Occurrence of Listeria monocytogenes in green table olives

Microbiological safety of green table olives from different cultivars, prepared by both the Spanish-style and biological methods and fermented with starter cultures of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus casei, and Lactobacillus pentosus), was investigated. The fermentation process was monitored by measuring pH values, titratable acidities, and growth of lactic acid bacteria over time. During fermentation, lactic acid bacteria and yeasts were major microbial populations. Microbiological safety was evaluated by analysis for Listeria monocytogenes with the use of an enrichment method during storage (from 55 days to 18 months). Results demonstrated that L. monocytogenes can survive and grow in green table olives. L. monocytogenes was found in one of the commercial (thermally treated) samples analyzed and in all samples older than 2 months, irrespective of olive cultivar, lactic acid bacteria starter used, pH and titratable acidity of brine samples, or treatment applied.     

Physicochemical, Microbiological, and Sensory Evaluation of Minimally Processed Tarocco Clone Oranges Packaged with 3 Different Permeability Films

ABSTRACT: Fruits of 3 Tarocco clones ('Gallo', 'Arcimusa', and 'Scirè') were sliced, packaged with different permeability films, and stored at 4°C for 14 to 15 d to find the best clone for processing and the most suitable packaging conditions to extend the shelf life of these products. Physicochemical parameters of Tarocco oranges slices, packaged with 3 films of different permeability, did not show marked decay phenomena during the storage days. Only a reduction in the ascorbic acid content was observed in almost all the examined clones, especially in products packaged with the most O₂ permeable films. Concerning microbiological contamination, all clones, packaged with the 3 films, showed, until the 12th storage day, a lower number of colony forming units (CFU)/g (≤ 3.6 × 10⁷ CFU/g) for mesophilic viable counts than the 2 microbiological criteria generally used for fresh-cut fruit and vegetables (10⁸ CFU/g for mesophilic viable counts). In fact, for these products it is possible to expect a shelf life longer than 12 to 13 d. Regarding sensory results, it was observed that the minimally processed Tarocco clone slices packaged with the most permeable to O₂ film were the most appreciated.     

Sulphadimethoxine and Azolla filiculoides Lam.: a model for drug remediation

Plants can be an interesting tool for in situ remediation of drug contaminated waters. In a laboratory model Azolla filiculoides Lam., an aquatic fern known to absorb pollutants, has been exposed to an environmental persistent antibiotic commonly used in intensive farming, sulphadimethoxine (S), to test its bioremediation capability. In a 5 week experiment, plants were cultivated outdoor at four drug concentrations (50, 150, 300 and 450 mg l(-1)) in N-free mineral medium. Drug affects growth rate (as biomass yield per week), N2-fixation, heterocyst frequency, but plants are able to survive. Notwithstanding, at all concentrations tested drug was actively removed from the medium and the accumulation in the biomass is in order of magnitude up to mg g(-1) plant dry weight (1000 ppm). Drug uptake and degradation rates increase with S concentrations in the culture medium. The efficacy of the model was very high. These results demonstrated that Azolla can be taken into consideration as a tool for sulphonamides environmental monitoring and decontamination.     

Structure and optical properties of silica-supported Ag-Au nanoparticles

Bimetallic Ag-Au nanoparticles are synthesized by sequential deposition of Au and Ag on amorphous silica by Radio Frequency (RF)-sputtering under mild conditions. Specimens are thoroughly characterized by a multi-technique approach, aimed at investigating the system properties as a function of the Ag/Au content, as well as the evolution induced by ex-situ annealing under inert (N2) or reducing (4% H2/N2) atmospheres. The obtained results demonstrate the possibility to obtain Ag-Au alloyed nanoparticles with controllable size, shape, structure, and dispersion under mild conditions, so that the optical properties can be finely tuned as a function of the synthesis and thermal treatment conditions.     

Development of novel peptidomimetics containing a vinyl sulfone moiety as proteasome inhibitors

Proteasome inhibition is a topic of great interest in anticancer research. The proteolytic activity of this multicatalytic complex relies on three subunits, β1, β2 and β5, containing a caspase-like, a trypsin-like and a chymotrypsin-like active site, respectively. Several studies have demonstrated that, of the three activities, the chymotrypsin-like activity was the most necessary for cell viability and protein processing. Thus, most efforts towards the development of proteasome inhibitors have focused on the selective inhibition of the β5 subunit active site. Herein, we report the design and synthesis of a series of conformationally constrained tripeptidyl vinyl sulfones were determined to be good inhibitors of the chymotrypsin-like activity of proteasome, with K(I) values in the sub-micromolar to micromolar range. These compounds were also tested against bovine pancreatic α-chymotrypsin and human cathepsin B and L, revealing a good selectivity for the target enzyme over these related enzymes.     

A systematic study on the effects of doping agents on polypyrrole coating of fabrics

Polypyrrole is widely used as coating to produce electrically conductive textiles. Counter‐ions (i.e. doping agents) were embedded in polypyrrole to improve electrical conductivity. Good electrical performances are required for several applications, such as microwave attenuation/electro‐magnetic interference shielding, heat generation, electro‐static discharge protection, sensing, and energy storage. In this work, a systematic study was carried out on the effects of doping agents in coating cotton fabrics with a thin polypyrrole layer. A total of 11 compounds were selected and compared as counter‐ions. The electrical performances of the coated fabrics were assessed with measures of electrical conductivity. Moreover, evenness and morphology of the resulting polypyrrole layer were discussed. As the final result, the best performances in terms of electrical conductivity (i.e. low surface resistivity) were measured using on dicyclohexyl sulfosuccinate, 2,6‐naphthalenedisulfonate or 1,5‐naphthalenedisulfonate as doping agents. The weight increases after polypyrrole deposition on the fabrics were greater than 15% and polypyrrole deposited on the fibers as a uniform film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42831.     

