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A study was made of the degradation of archaeological Scots pine (Pinus sylvestris L.) at the Iron Age archaeological site of Biskupin, Poland. Wood degradation was evaluated after 10 years of deposition of samples in different burial conditions (mineral soil, peat and water) and at different depths (25, 50 and 100 cm) at the location of the original archaeological wood from the Lusatian culture settlement. Changes in the wood samples were assessed on the basis of selected physical (maximum water content, basic density and porosity) and chemical (chemical composition, structure of cellulose and lignin) properties. The observed degradative changes were different for samples deposited in different locations of the archaeological site and at different depths. They relate mainly to carbohydrates—both cellulose and hemicelluloses—although the structure of lignin also underwent changes. The experiment using wood that had been degraded to a similar degree to the Biskupin wood enabled identification of the actual danger of degradation of the latter. It was found that the remains of the wooden structure of the Biskupin settlement are degrading, despite the favourable physicochemical conditions prevailing at the site, and it is necessary to take measures to prevent its further decomposition. [ABSTRACT FROM AUTHOR]

Plant essential oils have bacteriostatic activity in very low concentrations, thus they can be used as natural preservative in food products. The aim of this work was to understand the inhibitory and non-bactericidal effects of essential oils in low concentrations. To meet this aim some physical and biochemical properties of two P. orientalis strains isolated from food probes were investigated under the influence of plant oils. Control probes - without oils - played an important role in our investigations because P. orientalis is not a well-known and described species. Thus, these results allow us to gain additional knowledge about bacteria from P. orientalis species. The obtained results are proof that under the influence of oils, bacteria lose their ability to move, change their morphology, and also reduce their metabolic activity. However, they do not die, and properties such as the ability to produce ammonia, the ability to production of indole from the amino acid tryptophan as well as the ability to assimilation of saccharides are maintained.

Microbial biofilm formed on abiotic surfaces is an important area of research because of the wide range of possible affects and the disinfectant resistance of the cells. The colonization of solid surfaces by microorganisms is a very complicated process that depends mostly on extracellular molecule production. The biosynthesis of EPS reflected not only the attachment and aggregation process but also provided an optimal environment for the exchange of genetic material between the cells. The comparative and comprehensive analysis of all documented data concerning EPS production can enable the development and effective control strategies for biofilms. In this review some of the basic concepts concerning the biosynthesis of EPS and potential function of these compounds in biofilm development were discussed. In the paper the positive and negative aspects of EPS production in the environment also were described. [ABSTRACT FROM AUTHOR]

Antifungal activity of Bacillus coagulans creates the possibility to use this microorganism in biological control of fungal plant pathogens. Activity of Bacillus coagulans (No 6), isolated from lupine compost, against seven pathogenic species of indicator fungi: Bipolaris sorokiniana, Trichothecium roseum, Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium oxysporum, Fusarium solani and Fusarium culmorum were examined in this work. Ergosterol assessment and counting colony forming units (CFU) carried out determination of fungal growth. The addition of Bacillus coagulans to culture of fungi resulted in inhibition of ergosterol biosynthesis in mycelium. The strongest inhibition in all tested fungal plant pathogens was observed when Bacillus coagulans was co-inoculated at the beginning of culture. The decrease of ergosterol level did not always correlate with the decrease of CFU. [ABSTRACT FROM AUTHOR]

Examines the adenosine triphosphate (ATP) level and cell number in different composts prepared from lupine. Changes in microbial population in the different composts during the process; Comparison among the ATP extraction methods used; Determination of ATP levels during the composting process.

