Overnight Enumeration of Vibrio parahaemolyticus In Seafood by Hydrophobic Grid Membrane Filtration

1983 ◽  
Vol 46 (9) ◽  
pp. 783-786 ◽  
Author(s):  
PHYLLIS ENTIS ◽  
PETER BOLESZCZUK
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Membrane Filtration ◽  
Membrane Filter ◽  
New Method ◽  
Overnight Incubation ◽  
Differential Medium

A method was developed for direct enumeration of Vibrio parahaemolyticus in foods by hydrophobic grid membrane filter. The method consisted of a 4–5 h resuscitation step to recover injured cells, followed by overnight incubation at 42°C on V. parahaemolyticus Sucrose (VPS) agar, a new selective and differential medium. The confirmation rate of typical colonies on VPS agar was greater than 98%. The new method produced significantly higher counts of V. parahaemolyticus than the FDA method (P<0.01) when tested with chill-, freeze- or heat-stressed samples, and was equivalent to the FDA method (P>0.05) for recovery of osmotically stressed V. parahaemolyticus.

scholarly journals Filter made of cuprammonium regenerated cellulose for virus removal: a mini-review

Cellulose ◽  
2021 ◽  
Author(s):  
Shoichi Ide
Keyword(s):  
Membrane Filtration ◽  
Hollow Fiber Membrane ◽  
Membrane Filter ◽  
Three Dimensional ◽  
Protein Solutions ◽  
Regenerated Cellulose ◽  
Cellulose Solution ◽  
Virus Removal ◽  
Biological Products ◽  
Molecular Weights

AbstractIn 1989, Asahi Kasei commercialized a porous hollow fiber membrane filter (Planova™) made of cuprammonium regenerated cellulose, making it possible for the first time in the world to “remove viruses from protein solutions by membrane filtration”. Planova has demonstrated its usefulness in separating proteins and viruses. Filters that remove viruses from protein solutions, i.e., virus removal filters (VFs), have become one of the critical modern technologies to assure viral safety of biological products. It has also become an indispensable technology for the future. The performance characteristics of VFs can be summarized in two points: 1) the virus removal performance increases as the virus diameter increases, and 2) the recovery rate of proteins with molecular weights greater than 10,000 exceeds the practical level. This paper outlines the emergence of VF and its essential roles in the purification process of biological products, requirements for VF, phase separation studies for cuprammonium cellulose solution, comparison between Planova and other regenerated cellulose flat membranes made from other cellulose solutions, and the development of Planova. The superior properties of Planova can be attributed to its highly interconnected three-dimensional network structure. Furthermore, future trends in the VF field, the subject of this review, are discussed.

scholarly journals Emerging Developments Regarding Nanocellulose-based Membrane Filtration Material Against Microbes

2021 ◽  
Author(s):  
Mohd Nor Faiz Norrrahim ◽  
Noor Azilah Mohd Kasim ◽  
Victor Feizal Knight ◽  
Keat Khim Ong ◽  
Siti Aminah Mohd Noor ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Membrane Filter ◽  
Healthcare Providers ◽  
Antibacterial Properties ◽  
High Specific Surface Area ◽  
Oh Groups ◽  
Membrane Filters ◽  
Wide Availability ◽  
Considerable Problem ◽  
Filtration Material

Abstract Wide availability and diversity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies had proven its usefulness in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides that, the presence of an abundant OH groups in nanocellulose allows its surface modification which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism is also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.

