122 and 256 M−1, respectively. FT-IR and molecular modeling studies indicated that the phenyl ring with the aldehyde group of CUM was inserted into the hydrophobic HP β CD cavity. Further, the efficacy of CUM/HP β CD-IC for inactivation of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was investigated through plate colony counting method. According to the results, the inactivation was 100 ± 0.06% for both E. coli and S. aureus bacteria. The results demonstrated the inclusion of CUM within the harmless HP β CD cavity assisted by ultrasound technology, contributing the improvements of water solubility, thermal stability and antibacterial activities. [ABSTRACT FROM AUTHOR]

The construction of films has often been devoted to loading active substances to improve biological activity in recent years. However, the positive impacts on packaging properties by establishing a cross-linking reaction between the load materials and the substrate are frequently overlooked. The essence of this work was to cross-linked gelatin-based film with κ-carrageenan and dialdehyde β-cyclodextrin inclusion (IC/DA-β-CD) and the functionalities were also investigated. β-cyclodextrin was oxidized with sodium periodate to introduce aldehyde groups. The hydrophobic cavity was not disrupted and the modified cyclodextrin exhibited solubilization of carvacrol. In addition, the introduction of aldehyde group improved the dispersion effect of cyclodextrin in water, but the solid particles were more likely to gather when exposed to the air. Electrostatic complexation of gelatin and κ-carrageenan significantly (p < 0.05) enhanced the tensile strength (from 10.85 to 26.54 MPa), surface water contact angle (WCA) from 97.16 to 110.08° and thermal stability of the film. Contrarily, the elongation at break rate decreased significantly and the antibacterial activity was not potent. The crosslinked IC/DA-β-CD further improved the mechanical properties, and excellent barrier capabilities of the film. Consequently, the WCA and thermal stability were further enhanced as well as the antioxidant capacity and antibacterial activity against Listeria monocytogenes (the eradication rate reached 99.989%). Release experiments demonstrated cross-linked film was more suitable for fatty foods with excellent packaging application ability for ready-to-eat (RTE) ham. Based on the promising properties, the cross-linked film has great deal of potential as RTE active packaging. [Display omitted] • Schiff base cross-linked film based on gelatin was successfully prepared. • Dialdehyde cyclodextrin had a solubilizing effect on carvacrol. • Electrostatic complexation enhanced the rigidity, hydrophobicity and stability. • Schiff base reaction improved the packaging properties and biological activities. • The Cross-linked film had an excellent packaging effect for RTE ham (fatty foods). [ABSTRACT FROM AUTHOR]

Although clove oil is widely used in food preservation, very little is known about its possible antibacterial mechanism. In order to reveal its antibacterial mechanism, the inhibitory effect of clove oil on Listeria monocytogenes and its effect on cell membrane, respiratory metabolism, and its interaction with DNA were investigated, respectively. The results showed the treatment of clove oil can cause the leakage of three biological macromolecules (protein, ATP and DNA) and the reduction of two intracellular enzymes (β-galactosidase and AKP) activities, indicating that clove oil has an effect on cell membrane permeability. The inhibition rate and superposition rate test confirmed that the pathway of clove oil affecting the respiratory metabolism of Listeria monocytogenes is TCA pathway. The treatment of clove oil can reduce the activity of three key enzymes (isocitrate dehydrogenase, citrate synthase and α-ketoglutarate dehydrogenase) in TCA pathway, and affect the content of metabolites in the pathway. The results of ultraviolet absorption spectroscopy showed that eugenol, the main component of clove oil, can change the structure of DNA via the formation of eugenol-DNA chimera. [ABSTRACT FROM AUTHOR]

Salmonella is a kind of common pathogenic bacteria and most of them were associated with serovars, enteritidis and typhimurium. This study was aimed at evaluating the antibacterial activity of tea tree oil (TTO) liposomes-loaded chitosan electrospun nanofilms against Salmonella ( S. typhimurium and S. enteritidis ) on chicken meat. Liposomes were prepared using TTO at a concentration of 6.0 mg/mL. The particle size, polydispersity index (PDI), zeta potential and entrapment efficiency of prepared liposomes were 144.3 ± 1.08 nm, 0.230 ± 0.012, −54.7 ± 2.01 mV and 39.20 ± 1.45% respectively. The physical properties of TTO liposomes/chitosan nanofibers were also determined. The nanofiber membranes embedded with liposome-encapsulated TTO exhibited high antibacterial activity against Salmonella , which had almost no impact on the sensory properties of chicken meat. Results showed that around 5 log 10 reductions of Salmonella were observed in chicken meat by TTO liposomes/chitosan nanofibers treatment for 4 days at 12 °C and 25 °C. The investigation thus showed that the prepared TTO liposomes/chitosan nanofibers can prevent the microbial contamination by Salmonella to extend the shelf life of chicken meat. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a novel method of nisin encapsulation was developed by synthesizing electrostatic self‐assembled nanoparticles using poly‐γ‐glutamic acid (γ‐PGA) and poly‐l‐lysine (PLL). The prepared nisin encapsulated γ‐PGA/PLL nanoparticles were stable. Their encapsulation efficiency, average particle size, polydispersity index (PDI), and zeta potential were 52.56%, 451.1 nm, 0.334, and 30.8 mV, respectively. The effect of nisin encapsulated γ‐PGA/PLL nanoparticles on microbiological parameters, total volatile basic nitrogen values, and pH changes in pork meat at different storage temperatures (4°C for 14 days and 25°C for 7 days) were evaluated. Staphylococcal enterotoxin A was significant decreased in pork meat after the application of nisin‐loaded γ‐PGA/PLL nanoparticles. Practical applications: Nisin‐loaded poly‐γ‐glutamic acid/poly‐l‐lysine nanoparticles could effectively control the growth of Staphylococcal aureus in pork meat and does not have a negative effect on the quality of the pork meat samples. The concept in this study may be useful for the treatment of various infections caused by other bacteria and it have a broad prospect to be used in meat products preservation. [ABSTRACT FROM AUTHOR]