Whole cells of Propionibacterium freudenreichii subsp. shermanii (two strains) were immobilized in a living state in 2 and 4% alginate gel and 2, 4 and 6% carrageenan gel. Production of propionic acid, acetic acid, and vitamin B were examined. The best results were obtained in the fermentation with strains immobilized in 4% alginate gel when applied for the third time. [ABSTRACT FROM AUTHOR]

Four strains of Bacillus isolated from lupine compost exhibited an antifungal activity against six plant fungal pathogens ( Rhizoctonia solani, Bipolaris sorokiniana, Sclerotinia sclerotiorum, Trichothecium roseum, Fusarium solani, Fusarium oxysporum). It was significantly influenced by the composition of the cultivation media. [ABSTRACT FROM AUTHOR]

1,3-propanediol (1,3-PD) has a wide range of industrial applications. The most studied natural producers capable of fermenting glycerol to 1,3-PD belong to the genera Klebsiella , Citrobacter , and Clostridium . In this study, the optimization of medium composition for the biosynthesis of 1,3-PD by Citrobacter freundii AD119 was performed using the one-factor-at-a-time method (OFAT) and a two-step statistical experimental design. Eleven mineral components were tested for their impact on the process using the Plackett-Burman design. MgSO 4 and CoCl 2 were found to have the most pronounced effect. Consequently, a central composite design was used to optimize the concentration of these mineral components. Besides minerals, carbon and nitrogen sources were also optimized. Partial glycerol substitution with other carbon sources was found not to improve the bioconversion process. Moreover, although yeast extract was found to be the best nitrogen source, it was possible to replace it in part with (NH 4 ) 2 SO 4 without a negative impact on 1,3-PD production. As a part of the optimization procedure, an artificial neural network model of the growth of C. freundii and 1,3-PD production was developed as a predictive tool supporting the design and control of the bioprocess under study., Competing Interests: The authors declare no conflict of interest.

In this study, lignin-based spherical particles (Lig-IL) with the use of 1-(propoxymethyl)-1H-imidazolium hydrogen sulfate were prepared in different biopolymer and ionic liquid (IL) weight ratios. The application of IL during the preparation of spherical particles is an innovative method, which may be beneficial for further applications. The particles were obtained with the use of the soft-templating method and their chemical, structural and morphological characterization was performed. The spherical shape of products and their size (91-615 nm) was confirmed with the use of scanning electron microscopy (SEM) images and the particle size distribution results. The attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectra were analyzed to identify functional groups of all precursors and produced material and it was confirmed, that all materials exhibit characteristic hydroxyl and carboxylic groups, but the presence of carbonyl group was detected. Moreover, the zeta potential analysis was performed to evaluate the electrokinetic behavior of obtained materials. It was confirmed, that all materials are colloidally stable in pH above 4. Produced lignin-based spherical particles were used for evaluation of their antibacterial properties. Particles were tested against Staphylococcus aureus ( S. aureus ), a gram-positive bacterium, and Escherichia coli ( E. coli ), a gram-negative one. It was observed, that only the material with the highest addition of IL showed the antibacterial properties against both strains. A reduction of 50% in the number of microorganisms was observed for particles with the addition of hydrogen sulfate ionic liquid in a 1:1 ratio after 1 h. However, all prepared materials exhibited the antibacterial activity against a gram-positive bacterium., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Stanisz, Klapiszewski, Dobrowolska, Piasecki, Czaczyk and Jesionowski.)

The aim of the research was to design an advanced analytical tool for the precise characterization of microbial aggregates from biofilms formed on food-processing surfaces. The approach combined imaging flow cytometry with a machine learning-based interpretation protocol. Biofilm samples were collected from three diagnostic points of the food-processing lines at two independent time points. The samples were investigated for the complexity of microbial aggregates and cellular metabolic activity. Thus, aggregates and singlets of biofilm-associated microbes were simultaneously examined for the percentages of active, mid-active, and nonactive (dead) cells to evaluate the physiology of the microbial cells forming the biofilm structures. The tested diagnostic points demonstrated significant differences in the complexity of microbial aggregates. The significant percentages of the bacterial aggregates were associated with the dominance of active microbial cells, e.g., 75.3% revealed for a mushroom crate. This confirmed the protective role of cellular aggregates for the survival of active microbial cells. Moreover, the approach enabled discriminating small and large aggregates of microbial cells. The developed tool provided more detailed characteristics of bacterial aggregates within a biofilm structure combined with high-throughput screening potential. The designed methodology showed the prospect of facilitating the detection of invasive biofilm forms in the food industry environment.

