Search Results (1,717)

Foodborne pathogens and their biofilms threaten microbial safety in food systems, highlighting the need for antimicrobial candidates. This study compared nine essential oils derived from traditional Chinese medicinal herbs (TCM herb essential oils) for antibacterial activity, mature biofilm removal, volatile composition, and candidate compounds against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella paratyphi B using DIZ, MIC, crystal violet staining, GC–MS, growth curves, and SEM. Among the tested oils, Lonicera japonica, Sinomenium acutum, and Scutellaria baicalensis essential oils showed relatively broad antibacterial activity. Lonicera japonica essential oil (LJEO) displayed the most notable overall performance, producing DIZ values of 38.29, 25.29, and 24.75 mm against S. aureus, L. monocytogenes, and S. paratyphi B, respectively, and low MIC against S. aureus and L. monocytogenes at 0.15625% and 0.3125%. LJEO removed mature biofilms of L. monocytogenes, E. coli, and S. paratyphi B by 60.58%, 50.80%, and 47.82%, respectively, but showed limited activity against S. aureus biofilms. GC–MS identified 156 volatile compounds, with LJEO characterized by abundant linalool, p-cymene, borneol, cineoles, and limonene. Growth curves and SEM indicated that LJEO inhibited bacterial proliferation and damaged cell surface structures. These findings suggest that TCM herb essential oils, especially LJEO, may serve as natural antimicrobial candidates for foodborne pathogen control and food preservation. Full article

The European catfish (Silurus glanis) is an invasive predatory species threatening biodiversity in the Tagus River (Portugal), while remaining underexploited as a food resource. Despite its potential contribution to invasive species management, limited knowledge exists on its suitability for developing value-added food products, particularly using processing scraps. This study aimed to valorise this species through the development and characterisation of six value-added food products produced from fillets and processing scraps. Nutritional, microbiological, textural, and sensory properties were evaluated. Microbiological analyses confirmed the absence of Salmonella spp., Listeria monocytogenes, and E. coli in all products; however, the high microbial counts observed in Powerbites indicate the need for improved hygiene and process control. Protein content ranged from 10.05 to 16.89 g/100 g, with complete essential amino acid profiles and relevant contributions to adult daily indispensable amino acid requirements. The products also showed low to moderate fat content, favourable fatty acid profiles, and meaningful contributions of vitamins B12 and E. Sensory evaluation indicated overall positive acceptance, although some formulations require further optimisation. These findings highlight the nutritional, technological, and sustainable potential of European catfish-based products, supporting their use as value-added food alternatives while contributing to the valorisation of an underused invasive species. Full article

Bee bread is a fermented product derived from bee pollen, whose fermentation improves preservation, nutrient bioavailability, and functional properties. However, the microbial succession driving this process, particularly the role of yeasts, remains poorly understood. This study investigated microbial dynamics during fourteen-day spontaneous fermentation of five fresh bee pollen samples from different geographical origins, mimicking natural bee bread formation. Cultivable yeasts and lactic acid bacteria were monitored by viable cell counts and molecular identification. Physicochemical parameters, nutritional components, bioactivities, and pollen structure were evaluated. A clear microbial succession was observed, with Starmerella sp. dominating the early stages and the osmotolerant yeast Zygosaccharomyces rouxii prevailing during the final phase. Together with Apilactobacillus kunkeei, these microorganisms may constitute a cultivable fermentative core involved in bee bread formation. Fermentation significantly increased protein availability, with increases of up to 18%, reduced pH, promoted bee pollen degradation up to 16%, and enhanced antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes. Understanding of cultivable microbiota dynamics during spontaneous bee pollen fermentation could provide an effective natural strategy to stabilize bee pollen while improving its nutritional and functional properties, laying the foundation for developing controlled industrial fermentations to produce bee bread-like products with consistent quality and health-promoting characteristics. Full article

