The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
H. J. Busscher - One of the best experts on this subject based on the ideXlab platform.
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Biosurfactants from thermophilic dairy streptococci and their potential role in the fouling control of heat exchanger plates
Journal of Industrial Microbiology, 1996Co-Authors: H. J. Busscher, M Kuijl-booij, Hc MeiAbstract:Recent work on biosurfactant release by thermophilic dairy streptococci is reviewed. There is a suggestion that Streptococcus thermophilus isolates may release biosurfactants that stimulate detachment of already-adhering cells and leave an anti-adhesive coating on a substratum. A previously published rapid screening method is described for the identification of biosurfactant-releasing microorganisms, and growth medium supplements to enhance biosurfactant release by thermophilic dairy streptococci are reported. New experimental work described includes the isolation and purification of biosurfactants from dairy isolates by thin layer chromatography. Many compounds isolated were extremely surface-active and reduced the water surface tension to values around 30 mJ m^−2 at a concentration of 10 mg ml^−1. Most importantly, the thin layer chromatograms of various isolates resembled each other, and an adsorbed purified compound from one isolate retarded the deposition to glass of another isolate by a factor of two. Provided our findings implicate that these biosurfactants could also be adsorbed to heat exchanger plates in Pasteurizers and thereby retard colonization by thermophilic streptococci, these compounds may have major economic implications. Further work is required, however.
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Biosurfactant production by thermophilic dairy streptococci
Applied Microbiology and Biotechnology, 1994Co-Authors: H. J. BusscherAbstract:Biosurfactant production of eight Streptococcus thermophilus strains, isolated from heat exchanger plates in the downstream side of the regenerator section of Pasteurizers in the dairy industry has been measured using axisymmetric drop shape analysis by profile (ADSA-P). Strains were grown in M17 broth with either lactose, saccharose or glucose added. After harvesting, cells were suspended in water or in 10 m m potassium phosphate buffer, pH 7.0, and suspension droplets were put on a piece of FEP-Teflon. Changes in droplet profile were analysed by ADSA-P to yield the surface tension decrease due to biosurfactant production as a function of time. Surface tension decreases larger than 8 mJ·m^−2 were taken as indicative of biosurfactant production. Only five strains produced biosurfactants in water, solely when saccharose was added to the growth medium. In buffer, all strains produced biosurfactants and production was generally greater than in water. Also, most strains suspended in buffer produced maximally when saccharose was added to the growth medium, whereas one strain produced maximally in buffer upon the addition of glucose. Four strains suspended in buffer produced biosurfactants when glucose was added and only two strains when lactose was added. The possible role of these biosurfactants as anti-adhesives in the dairy industry and for the survival of these strains in natural systems is discussed.
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Hydrophobic and Electrostatic Cell Surface Properties of Thermophilic Dairy Streptococci
1993Co-Authors: Hc ,van Der Mei, De Vries Jacob, H. J. BusscherAbstract:Microbial adhesion to hydrocarbons (MATH) and microelectrophoresis were done in 10 mM potassium phosphate solutions to characterize the surfaces of thermophilic dairy streptococci, isolated from Pasteurizers. Regardless of whether they were grown (in M17 broth) with lactose, sucrose, or glucose added, strains were relatively hydrophilic (showing low initial removal rates by hexadecane) and slightly negatively charged. A tendency exists for cells grown with sucrose added to be more hydrophilic than cells grown with glucose or lactose added. Also, the lowest isoelectric points, i.e., the pH values for which the zeta potentials are zero, were measured for strains with glucose added to the growth medium. The isoelectric points for the strains were all rather high, between pH 3 and 5, indicative of protein-rich surfaces, although X-ray photoelectron spectroscopy did not measure excessively large amounts of nitrogen on the cell surfaces. Both MATH and microelectrophoresis were done as a function of pH. Maxima in hydrophobicity were observed at certain pH values. Usually these pH values were in the range of the isoelectric points of the cells. Thus it appears that MATH measures an interplay of hydrophobicity and electrostatic interactions. MATH measures solely hydrophobicity only when electrostatic interactions are absent, i.e., close to the isoelectric points of the cells. Considering that these thermophilic streptococci are all rather hydrophilic, a possible pathway to prevent fouling in the pasteurization process might be to render the heat exchanger plates of the pasteurizer more hydrophobic
A J Heinrichs - One of the best experts on this subject based on the ideXlab platform.