Environmental issues caused by plastic packaging materials have gotten increasingly severe, and substantial research has been conducted on environmentally friendly active packaging materials. In this study, the Litsea cubeba essential oil loaded soy protein isolate nanoparticles (LSNPs) with appropriate particle size, high storage stability and salt solution stability were fabricated. The LSNPs with the highest encapsulation efficiency of 81.76 % were added into the lentinan edible film. The microstructures of the films were observed by scanning electron microscopy. The physical properties of the films were measured. The results show that the lentinan film with LSNPs in the volume ratio of 4:1 (LF-4) had the highest elongation at break of 196 %, the lowest oxygen permeability of 12 meq/kg, and good tensile strength, water vapor barrier property, antibacterial property, oxidation resistance and thermal stability. The study suggested that LF-4 film could inhibit the growth of bacteria and delay the oxidation of lipid and protein on beef surface for 7 d. [ABSTRACT FROM AUTHOR]

Lipotoxicity is the dysregulation of the lipid environment and/or intracellular composition that leads to accumulation of harmful lipids and ultimately to organelle dysfunction, abnormal activation of intracellular signaling pathways, chronic inflammation and cell death. It plays an important role in the development of acute kidney injury and chronic kidney disease, including diabetic nephropathy, obesity-related glomerulopathy, age-related kidney disease, polycystic kidney disease, and the like. However, the mechanisms of lipid overload and kidney injury remain poorly understood. Herein, we discuss two pivotal aspects of lipotoxic kidney injury. First, we analyzed the mechanism of lipid accumulation in the kidney. Accumulating data indicate that the mechanisms of lipid overload in different kidney diseases are inconsistent. Second, we summarize the multiple mechanisms by which lipotoxic species affect the kidney cell behavior, including oxidative stress, endoplasmic reticulum stress, mitochondrial dysfunction, dysregulated autophagy, and inflammation, highlighting the central role of oxidative stress. Blocking the molecular pathways of lipid accumulation in the kidney and the damage of the kidney by lipid overload may be potential therapeutic targets for kidney disease, and antioxidant drugs may play a pivotal role in the treatment of kidney disease in the future. [Display omitted] • The mechanisms by which FABP1 and FABP4 mediate lipid accumulation are inconsistent in kidney disease. • Lipid accumulation plays an important role in the progression of kidney disease, and the mechanism of lipid accumulation varies with the etiology of kidney disease. • Oxidative stress may lie at the heart of lipotoxic kidney injury. • The prospect of improving lipid metabolism as a treatment for kidney disease is underlined. • Blocking lipid overload and renal injury from molecular mechanisms perspective may provide new promising therapeutic interventions for the treatment of kidney disease. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 ( E. coli O157:H7) is one of the most common pathogens in fresh vegetables and fruits, and most of the diseases produced by E. coli O157:H7 are associated with biofilms. Cold nitrogen plasma (CNP) is a cold sterilization technique which has no residue. However to completely eliminate the biofilm on the surface of vegetables the processing power and time of CNP have to be enhanced, which will impact on the quality of fruits and vegetables. Thus the sequential treatment of CNP and phage techniques was engineered in this study. Compared to treatment performed separately, sequential treatment not only had more mild treatment conditions as 400 W CNP treatment for 2 min and 5% phage treatment for 30 min, but also exhibited more remarkable effect on eradicating E. coli O157:H7 biofilms in vitro and on vegetables. The population of E. coli O157:H7 was approximately reduced by 2 log CFU/cm 2 after individual treatment of 5% phages for 30 min or 500 W CNP for 3 min. While the sequential treatment of CNP (400 W, 2 min) and phages (5%, 30 min) reduced the E. coli O157:H7 viable count in biofilm by 5.71 log CFU/cm 2 . Therefore, the sequential treatment holds a great promise to improve the current treatment systems of bacterial contamination on different vegetable surfaces. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the antibacterial activity of clove oil-loaded chitosan nanoparticles (CO@CNPs) and gelatin electrospun nanofibers against Escherichia coli O157:H7 ( E . coli O157:H7) biofilms on cucumbers. The optimal CO@CNPs were prepared when the initial concentration of clove oil (CO) was 2.5 mg/mL according to the ionic crosslinking method. CO@CNPs showed high antibacterial activity against E . coli O157:H7 biofilms. After 8 h treatment, almost 99.98% reduction in E . coli O157:H7 population was achie v ed when CO@CNPs were applied at 30% (w/v). Subsequently, the prepared CO@CNPs were incorporated successfully within gelatin nanofibers by electrospinning. After 9 mg/mL gelatin/CO@CNPs treatment for 24 h, the population of E . coli O157:H7 biofilm reduced by about 99.99% in vitro . Further, the application of gelatin/CO@CNPs nanofibers on cucumber against E . coli O157:H7 biofilm was evaluated as well. After 6 mg/mL and 9 mg/mL gelatin/CO@CNPs nanofibers treatment at 12 °C for 4 days, 4.28 and 4.97 log 10 reductions of E . coli O157:H7 biofilm in population were observed, respectively. Finally, the sensory evaluation results implied that the gelatin/CO@CNPs nanofibers treatment could maintain the color and flavor of cucumber well for > 4 days. [ABSTRACT FROM AUTHOR]

This work describes the effect of cold nitrogen plasma to enhance the antibacterial activity of poly(ethylene oxide) (PEO) nanofibers containing antibacterial agent. Beta-cyclodextrin (β-CD) and tea tree oil (TTO) were used as a host-guest to form water-soluble inclusion complex. The encapsulation efficiency of TTO in inclusion complex could reach 73.23% at 60 °C. As antibacterial agent, the inclusion complex was encapsulated into PEO matrix by electrospun. After plasma treatment, the release efficiency of antibacterial agent from PEO nanofibers was improved. As a result, the antibacterial activity of PEO nanofibers was enhanced accordingly. The plasma-treated nanofiber membranes achieved the highest antibacterial activity against Escherichia coli O157:H7, which was tested on the beef for 7 d, with inhibition efficiently of 99.99% whether at 4 °C or 12 °C. The plasma-treated PEO nanofiber membranes containing TTO/β-CD inclusion complex (TTO/β-CD-IC) can prolong the shelf-life of beef, suggesting it has potential application in active food packaging. [ABSTRACT FROM AUTHOR]