The transition toward reusable food packaging driven by European circular economy regulations introduces new food safety challenges related to microbial persistence and cross-contamination. GS-2 is a novel, food-safe antimicrobial formulation developed for use as a coating on reusable packaging materials. In the present study, the intrinsic antimicrobial activity of GS-2 was evaluated in liquid suspension against foodborne bacterial (Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica Agona) and fungal pathogens (Aspergillus flavus and Aspergillus niger), and the transcriptomic response of L. monocytogenes following sublethal GS-2 exposure was investigated. GS-2 exhibited concentration-dependent microbicidal activity, with strong reductions observed at ≥2.8–3.0% against bacterial strains and A. flavus, while A. niger demonstrated resistance. Among bacteria, L. monocytogenes showed the greatest sensitivity, with populations reduced below detection limits at 3% GS-2. To elucidate mechanistic responses, RNA sequencing was performed on L. monocytogenes exposed to sublethal GS-2 concentrations (0.1–1.0%). Transcriptomic analyses using discrete and continuous models revealed a pronounced adaptive stress response at 0.5% GS-2, characterized by coordinated upregulation of pathways involved in carbon, nitrogen, and nucleotide metabolism. At higher sublethal concentrations (1%), transcriptional profiles shifted toward growth arrest and cellular damage management. These findings support GS-2 as a promising antimicrobial for enhancing the microbial safety of reusable food packaging systems. Full article

The increasing interest in natural versus synthetic additives is a driving force for food industry innovation to develop alternative solutions for food safety and quality. Brown algae, described as containing potential antimicrobial and antioxidant compounds, are promising alternative sources. However, optimized food-grade extracts require preserving their bioactivity. In this study, the effects of seasonality and interannual variation, together with non-thermal high-hydrostatic-pressure (HHP) pretreatment, on the extraction of antioxidant and antimicrobial compounds from the macroalga Ericaria selaginoides, collected from the northwest of Spain between November 2021 and September 2023, were assessed. The HHP pretreatment of fresh algae did not significantly change the yield of the crude extracts and only slightly improved the antimicrobial activity of the extracts against L. monocytogenes, S. aureus and B. cereus, without significantly diminishing the antioxidant activity until 600 MPa for 5 min, the total polyphenol content (TPC), and the chlorophyll A content. Interannual and seasonal variations significantly influenced pigments and protein, carbohydrate and polyphenol contents, together with the antioxidant and antimicrobial activities, of the extracts. By NMR, phloroglucinol was identified as the major secondary metabolite, together with mannitol, alanine and a mixture of meroditerpenoids, which may contribute to the reported activities. The overall results demonstrated the role of environmental factors in driving seasonal and interannual changes in macroalgal metabolism, significantly influencing the bioactive properties of extracts, while the effect of HHP pretreatment was minimal. Full article

Agricultural and horticultural by-products represent an underexploited source of valuable bioactive compounds that can contribute to the development of more sustainable production systems. This study investigated the chemical composition and biological activities of the essential oil obtained from the horticultural byproducts of Artemisia dracunculus. The waste aerial biomass was subjected to steam distillation, and the essential oil was characterized by gas chromatography–mass spectrometry. Its antioxidant, α-amylase and α-glucosidase inhibitory, phytotoxic, antibacterial, and antibiofilm activities were subsequently evaluated. The essential oil was characterized as an estragole-rich chemotype (70.17%), with trans-β-ocimene and cis-β-ocimene as other main constituents. The essential oil showed moderate antioxidant activity and measurable enzyme inhibitory activity and, despite showing limited effects on seed germination, it significantly inhibited radical elongation in selected plant species. Furthermore, it demonstrated excellent antibiofilm activity, significantly reducing the metabolic activity of mature cells of bacteria associated with biofilm formation: Listeria monocytogenes, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae and Staphylococcus aureus. The results demonstrate how horticultural by-products from A. dracunculus maintain a chemical profile comparable to conventional plant material and represent a valuable source of bioactive compounds with promising potential for sustainable agri-food applications. Full article