Survival of Lactobacillus rhamnosus strains inoculated in cheese matrix during simulated human digestion

Survival of probiotic bacteria during transit through the gastrointestinal (GI) tract is influenced by a number of environmental variables including stomach acidity, bile salts, digestive enzymes and food matrix. This study assessed survival of seven selected Lactobacillus rhamnosus strains delivered within a model cheese system to the human upper GI tract using a dynamic gastric model (DGM). Good survival rates for all tested strains were recorded during both simulated gastric and duodenal digestion. Strains H12, H25 and N24 demonstrated higher survival capacities during gastric digestion than L. rhamnosus GG strain used as control, with H12 and N24 continuing to grow during duodenal digestion. Strains L. rhamnosus F17, N24 and R61 showed adhesion properties to both HT-29 and Caco-2 cells. The ability to attach to the cheese matrix during digestion was confirmed by scanning electron microscopy, also indicating production of extracellular polysaccharides as a response to acid stress.     

Functional foods as carriers for SYNBIO®, a probiotic bacteria combination

The popularity of functional foods continues to increase as consumers desire flavorful foods that will fulfil their health needs. Among these foods, probiotics may exert positive effects on the composition of gut microbiota and overall health. However, in order to be beneficial, the bacterial cultures have to remain live and active at the time of consumption. The aim of this study was to develop new probiotic food products, such as seasoned cheeses, salami, chocolate and ice-cream with a final probiotic concentration of approximately 10?CFU/daily dose of Lactobacillus rhamnosus IMC 501? and Lactobacillus paracasei IMC 502? mixed 1:1 (SYNBIO?). The survival and viability of probiotics were determined during the foods shelf-life. The values of viable probiotic bacteria of all dairy and non-dairy foods were between 10? and 10?CFU/g of food at the end of the shelf-life and for some of them the values were maintained even after the expiry date. Based on the results of the current study, all the dairy ("Caciotta" cheese, "Pecorino" cheese, "Büscion" Swiss cheese and "Fiordilatte" ice-cream) and non-dairy ("Ciauscolo" salami, Larded salami, Swiss small salami, milk chocolate, dark chocolate, organic jam and chocolate mousse) food products studied would be excellent vehicles to deliver the probiotic health effects because of the high viability of probiotics during the shelf-life of foods and in some cases even after their expiry date.     

Current challenges of microalgae applications: exploiting the potential of non-conventional microalgae species

The intensified attention to health, the growth of an elderly population, the changing lifestyles, and the medical discoveries have increased demand for natural and nutrient-rich foods, shaping the popularity of microalgae products. Microalgae thanks to their metabolic versatility represent a promising solution for a ‘green’ economy, exploiting non-arable land, non-potable water, capturing carbon dioxide (CO₂) and solar energy. The interest in microalgae is justified by their high content of bioactive molecules, such as amino acids, peptides, proteins, carbohydrates, polysaccharides, polyunsaturated fatty acids (as ω-3 fatty acids), pigments (as β-carotene, astaxanthin, fucoxanthin, phycocyanin, zeaxanthin and lutein), or mineral elements. Such molecules are of interest for human and animal nutrition, cosmetic and biofuel production, for which microalgae are potential renewable sources. Microalgae, also, represent effective biological systems for treating a variety of wastewaters and can be used as a CO₂ mitigation approach, helping to combat greenhouse gases and global warming emergencies. Recently a growing interest has focused on extremophilic microalgae species, which are easier to cultivate axenically and represent good candidates for open pond cultivation. In some cases, the cultivation and/or harvesting systems are still immature, but novel techniques appear as promising solutions to overcome such barriers. This review provides an overview on the actual microalgae cultivation systems and the current state of their biotechnological applications to obtain high value compounds or ingredients. Moreover, potential and future research opportunities for environment, human and animal benefits are pointed out. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Rate‐dependent self‐healing behavior of an ethylene‐co‐methacrylic acid ionomer under high‐energy impact conditions

In this work, the mechanical and the self‐healing behaviors of an ethylene‐co‐methacrylic acid ionomer were investigated in different testing conditions. The self‐healing capability was explored by ballistic impact tests at low‐velocity, midvelocity, and hypervelocity bullet speed; different experimental conditions such as sample thickness and bullet diameter were examined; in all impact tests, spherical projectiles were used. These experiments, in particular those at low and midspeed, allowed to define a critical ratio between sample thickness and bullet diameter below which full repair was not observed. After ballistic damage, the healing efficiency was evaluated by applying a pressure gradient through tested samples. Subsequently, morphology analysis of the affected areas was made observing all tested samples by scanning electron microscope. This analysis revealed different characteristic features of the damaged zones affected at different projectile speed. Stress–strain curves in uniaxial tension performed at different temperatures and strain rates revealed yield strength and postyield behavior significantly affected by these two parameters. A rise of temperature during high strain rate tests in the viscoplastic deformation region was also detected. This behavior has a strong influence on the self‐repairing mechanism exhibited by the studied material during high‐energy impact tests. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1949–1958, 2013