Surface active agents derived from the non-toxic sweetener sucralose and fatty acids of different chain length were synthesized. Obtained compounds were characterized chemically and with regard to their properties as emulsifying agents, antimicrobial preservatives and fat-soluble sweeteners. Results show that sucralose-fatty acid esters are possible multi-purpose additives, compatible with both cosmetic and edible emulsions, as well as purely oil-based, waterless formulations. Their relative effectiveness in those applications varies, and is highly dependent on the fatty acid chain length, with hydrophobic/hydrophilic character strongly impacting both emulsifying and antimicrobial properties. While the structural differences between sucrose and sucralose proved to be enough to push all of the newly synthesized compounds out of the detergent/solubilizer category of surfactants, the retention of the substrate's high sweetness is an indication that non-bitter compounds with washing capabilities are possible to obtain., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The TiO 2 -Fe 3 O 4 composite materials were fabricated via the hydrothermal-assisted technique. It was determined how the molar ratio of TiO 2 to Fe 3 O 4 influences the crystalline structure and morphology of the synthesized composite materials. The effect of the molar ratio of components on the antibacterial activity was also analyzed. On the basis of XRD patterns for the obtained titanium(IV) oxide-iron(II, III) oxide composites, the two separate crystalline forms-anatase and magnetite -were observed. Transmission electron microscopy revealed particles of cubic and tetragonal shape for TiO 2 and spherical for Fe 3 O 4 . The results of low-temperature nitrogen sorption analysis indicated that an increase in the iron(II, III) oxide content leads to a decrease in the BET surface area. Moreover, the superparamagnetic properties of titanium(IV) oxide-iron(II, III) oxide composites should be noted. An important aim of the work was to determine the antibacterial activity of selected TiO 2 -Fe 3 O 4 materials. For this purpose, two representative strains of bacteria, the Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus , were used. The titanium(IV) oxide-iron(II, III) oxide composites demonstrated a large zone of growth inhibition for both Gram-positive and Gram-negative bacteria. Moreover, it was found that the analyzed materials can be reused as antibacterial agents in three consecutive cycles with good results.

Essential oils can be used as preservatives in foods because of their ability to inhibit bacteria growth in low concentration, which does not influence on foods' organoleptic properties and does not generate the resistance mechanisms in cells. The aim of that work was to compare the effectiveness of commercial oils from black pepper ( Piper nigrum ), rosemary ( Rosmarinus officinalis ), lemongrass ( Cymbopogon citratus ) and juniper ( Juniperus communis L.) with oils obtained in our laboratory. The typical cultivation method was supported by the flow cytometry to detect the cells of very low physiologic and metabolic activity. Our investigation demonstrated that both types of oils can effectively inhibit the growth of saprophytic bacteria P. orientalis . The oils distilled in our laboratory had a bacteriostatic effect at a lower concentration, which is important for application in the food industry. Flow cytometry analyzes and confirmed the thesis that essential oils do not have a germicidal effect on bacteria cells., Competing Interests: The authors declare no conflicts of interest.

