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Fishery products are highly perishable foods because of activity of spoilage and pathogenic microbiota, which can rapidly grow under the usually adopted storage conditions (mainly low temperature and application of modified atmosphere or vacuum). For this reason, the need of prolonging their shelf life is crucial to improve their commercialization, reducing food losses, and assuring their safety. Among the strategies to reach this aim, the application of “natural” approaches received an increasing interest due to their relatively low costs and the acceptance by consumers. In this chapter, two of these possible strategies are reviewed. The use of essential oils can delay or inhibit the growth of undesirable microorganisms because of the antimicrobial activity of many of their components. On the other side, also the use of bioprotective cultures has been described, with particular emphasis on the bacteriocin producing lactic acid bacteria. Both these strategies have received a wide scientific interest in the last decade. Nevertheless, relatively few are practical and industrial applications based on essential oils and bioprotective cultures. Here, the advantages and the potentiality of these approaches are reviewed together with the weaknesses, which limit their application to real foods.

We discuss the $p$- and the $hp$-versions of the virtual element method for the approximation of eigenpairs of elliptic operators with a potential term on polygonal meshes. An application of this model is provided by the Schr\"odinger equation with a pseudo-potential term. We present in details the analysis of the p-version of the method, proving exponential convergence in the case of analytic eigenfunctions. The theoretical results are supplied with a wide set of experiments. We also show numerically that, in the case of eigenfunctions with finite Sobolev regularity, an exponential approximation of the eigenvalues in terms of the cubic root of the number of degrees of freedom can be obtained by employing $hp$-refinements. Importantly, the geometric flexibility of polygonal meshes is exploited in the construction of the $hp$-spaces., Comment: 25 pages, 7 figures

The high quantity of spontaneous fermented sausages from different Mediterranean European Countries represents a relatively unexplored reservoirs of microbial biodiversity within which it is possible to find new microorganisms with relevant technological properties. With this aim, several spontaneously fermented European meat products have been collected from artisanal producers in Italy, Spain, Slovenia and Croatia and analysed for their chemicophysical, aromatic and safety features. Moreover, their microbial populations have been studied both with cultivation-dependent and metagenomic techniques in order to highlight the richness of microbial biodiversity. The results showed that each product differed in terms of aromatic and microbiological characteristics depending on the raw material quality and type, recipes, production techniques and fermentation and maturation conditions. In addition, the lactic acid bacteria biodiversity found can valorise the bacterial genetic heritage present in Mediterranean fermented products. In fact, the exploitation of these microbial biodiversity by bioprospecting of strains isolated from these environments can represent an effective strategy to find strains of industrial importance, filling the gap between the laboratory results and efficacy in the production field, being autochthonous strains more suitable for adaptation in specific ecological niches.

Biogenic amines (BAs) are molecules, which can be present in foods and, due to their toxicity, can cause adverse effects on the consumers. BAs are generally produced by microbial decarboxylation of amino acids in food products. The most significant BAs occurring in foods are histamine, tyramine, putrescine, cadaverine, tryptamine, 2-phenylethylamine, spermine, spermidine, and agmatine. The importance of preventing the excessive accumulation of BAs in foods is related to their impact on human health and food quality. Quality criteria in connection with the presence of BAs in food and food products are necessary from a toxicological point of view. This is particularly important in fermented foods in which the massive microbial proliferation required for obtaining specific products is often relater with BAs accumulation. In this review, up-to-date information and recent discoveries about technological factors affecting BA content in foods are reviewed. Specifically, BA forming-microorganism and decarboxylation activity, genetic and metabolic organization of decarboxylases, risk associated to BAs (histamine, tyramine toxicity, and other BAs), environmental factors influencing BA formation (temperature, salt concentration, and pH). In addition, the technological factors for controlling BA production (use of starter culture, technological additives, effects of packaging, other non-thermal treatments, metabolizing BA by microorganisms, effects of pressure treatments on BA formation and antimicrobial substances) are addressed. © 2016 Gardini, özogul, Suzzi, Tabanelli and özogul.

The aim of this work was to assess if a sub-lethal high pressure homogenization (HPH) treatment could modulate in vitro functional and biological properties of probiotic bacteria. Lactobacillus paracasei A13, Lactobacillus acidophilus 08 and Dru, Lactobacillus delbrueckii subsp. lactis 200 and bile-resistant derivatives L. acidophilus Druþ and L. delbrueckii subsp. lactis 200þ were suspended in phosphate buffered saline solution and treated at 50 MPa. Data obtained showed that HPH can modulate hydrophobicity and auto-aggregation without modification of viability and decarboxylase activity. Resistance to simulated gastric conditions resulted strain-dependent. High resistance was observed for treated L. paracasei A13, L. acidophilus Dru and 08 and L. delbrueckii subsp. lactis 200. The HPH-treatment reduced the resistance to simulated stomach duodenum-passage of L. acidophilus Dru while increased it for L. paracasei A13. Strain viability and resistance to simulated gastric conditions were evaluated treating at 50 MPa cells suspended in acidified buttermilk (pH 4.6) and stored at 4 C for 30 days. The highest cell viability loss, after 30 d of refrigerated storage, was observed for L. acidophilus Dru, independently of the application of HPH. However, after 30 days of storage, the resistance of L. paracasei A13 to simulated gastric digestion significantly increased in HPH treated cells. Fil: Tabanelli, G.. Interdipartimental Center of Industrial Research (CIRI Agroalimentare); Italia Fil: Patrignani, F.. Universidad de Bologna; Italia Fil: Vinderola, Celso Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentina Fil: Reinheimer, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Lactología Industrial. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Lactología Industrial; Argentina Fil: Gardini, F.. Universidad de Bologna; Italia Fil: Lanciotti, R.. Universidad de Bologna; Italia

This research is devoted to mass conservation and CFL properties of the Finite Elements Immersed Boundary Method. We first explore an enhanced higher order scheme applied to the Finite Element Immersed Boundary Method technique introduced by Boffi and Gastaldi. This technique is based on a Pointwise (PW) formulation of the kinematic condition, and higher order elements show better conservation properties than the original scheme. A further improvement with respect to the classical PW formulation is achieved introducing a fully variational Distributed Lagrange Multiplier (DLM) formulation. Numerical experiments show that DLM is not affected by any CFL condition. Furthermore the mass conservation properties of this method are extremely competitive.