SKC 225-95 Series Gelatin Filters - Manual (Page 3)

Direct Method
Sample

Gelatin fi lter to agar

Dissolve gelatin on agar

Incubate

Count
Method 1
Note: This method prepares the sample for the indirect analysis method.
1. Turn off the pump.
2. Disassemble the cassett e and use forceps to gently remove the fi lter. Place it
in 10 ml of sterile water. (10 ml is recommended. Add more water, if needed.)
3. Once the fi lter dissolves, pour the solution in a water-tight container or tube.
4. Seal the container and ship to a laboratory for analysis. See Analysis &
Additional Application Notes.
Caution: Avoid extreme temperatures during storage and shipping.
Method 2
Note: Use this method only if there is an on-site laboratory. Determine the
appropriate agar before collecting the sample. These steps prepare the sample for the direct
analysis method.
1. Turn off the pump.
2. Open the cassett e.
3. Place a prepared agar-fi lled petri dish base over the fi lter in the cassett e until
they are touching. The gelatin fi lter will adhere to the agar surface.
4. Carefully lift the agar plate base with the gelatin fi lter.
5. Immediately cover the petri dish base with its lid.
6. The gelatin fi lter will dissolve due to the moisture in the agar culture
medium allowing the microbes to come into direct contact with the nutrient
medium. The plates are incubated and the colonies counted. See Analysis &
Additional Application Notes.
Analysis & Additional Application Notes
Direct Method
Note: This method is not recommended for virus aerosols.
1. Aft er transferring the fi lter to the culture medium,
incubate it in an incubator with the lid of the petri
dish facing up.
Note: To prevent liquid from collecting on the agar surface,
always use predried agar that is not freshly prepared.
2. Choose the time, temperature, and type of culture
medium suitable for the target microbes. Follow
these guidelines:
• Standard, Caso, or Plate Count Agar are suitable
for determining colony count (total CFU count).
• Sabouraud, Malt Extract, or Wort Agar can be
used for detecting yeasts and molds.
• Blood Agar is suitable for detecting pathogenic
microbes causing hemolysis.
3. Count the colonies that form.