Stability and Antibiofilm Efficiency of Slightly Acidic Electrolyzed Water Against Mixed-Species of Listeria monocytogenes and Staphylococcus aureus.

In the natural environment, most microorganisms live in mixed-species biofilms, in which the metabolism and growth of organisms are different from that in single-species biofilms. Adhesive bacteria and their biofilms on the surface of food processing equipment are the sources of cross-contamination, leading to the risk for humans. Slightly acidic electrolyzed water (SAEW) has been proposed as a novel sanitizer in the food and agriculture industry. In this study, we investigated the changes in the physical properties of SAEW under different conditions and the disinfection abilities of SAEW against spore-forming and non-spore-forming pathogens. Furthermore, we examined the disinfection abilities of SAEW after 12 months of shelf life on a mixed-species biofilm of Listeria monocytogenes Scott A and Staphylococcus aureus. The results showed that SAEW at 30 and 50 ppm achieved all-kill of the spore-forming pathogen Bacillus cereus within 30 s. Changes in the ACC and pH of the produced SAEW were generally affected by the storage conditions. Both spore-forming and non-spore-forming pathogens were not detected under treatment with 50 ppm SAEW for 5 min under HDPE-closed conditions throughout the whole storage period. Moreover, 25 mg/L SAEW can inactivate L. monocytogenes Scott A and S. aureus biofilm cells in ~2.45 and 2.57 log CFU/mL in biofilms within 5-min treatment. However, the decline of the two bacteria in the mixed-species biofilm was 1.95 and 1.43 log CFU/mL, respectively. The changes in the cell membrane permeability of the mixed-species biofilm under treatment with SAEW were observed by using atomic force microscopy and confocal laser scanning microscopy. L. monocytogenes Scott A was more sensitive to SAEW in the mixed-species biofilm cells. These findings exhibited strong antibiofilm activities of SAEW in impairing biofilm cell membranes, decreasing cell density, and eliminating biofilm, which suggest that SAEW is an excellent antibacterial agent in the food processing industries.

Optimization and Effect of Water Hardness for the Production of Slightly Acidic Electrolyzed Water on Sanitization Efficacy.

Slightly acidic electrolyzed water (SAEW) has been recently proposed as a novel promising sanitizer and cleaner in the agricultural and food industries. However, several factors, including water hardness, were considered to strongly affect the physical properties and sanitization efficacy of SAEW. To study the effect of water hardness on the SAEW production, we evaluated the production properties and sanitization effect of SAEW, which was generated from water sources in 16 representatively geographical locations of South Korea. The results showed that the hardness of water sources from Kangwon-do, Jeollanam-do, and Daegu was 22-41 ppm; that from Busan, Gyeongnam-do, Gwangju Bukgu was 80-443 ppm, and that from seven other locations was 41-79 ppm. SAEW is produced from water hardness less than 50 ppm and greater than 80 ppm was beyond the accepted pH range (5.0-6.5). Notably, high-hardness water (>80 ppm) containing 5% HCl could be used to produce SAEW with accepted pH. The SAEW generated from low-hardness water with additions of 2% HCl and 2 M NaCl at 7 A showed accepted pH and higher germicidal effect. Furthermore, SAEW with the available chlorine concentration of 27-41 mg/L for 1 min was sufficient to completely inactivate non-spore-forming foodborne pathogens. Sanitization efficacy was not markedly affected by storage conditions for SAEW at 40 ppm. Our results demonstrated that the degree of water hardness is an important factor in the production of SAEW, which would provide a foundation for commercial application of SAEW.

An effective datasets describing antimicrobial peptide produced from Pediococcus acidilactici - purification and mode of action determined by molecular docking.

Most of the probiotics Bacterial cells, express native antibacterial genes, resulting in the production of, antimicrobial peptides, which have various applications in biotechnology and drug development. But the identification of antibacterial peptide, structural characterization of antimicrobial peptide and prediction on mode of action. Regardless of the significance of protein manufacturing, three individual factors are required for the production method: gene expression, stabilization and specific peptide purification. Our protocol describes a straightforward technique of detecting and characterizing particular extracellular peptides and enhancing the antimicrobial peptide expression we optimized using low molecular weight peptides. This protocol can be used to improve peptide detection and expression. The following are the benefits of this method, (DOI - https://doi.org/10.1016/j.ijbiomac.2019.10.196 [1]). The data briefly describe a simple method in detection identification, characterization of antimicrobial extracellular peptide, predicating the mode of action of peptide in targeting pathogens (In-silico method), brief method on profiling of antimicrobial peptide and its mode of action [1]. Further the protocol can be used to enhance the specific peptide expressions, detection of peptides. The advantages of this technique are presented below:•Characterization protocol of specific antimicrobial peptide•The folded antimicrobial peptide expression were less expressed or non-expressed peptides.•Besides being low cost, less time-consuming, easy to handle, universal and fast to execute, the suggested technique can be used for multiple proteins expressed in probiotics (Lactobacillus species) expression system.