This study describes the use of liposomes as biological membrane models to evaluate the antibacterial activity of encapsulated thyme oil against Salmonella enteritidis ( S. enteritidis). Thyme oil was incorporated into a liposome system to enhance its chemical stability. The optimal liposomes were achieved at 5.0 mg/ml thyme oil encapsulation, with polydispersity index (PDI) of 0.203, zeta potential of −52.2 mV, and entrapment efficiency of 38.16%. Afterwards, the stability of liposomes was confirmed (during storage of 90 days). In addition, the antibacterial activities of the loaded thyme oil against S. enteritidis in vitro were detected by colony forming units counting method and results verified that controlled release of thyme oil induced the sustained inhibition of S. enteritidis growth. Long-term antibacterial activity assays illustrated thyme oil encapsulated in liposome could extend the treatment time and improve the antibacterial effect on S. enteritidis in chicken. Practical applications Liposome-encapsulated thyme oil has been proven to be a good antibacterial agent against Salmonella at a low concentration. Especially, controlled release of thyme oil can induce the sustained inhibition of bacteria growth and maintain food safety for a long time. Based on the results, we believe that thyme oil loaded liposomes can be applied in meat processing and preservation. [ABSTRACT FROM AUTHOR]

In recent years, phages used for the reduction of pathogenic bacteria have fostered many attentions, but they are liable to lost bioactivity in food due to the presence of acidic compounds, enzymes and evaporite materials. To improve the stability of phages, a chitosan edible film containing liposome-encapsulated phage was engineered in the present study. The characteristics of liposome-encapsulated phage and the chitosan film containing liposome-encapsulated phage were investigated. The encapsulation efficiency of phages in liposome reached 57.66 ± 0.12%. Besides, the desirable physical properties of chitosan film were obtained. The chitosan film embedded with liposome-encapsulated phage exhibited high antibacterial activity against Escherichia coli O157:H7, without the impact on the sensory properties of beef. Hence, chitosan film containing liposome-encapsulated phage could be a promising antibacterial packaging for beef preservation. [ABSTRACT FROM AUTHOR]

In this present work, to minimise the risk of contamination by biofilm of Staphylococcus aureus ( S. aureus), D-amino acid (D- AA) and nutmeg essential oil ( NEO) were used to synergistically eliminate S. aureus biofilm formation. Chitosan nanoparticles ( CNPs) were introduced to encapsulate D-Pro, D-Phe and NEO for getting better chemical stability during processing and storage. The optimal D- AA/ NEO@ CNPs possessed high stability (particle size 155.3 nm, zeta potential 42.2 mV), high uniformity (polydispersity index 0.267) and superior antibiofilm performance. Then, for the application in soya bean products, electrospun nanofibrous membranes were introduced to immobilise the D- AA/ NEO@ CNPs. And the antibiofilm assay of D- AA/ NEO@ CNP-loaded nanofibrous membranes exhibited excellent antibiofilm activity on soya bean products in this study. [ABSTRACT FROM AUTHOR]

Guided by the principle of hurdle technology, a high-efficiency antibacterial agent (AA) had been formulated, which contained six kinds of essential oils, three pieces of food additives and ethyl alcohol. The antibacterial effects of AA against E. coli O157:H7 biofilm on simulated and real cucumbers were testified by MTT staining method, colony-forming unit (CFU) counting method, scanning electron microscopy (SEM) analysis and confocal laser scanning microscopy (CLSM) assay. The remarkable anti-biofilm activity of AA was achieved under low concentration and short treatment duration. The results also revealed that AA inhibited the multiplication of E. coli O157:H7 via destroying the cell membrane integrity. Besides, color, texture and sensory evaluation illustrated that AA could be applied as a disinfectant to eliminate the biofilm formed on cucumber without impact on food quality. Practical Applications As a kind of high-efficiency antimicrobials, AA has significant inhibition and elimination effects on biofilm under a low concentration and short incubation time. Especially, AA was effective to eliminate the formed E. coli O157:H7 biofilm on the surface of cucumber without impact on the quality and flavor of the product. On the basis of the results, we believe that AA can be applied in vegetables or fruits processing and preservation. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes ( L. monocytogenes ) contamination in cheese production has received increasing attention. In order to inhibit the multiplication of the bacteria, the polyethylene oxide nanofibers containing nisin-loaded poly-γ-glutamic acid/chitosan (NGC) nanoparticles were engineered in this study. The physicochemical properties of NGC nanoparticles and anti-listeria activities of NGC nanoparticles-embedded polyethylene oxide nanofibers on cheese were investigated. The results indicated that NGC nanoparticles at 5 mg/mL of nisin had desirable polydispersity, zeta potential, encapsulation efficiency and load capacity. NGC nanoparticles-embedded polyethylene oxide nanofibers displayed satisfactory antibacterial activity against L. monocytogenes on cheese, without impact on the sensory quality. Therefore, the polyethylene oxide nanofibers containing NGC nanoparticles could be a promising active packaging for food preservation. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the synergetic antimicrobial effects of cold nitrogen plasma (CNP) and lemongrass oil against L. monocytogenes on pork loin. Their possible effects on the physicochemical properties of pork were investigated as well. Lemongrass oil displayed anticipant antibacterial activities against L. monocytogenes at high dose, which could damage the bacterial membrane, leading to the losses of intracellular constituents, including DNA, protein and ATP. Compared with control groups, the number of L. monocytogenes on pork samples was reduced by 2.80 log10 steps after synergy treatment of CNP (500 W, 120 s) and lemongrass oil (5 mg/mL, 30 min). With the assistance of CNP, the satisfactory antibacterial effect for L. monocytogenes on pork was achieved after treatment for low concentration of lemongrass oil. In addition, the potential impacts on sensory attributes of pork were also minimized via combined treatment. Practical applications Under low concentration, lemongrass oil achieved the desired antibacterial effect for L. monocytogenes on pork loin with the assistance of CNP. The potential impacts on sensory attributes of pork loin were minimized via synergetic treatment as well. The synergetic treatment provides a new way for application of plant essential oil in food preservation. [ABSTRACT FROM AUTHOR]

We herein evaluated the antibacterial effect of curry plant EO, a natural antibacterial agent, on B. cereus. The curry plant EO was encapsulated into liposomes to improve the chemical stability of EO and its active time. By a thin-film dispersion method, soy lecithin, in combination with cholesterol, were used to prepare liposomes at various curry plant EO concentrations. The optimal formula for preparing liposome is a curry plant EO concentration of 5.0 mg/ml. The average particle size of liposomes containing curry plant EO was 196.6 nm with a PDI of 0.218 and the entrapment efficiency was 56.34%. The optimal liposomes containing curry plant EO gave a zeta potential of −31.1 mV. Besides, liposome-encapsulated curry plant EO exhibited efficient antimicrobial activity for B. cereus in rice. Practical applications As a natural and safe antibacterial agent, curry plant EO shows an excellent antibacterial effect on B. cereus in rice. The concept in the present study may be useful in the future to deliver a variety of antimicrobials for the treatment of various infections caused by bacteria or other organisms. Hence, the antimicrobial agent has broad prospect in the field of food preservation. [ABSTRACT FROM AUTHOR]