Listeria monocytogenes is a leading cause of foodborne mortality in the European Union, with ready-to-eat (RTE) meat products representing a primary transmission vehicle. Traditional dry-cured and fermented meat products, produced under small-scale artisanal conditions, present particular microbiological challenges, yet systematic surveillance data from the Western Balkans remain limited. Microbiological testing results for L. monocytogenes in traditional Montenegrin meat products were extracted from the national food control monitoring system over the period 2016–2025. A total of 2471 samples from 58 product varieties were analysed using EN ISO 11290-1/2 standards. Prevalence was estimated with 95% confidence intervals; differences between product categories were assessed by Pearson chi-square with Bonferroni-corrected pairwise comparisons, and temporal trends by the Cochran–Armitage test. The overall prevalence was 6.6%, ranging from 0.5% (2017) to 14.7% (2024). Dry-fermented sausages (kobasica; 17.2%) and cured belly (pančeta; 9.9%) showed significantly higher prevalence than whole-muscle products (pršut 3.8%; pečenica 1.5%; p < 0.001). Njeguška kobasica and its vacuum-packed variant recorded the highest individual prevalence (30.1% and 47.6%, respectively). No significant monotonic trend was detected over the surveillance period (Z = 0.801, p = 0.423). Prevalence estimates varied considerably across years without evidence of a monotonic trend, supporting the need for a regulatory shift toward production-environment monitoring and integration of whole-genome surveillance in the traditional meat sector. Full article

Background/Objectives: Lactic acid bacteria (LAB) are essential drivers of food fermentation, yet systematic metabolic comparisons across different LAB strains remain underexplored. This study characterized and contrasted the metabolic fingerprints of Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus in vegetable fermentation and subsequently evaluated whether the same untargeted metabolomics pipeline could be applied to rapid foodborne pathogen detection. Methods: A multi-platform untargeted metabolomics strategy integrating GC-MS and UPLC-Q-TOF-MS was applied to profile four experimental conditions: non-fermented control, L. plantarum monoculture, L. rhamnosus monoculture, and mixed-culture fermentation. Multivariate statistical tools (PCA and PLS-DA) were used to identify differential metabolites and perturbed pathways. The identical analytical workflow was then applied to beef samples artificially contaminated with Escherichia coli O157:H7, Salmonella enterica, or Listeria monocytogenes. Results: Across all samples, 847 metabolites were annotated, of which 312 showed significant abundance changes upon fermentation. PLS-DA delivered robust group discrimination (R²X = 0.89, R²Y = 0.95, Q² = 0.91). Organic acids (32.0%) and amino acids (24.0%) dominated the metabolic landscape, with lactic acid, acetic acid, diacetyl, and acetoin as the most elevated compounds. KEGG analysis highlighted glycolysis/gluconeogenesis, pyruvate metabolism, and branched-chain amino acid degradation as the most heavily rewired pathways. When the same pipeline was applied to pathogen detection, it yielded AUC values of 0.89, 0.87, and 0.88 for E. coli O157:H7, S. enterica, and L. monocytogenes, respectively, with detection times of 18 h, 24 h, and 30 h. Conclusions: This work delivers a side-by-side metabolic atlas of two prominent LAB species and demonstrates the technical portability of an untargeted metabolomics pipeline from a fermentation model system to a pathogen detection scenario. The identified biomarker panels warrant further validation in diverse food matrices, and translation to routine monitoring will require matrix-specific model training and validation. Full article

Clustered regularly interspaced short palindromic repeats (CRISPR) are widespread in bacterial and archaeal genomes as an adaptive immune system against invading mobile genetic elements. This study investigated the distribution of CRISPR loci and their potential association with antimicrobial resistance (AMR) in 40 foodborne Listeria monocytogenes isolates. CRISPR analysis showed that 18 isolates harbored CRISPR Locus 1, five carried Locus 2, and five possessed both loci. Antimicrobial susceptibility testing against seven antimicrobial agents indicated that most isolates were highly susceptible to the tested agents. Specifically, all isolates were susceptible to gentamicin, ampicillin, penicillin, and tetracycline, whereas resistance was observed in a small subset of isolates: four were resistant to chloramphenicol, five to levofloxacin, and four to ciprofloxacin. Statistical analysis showed no statistically significant association between the presence of CRISPR loci and antimicrobial susceptibility phenotypes. These findings provide baseline information on CRISPR locus distribution and antimicrobial susceptibility profiles in foodborne L. monocytogenes isolates. Further studies based on larger isolate collections, whole-genome sequencing, and characterization of associated cas genes are needed to clarify the potential role of CRISPR-Cas systems in AMR evolution in this species. Full article

