1,721,181 research outputs found
Potential of high pressure homogenisation on probiotic Caciotta cheese quality and functionality
Full text linkThe probiotic Lactobacillus paracasei A13, treated at 50 MPa sub-lethal high pressure homogenisation (HPH), was used as adjunct for producing Caciotta cheese. The cell HPH treatment was used because it has been proven to increase the in vitro strain functionality. The starters and Lb. paracasei A13 viability, the cheese hydrolytic patterns and organoleptic profiles were monitored. After cheesemaking and during ripening, the Lb. paracasei A13 gastric acid resistance in cheese and the ability of the cheese, containing HPH-treated or untreated cells, to modulate the gut mucosal immune system in mice were evaluated. Traditional Caciotta was used as controls. The HPH-treated probiotic strain maintained high viability for 14 days whilst the physico-chemical analyses on Caciotta cheese containing HPH-treated cells showed a faster ripening, compared to other cheeses. For functional properties, the 50 MPa treatment increased the Lb. paracasei gastric resistance in Caciotta, maintaining high strain viability, but IL-10 producing capacity was lost by HPH-treatment whilst IgA production was not modified.Fil: Burns, Patricia Graciela. 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; ArgentinaFil: Patrignani, Francesca. Universidad de Bologna; ItaliaFil: Tabanelli, Giulia. Universidad de Bologna; ItaliaFil: 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; ArgentinaFil: Siroli, Lorenzo. Universidad de Bologna; ItaliaFil: 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; ArgentinaFil: Gardini, Fausto. Universidad de Bologna; ItaliaFil: Lanciotti, Rosalba. Universidad de Bologna; Itali
Biogenic Amine Production by Lactic Acid Bacteria: A Review
Full text linkLactic acid bacteria (LAB) are considered as the main biogenic amine (BA) producers in fermented foods. These compounds derive from amino acid decarboxylation through microbial activities and can cause toxic effects on humans, with symptoms (headache, heart palpitations, vomiting, diarrhea) depending also on individual sensitivity. Many studies have focused on the aminobiogenic potential of LAB associated with fermented foods, taking into consideration the conditions affecting BA accumulation and enzymes/genes involved in the biosynthetic mechanisms. This review describes in detail the different LAB (used as starter cultures to improve technological and sensorial properties, as well as those naturally occurring during ripening or in spontaneous fermentations) able to produce BAs in model or in real systems. The groups considered were enterococci, lactobacilli, streptococci, lactococci, pediococci, oenococci and, as minor producers, LAB belonging to Leuconostoc and Weissella genus. A deeper knowledge of this issue is important because decarboxylase activities are often related to strains rather than to species or genera. Moreover, this information can help to improve the selection of strains for further applications as starter or bioprotective cultures, in order to obtain high quality foods with reduced BA content
Impact of Cell-free Supernatant of Lactic Acid Bacteria on Putrescine and Other Polyamine Formation by Foodborne Pathogens in Ornithine Decarboxylase Broth
No full textConversion of ornithine to putrescine by Salmonella Paratyphi A, Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli was investigated in ornithine decarboxylase broth (ODB) using cell-free supernatants (CFSs) obtained from Leuconostoc mesenterodies subsp. cremoris, Pediococcus acidilactici, Lactococcus lactis subsp. lactis, Streptococcus thermophilus. Two groups of cell-free supernatants (25 or 50%) and control (only ODB) were prepared to investigate putrescine (PUT) and other polyamine formation by foodborne pathogens (FBPs). Significant differences (p < 0.05) were observed among the species for each amine. All of the CFSs reduced the formation of PUT by ≥65%. The production of cadaverine (CAD) was scarcely affected by the presence of CFSs, with the exception of the samples inoculated with L. monocytogenes. The variation in polyamine was found with respect to the control samples. Spermidine (SPD) was produced in lower amount in many samples, especially in Gram-negative FBPs, whereas spermine (SPN) increased drastically in the major part of the samples concerning the control. Histamine (HIS) was characterized by a marked concentration decrease in all of the samples, and tyramine (TYR) was accumulated in very low concentrations in the controls. Therefore, the ability of bacteria to produce certain biogenic amines such as HIS, TYR, PUT, and CAD has been studied to assess their risk and prevent their formation in food products. The results obtained from this study concluded that the lactic acid bacteria (LAB) strains with non-decarboxylase activity are capable of avoiding or limiting biogenic amine formation by FBP
Contribution of Two Different Packaging Material to Microbial Contamination of Peaches: Implications in Their Microbiological Quality
