To overcome the poor water solubility of curcumin, a curcumin-β-cyclodextrin (Cur-β-CD) complex was prepared as a novel photosensitizer. Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to verify the formation of Cur-β-CD. Furthermore, the ROS generation capacity and photodynamic bactericidal effect were measured to confirm this Cur-β-CD complex kept photodynamic activity of curcumin. The result showed Cur-β-CD could effectively generate ROS upon blue-light irradiation. The plate count assay demonstrated Cur-β-CD complex possess desirable photodynamic antibacterial effect against food-borne pathogens including Staphylococcus aureus, Listeria monocytogenes and Escherichia coli. The cell morphology determined by scanning electron microscope (SEM) and transmission electron microscope (TEM) showed Cur-β-CD could cause cell deformation, surface collapse and cell structure damage of the bacteria, resulting in the leakage of cytoplasmic; while agarose gel electrophoresis and SDS-PAGE further illustrated the inactivation mechanisms by Cur-β-CD involve bacterial DNA damage and protein degradation.
Campylobacter, Salmonella, and Listeria monocytogenes are important bacterial pathogens associated with gastroenteritis. The consumption of poultry meat and their products is considered as a major and leading source of human infection. While surveys of chicken meat and products, and its association with foodborne pathogens are widely available, such information on ducks is scarce. This survey examines the prevalence and antibiotic resistance of Campylobacter, Salmonella and L. monocytogenes isolated from ducks. Data obtained from key surveys are summarized. The observed prevalence of these pathogens and their resistance to various antibiotics varies from one study to the other. The mean prevalence (and range means from individual surveys) are duck 53.0% (0.0-83.3%), duck meat and parts 31.6% (12.5-45.8%), and duck rearing and processing environment 94.4% (92.0-96.7%) for Campylobacter spp. For Salmonella spp., the mean prevalence data are duck 19.9% (3.3-56.9%), duck meat and parts 28.4% (4.4-75.6%), duck egg, shell, and content 17.5% (0-4.17%), and duck rearing and processing environment 32.5% (10.5-82.6%). Studies on the prevalence and antibiotic resistance of L. monocytogenes in ducks are by far very rare compared to Campylobacter and Salmonella, although ducks have been noted to be a potential source for these foodborne pathogens. From our survey, ducks were more frequently contaminated with Campylobacter than Salmonella. Campylobacter and Salmonella spp. also exhibited varying resistance to multiple antibiotics.
Tuning the characteristics of solvents to fit industrial requirements has currently become a major interest in both academic and industrial communities, notably in the field of room temperature ionic liquids (RTILs), which are considered one of the most promising green alternatives to molecular organic solvents. In this work, several sets of imidazolium-based ionic liquids were synthesized, and their toxicities were assessed towards four human pathogens bacteria to investigate how tunability can affect this characteristic. Additionally, the toxicity of particular RTILs bearing an amino acid anion was introduced in this work. EC50 values (50% effective concentration) were established, and significant variations were observed; although all studied ILs displayed an imidazolium moiety, the toxicity values were found to vary between 0.05 mM for the most toxic to 85.57 mM for the least toxic. Linear quantitative structure activity relationship models were then developed using the charge density distribution (σ-profiles) as molecular descriptors, which can yield accuracies as high as 95%.
The goal of this study was to determine inhibitory effect of palm kernel expeller (PKE) peptides of different degree of hydrolysis (DH %) against spore-forming bacteria Bacillus cereus, Bacillus circulans, Bacillus coagulans, Bacillus licheniformis, Bacillus megaterium, Bacillus pumilus, Bacillus stearothermophillus, Bacillus subtilis, Bacillus thuringiensis, Clostridium perfringens; and non-spore-forming bacteria Escherichia coli, Lisinibacillus sphaericus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella Typhimurium and Staphylococcus aureus.
Lactic acid bacteria (LAB) can be isolated from traditional milk products. LAB that secrete substances that inhibit pathogenic bacteria and are resistant to acid, bile, and pepsin but not vancomycin may have potential in food applications.