Review on Stress Tolerance in Campylobacter jejuni.

Campylobacter spp. are the leading global cause of bacterial colon infections in humans. Enteropathogens are subjected to several stress conditions in the host colon, food complexes, and the environment. Species of the genus Campylobacter, in collective interactions with certain enteropathogens, can manage and survive such stress conditions. The stress-adaptation mechanisms of Campylobacter spp. diverge from other enteropathogenic bacteria, such as Escherichia coli, Salmonella enterica serovar Typhi, S. enterica ser. Paratyphi, S. enterica ser. Typhimurium, and species of the genera Klebsiella and Shigella. This review summarizes the different mechanisms of various stress-adaptive factors on the basis of species diversity in Campylobacter, including their response to various stress conditions that enhance their ability to survive on different types of food and in adverse environmental conditions. Understanding how these stress adaptation mechanisms in Campylobacter, and other enteric bacteria, are used to overcome various challenging environments facilitates the fight against resistance mechanisms in Campylobacter spp., and aids the development of novel therapeutics to control Campylobacter in both veterinary and human populations.

Unveiling the potentials of bacteriocin (Pediocin L50) from Pediococcus acidilactici with antagonist spectrum in a Caenorhabditis elegans model.

Human-milk-based probiotics play a major role in the early colonization and protection of infants against gastrointestinal infection. We investigated potential probiotics in human milk. Among 41 Lactic acid bacteria (LAB) strains, four strains showed high antimicrobial activity against Escherichia coli 0157:H7, Listeria monocytogenes ATCC 15313, Bacillus cereus ATCC 14576, Staphylococcus aureus ATCC 19095, and Helicobacter pylori. The selected LAB strains were tested in simulated gastrointestinal conditions for their survival. Four LAB strains showed high resistance to pepsin (82%-99%), bile with pancreatine stability (96%-100%), and low pH (80%-94%). They showed moderate cell surface hydrophobicity (22%-46%), auto-aggregation abilities (12%-34%), and 70%-80% co-aggregation abilities against L. monocytogenes ATCC 15313, S. aureus ATCC 19095, B. cereus ATCC 14576, and E. coli 0157:H7. All four selected isolates were resistant to gentamicin, imipenem, novobiocin, tetracycline, clindamycin, meropenem, ampicillin, and penicillin. The results show that Pediococcus acidilatici is likely an efficient probiotic strain to produce < 3 Kda pediocin-based antimicrobial peptides, confirmed by applying amino acid sequences), using liquid chromatography mass spectrometry and HPLC with the corresponding sequences from class 2 bacteriocin, and based on the molecular docking, the mode of action of pediocin was determined on LipoX complex, further the 13C nuclear magnetic resonance structural analysis, which confirmed the antimicrobial peptide as pediocin.

Biological activities of a garlic-Cirsium setidens Nakai blend fermented with Leuconostoc mesenteroides.

In this study, we investigated the antioxidant- and immune-stimulating activities of various garlic-Cirsium setidens Nakai blends (fermented and unfermented). The levels of S-allyl cysteine increased by 2.5 times while pectolinarigenin (an anti-inflammatory compound) increased about six times (from 1.1 ± 0.04 mg/g to 6.70 ± 0.12 mg/g) after the garlic-Cirsium setidens Nakai (80:20%, respectively) blend (S4) was fermented with Leuconostoc mesenteroides KCTC 13302. The ferric reducing ability and DPPH radical scavenging activities of all the samples increased significantly after fermentation. Ethanolic extracts of the fermented samples significantly enhanced RAW 264.7 macrophage proliferation in a dose-dependent manner and induced nitric oxide production. Among the samples, S6 and S8 stimulated the highest levels of nitric oxide (NO) production. S6 significantly induced proinflammatory cytokines TNF-α and IL-1ß as well as an anti-inflammatory cytokine IL-10 relative to control. Since the resolution of an infection would require a harmonized interplay of proinflammatory factors and anti-inflammatory cytokines, consumption of S6 could be helpful in promoting health.