Full text linkAim: Aim of this work was understanding the microbial transfer dynamics from packaging to packed peaches in relation to the packaging used. Method and Results: A challenge test was performed, inoculating Escherichia coli, Pseudomonas spp. and Saccharomyces cerevisiae on cardboards and RPC (Reusable Plastic Containers), and monitoring their cell loads on fruits according to a probabilistic model and a Response Surface Methodology (RSM) in relation to several independent variables (number of fruit lesions, fruit temperature storage and commercialization time). The data recorded on packed peaches for Pseudomonas and S. cerevisiae were modeled to fit the second order model to study the main, interactive and quadratic effects of the independent variables on the cell loads of target microorganisms as well as on the shelf-life of the fruits in relation to packaging material used. The data collected for E. coli were codified as presence (1) or absence (0) and modeled with a logistic regression analysis to assess the probability of E. coli transferring from packaging to fruits in relation to the adopted variables. The data showed a higher contamination frequency of the fruits packed in plastic than in cardboard. Increasing the storage temperature and the number of lesions, the probability of transferring of E. coli from packaging materials to fruits increased, independently on commercialization time or packaging used. For Pseudomonas, the contamination levels detected on fruits packaged in plastic were significantly higher compared to those found on fruits packed in cardboard, independently on the considered variables. The polynomial equations showed the S. cerevisiae cell loads of fruits stored in plastic was positively affected by the quadratic term of temperature. Conclusions: the use of cardboard, compared to plastic, can significantly reduce the potential of microbial transferring from packaging to fruits. The probabilistic and kinetic models used showed a higher microbiological qualities of peaches stored in cardboard boxes, independently on the independent variables considered. The best performances of cardboard, compared to plastic, was probably due to its capability to entrap microbial cells. Significance and Impact: cardboard reduces fruit contamination and increases their shelf-life with positive fallouts on fruit shelf-life and all the logistic and distribution chain
Effects of sub-lethal concentrations of thyme and oregano essential oils, carvacrol, thymol, citral and trans-2-hexenal on membrane fatty acid composition and volatile molecule profile of Listeria monocytogenes, Escherichia coli and Salmonella enteritidis
Full text linkThe aim of this work was to investigate the modifications of cell membrane fatty acid composition and
volatile molecule profiles of Listeria monocytogenes, Salmonella enteritidis, Escherichia coli, during growth
in the presence of different sub-lethal concentrations of thyme and oregano essential oils as well as carvacrol,
thymol, trans-2-hexenal and citral. The results evidenced that the tested molecules induced
noticeable modifications of membrane fatty acid profiles and volatile compounds produced during the
growth. Although specific differences in relation to the species considered were identified, the tested
compounds induced a marked increase of some membrane associated fatty acids, particularly unsaturated
fatty acids, trans-isomers, and specific released free fatty acids. These findings can contribute to the
comprehension of the stress response mechanisms used by different pathogenic microorganisms often
involved in food-borne diseases in relation to the exposure to sub-lethal concentrations of natural
antimicrobials
Microbiota of Cheese Ecosystems: A Perspective on Cheesemaking
Full text linkThis review contributes to the knowledge on the complex and adaptive microbial ecosystems within cheese, emphasizing their critical role in determining cheese quality, flavor, and safety. This review synthesizes the current knowledge on the microbial interactions and the dynamics of lactic acid bacteria (LAB), encompassing both starter (SLAB) and non-starter (NSLAB) strains, which are pivotal to the curd fermentation and ripening processes. The adaptability of these microbial consortia to environmental and technological stressors is explored, highlighting their contributions to acidification, proteolysis, and the development of distinctive organoleptic characteristics. Historical and technological perspectives on cheesemaking are also discussed, detailing the impact of milk treatment, starter culture selection, and post-renneting procedures on microbial activity and biochemical transformations. This review underscores the importance of microbial diversity and cooperative interactions in fostering ecosystem resilience and metabolic functionality, and it addresses the challenges in mimicking the technological performance of natural starters using selected cultures. By understanding the ecological roles and interactions of cheese microbiota, this review aims to guide improvements in cheese production practices. Additionally, these insights could spark the development of innovative strategies for microbial community management
Effects of sub-lethal high-pressure homogenization treatment on the outermost cellular structures and the volatile-molecule profiles of two strains of probiotic lactobacilli
Full text linkApplying sub-lethal levels of high-pressure homogenization (HPH) to lactic acid bacteria has been proposed as a method of enhancing some of their functional properties. Because the principal targets of HPH are the cell-surface structures, the aim of this study was to examine the effect of sub-lethal HPH treatment on the outermost cellular structures and the proteomic profiles of two known probiotic bacterial strains. Moreover, the effect of HPH treatment on the metabolism of probiotic cells within a dairy product during its refrigerated storage was investigated using SPME-GC-MS. Transmission electron microscopy was used to examine the microstructural changes in the outermost cellular structures due to HPH treatment. These alterations may be involved in the changes in some of the technological and functional properties of the strains that were observed after pressure treatment. Moreover, the proteomic profiles of the probiotic strains treated with HPH and incubated at 37°C for various periods showed different peptide patterns compared with those of the untreated cells. In addition, there were differences in the peaks that were observed in the low-mass spectral region (2000-3000 Da) of the spectral profiles of the control and treated samples. Due to pressure treatment, the volatile-molecule profiles of buttermilk inoculated