A Simple Reflectance Method for the Measurement of Particulate Pigment in Lake Water and its Application to Phosphorus–Chlorophyll–Seston Relationships

1980 ◽  
Vol 37 (1) ◽  
pp. 111-114 ◽  
Author(s):  
Martin Bergmann ◽  
Robert Henry Peters
Keyword(s):  
Total Phosphorus ◽  
Lake Water ◽  
Membrane Filter ◽  
New Method ◽  
Pigment Analysis ◽  
Membrane Filters ◽  
Total Pigment ◽  
Residual Variation

This paper describes a new method to measure total sestonic pigment based on the reduction in the amount of light reflected from a membrane filter after a given volume of lake water has passed through the filter. For a sample of 30 lakes, this index of "reflectance" gave a better regression on total phosphorus than did chlorophyll which suggests that part of the variation in published phosphorus–chlorophyll relationships results from the association of phosphorus with pigments other than chlorophyll. But the residual variation suggests both that the amount of pigment developed per unit of phosphorus varies among lakes and that the index does not completely represent the seston. Relationships between reflectance and concentration of chlorophyll, phosphorus, and seston are good enough to suggest that this rapid, easy analysis may find application as an adjunct to more traditional analyses whereever membrane filters are routinely used in the analysis of lake water.Key words: Total pigment analysis, seston, phosphorus–chlorophyll

Separation and Preconcentration of Sudan Blue II Using Membrane Filtration and UV-Visible Spectrophotometric Determination in River Water and Industrial Wastewater Samples

2015 ◽  
Vol 98 (1) ◽  
pp. 213-217 ◽  
Author(s):  
Yunus Emre Unsal ◽  
Mustafa Tuzen ◽  
Mustafa Soylak
Keyword(s):  
Spectrophotometric Determination ◽  
Industrial Wastewater ◽  
Membrane Filtration ◽  
Matrix Effects ◽  
Membrane Filter ◽  
Cellulose Acetate Membrane ◽  
Separation And Preconcentration ◽  
Wastewater Samples ◽  
Working Media

Abstract A new separation and preconcentration method based on adsorption on a cellulose acetate membrane filter and elution with ethanol was established for the UV-Vis spectrophotometric determination of Sudan blue II. Various analytical parameters such as pH of working media, flow rates of solutions, and sample volumes were optimized. Matrix effects of concomitants were investigated for the quantitative recovery values of Sudan blue II. The preconcentration factor was200. LOD was calculated as 0.96 μg/L. RSD was5.1%. The optimized procedure was applied to the spectrophotometric determination of Sudan blue II in river and industrial wastewater samples from oil and dye products.

scholarly journals Usefulness of the MALDI-TOF MS technology with membrane filter protocol for the rapid identification of microorganisms in perioperative drainage fluids of hepatobiliary pancreatic surgery

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246002
Author(s):  
Kazuyuki Sogawa ◽  
Shigetsugu Takano ◽  
Takayuki Ishige ◽  
Hideyuki Yoshitomi ◽  
Shingo Kagawa ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
High Reliability ◽  
Membrane Filter ◽  
Perioperative Complications ◽  
Bacterial Species ◽  
Bacterial Identification ◽  
Maldi Tof Ms ◽  
Drainage Fluid ◽  
Maldi Tof ◽  
Tof Ms

Surgical site infections (SSIs) are significant and frequent perioperative complications, occurring due to the contamination of the surgical site. The late detection of SSIs, especially organ/space SSIs which are the more difficult to treat, often leads to severe complications. An effective method that can identify bacteria with a high accuracy, leading to the early detection of organ/space SSIs, is needed. Ninety-eight drainage fluid samples obtained from 22 patients with hepatobiliary pancreatic disease were analyzed to identify microorganisms using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) with a new membrane filtration protocol and rapid BACpro® pretreatment compared to sole rapid BACpro® pretreatment. The levels of detail of rapid BACpro® pretreatment with or without filtration were also evaluated for the accuracy of bacterial identification. We found that reliable scores for E. coli and E. faecalis were obtained by inoculation with 1.0 × 104 CFU/ml after preparation of the membrane filter with rapid BACpro®, indicating approximately 10-folds more sensitive compared to sole rapid BACpro® pretreatment in drainage fluid specimens. Among 60 bacterial positive colonies in drainage fluid specimens, the MALDI-TOF MS and the membrane filtration with rapid BACpro® identified 53 isolates (88.3%) with a significantly higher accuracy, compared to 25 isolates in the rapid BACpro® pretreatment group (41.7%) (p < 0.001). Among the 78 strains, 14 enteric Gram-negative bacteria (93.0%) and 55 Gram-positive cocci (87.3%) were correctly identified by the membrane filtration with rapid BACpro® with a high reliability. This novel protocol could identify bacterial species within 30 min, at $2-$3 per sample, thus leading to cost and time savings. MALDI-TOF MS with membrane filter and rapid BACpro® is a quick and reliable method for bacterial identification in drainage fluids. The shortened analysis time will enable earlier selection of suitable antibiotics for treatment of organ/space SSIs to improve patients’ outcomes.

