Search results for "Microbial Viability"
showing 10 items of 69 documents
Anaemia in advanced chronic fasciolosis
2008
Abstract The association between fasciolosis-induced anaemia and related factors has been quantified in a rodent model. Haematological parameters were analysed in Wistar rats at 20 and 60 weeks post-infection (p.i.). Pigment stones and bile specimens were collected. Serum IgG1, IgG2a and IgE were determined in rat serum samples. Cytokine levels have been correlated with haematological parameters. The screening for gastrointestinal bleeding was carried out. Bacteriological bile cultures revealed viable bacteria in 53.8% of specimens at 60 weeks p.i. The results show that the type of anaemia in fasciolosis might be considered a biomarker of the chronicity period of the disease, changing from …
Microbial inactivation and evaluation of furan formation in high hydrostatic pressure (HHP) treated vegetable-based infant food.
2017
Abstract The inactivation of pathogenic and spoilage bacteria as well as the formation of food processing contaminants (e.g. acrylamide, furan, etc.) in infant foods is of utmost importance for industry, consumers as well as regulatory bodies. In this study, the potential of high hydrostatic pressure (HHP) for microorganism inactivation including total mesophilic aerobic bacteria (TMA) and total yeasts and molds (TYM) at equivalent processing conditions, as well as its effects on furan formation in vegetable-based infant food was evaluated. The process parameters evaluated were combinations of pressures (200, 300, and 400 MPa), temperatures (25, 35, and 45 °C), and treatment times (5, 10, a…
Inactivation of dried spores of Bacillus subtilis 168 by a treatment combining high temperature and pressure
2019
International audience; Specific treatments combining high temperatures of up to 150 °C and moderate pressure of up to 0.6 MPa have been applied to Bacillus subtilis 168 spores conditioned at different aw levels (between 0.10 and 0.70) corresponding to different residual water contents within the spore core. The spores were treated as a dry powder in a pressurized nitrogen environment or in water/glycerol solutions.These thermodynamic conditions were intended to prevent any water evaporation from the spore core during time/temperature treatments.Our results clearly show that retaining liquid water in the core by applying pressure during the treatment resulted in greater spore destruction (b…
Oxidative stress tolerance, adenylate cyclase, and autophagy are key players in the chronological life span of Saccharomyces cerevisiae during winema…
2012
Most grape juice fermentation takes place when yeast cells are in a nondividing state called the stationary phase. Under such circumstances, we aimed to identify the genetic determinants controlling longevity, known as the chronological life span. We identified commercial strains with both short (EC1118) and long (CSM) life spans in laboratory growth medium and compared them under diverse conditions. Strain CSM shows better tolerance to stresses, including oxidative stress, in the stationary phase. This is reflected during winemaking, when this strain has an increased maximum life span. Compared to EC1118, CSM overexpresses a mitochondrial rhodanese gene-like gene, RDL2, whose deletion lead…
Estimation of Microbial Viability Using Flow Cytometry.
2020
For microorganisms in particular, viability is a term that is difficult to define and a state consequently difficult to measure. The traditional (and gold standard) usage equates viability and culturability (i.e., the ability to multiply) but the process of determining culturability is often too slow. Flow cytometry provides the opportunity to make rapid and quantitative measurements of dye uptake in large numbers of cells and we can therefore exploit the flow cytometric approach to evaluate so-called viability stains and to develop protocols for more routine assessments of microbial viability. This article provides a commentary and several protocols have been included to ensure that users …
Response of soil bacterial community structure to successive perturbations of different types and intensities
2008
SummaryIn soil, genetic structure modifications of indigenousbacterial community consecutively to a severe stress(mercury contamination) were delayed when thecommunity was pre-exposed to various minor per-turbations (heat, copper and atrazine). Such minorperturbations induced transitory community struc-ture modifications leading to an increase of commu-nity stability towards a severe mercury stress. Theseresults illustrated well the short-term pre-adaptationprocess for bacterial community hypothesizing thatcommunity submitted to perturbations become moreresistant to withstand another stress. Compared with other environmental matrices of the bio-sphere, soils are considered as the main reservo…
Microbiological investigation of Raphanus sativus L. grown hydroponically in nutrient solutions contaminated with spoilage and pathogenic bacteria
2012
Abstract The survival of eight undesired (spoilage/pathogenic) food related bacteria (Citrobacter freundii PSS60, Enterobacter spp. PSS11, Escherichia coli PSS2, Klebsiella oxytoca PSS82, Serratia grimesii PSS72, Pseudomonas putida PSS21, Stenotrophomonas maltophilia PSS52 and Listeria monocytogenes ATCC 19114T) was investigated in mineral nutrient solution (MNS) during the crop cycle of radishes (Raphanus sativus L.) cultivated in hydroponics in a greenhouse. MNSs were microbiologically analyzed weekly by plate count. The evolution of the pure cultures was also evaluated in sterile MNS in test tubes. The inoculated trials contained an initial total mesophilic count (TMC) ranging between 6.…
Production of functional probiotic, prebiotic, and synbiotic ice creams
2010
In this work, 3 types of ice cream were produced: a probiotic ice cream produced by adding potentially probiotic microorganisms such as Lactobacillus casei and Lactobacillus rhamnosus; a prebiotic ice cream produced by adding inulin, a prebiotic substrate; and a synbiotic ice cream produced by adding probiotic microorganisms and inulin in combination. In addition to microbial counts, pH, acidity, and physical and functional properties of the ice creams were evaluated. The experimental ice creams preserved the probiotic bacteria and had counts of viable lactic acid bacteria, after frozen storage that met the minimum required to achieve probiotic effects. Moreover; most of the ice creams show…
Antibody persistence and immune memory 15 months after priming with an investigational tetravalent meningococcal tetanus toxoid conjugate vaccine (Me…
2012
The present extension study, conducted in children originally vaccinated at 12–14 mo or 3–5 y of age, assessed antibody persistence and immune memory induced by an investigational tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine (MenACWY-TT). In the original study, participants were randomized to receive one dose of MenACWY-TT or licensed age-appropriate meningococcal control vaccines. Fifteen months post-vaccination, all participants underwent serum sampling to evaluate antibody persistence and participants previously vaccinated as toddlers received a polysaccharide challenge to assess immune memory development. Exploratory comparisons showed that (…
Two versus three doses of a meningococcal C conjugate vaccine concomitantly administered with a hexavalent DTaP-IPV-HBV/Hib vaccine in healthy infant…
2007
The immunogenicity and reactogenicity of a meningococcal serogroup C (MenC) conjugate vaccine given concomitantly with DTaP-IPV-HBV/Hib vaccine according to a two- or three-dose schedule in healthy infants was evaluated. At 1 month post-vaccination, 98% (two doses) and 100% (three doses) of subjects had serum bactericidal antibody using human complement assay (hSBA) titres > or =1:8; at 12 months of age > or =89% of subjects in each group remained seroprotected. Induction of immunological memory, as evaluated by administration of a meningococcal serogroup A/C polysaccharide vaccine challenge dose, was similar for both regimens and no interference was observed in the immune response to MenC …