with treated or control cells and stored at 4°C for 30 days exhibited overall changes in the aroma profile and in the production of molecules that improved its sensory profile, although the two different species imparted specific fingerprints to the product. The results of this study will contribute to understanding the changes that occur in the outermost cellular structures and the metabolism of LAB in response to HPH treatment. The findings of this investigation may contribute to elucidating the relationships between these changes and the alterations of the technological and functional properties of LAB induced by pressure treatment.Fil: Tabanelli, Giulia. Universidad de Bologna; ItaliaFil: Vernocchi, Pamela. Irccs Ospedale Pediatrico Bambino Gesu; . Universidad de Bologna; ItaliaFil: Patrignani, Francesca. Università Degli Studi Di Bologna - Sede Di Cesena;Fil: Del Chierico, Federica. Irccs Ospedale Pediatrico Bambino Gesu;Fil: Putignani, Lorenza. Irccs Ospedale Pediatrico Bambino Gesu;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; ArgentinaFil: 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; ArgentinaFil: Gardini, Fausto. Universidad de Bologna; Italia. Università Degli Studi Di Bologna - Sede Di Cesena;Fil: Lanciotti, Rosalba. Universidad de Bologna; Italia. Università Degli Studi Di Bologna - Sede Di Cesena
Use of indigenous lactic acid bacteria for industrial fermented sausage production: microbiological, chemico-physical and sensory features and biogenic amine content
Full text linkThe use of starter cultures in the meat industry is common, even if the number of available commercial cultures is limited, inducing product standardisation and microbial diversity reduction. On the other hand, some artisanal products relying on spontaneous fermentation can represent a source of isolation of new interesting strains. In this work, four LAB strains derived from Mediterranean spontaneously fermented sausages were tested as new starter cultures for the industrial production of fermented sausages, in comparison to a commercial starter culture. The products obtained were analysed for physico-chemical parameters, microbiota, biogenic amines and aroma profile. A consumer test was also performed to evaluate product acceptability. The strains induced different acidification kinetics. LAB counts showed high persistence when Latilactobacillus curvatus HNS55 was used as the starter culture, while the addition of Companilactobacillus alimentarius CB22 resulted in a high concentration of enterococci (6 log CFU/g), 2 log higher than in other samples. Tyramine was detected at concentrations of 150-200 mg/kg, except for in the sample produced with Lactiplantibacillus plantarum BPF2 (60 mg/kg). Differences were observed in the aroma profile, with a high amount of 2-butanone found in the samples obtained with Comp. alimentarius CB22. These latter sausages also showed the lowest score in terms of acceptability. This study allowed us to select new LAB strains for fermented sausage starter cultures, increasing the product diversification
Technological Factors Affecting Biogenic Amine Content in Foods: A Review
Full text linkBiogenic 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
Use of High-Pressure Homogenization for Improving the Quality and Functionality of Probiotics
No full textBesides to their industrial importance, Lactic Acid Bacteria (LAB) are currently studied for their potential role as probiotic. In recent years, worldwide interest in the use of functional foods containing probiotic bacteria for health promotion and disease prevention has increased significantly. Thus, probiotics and their technological and functional properties are the focus of an intensive international research that has stimulated innovation and new product development. The study of some process variables able to optimize and enhance probiotic viability and functionality over the storage and to stimulate innovation and the development of new products.
Among the innovative technological processes, High Pressure Homogenization (HPH) seems to have a great potential in functional dairy sector. In fact, HPH has been proposed to produce probiotic fermented milk, bio-yogurt and probiotic cheeses with improved sensorial or functional properties (Patrignani et al., 2008; Burns et al, 2008a). Moreover, Lanciotti et al. (2007b) demonstrated that HPH is able to affect, in relation to the strain and to the treatment applied, both the fermentation kinetics and the enzymatic activities of LAB without detrimental effect on cell viability, confirming the pressure tolerance of LAB. Even if the response to the HPH varied according to the species and the characteristics of the individual strains (Burns et al., 2008a), HPH treatment, applied at sub-lethal level, could increase important technological and probiotic properties of some strains.
This chapter will focus the attention on the HPH application potential to increase functional features of probiotic strains both in vitro and in vivo. In particular, pressure effects on strain intestinal transit conditions in the gut and on mice immune system stimulation will be described.
Moreover, considering that probiotic properties are related to the cell wall, which is also the principal target of HPH, the effects of a sub-lethal HPH treatment on cell response mechanisms will be described. Specifically, the membrane fatty acid composition of cells before and after the sub-lethal HPH treatment will be studied and cellular morphological changes after HPH will be described by using a transmission electron microscope.
Also the potential of HPH applied to probiotic strain cells inoculated in milk employed in the production of a traditional Italian cheese will be considered in order to evaluate strain viability and probiotic features over storage as well as cheese quality and functionality
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