As a natural antibacterial agent, Artemisia annua oil ( AAO) exhibited significant antibacterial effect on Escherichia coli O157:H7. However, AAO was volatile and not suitable for surface coatings of fresh produce. Therefore, the edible agar films containing chitosan and AAO liposomes were engineered to overcome the defect. Chitosan was added in the film to enhance the antibacterial activity. Finally, the results showed the mean size of AAO liposomes was about 191.8 nm with a polydispersity index ( PDI) of 0.463. The absolute zeta potential value was greater than 30 mV, and the loading efficiency ( LE) of 5.0 mg mL−1 AAO liposome was 67.45%. As a proof of concept, the antibacterial activity of the films against E. coli O157:H7 on cherry tomatoes was evaluated. The results indicated that the incorporation of AAO liposomes as a natural antibacterial agent possessed bacteriostatic effect, which had potential for using the developed film as an active packaging. [ABSTRACT FROM AUTHOR]

Salmonella is the main source of microbial contamination on eggs. In the present study, the eggshells infected with Salmonella were employed as the test subjects. Thyme oil and cold nitrogen plasma (CNP) were introduced to treat Salmonella on eggshells. Both thyme oil and CNP showed low antimicrobial activities against microorganisms when they individually acted to infected eggs for short time. On the contrast, the loss of bacterial viability was obviously enhanced by combined treatment. The subsequent experiments demonstrated that thyme oil concentration and CNP treatment time were positively correlated with antibacterial effects. By CNP assist, thyme oil can effectively inhibit the multiplication of Salmonella on eggs under low concentrations. Among various combination groups, 0.5 mg/mL thyme oil and 400 W CNP exhibited the best synergistic antibacterial activity when they were applied for 20 min and 1 min, respectively. The populations of Salmonella enteritidis and Salmonella typhimurium were reduced below 10 CFU/egg. More importantly, the treatment in combination limited the growth of bacteria on eggs below undetected level during 14 days of storage at different temperatures (4, 12 and 25 °C). [ABSTRACT FROM AUTHOR]

Staphylococcus aureus is the most common pathogen in human, and the most diseases produced by S. aureus are associated with biofilms. Helichrysum italicum essential oil ( EO), as a natural and safe spice, was employed to disperse S. aureus biofilm by cold nitrogen plasma ( CNP) assist. After S. aureus biofilm formation on food container surfaces, they were exposed to CNP and then treated with Helichrysum italicum EO for biofilm dispersion. The population of S. aureus biofilm was approximately reduced by 2 logs after individual treatment of 0.5 mg mL−1 Helichrysum italicum EO or 400 W CNP. Interestingly, the combined treatment of Helichrysum italicum EO (0.5 mg mL−1, 40 min) and CNP (400 W, 1 min) reduced the S. aureus viable count in biofilm below 2 logs CFU per cm2 after 1-day storage. Therefore, the synergetic treatment holds great promise to improve the current treatment systems of bacterial contamination on different food-contact surfaces. [ABSTRACT FROM AUTHOR]

Inspired by the hydrolysis of casein by protease, a new approach to deliver antimicrobials against bacterial infections was developed in this study. As a natural antibacterial agent, cinnamon oil was encapsulated into engineered liposomes inlaid with casein. The average particle size of proteoliposomes was 615.0 nm and their entrapment efficiency (EE) was 40.0%. In this work, Bacillus cereus ( B. cereus ) was chosen as model bacterium. The controlled release of liposome-encapsulated cinnamon oil was realized via bacterial protease secreted from B. cereus . As a result, 99.99% of the bacteria could be efficiently inhibited in rice and wheat flour. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the antimicrobial effects of cold nitrogen plasma (CNP) and clove oil against Escherichia coli O157:H7 ( E. coli O157:H7) biofilm on lettuce. Both clove oil (1 mg/mL, 2 mg/mL and 4 mg/mL) and CNP (400–600 W) displayed significant eradication effect on E. coli O157:H7 biofilms in vitro ( p < 0.001). Subsequently, the antibiofilm effect of combined treatment was studied as well. Compared with the respective treatment, combined treatment exhibited remarkable synergistic effect on eradicating E. coli O157:H7 biofilms. The confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) had also visually testified that the antibacterial effects of clove oil on E. coli O157:H7 biofilms (in vitro and on lettuce) were enhanced by CNP at 400 W for short treatment duration. The results of sensory evaluation indicated that combined treatment has mild negative effect on lettuce quality. Moreover, the synergetic antibacterial mechanism of clove oil and CNP against E. coli O157:H7 was concluded as that they could damage the bacterial cell wall and the outer membrane, leading to leakage of cellular components, such as nucleic acid and ATP. [ABSTRACT FROM AUTHOR]

Escherichia coli O157:H7 (E. coli O157) is still one of the main pathogenic strains causing food poisoning. Here in, we established a strategy that can simultaneously remove free E. coli O157 and the biofilms it forms. Composite nanofiber (fP-NF) films were synthesized successfully by co-encapsulating E. coli O157 phages which isolated from domestic sewage and D -phenylalanine (D-Phe) into sodium alginate (SA)/polyethylene oxide (PEO) nanofibers by electrospinning. And dehydrated trehalose was added as a phage protectant. When SA:PEO is 3:9, the spinning solution has the optimum conductivity and viscosity, the average diameter of the obtained fP-NFs is 421.87 nm, and the mechanical strength and transparency of the fP-NF film are the best. The thermal stability of the fP-NF film was good, and the phage activity in the fiber was well preserved. The remaining population of phages in fP-NF membranes was still close to 106 PFU/mL after one week of placement, and the cumulative release efficiencies of phages at both room temperature (25 °C) and refrigerated storage temperature (4 °C) were above 70%. The antibacterial experiment showed that compared with the control group, the addition of D-Phe slightly enhanced the antibacterial activity of the nanofiber films against free E. coli O157, and the bactericidal rate within 8 h was 99.74%. On the other hand, D-Phe significantly enhanced the inhibitory activity of the nanofiber films against E. coli O157 biofilms, with the inhibition rate exceeding 99.99% within 72 h. The application results further confirmed that the addition of D-Phe could significantly enhance the inhibitory activity of nanofiber films on E. coli O157 proliferation and biofilm formation during short-term storage of beef and fruits and vegetables. It provides an important strategy and reference for the development of new active food packaging materials. • A new nanofiber film that efficiently eliminates E. coli O157 biofilms was assembled. • The addition of D-Phe enhanced the inhibition effect of the nanofibers on biofilms. • Nanofiber film efficiently reduced the risk of foods contamination with E. coli O157. [ABSTRACT FROM AUTHOR]