scholarly journals New method for concentration and quantitation of Mycobacterium leprae

1977 ◽  
Vol 5 (3) ◽  
pp. 326-328
Author(s):  
N Sato ◽  
A H Fieldsteel
Keyword(s):  
Pore Size ◽  
Standard Method ◽  
Membrane Filter ◽  
Mycobacterium Leprae ◽  
Glass Slide ◽  
New Method ◽  
Original Material ◽  
Polycarbonate Membrane ◽  
Standard Acid ◽  
Polycarbonate Filter

A new method of enumerating Mycobacterium leprae has been developed. Suspensions containing the organisms were filtered through a polycarbonate membrane filter (25-mm diameter, 0.4-micronm pore size, 10-micronm thick; Nucleopore) to concentrate the organisms. The membrane was then mounted on a glass slide and stained with a standard acid-fast stain. Finally, the membrane was treated with a small amount of chloroform to fix it to the slide and make it transparent. This method enabled us to detect M. leprae in quantities as small as 4.98 X 10(2) regardless of the total volume of the original material. Comparison with a standard method for enumerating M. leprae showed that both methods gave similar results when the organisms counted by the standard method were present in sufficient quantity for reproducibility. Because the least number of organisms that can be detected with the standard method is 10(4) ml and because the organisms detected with the new method could be concentrated on the polycarbonate filter from a large amount of infected fluid, a substantial number of suspensions were shown by the new method, but not by the standard method, to contain M. leprae.

scholarly journals Membrane Filtration Test for Rapid Presumptive Differentiation of Four Candida Species

1999 ◽  
Vol 37 (5) ◽  
pp. 1498-1502 ◽  
Author(s):  
T. G. Bauters ◽  
R. Peleman ◽  
M. Moerman ◽  
H. Vermeersch ◽  
D. de Looze ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Uv Light ◽  
Membrane Filter ◽  
False Negative ◽  
Single Species ◽  
Step Test ◽  
Clinical Samples ◽  
Glucose Agar ◽  
Sabouraud Glucose Agar ◽  
Multiple Species

A rapid enzymatic two-step test for the presumptive differentiation of four Candida species commonly occurring in various clinical samples is described. The technique involves membrane filtration of a liquid sample, followed by preincubation of the membrane filter on Sabouraud glucose agar supplemented with ticarcillin-clavulanic acid to yield microcolonies. In a separate assay step, parts of the filter are placed on absorbent pads impregnated with fluorogenic 4-methylumbelliferyl (4-MU) enzyme substrates (4-MU-N-acetyl-β-d-galactosaminide, 4-MU-phosphate, 4-MU-pyrophosphate, and 4-MU-β-d-galactoside) in combination with 0.1% digitonin acting as a membrane permeabilizer. The membrane filter in contact with the assay medium is incubated to allow cleavage of the enzyme substrate, resulting in fluorescent microcolonies under long-wavelength UV light. This approach, tested on 301 clinical samples, is able to presumptively differentiate C. albicans, C. glabrata, C. krusei, and C. tropicalisand to distinguish them from other Candida spp. in about 9 to 11 h. Overall agreement with the conventional methods of 94.4% (one Candida species present in the sample) to 83.8% (multiple Candida spp. present) was obtained. The false-negative rates with reference to identification by traditional methods were 1.3% (single species) and 3.8% (multiple species).

scholarly journals Effects of Particles Diffusion on Membrane Filters Performance