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evaluation of calf milk pasteurization systems on 6 pennsylvania dairy farms
Journal of Dairy Science, 2010Co-Authors: J A Elizondosalaza, C M Jones, A J HeinrichsAbstract:Waste milk has been fed to calves for many years, but concerns with bacterial contamination as well as possible transmission of diseases have discouraged widespread use of this feed. Pasteurization of waste milk is one option to reduce management risk while utilizing a valuable, low-cost, liquid feed source for calves. However, many farms currently pasteurizing waste milk lack a system to adequately monitor the efficiency of the process. A study was carried out to evaluate 6 on-farm pasteurization systems, including high-temperature, short-time Pasteurizers and low-temperature, batch Pasteurizers. Milk samples were taken pre- and postpasteurization as well as from the calf buckets and immediately frozen for later bacterial culture. Samples were collected twice daily for 15 d. Milk samples were examined for standard plate count (SPC), coagulase-negative staphylococci count, environmental streptococci count, coliform count, gram-negative noncoliform count, Streptococcus agalactiae count, and Staphylococcus aureus count. Before pasteurization, 68% of the samples had SPC 90% of samples. These results indicate that pasteurization can be very effective in lowering bacterial contamination of milk. However, bacteria numbers significantly increased after pasteurization and, in some cases, bacteria counts in milk fed to calves were similar to prepasteurization levels. Milk handling after pasteurization was identified as an important issue on the farms studied.
Norbert Räbiger - One of the best experts on this subject based on the ideXlab platform.
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Reduction of milk fouling inside gasketed plate heat exchanger using nanocoatings
Food and Bioproducts Processing, 2010Co-Authors: A. Bani Kananeh, E. Scharnbeck, U.d. Kück, Norbert RäbigerAbstract:Fouling inside gasketed plate heat exchangers used in milk production has been reduced using nano-composites coatings. An antifouling coating with low surface energy (low wettability) led to a hydrophobic and oleophobic effect. Test facilities were constructed by the Institute of New Materials (INM) and Institute of Environmental Process Engineering (IUV), University of Bremen in Germany for the investigation of milk adhesion and the stability of the coatings on rectangular plates and small cylindrical ducts. A number of coatings and surface treatments were tested. Certain polyurethane-coated plates and tubes formed thinner deposit layer compared to standard uncoated stainless steel plates and tubes. The cleaning time for one coated tube was reduced by 80% compared to the standard stainless steel one. A pilot plant including a milk pasteurizer at LUFA Nord-West in Oldenburg-Germany was used for the thermal treatment of whey protein solutions. Plates coated with different nano-composites as well as electropolished plates were installed in the heating section of the pasteurizer. Significant differences were observed between coated and uncoated plates. The coated plates showed reduced deposit buildup in comparison with the uncoated stainless steel plates. Polyurethane-coated plates exhibited the thinnest deposit layer. Electro-polished plates also reduced deposit buildup in comparison to the standard stainless steel plates and were almost comparable to the coated plates. The time required for cleaning in place (CIP) with the coated plates was reduced by 70% compared to standard stainless steel plates.
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Reduction of milk fouling inside gasketed plate heat exchanger using nano-coatings.