In this paper, frequency, temperature, film thickness, surface effects, and various parameters dependence of dielectric susceptibility is investigated theoretically for ferroelectric thin films by the modified Landau theory under an AC applied field. The dielectric susceptibility versus AC applied field shows butterfly-shaped behavior, and depends strongly on the frequency and amplitude of the field and temperature. Our study shows that the existence of the surface transition layer can depress the dielectric susceptibility of a ferroelectric thin film. These results are well consistent with the phenomena reported in experiments. [ABSTRACT FROM AUTHOR]

The Staphylococcus aureus (S. aureus ) biofilm on container is the main source of microbial contamination in milk. In this study, the nanoliposomes encapsulating Salvia oil (SO) has been prepared. Based on the damage effect of pore-forming toxin on cell membrane, α-toxin secreted from S. aureus has been used to trigger the release of SO from nanoliposomes to achieve antibacterial effect on S. aureus biofilm on milk container. Firstly, the minimum biofilm eradication concentration (MBEC) and biofilms time-dependent killing of SO were tested. The results showed that the MBEC of SO against S. aureus biofilms was 0.2% and SO effectively eradicated the biofilms after treating for 4 h. Subsequently, SO was encapsulated into nanoliposomes in order to increase its stability. The particle size, poly dispersity index (PDI), zeta potential, pH, turbidity, and entrapment efficiency of SO nanoliposomes were analyzed systematically. Gas chromatography–mass spectrometry (GC–MS) has been utilized to observe the controlled release of SO form nanoliposomes incubated with S. aureus . The scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images have also visually showed that SO nanoliposomes have high anti-biofilm activity against S. aureus biofilms on milk container. [ABSTRACT FROM AUTHOR]

In the present paper, the chemical composition of Helichrysum italicum oil was analyzed by gas chromatography-mass spectrometry (GC-MS). Neryl acetate (32.65%) was the main component. The minimum inhibitory concentration and minimum bactericidal concentration of H. italicum oil against several bacteria were evaluated. The results showed that H. italicum oil exhibited high antibacterial activity against all of the bacteria tested. In addition, H. italicum oil also displayed a significant effect on inhibiting the growth rate of surviving Escherichia coli and Staphylococcus aureus in vitro and on vegetables. Meanwhile, addition of H. italicum oil to vegetable exerted a bacteriostatic effect. Besides, the mechanisms of the antimicrobial action of H. italicum oil to E. coli and S. aureus were concluded as that H. italicum oil could disrupt the cell membrane integrity, leading to the losses of intracellular constituents, such as the 260 nm absorbing materials, DNA and ATP. [ABSTRACT FROM AUTHOR]

In this study, the antibacterial activities of Clove oil and liposome-encapsulated Clove oil were investigated. First, the antibacterial activity of Clove oil demonstrated that the essential oil exhibited favorable antimicrobial activity for both Escherichia coli and Staphylococcus aureus . However, a setback of using Clove oil as a disinfectant is its low chemical stability. Then Clove oil was incorporated into a liposome formulation to increase its stability. The optimal polydispersity index (PDI) (0.196), Zeta potential (−24.5 mV) and entrapment efficiency (20.41%) of liposome were obtained at the concentration of Clove oil to 5.0 mg/mL. In addition, selective antimicrobial activity for S. aureus by utilizing pore-forming toxins (PFTs) to activate Clove oil release from liposome was observed. By contrast, liposome-encapsulated Clove oil has no effect on E. coli that doesn't secrete PFTs because antimicrobial component can't reach bacteria. Gas chromatography (GC) assay found that when liposome met S. aureus that secrete PFTs, PFTs would insert into the liposome membranes and form pores, through which the encapsulated Clove oil was released. Besides, liposome-encapsulated Clove oil exhibited efficient antimicrobial activity for S. aureus in tofu. [ABSTRACT FROM AUTHOR]

Variations in the carbon isotope signature of leaf dark-respired CO2 (δ13CR) within a single night is a widely observed phenomenon. However, it is unclear whether there are plant functional type differences with regard to the amplitude of the nighttime variation in δ13CR. These differences, if present, would be important for interpreting the short-term variations in the stable carbon signature of ecosystem respiration and the partitioning of carbon fluxes. To assess the plant functional type differences relating to the magnitude of the nighttime variation in δ13CR and the respiratory apparent fractionation, we measured the δ13CR, the leaf gas exchange, and the δ13C of the respiratory substrates of 22 species present in the agricultural-pastoral zone of the Songnen Plain, northeast China. The species studied were grouped into C3 and C4 plants, trees, grasses, and herbs. A significant nocturnal shift in δ13CR was detected in 20 of the studied species, with the magnitude of the shift ranging from 1‰ to 5.8‰. The magnitude of the nighttime variation in δ13CR was strongly correlated with the daytime cumulative carbon assimilation, which suggests that variation in δ13CR were influenced, to some extent, by changes in the contribution of malate decarboxylation to total respiratory CO2 flux. There were no differences in the magnitude of the nighttime variation in δ13CR between the C3 and C4 plants, as well as among the woody plants, herbs and graminoids. Leaf respired CO2 was enriched in 13C compared to biomass, soluble carbohydrates and lipids; however the magnitude of enrichment differed between 8 pm and 4 am, which were mainly caused by the changes in δ13CR. We also detected the plant functional type differences in respiratory apparent fractionation relative to biomass at 4 am, which suggests that caution should be exercised when using the δ13C of bulk leaf material as a proxy for the δ13C of leaf-respired CO2. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the antibacterial characteristics and mechanisms of nutmeg oil. In this paper, 54 chemical compositions of nutmeg oil were analyzed by gas chromatography-mass spectrometry ( GC- MS). The major volatile components of nutmeg oil were sabinene (39.12%) and alpha-pinene (11.96%). In addition, nutmeg oil showed significant antibacterial activity, minimum inhibitory concentration, and minimum bactericide concentration of seven pathogens are 0.05 and 0.1%, respectively, and the nutmeg oil also had a significant effect on inhibiting the growth of E scherichia coli and S taphyloccocus aureus in phosphate buffer saline and pork. Subsequently, in order to reveal the possible antibacterial mechanisms of nutmeg oil against pathogens, the damage of cell membrane was observed by scanning electron microscopy, the loss of 260 nm absorbing material was tested by ultraviolet spectrophotometer, and the cellular adenosine triphosphate concentrations were measured by the Surface Hygiene Test Kit. Finally, the decrease of nucleic acid was evaluated by inverted fluorescence microscope. These results indicated that the antibacterial mechanisms of the nutmeg oil against bacteria might be interpreted as disrupting cell membrane and inhibiting synthesis of DNA. Practical Applications As a natural and safe antibacterial agent, nutmeg oil exhibited good antimicrobial activity against a wide range of spoilage and pathogenic bacteria. Meanwhile, the antimicrobial activity of nutmeg oil has been proved on pork. Based on the results, we believe that nutmeg oil can be applied in meat storage and preservation. [ABSTRACT FROM AUTHOR]

