การตรวจนับจุลชีพในตัวอย่างของเหลว Membrane filter method
Commonly tested parameters ( Water Analysis )
- Heterotrophic Bacteria in water (AQ),
- Ecoli and Coliform (EC),
- Enterococcus (ETC),
- Pseudomonas aeruginosa (PA)
- Salmonella (SL)
Sample Preparation
For indicator organisms (AQ, EC, ETC, and PA):
For samples with very low microbial load (e.g potable water)
- Filter 100ml of liquid sample using a 47mm membrane filter with 0.45µ pore size.
For samples with low to high microbial load (e.g surface water and waste water)
- Directly inoculate 1ml of sample or if suspected to be high, dilute to 10-1 using sterile diluent.
For Pathogen (SL):
Direct – Measure 100ml water sample and dilute with 100ml sterile double strength Buffered Peptone Water (BPW).
Filtration – Filter 100ml water sample and transfer filter to 100ml sterile BPW.
Regulatory Limits
Refer to Word Health Organization (WHO), Environmental Protection Agency (EPA), or other local regulatory bodies.