Fluids ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 121
Author(s):  
Shi Yue Liu ◽  
Zhengyi Chen ◽  
Pejman Sanaei
Keyword(s):  
Pore Structure ◽  
Flow Rate ◽  
Membrane Filtration ◽  
Membrane Filter ◽  
Membrane Properties ◽  
Filtration Process ◽  
Membrane Pore ◽  
Filtration Performance ◽  
Structure Flow ◽  
Slow Filtration

Membrane filtration fouling is a very complex process and is determined by many properties such as the membrane internal morphology, membrane pore structure, flow rate and contaminant properties. In a very slow filtration process or during the late stage of filtration, when the flow rate is naturally low and Péclet number is small, particle diffusion is essential and cannot be neglected, while in typical filtration models, especially in moderate and fast filtration process, the main contribution stems from the particle advection. The objectives of this study is to formulate mathematical models that can (i) investigate how filtration process varies under possible effects of particles diffusion; and (ii) describe how membrane morphology evolves and investigate the filtration performance during the filtration process. We also compare the results with the case that diffusion is less important and make a prediction about what kind of membrane filter pore structure should be employed to achieve a particular optimum filtration performance. According to our results, the filtrate and efficiency of particle separation are found to be under the trade-off relationship, and the selection of the membrane properties depends on the requirement of the filtration.

Direct Enumeration of Coliforms and Escherichia coli by Hydrophobic Grid Membrane Filter in 24 Hours using MUG

1990 ◽  
Vol 53 (11) ◽  
pp. 948-952 ◽  
Author(s):  
P. ENTIS ◽  
P. BOLESZCZUK
Keyword(s):  
Escherichia Coli ◽  
Conventional Method ◽  
Validation Study ◽  
Membrane Filter ◽  
Food Products ◽  
New Method ◽  
E Coli

An improved 24-hour hydrophobic grid membrane filter HGMF method for coliform and Escherichia coli enumeration was developed. The new method, which uses a buffered MUG agar for the E. coli portion of the test, was subjected to a precollaborative validation study against the 3-tube MPN procedure encompassing 375 naturally contaminated and inoculated samples representing 25 food products. The HGMF/MUG method produced coliform and E. coli counts equivalent to the conventional method. The confirmation rate of MUG-positive colonies in this study was 98.1%.

Filterability assessment in membrane bioreactors using an in-situ filtration test cell

2010 ◽  
Vol 61 (11) ◽  
pp. 2809-2816 ◽  
Author(s):  
Teresa de la Torre ◽  
Moritz Mottschall ◽  
Boris Lesjean ◽  
Anja Drews ◽  
Andrew Iheanaetu ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Membrane Filtration ◽  
Membrane Bioreactors ◽  
Operating Conditions ◽  
Test Cell ◽  
New Method ◽  
Hysteresis Curve ◽  
Critical Flux ◽  
Filtration Method

A new method for the assessment of the filterability in membrane bioreactors was tested for five months in four MBR units in Berlin. The new method BFM (Berlin Filtration Method) for filterability assessment uses a small membrane filtration test cell which can be submerged directly in the biological tanks to determine the filterability of the activated sludge in-situ. The test cell contains an aerated flat-sheet membrane which operates at similar conditions as in the plant. Filterability is expressed in terms of critical flux obtained by performing flux-stepping experiments. The ultimate goal of monitoring the filterability with the device is to detect in real time fouling occurrences due to changes in sludge composition and to adapt accordingly the operating conditions. The usefulness of the device for this purpose was evaluated for five months after monitoring four MBR plants in Berlin with different activated sludge characteristics (MLSS from 5 to 21 g/L, SRT 12–35 d and COD in the supernatant 30–400 mg/L). The first results show a good agreement between the filterability of the sludge with the portable filtration test cell and the filtration performance of the plant. Critical flux values varied between 3 and 30 L/m2 h during the studied period. Useful information concerning the irreversibility of the fouling was provided by looking at the hysteresis curve of the flux-stepping experiments.

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