Antibacterial Activity of Hexanol Vapor In Vitro and on the Surface of Vegetables.

Hexanol is a volatile alcohol and a major component of plant essential oils (EOs). However, the antibacterial activity of hexanol vapor has not been well studied. This study aimed to evaluate the antibacterial activity of hexanol.

Identification of changes in the microflora composition of Japanese horse mackerel () during storage to identify specific spoilageorganisms.

Japanese horse mackerel () is an important marine resource, and its loss and waste should be reduced. This study aimed to identify the changes in the microflora composition during storage and specific spoilage organisms (SSOs) in Japanese horse mackerel, for spoilage prevention. They were stored at either 20 °C or 4 °C aerobically, and the bacterial viable counts, concentration of total volatile basic nitrogen (TVB-N), and microflora composition for each group were analyzed.

Comparative Evaluation of Selective Media for the Detection of Bacillus cereus.

The commercially available 3 types of selective media in Japan were compared for the detection of Bacillus cereus. When assessed inclusivity using 25 B. cereus strains, MYP agar, NGKG agar, and chromogenic X-BC agar demonstrated excellent inclusivity.

Steric microstructure of mixed-species biofilm formed by interaction between ML11-11 and .

The mixed-species biofilm of ML11-11 (LAB) and yeast had a double-layered structure with the ground layer composed of LAB cells, and the upper layer composed of coaggregates of LAB and yeast cells. The ability of LAB to adhere to both, the solid surface and the yeast cells, enabled the formation and maintenance of the biofilm as an ecosystem for LAB and yeast.

Evaluation of the Novel Dry Sheet Culture Method for the Enumeration of Enterobacteriaceae.

MC-Media Pad EB (MMP-EB) , a novel sheet culture method for the enumeration of Enterobacteriaceae, has been evaluated. When both inclusivity and exclusivity of MMP-EB were assessed using 104 microbes including 51 Enterobacteriaceae strains, all tested Enterobacteriaceae strains grew and formed obvious red-colored colonies and all tested non-Enterobacteriaceae strains were shown different appearance from Enterobacteriaceae strains. For the comparison study of the method, MMP-EB was compared with violet red bile glucose agar (VRBG) according to ISO 21528-2:2017 and Petrifilm Enterobacteriaceae Count Plate (Petrifilm EB) method using 100 naturally contaminated food samples.

Complete Genome Sequence of Lactobacillus curvatus NFH-Km12, Isolated from the Japanese Traditional Fish Fermented Food Kabura-zushi.

Kabura-zushi is a traditional Japanese fermented food made from yellowtail, rice, salt, and kōji. In this study, the complete genomic sequence of Lactobacillus curvatus NFH-Km12, isolated from this unique food, is reported. NFH-Km12 has a 1.

Comparison of Chromogenic Selective Media for the Detection of Cronobacter spp. (Enterobacter sakazakii).

　The four types of chromogenic selective media that are commercially available in Japan were compared for establishing a Japanese standard method for detecting Cronobacter spp. based on ISO/TS 22964:2006. When assessed using 9 standard Cronobacter spp.

Increase in hydrophobicity of Bacillus subtilis spores by heat, hydrostatic pressure, and pressurized carbon dioxide treatments.

The effects of heat treatment (HT), hydrostatic pressure treatment (HPT), and pressurized carbon dioxide treatment (CT) on surface hydrophobicity of B. subtilis 168 spores were investigated. The spore surface hydrophobicity was measured by determining the ratio of hydrophobic spores (RHS) that were partitioned into the n-hexadecane phase from the aqueous spore suspension.

Evaluation of the Quantitative Dry Culture Method (Sanitakun(TM) SA) for the Enumeration of Staphylococcus aureus in Artificially Contaminated Food Samples.

Sanita-kun(TM) SA for Staphylococcus aureus (SkSA), a novel dry sheet quantitative culture system, was evaluated. When the inclusivity and exclusivity of SkSA were assessed using 121 microorganisms including 47 S. aureus strains, the tested S.

Evaluation of a Novel Dry Sheet Culture Method for Rapid Enumeration of Total Aerobic Count in Foods.