Diverse fields of modern technology and biomedicine can benefit from the application of ready-to-use chitin-based scaffolds. In this work we show for the first time the applicability of tubular and porous chitin from Caribena versicolor spiders as a scaffold for the development of an effective CuO/Cu(OH) 2 catalyst for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AM), and as a scaffold for the tissue engineering of selected cells. The formation of CuO/Cu(OH) 2 phases on and within the chitinous tubes leads to a hybrid material with excellent catalytic performance with respect to the reduction of p-nitrophenol. On the other hand, experimental results provide for the first time strong evidence for the biocompatibility of spider chitin with different cell types, a human progenitor cell line (hPheo1), as well as cardiomyocytes differentiated from induced pluripotent stem cells (iPSC-CMs) that were cultured on a tube-like scaffold., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Binary oxide systems containing TiO 2 and CuO were synthesized using hydrothermal treatment and shown to have enhanced antibacterial properties. A detailed investigation was made of the effect of the molar ratio of components (TiO 2 :CuO = 7:3, 5:5, 3:7, 1:9) on the physicochemical parameters and antibacterial activity. Analysis of morphology (SEM, TEM and HRTEM) confirmed the presence of spherical and sheet-shaped particles. On the XRD patterns for the binary oxide materials, two crystalline forms (anatase and monoclinic CuO) were observed. It was found that an increase in CuO content led to a decrease in the BET surface area of the TiO 2 -CuO binary oxide systems. The synthesized TiO 2 -CuO materials exhibited very good antibacterial activity against both Gram-positive (methicillin-resistant Staphylococcus aureus and Bacillus cereus) and Gram-negative (Salmonella Enteritidis and Pseudomonas aeruginosa) bacteria. The obtained results show that TiO 2 -CuO oxide materials may have applications in the biomedical and food industries., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Chitin, as a fundamental polysaccharide in invertebrate skeletons, continues to be actively investigated, especially with respect to new sources and the development of effective methods for its extraction. Recent attention has been focused on marine crustaceans and sponges; however, the potential of spiders (order Araneae) as an alternative source of tubular chitin has been overlooked. In this work, we focused our attention on chitin from up to 12 cm-large Theraphosidae spiders, popularly known as tarantulas or bird-eating spiders. These organisms "lose" large quantities of cuticles during their molting cycle. Here, we present for the first time a highly effective method for the isolation of chitin from Caribena versicolor spider molt cuticle, as well as its identification and characterization using modern analytical methods. We suggest that the tube-like molt cuticle of this spider can serve as a naturally prefabricated and renewable source of tubular chitin with high potential for application in technology and biomedicine., Competing Interests: The authors declare no conflict of interest.

The aim of this work was to estimate the antibacterial activity of selected essential oils on Pseudomonas orientalis strains isolated from foods. An attempt was also made to identify the mechanisms of the action of the plant oils. Classical methods of assessment of the effectiveness of antimicrobial activity of oils were linked with flow cytometry. It was observed that bergamot, lemongrass, bitter orange, juniper, and black pepper oils have bacteriostatic effect against P. orientalis P49. P. orientalis P110 is sensitive to lime, lemongrass, juniper, rosemary, and black pepper oils. Additionally, plant oils with biostatic effect on P. orientalis limited the intracellular metabolic activity of cells; this was closely linked with the ability of plant oils' bioactive components to interact with bacteria cell membrane, causing the release of membrane proteins. As a result, the selective permeability of the cell membranes were damaged and the bacterial shape was transformed to coccoid in form.

Bacteria from the genus Bacillus are a rich source of commercial enzymes, including amylases, proteases, cellulases, glucose isomerase, and pullulanase. Cellulases account for 15% of the global market of industrial enzymes; thus, new microorganisms producing cellulases in a higher concentration and new ingredients, which can enhance the level of enzyme synthesis, are still needed. Many of cellulose-degrading microorganisms have been isolated so far and characterized in various regions of the world. In this study, we were looking for the bacteria isolated from the natural environment with the high cellulolytic potential, which could be used as components of a biopreparation to accelerate decomposition of postharvest leftovers in agriculture. The 214 bacterial strains were isolated from environmental samples rich in cellulose and their ability to synthesize cellulases were examined using the diffusion method. Six strains, which have the highest diameter of clearing zone both for biomass and supernatant, were selected for identification. Optimization of biosynthesis of the cellulose-degrading enzymes indicated that optimal temperature of this process fluctuated in the range of 21-42°C (depending on the strain and carbon source). The highest cellulolytic activity was observed for the isolates designed as 4/7 (identified as Bacillus subtilis ) and 4/18 (identified as Bacillus licheniformis ) in a temperature of 32°C. With the use of a desirability function methodology, the optimal medium composition to achieve a simple, cost-efficient process of cellulases production was developed for both strains. These experiments show that microorganisms isolated from natural environmental samples have unique properties and potential for commercial applications (e.g. for biopreparations production)., Bacteria from the genus Bacillus are a rich source of commercial enzymes, including amylases, proteases, cellulases, glucose isomerase, and pullulanase. Cellulases account for 15% of the global market of industrial enzymes; thus, new microorganisms producing cellulases in a higher concentration and new ingredients, which can enhance the level of enzyme synthesis, are still needed. Many of cellulose-degrading microorganisms have been isolated so far and characterized in various regions of the world. In this study, we were looking for the bacteria isolated from the natural environment with the high cellulolytic potential, which could be used as components of a biopreparation to accelerate decomposition of postharvest leftovers in agriculture. The 214 bacterial strains were isolated from environmental samples rich in cellulose and their ability to synthesize cellulases were examined using the diffusion method. Six strains, which have the highest diameter of clearing zone both for biomass and supernatant, were selected for identification. Optimization of biosynthesis of the cellulose-degrading enzymes indicated that optimal temperature of this process fluctuated in the range of 21–42°C (depending on the strain and carbon source). The highest cellulolytic activity was observed for the isolates designed as 4/7 (identified as Bacillus subtilis ) and 4/18 (identified as Bacillus licheniformis ) in a temperature of 32°C. With the use of a desirability function methodology, the optimal medium composition to achieve a simple, cost-efficient process of cellulases production was developed for both strains. These experiments show that microorganisms isolated from natural environmental samples have unique properties and potential for commercial applications (e.g. for biopreparations production).