Single-needle electrospinning and needle-free electrospinning were applied to fabricate cellulose acetate (CA) fibrous mats containing rosemary (RO), clove (CL) and thyme (TH) essential oils (EO) from binary or ternary solvent mixture solutions. When an acetone, dichloromethane, and dimethylformamide mixture was used as the solvent system, cylindrical nanofibers with an average diameter between 255 and 617 nm were obtained. Removing dimethylformamide from the spinning solution resulted in flattened microfibers with significantly larger diameters, varying from 1242 to 2939 nm. Furthermore, CA nanofibers loaded with RO, CL or TH essential oils with diameter distributions ranging from 55 to 176 nm, from 69 to 215 nm and from 44 to 291 nm, respectively, were produced from ternary solvent mixture solutions using needle-free electrospinning equipment. FTIR and TGA studies revealed the incorporation of essential oils into the fiber structure, and GC-MS was used to evaluate the release of bioactive components from fibrous mats. The electrospun nanofibers of CA/RO, CA/CL and CA/TH showed excellent antioxidant activity and antimicrobial properties against Escherichia coli, Pseudomonas aeruginosa and Listeria monocytogenes. In addition, the CA/CL fibrous mat was tested in the storage of fresh beef steaks. Full article

Listeria monocytogenes (L. monocytogenes) is a zoonotic foodborne pathogen that triggers life-threatening invasive illnesses. MarR-type transcriptional regulators widely control bacterial stress adaptation, antibiotic tolerance and virulence, playing crucial roles in the pathogenesis of diverse bacterial pathogens. Lmo0840 is a conserved member of this family; however, its physiological functions and regulatory networks in L. monocytogenes remain completely unexplored. To this end, we constructed an lmo0840 deletion mutant and its complemented strain in the L. monocytogenes EGD-e background and systematically characterized the biological functions of Lmo0840 using phenotypic assays, transcriptomic profiling, and electrophoretic mobility shift assays (EMSA). Phenotypic characterization revealed that loss of lmo0840 impaired growth rate under hyperosmotic, oxidative, and iron-limitation stresses, while unexpectedly promoting growth rate at 30 °C and under tetracycline stress. Consistently, Disk diffusion assays further showed that the Δlmo0840 mutant exhibited significantly reduced inhibition zone diameters against tetracycline antibiotics compared to the EGD-e strain. Moreover, the Δlmo0840 mutant exhibited reduced early biofilm formation and attenuated macrophage adhesion, yet showed enhanced cellular invasion and decreased virulence in a murine model. EMSA further demonstrated that Lmo0840 directly binds to the promoter region of lmo0839 and represses its transcription, thereby contributing to bacterial adaptation to tetracycline stress. Collectively, these findings establish Lmo0840 as a pleiotropic regulator involved in environmental stress responses, tetracycline adaptation, and virulence in L. monocytogenes. Notably, this study identifies for the first time an Lmo0840–Lmo0839 regulatory cascade underlying tetracycline adaptation. These insights not only deepen our understanding of the molecular mechanisms governing Lm environmental adaptation and pathogenicity but also provide a potential target for the prevention and control of listeriosis. Full article

The recovery of polyphenols from pomegranate peel is limited by conventional extraction methods that rely on organic solvents. This study evaluated the ultrasound-assisted extraction (UAE) of dehydrated pomegranate peel using greener solvent systems based on distilled vinegar combined with α-cyclodextrin (αCD) to enhance the solubilization and recovery of phenolic compounds. The resulting extracts were characterized by total antioxidant capacity (DPPH free radical scavenging assay), total phenolic content (TPC, Folin–Ciocalteu assay), targeted phenolic analysis (HPLC-QTOF-MS analysis) and antimicrobial activity (Kirby–Bauer well-diffusion assay) against Listeria monocytogenes and Salmonella enterica. The unbuffered vinegar system (V2) exhibited the highest antioxidant capacity (2372.1 ± 109.7 µmol TE/g DW), significantly exceeding the methanolic control (1147.5 ± 477.6 µmol TE/g DW; p < 0.05). The vinegar-αCD system (V2-10) showed the highest TPC (196.2 ± 15.6 mg GAE/g DW), while HPLC-QTOF-MS identified punicalagin as the predominant phenolic compound (26.1–64.5 mg/g DW), with the highest total quantified phenolic content (76.2 mg/g DW). Vinegar-based extracts also inhibited L. monocytogenes (33.1–46.7 mm) and S. enterica (19.9–24.3 mm). Overall, UAE combined with vinegar-αCD solvents represents a promising green extraction strategy for obtaining polyphenol-rich extracts from pomegranate byproducts, providing comparative insights into solvent-dependent differences in phenolic profiles and bioactivity. Full article