A novel dry sheet culture method (Sanita-kun ACplus; SkACp) for rapid enumeration of total viable count has been developed. This rehydrated plate system comprises an adhesive sheet, nonwoven fabric coated with nutrients, and two types of water absorption polymers. In addition, SkACp facilitates methods for both rapid count (rapid mode: 24-h incubation) and accurate enumeration (standard mode: 48-h incubation) because it not only contains conventional 2,3,5-triphenyltetrazolium chloride but also contains two kinds of new tetrazolium salts for rapid and accurate enumeration of total aerobic count.

Development of a Novel Chromogenic Medium for Improved Campylobacter Detection from Poultry Samples.

The presence of expanded-spectrum β-lactamase (ESBL)-producing Escherichia coli is a common problem in the isolation of Campylobacter from poultry samples using conventional cefoperazone-based selective media. A novel chromogenic medium (CM-HT), based on modified charcoal cefoperazone deoxycholate agar (mCCDA), has been developed as a solution for improved Campylobacter detection from poultry samples. Although the basic components of CM-HT are the same as mCCDA, CM-HT uses both granular charcoal and sodium cefoxitin to enhance viewability and inhibit ESBL-producing bacteria.

Screening of lactic acid bacteria that can form mixed-species biofilm with Saccharomyces cerevisiae.

The abilities of lactic acid bacteria (LAB) to form mixed-species biofilm with Saccharomyces cerevisiae in a static co-culture were investigated out of 168 LAB stock cultures, and two Lactobacillus plantarum strains (D71 and E31) and one Leuconostoc mesenteroides strain K01 were found to form mixed-species biofilm with S. cerevisiae BY4741. SEM observation showed that there was no significant difference in morphological properties among these three mixed-species biofilms and they resembled that formed by S.

Evaluation of a novel dry sheet culture method (Sanita-kun(R)) for rapid enumeration of yeasts and molds in foods.

Sanita-kun(R) Yeasts and Molds (SkYM), a novel dry sheet culture method for rapid enumeration of fungi, has been developed. This re-hydrated plate consists of a unique adhesive sheet, non-woven fabric coated with nutrients, antibiotic, water absorption polymer and uniquely synthesized 2-(2-methoxyphenyl)-3-(4-nitrophenyl)-5-phenyl-tetrazolium chloride for rapid enumeration of yeasts and molds. When SkYM was assessed using 37 microbes including 33 fungal strains, 29 fungal strains (87.

Awa1p on the cell surface of sake yeast inhibits biofilm formation and the co-aggregation between sake yeasts and Lactobacillus plantarum ML11-11.

We examined mixed-species biofilm formation between Lactobacillus plantarum ML11-11 and both foaming and non-foaming mutant strains of Saccharomyces cerevisiae sake yeasts. Wild-type strains showed significantly lower levels of biofilm formation compared with the non-foaming mutants. Awa1p, a protein involved in foam formation during sake brewing, is a glycosylphosphatidylinositol (GPI)-anchored protein and is associated with the cell wall of sake yeasts.

Fimbriae and lipopolysaccharides are necessary for co-aggregation between Lactobacilli and Escherichia coli.

Cells of Lactobacilli co-aggregated with Escherichia coli K-12 cells to form co-aggregates under mixed-culture conditions at 37 °C for 24 h. Co-aggregation was inhibited by sodium dodecyl sulfate but not by protease. E.

Acid resistance contributes to the high-pressure carbon dioxide resistance of Escherichia coli K-12.

Effect of deletion of acid resistant genes of E. coli on the high-pressure carbon dioxide (HPC) resistance was investigated. Genes coding amino acid decarboxylases, such as lysine, arginine, and glutamate decarboxylase, were found to contribute to HPC resistance.

Manganese Ion Increases LAB-yeast Mixed-species Biofilm Formation.

Remarkable LAB-yeast mixed-species biofilm was formed by lactic acid bacteria (LAB) Lactobacillus plantarum ML11-11 isolated from Fukuyama pot vinegar and Saccharomyces cerevisiae. This mixed-species biofilm formation increased in proportion to the YPD medium concentration but decreased in proportion to the MRS medium concentration. The effect of MRS components on mixed-species biofilm formation was investigated in a YPD medium environment, and it was clarified that beef extract (one of the MRS medium components) decreased mixed-species biofilm formation.