Food and Bioproducts Processing, 2010Co-Authors: A. Bani Kananeh, E. Scharnbeck, U.d. Kück, Norbert RäbigerAbstract:Fouling inside gasketed plate heat exchangers used in milk production has been reduced using nano-composites coatings. An antifouling coating with low surface energy (low wettability) led to a hydrophobic and oleophobic effect. Test facilities were constructed by the Institute of New Materials (INM) and Institute of Environmental Process Engineering (IUV), University of Bremen in Germany for the investigation of milk adhesion and the stability of the coatings on rectangular plates and small cylindrical ducts. A number of coatings and surface treatments were tested. Certain polyurethane-coated plates and tubes formed thinner deposit layer compared to standard uncoated stainless steel plates and tubes. The cleaning time for one coated tube was reduced by 80% compared to the standard stainless steel one. A pilot plant including a milk pasteurizer at LUFA Nord-West in Oldenburg-Germany was used for the thermal treatment of whey protein solutions. Plates coated with different nano-composites as well as electropolished plates were installed in the heating section of the pasteurizer. Significant differences were observed between coated and uncoated plates. The coated plates showed reduced deposit buildup in comparison with the uncoated stainless steel plates. Polyurethane-coated plates exhibited the thinnest deposit layer. Electro-polished plates also reduced deposit buildup in comparison to the standard stainless steel plates and were almost comparable to the coated plates. The time required for cleaning in place (CIP) with the coated plates was reduced by 70% compared to standard stainless steel plates.
Peter E Hartmann - One of the best experts on this subject based on the ideXlab platform.
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Retention of the Immunological Proteins of Pasteurized Human Milk in Relation to Pasteurizer Design and Practice
Pediatric Research, 2009Co-Authors: Charles Czank, Danielle K Prime, Ben Hartmann, Karen Simmer, Peter E HartmannAbstract:Pasteurizing donor human milk inactivates bacteria that may be of concern to the preterm infant. However, current practice for Holder Pasteurization (62.5°C for 30 min) is detrimental to the bioactivity of human milk. An experimental pasteurizer was used to determine the maximum temperature at which 90% of secretory IgA, lysozyme, and lactoferrin were retained and whether this temperature was capable of inactivating five common bacterial contaminants. The retention of these proteins was also compared using a commercially available bottle immersion or holding chamber system. After pasteurization at 62.5°C for 30 min, the retention across all three systems was 72.3 ± 3.6%, 21.8 ± 3.3%, and 39.4 ± 11.5% for sIgA, lactoferrin, and lysozyme, respectively ( n = 22). The retention of all three proteins was at least 90% when human milk was pasteurized at 57°C for 30 min, and this temperature was also effective at removing 99.9% of all inoculated bacterial species. In addition, human milk that was pasteurized in the experimental system had a significantly higher proportion of lysozyme compared with samples pasteurized in the bottle immersion system. These findings suggest that optimizing pasteurization temperature and improving pasteurizer design enhances the quality of pasteurized donor human milk.
Sadhana Rayalu - One of the best experts on this subject based on the ideXlab platform.
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Plasmonics driven engineered Pasteurizers for solar water disinfection (SWADIS)
Journal of Hazardous Materials, 2019Co-Authors: Aditi Kulkarni, Rita Dhodapkar, Penumaka Nagababu, Atya Kapley, Sadhana RayaluAbstract:Rampant environmental pollution is the most ubiquitous concern of current world. A sustainable panacea to overarching contamination of water-borne pathogens demands cheap and eco-friendly oriented research. Solar energy is effortlessly accessible in most of the weather conditions and can be used for water decontamination. In this context, Solar Water Disinfection (SWADIS) appears to be feasible solution. Herein we are reporting newly developed Carbon nanoparticles (CNP) which shows absorption of light in broad region extending from Ultraviolet–Visible (UV) to Infrared Spectroscopy (IR). This CNP with pronounced photothermal effect has been used for SWADIS. Photothermal effect of plasmonic nanomaterials has massive potential and has exploited for disinfection of water. Moving towards practical device design we have developed an efficient CNP based Multipurpose Solar Pasteurizer (MSP) and Nano-Solar Pasteurizer (NSP) which can efficiently perform the SWADIS. Result shows that upon irradiation under natural solar radiation Pasteurizers can thermally inactivate the bacteria. The system proves to be able to perform 100% bacterial inactivation in sunny days. We also conducted bacterial inactivation experiments by simulating 106 CFU mL−1 concentration of E. coli in water to mimic field conditions. Results are evident that Pasteurizers achieved 100% bacterial inactivation within period of ˜45 min under sunlight.