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Eleutherine americanabulb known mainly as a flavouring agent has also beneficial role in food safety and preservation. The present study aims to evaluate the efficacy of Eleutherine americanabulb extract in controlling contamination of a major foodborne pathogen, Campylobacter jejuniin chicken meat. The treatment was divided into 3 sets (i) dipping chicken meat in the extract (ii) mixing the extract with chicken meat, and (iii) combination of the extract treatment with short-term freezing at − 20 °C. With dipping method, the addition of 8 mg mL−1of the extract lowered C. jejuniATCC 33560 counts in chicken meat to approximately 2 log on day 6. One log-fold decrease in the bacterial counts in chicken meat mixed with E. americanaextract at 4 mg mL−1was observed at day 7. Furthermore, the extract at 8 mg mL−1caused reduction in the bacterial counts up to 2 log from day 4 till day 7 (P< 0.05). Combined treatment with the extract at 4 and 8 mg mL−1and subsequent short-term freezing of chicken meat reduced survival of C. jejuniabout 2 log from day 5 and day 3, respectively (P< 0.05). Sensory scores analysis demonstrated that addition of the extract did not adversely affect the properties of cooked chicken meat until day 5 (P< 0.05). The results suggest that E. americanaextract could be a promising novel agent to control Campylobactercontamination in chicken meat.

Biofilms play a key role in the development of chronic tissue infections and antimicrobial resistance. In situ-forming thermosensitive hydrogel containing biosynthesized silver nanoparticles using aqueous Eucalyptus camaldulensisleaf extract (bio-AgNPs) was developed as an efficient anti-biofilm agent with a sustained release for tissue infection treatment. The formulation with 24% poloxamer 407, 5% poloxamer 188, and 1% hydroxypropyl methylcellulose demonstrated gelation temperature at 33 °C and homogeneous dispersion of bio-AgNPs throughout three-dimensional networks. Pharmaceutical properties of bio-AgNPs-loaded hydrogel presented shear-thinning behavior and zero-order release profile. The formulation showed broad-spectrum antimicrobial activity and comparable effects with existing antibiotics against important pathogens, including Gram-positive, Gram-negative bacteria, and fungi. The formulation at 1/8–1/2 minimum inhibitory concentrations (MIC) significantly inhibited biofilm production in all tested pathogens (p < 0.05). Confocal laser scanning microscopy images clearly illustrated dead cells within mature biofilm upon the treatment with the formulation at 2MIC for 4 h. The formulation effectively scavenged free radicals and decreased nitric oxide production up to 98%. Decrease in mRNA levels of inflammation-related enzymes and pro-inflammatory cytokines in lipopolysaccharide-stimulated RAW 264.7 cells confirmed the formulation as a potential anti-inflammatory agent. The findings suggested that bio-AgNPs-loaded hydrogel represents a promising therapeutic approach for tissue infections.

Polyvinyl alcohol-chitosan (PVA–CH) films containing biogenic silver nanoparticles were prepared using solvent casting and particulate leaching. The films were characterized for structural, thermal, mechanical, and physical properties. Antimicrobial and antioxidant activities of the films were measured. The FTIR and XRD analysis showed that addition of Ag nanoparticles did not alter the structure of the PVA–CH films. Thermal analysis of the films showed that PVA–CH/Ag nanoparticles films were thermally stable. The thickness and contact angles showed significant difference after the addition of Ag nanoparticles (p < 0.05). Antimicrobial activity of PVA–CH/Ag nanoparticles (1:1) films showed bactericidal effects against important foodborne pathogenic bacteria (Escherichia coliO157:H7, Listeria monocytogenes, Staphylococcus aureus,and Bacillus cereus), with >99.9% reduction.Antioxidant activities suggested an increased concentration–dependent free radical scavenging activity. In addition, PVA–CH/Ag nanoparticles showed first order release with Fickian diffusion and were non-toxic to Caco-2 cells at 1 mg/mL. The results suggested that addition of Ag nanoparticles did not alter the properties of the film, but rather increased its antimicrobial and antioxidant properties. Thus, this environmentally friendly packaging material may be able to be used to extend shelf life.