Our previous studies showed that glycerol fermentation by Hafnia alvei AD27 strain was accompanied by formation of high quantities of lactate. The ultimate aim of this work was the elimination of excessive lactate production in the 1,3-propanediol producer cultures. Group II intron-mediated deletion of ldh (lactate dehydrogenase) gene in an environmental isolate of H. alvei AD27 strain was conducted. The effect of the Δldh genotype in H. alvei AD27 strain varied depending on the culture medium applied. Under lower initial glycerol concentration (20 gL -1 ), lactate and 1,3-propanediol production was fully abolished, and the main carbon flux was directed to ethanol synthesis. On the other hand, at higher initial glycerol concentrations (40 gL -1 ), 1,3-propanediol and lactate production was recovered in the recombinant strain. The final titers of 1,3-propanediol and ethanol were similar for the recombinant and the WT strains, while the Δldh genotype displayed significantly decreased lactate titer. The by-products profile was altered upon ldh gene deletion, while glycerol utilization and biomass accumulation remained unaltered. As indicated by flow-cytometry analyses, the internal pH was not different for the WT and the recombinant Δldh strains over the culture duration, however, the WT strain was characterized by higher redox potential.

The dairy propionibacteria, which are traditionally used for the production of Swiss cheeses, are able to synthesize valuable biomolecules, e.g. B group vitamins, propionic acid, and trehalose with unique chemical and physical properties. Both, dairy propionibacteria cells and trehalose, have found many applications as attractive and effective components in food, beauty and health care products. This study confirmed the ability of several strains from the Propionibacterium genus to create trehalose from glycerol. The research aimed to investigate the effect of crude and pure glycerol on biomass production and on trehalose accumulation by Propionibacterium freudenreichii ssp. shermanii 1. The results indicated that the capacity for trehalose accumulation by Propionibacterium spp. was strain dependent. Propionibacterium freudenreichii ssp. shermanii 1 was able to grow on crude glycerol. For both, pure and crude glycerol, the highest amount of dry biomass leveled off at about 4 g/L. While the use of crude glycerol had no effect on the final concentration of biomass, it reduced the accumulation of trehalose in the cells. An increase in the concentration of carbon source (2-8%) resulted in more than a 5-fold rise in trehalose production. The highest trehalose concentration of 195.04 mg/L was obtained with cultures of the said strain supplemented to 8% with pure glycerol.

Herbs and spices have been used for food and medicinal purposes for centuries - the first recorded evidence of their use dates back to 1500BC and the Ebers Papyrus, which mentioned spices such as anise, mustard, saffron, cinnamon, and cassia. Now, in the 21st century, a variety of secondary compounds produced by plants are used in many fields of industry, such as food production (to improve taste, to provide vitamins and macro- and microelements, and also to inhibit food spoilage caused by foodborne bacteria), in medicine (in the treatment of various diseases; in chemoprevention and cancer therapy; as a source of natural antimicrobials for the treatment of infectious disease), and in pharmacology and cosmetology (in dietary supplements, and as a result of the demand for preservative-free cosmetics, to reduce the risk of methylparaben allergies). The aim of this review is to present the major active compounds in herbs and spices and explore their potential applications in industry.