Background: Nowadays, essential oils are recognized as safe substances and can be used as antibacterial additives. Salvia sclarea is one of the most important aromatic plants cultivated world-wide as a source of essential oils. In addition to being flavoring foods, Salvia sclarea essential oil can also act as antimicrobials and preservatives against food spoilage. Understanding more about the antibacterial performance and possible mechanism of Salvia sclarea essential oil will be helpful for its application in the future. But so far few related researches have been reported. Results: In our study, Salvia sclarea oil showed obvious antibacterial activity against all tested bacterial strains. Minimum inhibitory concentration (MIC) and minimum bactericide concentration (MBC) of seven pathogens were 0.05 and 0.1 % respectively. In addition, Salvia sclarea oil also exhibited a significant inhibitory effect on the growth of Escherichia coli ( E. coli) in phosphate buffer saline (PBS) and meats. After treated with Salvia sclarea oil, Scanning Electron Microscope (SEM) images can clearly see the damage of cell membrane; the intracellular ATP concentrations of E. coli and S. aureus reduced 98.27 and 69.61 % respectively, compared to the control groups; the nuclear DNA content of E. coli and S. aureus was significantly reduced to 48.32 and 50.77 % respectively. In addition, there was massive leakage of cellular material when E. coli and S. aureus were exposed to Salvia sclarea oil. Conclusions: Salvia sclarea essential oil damaged the cell membrane and changed the cell membrane permeability, leading to the release of some cytoplasm such as macromolecular substances, ATP and DNA. In general, the antimicrobial action of Salvia sclarea essential oil is not only attributable to a unique pathway, but also involves a series of events both on the cell surface and within the cytoplasm. Therefore, more experiments need to be done to fully understand the antimicrobial mechanism of Salvia sclarea essential oil. [ABSTRACT FROM AUTHOR]

This study aimed to prepare KF/CaO catalyst with high catalytic activity that can be applied to produce bio-fuel from Cornus wisoniana oil. The KF/CaO catalyst was characterized by Brunauer-Emmett-Teller surface area (BET), XRD, scanning electron microscopy (SEM), and temperature programmed desorption (TPD). The chemical compositions of C. wisoniana oil and bio-fuel oil were analyzed by GC-MS. The effect of the catalyst preparation conditions on catalytic activity was investigated. The optimal process conditions for the KF/CaO preparation were KF loading rate of 40%, calcination temperature of 600°C, and 4 h calcination time. Under the optimum process conditions, the bio-fuel yield reached 82.7 and 65% bio-fuel yield was obtained after being reused nine times. The bio-fuel oil obtained by catalytic cracking has similar chemical compositions to petroleum-based diesel, which exhibited good fuel properties. KF/CaO was used as a catalyst for the production of bio-fuel from cracking of Cornus wisoniana oil. [ABSTRACT FROM AUTHOR]

Bacillus cereus (B. cereus) is a recognized foodborne pathogen widely distributed in various protein-rich foods, which is a huge challenge to food safety. Herein, a novel enzyme-responsive nanomaterial based on cationic starch (CSt) nanofibers loaded with carvacrol@casein nanoparticles (CL@CSNPs) was constructed (CL@CS/CSt nanofiber) to prevent the contamination of B. cereus in soybean products. Considering the excellent antibacterial activity of carvacrol (CL) against B. cereus , CL@CSNPs were prepared by electrostatic adsorption and hydrophobic interaction and characterized by SEM and FTIR.CL@CS/CSt nanofibers with better performance were determined by comparing the physical properties of the electrospinning solution and the prepared nanofiber. Nanofibers were prepared by electrospinning technology and analyzed by SEM and AFM to investigate the size and structural morphology of fibers. FTIR analyses were done to confirm the successful embedding of CL@CSNPs in CSt nanofibers. Subsequently, the controlled release of CL was verified by GC–MS and disc diffusion method. The application experiment results indicated that the treatment based on CL@CS/CSt nanofibers reduced the B. cereus in soy products by 2 log CFU/g, which reflected a significant antibacterial activity. In addition, CL@CS/CSt nanofibers could also prevent texture and chroma changes under refrigeration and maintain the sensory quality of soy products. Thus, CL@CS/CSt nanofibers appear to have great potential in controlling the contamination of soybean products by B. cereus while maintaining the physical quality. • Carvacrol (CL) shown an excellent antibacterial activity against B. cereus. • Bacterial enzymes enabled the controlled release of CL from nanofibers. • CL@CS/CSt nanofibers inhibited the growth of B. cereus in soy products. • Prepared nanofibers can maintain the physical quality of soy products during storage. [ABSTRACT FROM AUTHOR]