The development of sustainable biopolymer-based active packaging materials is essential to replace single-use petroleum-derived plastics and reduce food deterioration. In this study, chitosan-based films incorporating green-synthesized silver microparticles (Ag microparticles) obtained from pecan nutshell extract rich in phenolic compounds were developed as multifunctional materials with antioxidant and antibacterial properties. Films were prepared by the casting method using chitosan solutions at different concentrations (1.5–2.5% w/v), with Ag microparticles incorporated at 0.25% (w/v). The phenolic profile of the extract (gallic acid, catechin, ferulic acid, and ellagic acid), determined by UPLC-DAD, confirmed its role as a reducing and stabilizing agent during Ag microparticle synthesis. All film-forming solutions exhibited non-Newtonian pseudoplastic behavior, and variations in viscosity and consistency were directly reflected in the mechanical behavior of the films. Strong antioxidant activity, mainly governed by single-electron transfer mechanisms, was observed in ABTS, DPPH, and FRAP assays. The films also showed pronounced antibacterial activity, achieving complete inhibition of Listeria monocytogenes. Finally, it is concluded that film mechanical properties are strongly governed by the rheological behavior of the chitosan-based film-forming solutions. The resulting chitosan-Ag microparticle films combine suitable mechanical behavior with antioxidant activity and antibacterial effects against Listeria monocytogenes, suggesting their potential for future application in active food-packaging systems. Full article

Foodborne pathogens remain a major public health challenge, particularly in the context of antimicrobial resistance and persistent contamination across animal, food-processing, and retail environments. This review examines bacteriophages as precision antimicrobials for controlling major foodborne bacteria, including Salmonella, Campylobacter, Shiga toxin-producing Escherichia coli (STEC), Listeria monocytogenes, and Vibrio spp., and summarizes the biological basis of phage-mediated control: strictly lytic life cycles, receptor-specific adsorption, direct bacterial killing, biofilm disruption, and resistance-associated fitness trade-offs. It further discusses pre-harvest, post-harvest, and processing-environment applications, with emphasis on matrix-dependent efficacy, delivery strategies, commercial products, and regulatory status. While bacteriophages offer high specificity and may help preserve the native microbiome, their integration into multi-hurdle food-safety systems require careful validation because their performance is influenced by narrow host ranges, bacterial resistance, food-matrix effects, formulation constraints, and regulatory complexity and scale-up challenges. Broader implementation will require rationally designed phage-cocktails, thorough genomic safety screening, matrix-specific validation studies, scalable manufacturing processes, and continuous monitoring for post-application resistance. Overall, bacteriophages should be viewed as promising but context-dependent adjuncts to validated food-safety and One Health frameworks, rather than stand-alone solution for reducing foodborne pathogen burdens. Full article

Foodborne diseases remain a major global public health concern. According to the World Health Organization (WHO), contaminated food causes nearly 500,000 deaths annually. Consequently, the development of novel strategies to control foodborne pathogens and prevent microorganism-induced plant diseases remains an important research priority, attracting considerable scientific attention worldwide. This study describes the design and synthesis of novel dihydropyrazolines containing an ethylpiperazine moiety as potential antimicrobial agents. The antibacterial activity of the newly synthesized heterocyclic compounds, along with their corresponding chalcone precursors, was evaluated against Gram-positive and Gram-negative foodborne pathogens and phytopathogenic bacteria. The assessment was performed using a two-step protocol comprising an initial qualitative screening of selected bacterial species, followed by a quantitative evaluation of the inhibitory effects of individual compounds and their combinations. Among the tested compounds, pyrazolines 4a and 4b and chalcone 3b exhibited notable strain-dependent antibacterial activity, particularly against phytopathogenic strains of Pseudomonas syringae, while compound 4a demonstrated the highest efficacy against the Gram-negative foodborne pathogens Escherichia coli, Salmonella enterica and Listeria monocytogenes. Thus, the potential of the N-ethylpiperazine moiety as a key structural feature contributing to the antimicrobial activity of the studied compounds is revealed. Full article