Experiment No: 5 Membrane Filtration Method in “Basic methods for the Microbiological Analysis of Foods” by Prof. Dr. Osman ERKMEN. Nobel Yayınevi. Ankara 2007.
Sample:
1- Dirty river water (100, 150, 200 ml)
2- Drinking water (100, 150, 200 ml)
Materials:
1- Membrane Filtration Apparatus and Vacuum pump.
2- Plate Count Agar.
3- Sterile filter paper (0.45 mm)
4- Forceps
Procedure:
1- First Sterilize the Filtration apparatus and forceps by passing through flame.
2- Place the coarse filter between flask and funnel and close the lid. Make sure the tap of funnel is closed.
3- Take 50ml of water sample and pour into funnel without filter paper to make a trial run to wet the surface of coarse filter. Run the vacuum pump and open the tap of funnel.
4- All of the sample should be passed through coarse filter.
5- Release the funnel lock and take a sterile filter paper.
6- Open the package of filter paper at aseptic conditions and take it by using sterile forceps.
7- Place the filter paper on the coarse (green side upper) filter let it get wet and remove the green upper cover by using forceps. Filter paper should be stick on the surface of coarse filter.
8- Then place the funnel close the lock. Close the tap of funnel.
9- Add 100 ml of sample in the funnel at aseptic conditions and run the vacuum pump. Open the tap of funnel to pass the entire sample through the filter paper.
10- After all of the sample was passed, remove the funnel and remove the filter paper from the surface of coarse filter.
11- Place the filter paper on PCA at aseptic conditions. And close the lid of petri dish.
12- Repeat the procedure for 150, 200 ml of sample amounts.
13- Incubate the petri dishes in the 37°C Incubator.
14- Count formed colonies on the filter paper. Calculate number of microorganisms per ml of water sample.