The environmental factors controlling soil biodiversity along resource gradients remain poorly understood in wet tropical ecosystems. Aboveground biodiversity is expected to be driven by changes in nutrient availability in these ecosystems, however, much less is known about the importance of nutrient availability in driving soil biodiversity. Here, we combined a cross-continental soil survey across tropical regions with a three decades' field experiment adding nitrogen (N) and phosphorus (P) (100 kg N ha−1y−1 and 100 kg P ha−1y−1) to Hawai'ian tropical forests with contrasting substrate ages (300 and 4,100,000 years) to investigate the influence of nutrient availability to explain the biodiversity of soil bacteria, fungi, protists, invertebrates and key functional genes. We found that soil biodiversity was driven by soil acidification during long-term pedogenesis and across environmental gradients, rather than by nutrient limitations. In fact, our results showed that experimental N additions caused substantial acidification in soils from Hawai'i. These declines in pH were related to large decreases in soil biodiversity from tropical ecosystems in four continents. Moreover, the microbial activity did not change in response to long-term N and P additions. We concluded that environmental filtering drives the biodiversity of multiple soil organisms, and that the acidification effects associated with N additions can further create substantial undesired net negative effects on overall soil biodiversity in naturally tropical acid soils. This knowledge is integral for the understanding and management of soil biodiversity in tropical ecosystems globally. Results of SEMs identify the direct and indirect relationships between the diversity of soil organisms and N and P additions, and soil substrate ages in Hawai'i experiments (a-c) and tropical ecosystems in four continents (d-f). The diversity (OTU number, richness) of soil organisms includes bacteria, fungi, and protists. The variance explained by the model (R 2) of each parameter is given. R2 conditional denotes the proportion of variance explained by the included predictors without accounting for random effects of country/site. R2 marginal denotes the proportion of variance explained by the included predictors by accounting for random effects of country/site. Grey dashed arrows represent non-significant relationships in the models, which, however, improved the model fit when used (p > 0.05). Other non-significant SEM arrows were removed from the model to improve the model fit. Avail N, available N; Avail P, available P; MAP, mean annual precipitation; MAT, mean annual temperature; RMSEA, root mean square error of approximation. * P < 0.05, ** P < 0.01 and *** P < 0.001. [Display omitted] • Biodiversity is driven more by soil acidification more than, nutrient limitation in a Hawai'i long-term, cross-site experiment. • Negative effects of soil acidification on biodiversity are stronger in old, more weathered soils. • Microbial diversity and microbial activity had contrasting responses to N and P additions. • pH was positively correlated with biodiversity in tropical soils across continents. [ABSTRACT FROM AUTHOR]

Abstract: In this study, the effect of ultrasonic treatment duration on the morphology of self-assembled casein particles was investigated by atomic force microscopy (AFM), low vacuum scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the case of AFM images, the particle analysis which was carried out by the SPIP program showed that the self-assembled casein particles after being ultrasonically treated for 2min got smaller in size compared to the casein particles that have not been exposed to any ultrasonic treatment. Surprisingly, however, increasing the ultrasonic time exposure of the particles resulted in an opposite effect where larger particles or aggregates seemed to be present. We show that by comparing the results obtained by AFM, SEM and TEM, the information extracted from the AFM images and analyzed by SPIP program give more detailed insights into particle sizes and morphology at the molecular level compared to SEM and TEM images, respectively. [Copyright &y& Elsevier]

As an emerging packaging material, hydrogels have been attracting attention to inhibit foodborne pathogens by encapsulating antimicrobial substances. Herein, an antibacterial packaging material was prepared via incorporation of methyl-β-cyclodextrin/ Satureja montana L. essential oil inclusion complexes (MCD/SEO-ICs) into soy soluble polysaccharide (MCD/SEO-SSPS) hydrogel. During, the addition of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) facilitated the formation of amido linkage between -NH2 and –COOH. Compared with SSPS hydrogel, the MCD/SEO-SSPS hydrogel exhibited a more compact structure. What's more, physical characterization indicated that combining MCD/SEO-ICs with SSPS could improve the hardness, adhesiveness and springiness of hydrogel. More importantly, a good antibacterial activity of SPSS hydrogel was obtained with the addition of MCD/SEO-ICs. On this basis, the application test demonstrated that the prepared MCD/SEO-SSPS hydrogel could reduce the visible count of Staphylococcus aureus (S. aureus) in meat samples by 3.5 Log CFU/g during 7-days storage, which retained the freshness of chilled pork and extended the shelf life. The above results indicated that MCD/SEO-SSPS hydrogel can be used as a safe and effective active packaging material for chilled meat preservation. [Display omitted] • Satureja montana L. essential oil (SEO) have a good inhibitory effect on S. aureus. • Methyl-β-cyclodextrin inclusion complex (MCD-IC) improved the solubility and stability of SEO. • MCD-IC enhanced the mechanical strength and release characteristics of the hydrogel. • MCD/SEO-soy soluble polysaccharide hydrogels can be used as antibacterial packaging material. [ABSTRACT FROM AUTHOR]

Abstract: Graphene oxide (GO)-enwrapped Ag3PO4 composites were successfully fabricated by the electrostatically-driven assembly of positively charged silver ions on the negatively charged GO sheets, followed by the controlled growth of sphere-like Ag3PO4 particles on GO sheets via an in-situ ion-exchange method. Moreover, GO–Ag3PO4 composites were fully characterized and the visible light photocatalytic performance of the GO–Ag3PO4 sample was investigated. The results indicated that the presence of GO sheets could effectively tailor the size of Ag3PO4 particles, GO–Ag3PO4 composites exhibited excellent visible-light absorption, and the photocatalytic degradation efficiency of Rhodamine B (RhB) over GO–Ag3PO4 composites is apparently higher than with pure Ag3PO4 mainly due to the photo-induced holes and the generation of irradiated active superoxide radicals. [Copyright &y& Elsevier]

Abstract: The effects of ethanol-soluble fractions of 12 plant extracts were tested for heat-sensitizing effects on the spores of Clostridium botulinum (type A and type B) and Clostridium sporogenes PA 3679. Licorice, pineapple sage and lemon eucalyptus extracts were respectively found to significantly decrease (P < 0.05) the thermal resistance of C. botulinum 62A (type A), C. botulinum Okra (type B), and C. sporogenes; reducing initial spore populations at 0.5–1.0% level of addition. Further investigations showed that increasing acidity and licorice extract (0.5%) had an additive heat- sensitizing effect on C. botulinum 62A while increasing NaCl counteracted the effect of the extract on the spores. Exposure of spores to 0.5% licorice extract for 7 d prior to heating significantly reduced the heat resistance of the spores. Finally, a post-heating sporicidal property of licorice extract was also observed, resulting in significantly greater spore population reductions compared to that when licorice extract was removed by washing with Tween 80 prior to enumeration on growth medium. The use of naturally occurring compounds in plants as potential food additives may help address the consumer demands for products with highly acceptable sensory and nutritive qualities, and safety. [ABSTRACT FROM AUTHOR]