In this study, Hippospongia communis marine demosponge skeleton was used as an adsorbent for sodium copper chlorophyllin (SCC). Obtained results indicate the high sorption capacity of this biomaterial with respect to SCC. Batch experiments were performed under different conditions and kinetic and isotherms properties were investigated. Acidic pH and the addition of sodium chloride increased SCC adsorption. The experimental data were well described by a pseudo-second order kinetic model. Equilibrium adsorption isotherms were determined and the experimental data were analyzed using both Langmuir and Freundlich isotherms. The effectiveness of the process was confirmed by 13 C Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance ( 13 C CP/MAS NMR), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS) and thermogravimetric analysis (TG). This novel SCC-sponge-based functional hybrid material was found to exhibit antimicrobial activity against the gram-positive bacterium Staphylococcus aureus ., Competing Interests: The authors declare no conflict of interest.

Background: In the process of Pseudomonas fluorescens biofilm formation, N-acyl-l-homoserine lactone (AHL)-mediated flagella synthesis plays a key role. Inhibition of AHL production may attenuate P. fluorescens biofilm on solid surfaces. This work validated the anti-biofilm properties of p-coumaric and gallic acids via the ability of phenolics to suppress AHL synthesis in P. fluorescens KM120. The dependence between synthesis of AHL molecules, expression of flagella gene (flgA) and the ability of biofilm formation by P. fluorescens KM120 on a stainless steel surface (type 304L) was also investigated., Results: Research was carried out in a purpose-built flow cell device. Limitations on AHL synthesis in P. fluorescens KM120 were observed at concentrations of 120 and 240 µmol L(-1) of phenolic acids in medium. At such levels of gallic and p-coumaric acids the ability of P. fluorescens KM120 to synthesize 3-oxo-C6-homoserine lactone (HSL) was not observed. These concentrations caused decreased expression of flgA gene in P. fluorescens KM120. The changes in expression of AHL-dependent flgA gene significantly decreased the rate of microorganism colonization on the stainless steel surface., Conclusion: Phenolic acids are able to inhibit biofilm formation. The results obtained in the work may help to develop alternative techniques for anti-biofilm treatment in the food industry. © 2015 Society of Chemical Industry., (© 2015 Society of Chemical Industry.)

Advanced functional silica/lignin hybrid materials, modified with nanosilver, were obtained. The commercial silica Syloid 244 was used, modified with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to increase its chemical affinity to lignin. Similarly, kraft lignin was oxidized using a solution of sodium periodate to activate appropriate functional groups on its surface. Silver nanoparticles were grafted onto the resulting silica/lignin hybrids. The systems obtained were comprehensively tested using available techniques and methods, including transmission electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, elemental analysis and atomic absorption spectroscopy. An evaluation was also made of the electrokinetic stability of the systems with and without silver nanoparticles. Conclusions were drawn concerning the chemical nature of the bonds between the precursors and the effectiveness of the method of binding nanosilver to the hybrid materials. The antimicrobial activity of the studied materials was tested against five species of Gram-positive and Gram-negative bacteria. The addition of silver nanoparticles to the silica/lignin hybrids led to inhibition of the growth of the analyzed bacteria. The best results were obtained against Pseudomonas aeruginosa, a dangerous human pathogen., (Copyright © 2015 Elsevier B.V. All rights reserved.)

