MF Technique Certified for Bacterial Analysis

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | Table of Contents | Download PDF

The Membrane Filter (MF) Technique is accepted worldwide as an effective method for analyzing aqueous solutions for microbial or particulate contamination. It is approved by the United States Environmental Protection Agency (U.S. EPA) and other comparable agencies around the world for detecting the presence of Total and Fecal Coliforms in drinking water. Plus, the MF Technique is widely used for:
  • Heterotrophic plate counts
  • Fungal (yeast and mold) counts 
  • Isolation of E. coli, Pseudomonas sp., Lactobacillus sp. and other specific organisms
Pall’s individually packaged membrane filters are certified for bacterial analysis in accordance with the MF Technique. When you purchase and use our membrane filters, we’ll provide you with a signed certificate that can be kept as a permanent record at your facility.

Process Advantages

The MF Technique provides numerous benefits when analyzing water samples for microbiological contamination.
  • Requires less preparation time than many other traditional methods, allowing isolation and enumeration of microorganisms – while providing presence or absence information – in as little as 24 hours.
  • Permits concentration of large sample volumes. 
  • Allows isolation and enumeration of discrete colonies.
  • Enables optimization of buffers and rinse volumes. 
  • Facilitates the removal of inhibitory or biocidal agents that would not be removed in Pour Plate, Spread Plate, or Most Probable Number techniques.

Applying the MF Technique

Starting with a Pall 47 mm filter, pass 100 mL of your sample fluid through the membrane, utilizing a filter funnel and vacuum system. Any organisms present in the sample will concentrate on the surface of the membrane. Next, place the membrane into a Petri dish on top of an absorbent pad soaked with a nutrient medium. The passage of nutrients through the filter will facilitate the growth of organisms on the upper surface of the membrane. For a more detailed description of how to analyze a sample using the MF Technique, see the step-by-step process outlined below.

1. Collect the sample and make any necessary dilutions. Select the 
    appropriate medium, dispense the broth into a sterile Petri dish,
    evenly saturating the absorbent pad. Flame the forceps and 
    remove the membrane from the sterile package. Place the
    membrane filter into the funnel assembly.
2. Flame the pouring lip of the sample container and pour the
    sample into the funnel. Turn on the vacuum and allow the sample
    to draw completely through the filter. Rinse the funnel with sterile
    buffered water. Turn on vacuum and allow the liquid to draw
    completely through the filter.
3. Place the membrane filter into the prepared Petri dish. Incubate at
    the proper temperature for the appropriate time period.
4. Count the colonies under 10-15x magnification and identify type
    of contamination.

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | Table of Contents | Download PDF