Bacteriological Examination of Waters: Membrane Filtration Protocol
- Authors: Brian Forster1, Catalina Arango Pinedo 1
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VIEW AFFILIATIONS HIDE AFFILIATIONSAffiliations: 1: Saint Joseph's University, Philadelphia, PA
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Citation: Brian Forster, Catalina Arango Pinedo. 2015. Bacteriological examination of waters: membrane filtration protocol.
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Publication Date : June 2015
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Category: Protocol

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Figures
This membrane is used for the detection of total coliform and fecal coliformbacteria from samples of water. It has a 47 mm diameter and a pore size of 0.45 µm. The small pore size in the membrane filter will capture bacterial cells present in a sample of water during filtration. A grid is printed on the membrane to assist with counting colonies after incubation. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 1
This membrane is used for the detection of total coliform and fecal coliformbacteria from samples of water. It has a 47 mm diameter and a pore size of 0.45 µm. The small pore size in the membrane filter will capture bacterial cells present in a sample of water during filtration. A grid is printed on the membrane to assist with counting colonies after incubation. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)
This filtration column can be used for the detection of total coliform and fecal coliform bacteria from samples of water. The column is first connected to a vacuum pump. A nitrocellulose membrane is placed between the chamber and catchment vessels. The water sample is then poured into the chamber of the column. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 2
This filtration column can be used for the detection of total coliform and fecal coliform bacteria from samples of water. The column is first connected to a vacuum pump. A nitrocellulose membrane is placed between the chamber and catchment vessels. The water sample is then poured into the chamber of the column. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)
This figure shows the filtration column with filter paper assembled and connected to a vacuum pump. When the vacuum is turned on, the water will filter through the nitrocellulose membrane into the catchment vessel. Any bacteria present in the water will be trapped on the nitrocellulose membrane. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 3
This figure shows the filtration column with filter paper assembled and connected to a vacuum pump. When the vacuum is turned on, the water will filter through the nitrocellulose membrane into the catchment vessel. Any bacteria present in the water will be trapped on the nitrocellulose membrane. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)
(Labeled view) (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 4
(Labeled view) (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)
After filtering the water sample using the filtration column, the filter is aseptically transferred onto the plate, grid side up. The grid should be gently pressed onto the agar such that the nutrient agar can be absorbed into the membrane, allowing bacterial colonies to develop. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 5
After filtering the water sample using the filtration column, the filter is aseptically transferred onto the plate, grid side up. The grid should be gently pressed onto the agar such that the nutrient agar can be absorbed into the membrane, allowing bacterial colonies to develop. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)
Metallic green colonies indicate the presence of E. coli in a water sample. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 6
Metallic green colonies indicate the presence of E. coli in a water sample. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)
Blue colonies are indicative of fecal coliform bacteria. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 7
Blue colonies are indicative of fecal coliform bacteria. (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)
(Labeled view) (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)

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Figure 8
(Labeled view) (Brian Forster and Catalina Arango Pinedo, Saint Joseph's University, Philadelphia, PA)