A community-based sessile life style is the normal mode of growth and survival for many bacterial species. Under such conditions, cell-to-cell interactions are inevitable and ultimately lead to the establishment of dense, complex and highly structured biofilm populations encapsulated in a self-produced extracellular matrix and capable of coordinated and collective behavior. Remarkably, in food processing environments, a variety of different bacteria may attach to surfaces, survive, grow, and form biofilms. Salmonella enterica, Listeria monocytogenes, Escherichia coli, and Staphylococcus aureus are important bacterial pathogens commonly implicated in outbreaks of foodborne diseases, while all are known to be able to create biofilms on both abiotic and biotic surfaces. Particularly challenging is the attempt to understand the complexity of inter-bacterial interactions that can be encountered in such unwanted consortia, such as competitive and cooperative ones, together with their impact on the final outcome of these communities (e.g., maturation, physiology, antimicrobial resistance, virulence, dispersal). In this review, up-to-date data on both the intra- and inter-species interactions encountered in biofilms of these pathogens are presented. A better understanding of these interactions, both at molecular and biophysical levels, could lead to novel intervention strategies for controlling pathogenic biofilm formation in food processing environments and thus improve food safety.

The modern day consumer tends to choose products with health enhancing properties, enriched in bioactive substances. One such bioactive food component is dietary fibre, which shows a number of physiological properties including the binding of bile acids. Dietary fibre should be contained in everyday, easily accessible food products. Therefore, the aim of this study was to determine sorption capacities of primary bile acid (cholic acid - CA) and secondary bile acids (deoxycholic - DCA and lithocholic acids - LCA) by muffins (BM) and cookies (BC) with bioactive substances and control muffins (CM) and cookies (CC) in two sections of the in vitro gastrointestinal tract. Variations in gut flora were also analysed in the process of in vitro digestion of pastry products in a bioreactor. Enzymes: pepsin, pancreatin and bile salts: cholic acid, deoxycholic acid and lithocholic acid were added to the culture. Faecal bacteria, isolated from human large intestine, were added in the section of large intestine. The influence of dietary fibre content in cookies and concentration of bile acids in two stages of digestion were analysed. Generally, pastry goods with bioactive substances were characterized by a higher content of total fibre compared with the control samples. These products also differ in the profile of dietary fibre fractions. Principal Component Analysis (PCA) showed that the bile acid profile after two stages of digestion depends on the quality and quantity of fibre. The bile acid profile after digestion of BM and BC forms one cluster, and with the CM and CC forms a separate cluster. High concentration of H (hemicellulose) is positively correlated with LCA (low binding effect) and negatively correlated with CA and DCA contents. The relative content of bile acids in the second stage of digestion was in some cases above the content in the control sample, particularly LCA. This means that the bacteria introduced in the 2nd stage of digestion synthesize the LCA.

This study evaluated the effectiveness of selected disinfectants against bacterial cells within a biofilm using flow cytometry, the conventional total viable count test and scanning electron microscopy (SEM). A flow cytometric procedure based on measurement of the cellular redox potential (CRP) was demonstrated to have potential for the rapid evaluation of activity against biofilm and planktonic forms of microbes. Quaternary ammonium compound-based disinfectant (QACB) demonstrated a higher level of anti-microbial activity than a performic acid preparation (PAP), with mean CRP values against P. aeruginosa cells of 2 and 1.33 relative fluorescence units (RFU) vs 63.33 and 61.33 RFU for 8 and 24 h cultures respectively. Flow cytometric evaluation of the anti-biofilm activity demonstrated a higher efficacy of QACB compared to PAP for P. aeruginosa cells of 1 and 0.66 RFU vs 18.33 and 22.66 RFU for 8 and 24 h cultures respectively. SEM images of treated P. aeruginosa cells demonstrated disinfectant-specific effects on cell morphology.

The purpose of these investigations was to evaluate the reduction capability of phenolic acids (ferulic, chlorogenic, gallic, and p-coumaric acids) on indole acetic acid synthesis by food-associated Pseudomonas fluorescens KM05. Specific genetic primer for the type III secretion system (TTSS) in P. fluorescens KM05 was designed and the influence of phenolic acids on its expression was investigated. In the work the ferulic and chlorogenic acids at the concentration of 0.02 and 0.04 μg/ml affected on bacterial growth pattern and the signal molecules production. The phenolic acids, that were appreciable effective against P. fluorescens KM05 indole acetic acid production, significantly suppressed TTSS gene., (Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)