Chinese | Phone | Facebook | WeChat
Products
Your position：Home<< Microorganisms

Microbiological test paper

Water coliform count plate

Num： BD104
Spec： 1 time/bag
Details： Rapid detection of coliform in water
Other： Expiration time：one year
           
Details
1. Application scope
This product is suitable for rapid detection of coliform in source water, drinking water and other kinds of water.

2. Principle
Water coliform count plate contains lactose bile selective medium and TTC chromogenic reagents. After culturing, those colonies growing on the count plate that can ferment lactose to produce acid are coliform. Record the quantity of count plates which show positive result for each dilution ratio. Quantity of coliform could be calculated according to MPN table.
 
Executive standard:
National drinking water sanitary standard (GB 5749);
Standard examination methods for drinking water——Microbiological parameters (GB/T 5750.12)
 
3. Characteristic
Corresponding to 15 tubes method of National standard, it simplifies the test process and shorten the time. Water coliform count plate greatly saves the time and energy of medium preparation, disinfection and Petri dish washing.

4. Using method
4.1 Inoculation:
4.1.1 Suck 10mL of sample solution with a sterile pipette and drip it evenly into the plastic bag which contains the big count plate. Make 5 replicates for each treatment.

4.1.2 Suck 1mL of sample solution with a sterile pipette and drip it evenly into the plastic bag which contains the small count plate. Make 5 replicates for each treatment.

4.1.3 Prepare 1:10 diluted solution by sucking 1mL of sample solution into 9mL of sterile saline and mix them well. Then suck 1mL of diluted sample solution (namely 0.1mL of original water sample) and drip it evenly into the plastic bag which contains the small count plate. Make 5 replicates for each treatment.

4.2 Culture: Place the above plastic bags which contain the treated count plates in the incubator at 36℃±1℃ for 15~24hs.

5. Results
Negative result would be shown as no color change or red spots without yellow halo around; positive result would be shown as red spots with yellow halo around, or the count plate turns yellow.
 
6. Report of the result
According to the quantity of count plates which show positive results, check the corresponding MPN value of coliform. If water is seriously polluted, make dilution (1:10 and 1:100) to test. Namely the original water sample amount for detection is 1mL, 0.1mL and 0.01mL respectively, and thus the actual MPN value should be multiply by10.

For example:
If inoculating 15 pieces of count plates, the quantity of count plates showing positive result of each dilution is 5, 3 and 1 respectively. By checking the MPN table, the MPN value of coliform is 110/100mL. If the original sample volumes are 1mL, 0.1mL and 0.01mL respectively, the MPN value of coliform is 1100/100mL.

7. Preservation condition
This kind of count plate should be placed in the fridge at 4℃-10℃, and expiration time is one year. Once the package is opened, those unused count plates should be placed back to the package and then seal it well. Store them in the fridge and exhaust them within one month. Condensation may occur in high humid environment, it is better to warm it to the room temperature before unfolding the package.

 

Related