Search results for "Endospore"
showing 10 items of 10 documents
Safety and immunomodulatory effects of three probiotic strains isolated from the feces of breast-fed infants in healthy adults: SETOPROB study.
2013
We previously described the isolation and characterization of three probiotic strains from the feces of exclusively breast-fed newborn infants: Lactobacillus paracasei CNCM I-4034, Bifidobacterium breve CNCM I-4035 and Lactobacillus rhamnosus CNCM I-4036. These strains were shown to adhere to intestinal mucus in vitro, to be sensitive to antibiotics and to resist biliary salts and low pH. In the present study, a multicenter, randomized, double-blind, placebo-controlled trial with 100 healthy volunteers in three Spanish cities was carried out to evaluate the tolerance, safety, gut colonization and immunomodulatory effects of these three probiotics. Volunteers underwent a 15-day washout perio…
Direct investigation of viscosity of an atypical inner membrane of Bacillus spores: A molecular rotor/FLIM study
2013
Abstract We utilize the fluorescent molecular rotor Bodipy-C12 to investigate the viscoelastic properties of hydrophobic layers of bacterial spores Bacillus subtilis. The molecular rotor shows a marked increase in fluorescence lifetime, from 0.3 to 4 ns, upon viscosity increase from 1 to 1500 cP and can be incorporated into the hydrophobic layers within the spores from dormant state through to germination. We use fluorescence lifetime imaging microscopy to visualize the viscosity inside different compartments of the bacterial spore in order to investigate the inner membrane and relate its compaction to the extreme resistance observed during exposure of spores to toxic chemicals. We demonstr…
Evaluation of a Real-Time PCR Assay for the Detection and Quantification of Group Spores in Food
2010
A procedure based on quantitative real-time PCR was evaluated for the detection and quantification of Bacillus cereus spores. Several methods for DNA isolation, such as various heat treatments and germination solutions, were evaluated on spore suspensions of representative strains of the B. cereus group. Overall, the commercially available DNeasy tissue kit yielded the maximum amount of DNA. The procedure also was used to construct calibration curves for different food matrices, with a wide spore quantification range of 5 log units using serial dilutions of spore suspensions of B. cereus CECT 148T. The detection limit for B. cereus in artificially contaminated liquid egg and reconstituted i…
Effects of high pressure processing and biopreservation on the inactivation and the germination of spores of Bacillus and Clostridium
2018
Bacterial endospores are one of the most resistant life form on earth. Their capacity to survive to decontamination processes and their potential pathogenicity represent a real problem for the food industry. Currently, the only way to prevent their development in foods is the application of thermal treatments or the use of preservatives. However, these two methods have negative impacts on the nutritional properties of foods and on the consumers’ health. High hydrostatic pressure (HP) is a non-thermal process widely used for commercial pasteurization of foods. However, this process has a very low effect on spores and has therefore to be combined with other decontamination processes to enhanc…
Effects of high-pressure processing on fungi spores: Factors affecting spore germination and inactivation and impact on ultrastructure.
2020
Food contamination with heat-resistant fungi (HRF), and their spores, is a major issue among fruit processors, being frequently found in fruit juices and concentrates, among other products, leading to considerable economic losses and food safety issues. Several strategies were developed to minimize the contamination with HRF, with improvements from harvesting to the final product, including sanitizers and new processing techniques. Considering consumers' demands for minimally processed, fresh-like food products, nonthermal food-processing technologies, such as high-pressure processing (HPP), among others, are emerging as alternatives to the conventional thermal processing techniques. As no …
Proton dynamics in bacterial spores, a neutron scattering investigation
2014
International audience; Results from first neutron scattering experiments on bacterial spores are reported. The elastic intensities and mean square displacements have a non-linear behaviour as function of temperature, which is in agreement with a model presenting more pronounced variations at around 330 K (57 • C) and 400 K (127 • C). Based on the available literature on thermal properties of bacterial spores, mainly referring to differential scanning calorimetry, they are suggested to be associated to main endothermic transitions induced by coat and/or core bacterial response to heat treatment.
Understanding the Effects of High Pressure on Bacterial Spores Using Synchrotron Infrared Spectroscopy
2020
International audience; Bacterial spores are extremely resistant life-forms that play an important role in food spoilage and foodborne disease. The return of spores to a vegetative cell state is a three-step process, these being activation, germination, and emergence. High-pressure (HP) processing is known to induce germination in part of the spore population and even to inactivate a high number of Bacillus spores when combined with other mild treatments such as the addition of nisin. The aim of the present work was to investigate the mechanisms involved in the sensitization of spores to nisin following HP treatment at ambient temperature or with moderate heating leading to a heterogeneous …
Thermal inactivation kinetics of Bacillus stearothermophilus spores using a linear temperature program.
1999
A systematic study of the inactivation kinetics of Bacillus stearothermophilus spores was carried out in nonisothermic heating conditions using a linear temperature increase program and analyzing the experimental data by means of a one-step nonlinear regression. The D and z values estimated are close to those obtained in isothermic conditions and estimated by using a two-step model, first D values are calculated, and then in the second step a z value is deduced (D(121 degrees C) = 3.08 and 4.38 min, respectively, and z = 7 and 7.9 degrees C, respectively). No convergence problems were observed when using the one-step nonlinear regression proposed. The results indicated that the methodology …
High gas pressure: An innovative method for the inactivation of dried bacterial spores
2012
In this article, an original non-thermal process to inactivate dehydrated bacterial spores is described. The use of gases such as nitrogen or argon as transmission media under high isostatic pressure led to an inactivation of over 2 logs CFU/g of Bacillus subtilis spores at 430 MPa, room temperature, for a 1 min treatment. A major requirement for the effectiveness of the process resided in the highly dehydrated state of the spores. Only a water activity below 0.3 led to substantial inactivation. The solubility of the gas in the lipid components of the spore and its diffusion properties was essential to inactivation. The main phenomenon involved seems to be the sorption of the gas under pres…
Supression of Botrytis cinerea causing grey mould disease of grape vine (Vitis vinifera) and its pectinolytic activities by a soil bacterium
1997
Abstract Botrytis cinerea was found to be pathogenic to grapevine, producing characteristic grey mould symptoms within 7 days of inoculation into vitroplants. An endospore forming bacterial strain (GI 070), Bacillus circulans, was found to be antagonist against this disease causing fungus. Under laboratory conditions the bacterial culture or its filtrate brings about complete suppression of the fungus in Petri-dishes and the grey mould symptoms on grapevine vitroplants. Pectinolytic activities (Polygalacaturonase, Pectin lyases) of Botrytis cinerea were also influenced by these bacteria. Details of the fungal parasite, its biological control and its pectinolytic activities are discussed in …