Cronobacter spp. in commercially available dried food in Japan.

A total of 140 samples of dried food sold in Japan were surveyed and tested for the presence of viable bacteria, distribution of coliform bacteria, and contamination with Cronobacter spp. The samples were purchased from retail stores in Tokyo and Kanagawa Prefecture. Out of the 140 samples tested, viable bacteria were found in 135 samples and coliform bacteria were found in 23 samples.

Antimicrobial activity of the carnivorous plant Dionaea muscipula against food-related pathogenic and putrefactive bacteria.

Solvent extracts from the carnivorous plant Dionaea muscipula (Venus flytrap) were prepared using eight different organic solvents, and examined for antibacterial activity against food-related pathogenic and putrefactive bacteria. All solvent extracts showed higher antibacterial activity against gram positive bacteria than against gram negative bacteria. The TLC-bioautography analysis of the extracts revealed that a yellow spot was detected at Rf value of 0.

Sublethal high hydrostatic pressure treatment reveals the importance of genes coding cytoskeletal protein in Escherichia coli morphogenesis.

We studied morphologic changes after sublethal high hydrostatic pressure treatment (HPT) of Escherichia coli K-12 strains in which genes related to the cytoskeleton, cell wall, and cell division had been deleted. Some long filamentous and swelling cells were observed in wild-type bacteria, while some spherical, branched, or collapsed cells were observed in deletion mutants. In particular, ΔzapA and ΔrodZ showed distinguished morphologies.

L-Tryptophan prevents Escherichia coli biofilm formation and triggers biofilm degradation.

The effect of deletion of trp operon and tna operon on the Escherichia coli biofilm formation was investigated in order to elucidate the role of L-tryptophan metabolism in biofilm formation. trp operon deletion mutants ΔtrpC, ΔtrpD and ΔtrpE deficient in L-tryptophan biosynthesis showed higher biofilm formation. In addition, ΔtnaC with increased L-tryptophan degradation activity showed higher biofilm formation.

Yeast mannan structure necessary for co-aggregation with Lactobacillus plantarum ML11-11.

Lactic acid bacteria (LAB) Lactobacillus plantarum ML11-11, an isolate from Fukuyama pot vinegar, and yeast Saccharomyces cerevisiae form significant mixed-species biofilm with direct cell-cell contact. Co-aggregation of L. plantarum ML11-11 and S.

Mutants of Lactobacillus plantarum ML11-11 deficient in co-aggregation with yeast exhibited reduced activities of mixed-species biofilm formation.

Lactic acid bacteria (LAB) mutants deficient in inter-species co-aggregation with yeast were spontaneously derived from Lactobacillus plantarum ML11-11, a significant mixed-species biofilm former in static co-cultures with budding yeasts. These non-co-aggregative mutants also showed significant decreases in mixed-species biofilm formation. These results suggest the important role of co-aggregation between LAB and yeast in mixed-species biofilm formation.

The importance of inter-species cell-cell co-aggregation between Lactobacillus plantarum ML11-11 and Saccharomyces cerevisiae BY4741 in mixed-species biofilm formation.

Cells of Lactobacillus plantarum ML11-11, an isolate from Fukuyama pot vinegar, and the yeast Saccharomyces cerevisiae formed significant mixed-species biofilms with concurrent inter-species co-aggregation. The co-aggregation did not occur with heated or proteinase K-treated ML11-11 cells, or in the presence of D-mannose, suggesting that surface proteins of ML11-11 and mannose-containing surface substance(s) of yeast were the predominant contributing factors. Sugar fatty acid ester inhibited mixed-species biofilm formation, but did not inhibit co-aggregation, suggesting that the cell-cell adhesion and cell-polystylene adhesion are controlled by different mechanisms.

Roles of multidrug efflux pumps on the biofilm formation of Escherichia coli K-12.

We genetically analyzed the roles of multidrug efflux pumps on the biofilm formation of Escherichia coli K-12 BW25113. We used 22 mutants missing various genes related to the multidrug efflux pumps and found that the biofilm formation of emrD, emrE, emrK, acrD, acre and mdtE-deleted mutants was extremely decreased. These results indicate that some multidrug efflux pumps significantly contribute to the biofilm formation of E.