Abstract: This study was conducted to evaluate the antibotulinal activities of some plant extracts, alone or in combination with nitrite (NaNO2). Water- and 99.5% ethanol-soluble extracts (1:9 plant material weight-by-solvent volume, 25°C, 48h) of 90 kinds of fresh and dehydrated herbs and spices were tested. The aqueous extract of clove and alcohol extracts of lemon eucalyptus, mace and licorice exhibited greater antibotulinal activities in TPGY medium with MIC ranging from 0.05% to 0.2%. However in TPGY, only the aqueous extract of Coptis rhizome exhibited synergistic antibotulinal activity with NaNO2, reducing the individual MIC of NaNO2 from 6–8ppm to 2ppm with 0.05% Coptis extract. In a model meat food, the alcohol-soluble extracts of nutmeg (0.05%) and sage (0.02%), and the aqueous fraction of clove extract (0.05%) exhibited antibotulinal activities in combination with 10ppm NaNO2. The observed synergy between plant extracts and NaNO2 that resulted in lower MIC of both additives have significant repercussion in the control of botulism in minimally processed meat products without compromising organoleptic properties. [Copyright &y& Elsevier]

A novel controlled-release antibacterial nanofiber was fabricated by electrospinning to load eugenol@cationic starch nanoparticles (EG@CStNPs) into phospholipid nanofibers (EG@CSt/P nanofibers). Taking advantage of the phospholipase and amylase secreted by Bacillus cereus (B. cereus), the controlled release of eugenol in EG@CSt/P nanofibers was achieved through the hydrolysis of the phospholipids in the nanofibers and the cationic starch of the nanoparticles. EG@CStNPs were prepared by nanoprecipitation and characterized by SEM, FTIR, and Raman spectroscopy. The preparation method of phospholipid nanofibers was improved, and nanofibers with enhanced properties were identified through their physical properties. The success of EG@CStNP loading into phospholipid nanofibers was confirmed by FTIR, SEM, AFM and TGA. Subsequently, the success of controlled release was verified by GC-MS, inhibition-zone experiments and TEM. After treatment with EG@CSt/P nanofibers for 5 days, the number of B. cereus decreased by around 2 log 10 reductions at 4 °C and 25 °C. The results of experiments performed for application in beef further showed that EG@CSt/P nanofibers had significant antibacterial activity against B. cereus and did not damage the color and texture of beef samples. • The preparation of phospholipid nanofiber is safe and environment friendly. • Bacterial enzymes enabled the controlled release of eugenol from EG@CSt/P nanofibers. • EG@CSt/P nanofibers had high antibacterial activity against B. cereus on beef. [ABSTRACT FROM AUTHOR]

Bacterial infections are a serious issue for public health and represent one of the major challenges of modern medicine. In this work, a selective antimicrobial strategy based on triggering of pore-forming toxin, which is secreted by infective bacteria, was designed to fight Staphylococcus aureus. The antimicrobial activity is realized by employing Eucalyptus citriodora oil as antibiotic which in this study is encapsulated in nanoliposomes. [ABSTRACT FROM AUTHOR]

Aeromonas veronii is an important pathogen found in various aquatic environments and products, posing a threat to public health. The Hanks‐like serine/threonine protein kinase is closely linked to the pathogenesis of pathogenic bacteria, but the exact role of YihE in A. veronii remains still unknown. To study the specific function of the YihE kinase, we constructed a knockout mutant of the yihE gene in A. veronii. The deletion of the yihE gene resulted in changes to the metabolism of L‐arginine‐AMC and acetic acid, as well as enhanced resistance to ampicillin and kanamycin in A. veronii. Additionally, the ΔyihE strain demonstrated a 1.4‐fold increase in biofilm formation ability and a 1.8‐fold decrease in adhesion and invasion to EPCs when compared to the wild‐type strain. A significant decrease in cytotoxicity was observed at 2 and 3 h post‐infection with EPCs compared to the wild‐type strain. Additionally, the deletion of the yihE gene was associated with a significant decrease in motility of the strain. Furthermore, the deletion of the yihE gene resulted in a 1.44‐fold increase in the LD50 of A. veronii in zebrafish. These findings offer valuable insights into the pathogenic mechanisms of A. veronii. [ABSTRACT FROM AUTHOR]

The antibacterial activity and mechanisms of Lactiplantibacillus plantarum LP22541 against Staphylococcus aureus in fermented milk were determined here. Results showed L. plantarum inhibited S. aureus in UHT and fermented milk. Non‐volatiles and volatiles were identified to contribute to the overall antibacterial activity of L. plantarum. The addition of manganese to fermented milk restored S. aureus growth, demonstrating that manganese depletion played a key role in the anti‐S. aureus activity. Our findings developed a promising bioprotective culture and provided a strategy to suppress S. aureus in a non‐bactericidal manner in dairy products. [ABSTRACT FROM AUTHOR]

Campylobacter jejuni (C. jejuni) is one of the most common foodborne pathogens that cause human sickness mostly through the poultry food chain. Cinnamon essential oil (CEO) has excellent antibacterial ability against C. jejuni growth. This study investigated the antibacterial mechanism of CEO against C. jejuni primarily through metabolism, energy metabolism of essential enzymes (AKPase, β -galactosidase, and ATPase), and respiration metabolism. Results showed that the hexose monophosphate pathway (HMP) was inhibited, and that the enzyme activity of G 6 DPH substantially decreased upon treatment with CEO. Analysis of the effect of CEO on the expression of toxic genes was performed by the real-time PCR (RT-PCR). The expression levels of the toxic genes cadF, ciaB, fliA, and racR under CEO treatment were determined. Casein/CEO nanospheres were further prepared for the effective inhibition of C. jejuni and characterized by particle-size distribution, zeta-potential distribution, fluorescence, TEM, and GC–MS methods. Finally, the efficiency of CEO and casein/CEO nanospheres in terms of antibacterial activity against C. jejuni was verified. The casein/CEO nanospheres displayed high antibacterial activity on duck samples. The population of the test group decreased from 4.30 logCFU/g to 0.86 logCFU/g and 4.30 logCFU/g to 2.46 logCFU/g at 4 °C and at 25 °C for C. jejuni , respectively. Sensory evaluation and texture analysis were also conducted on various duck samples. • The antibacterial mechanism of cinnamon essential oil (CEO) against C. jejuni was explored. • High sensitive controlled-release casein/CEO nanosphere was successfully fabricated. • The casein/CEO nanosphere had a good sterilization effect on the duck. [ABSTRACT FROM AUTHOR]