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| Micrology Laboratories L.L.C. |
| Easygel |
| 1999 |
| Descriptive Name: E. coli and other coliform bacteria by Coliscan Easygel method Official Name: Detection of waterborne coliforms and E. coli with Coliscan Easygel |
| Media: WATER |
| Microbiological |
| Detection of waterborne coliforms and E coli with Coliscan Easygel |
This is a proprietary method.
Please visit the method owner's site for method documentation |
| Preferred approach for all water samples (ideally 1 to 5 mL): a sample may be dispensed into the presterilized liquid medium and the mixture poured into a pretreated petri plate. Gelling occurs within 45 min. [Alternative approach: Presterilized liquid medium (13 mL/bottle for one plate) is poured into a pretreated (supplied with medium) petri plate and allowed to gel on a level surface. The solid surface may then be innoculated.] Gelled plates are incubated at a temperature of 35 C for 24 h. The presence of pink colonies is indicative of coliforms and blue/purple colonies is indicative of E. coli. Innoculum added to the liquid medium is limited to a maximum of 5 mL. Requirements: a low power (10 - 15 magnification) binocular wide-field dissecting microscope of equivalent may be necessary to provide optimal viewing of the colonies. |
| ambient monitoring: all water: surface water, ground water, waste effluents |
| 20 - 80 CFU/100 mL is considered ideal for enumeration. Maximum: 200 CFU/100 mL; dilution is required for samples that exceed this level. |
| Aeromonas may yield a positive coliform reaction under certain conditions, such as if one of the inhibitors in the medium is eliminated through adverse storage or outdating. Aeromonas does not interfere with E. coli determination. Sources of interference in MF methods (USEPA Fed Reg Aug. 2001): high turbidity, toxic compounds, or large numbers of non-coliform (background) bacteria, and organisms damaged by chlorine or toxic compounds. |
| (Standard Methods, 20th ed., Section 9020 B8 and B9). Testing should be conducted on every lot of reagent with a known positive and negative strain. |
Chill samples, 1oC to 4oC. Techniques for collection: Standard Methods for the Examination of Water and Wastewater, 20th Edition. L. Clesceri, A. Greenberg, and A. Eaton (editors). APHA: Washington, DC. 1998. Section 9060A
Sample processing time: greater than 10 minutes. To minimize interferences causing underestimation of organism density in MF methods (USEPA Fed Reg Aug. 2001): replicates of smaller sample dilutions/volumes may be filtered and the results combined. |
| Sample should be analyzed within 6 h after sampling and within 2 h from receipt of sample in lab for compliance or 24 h for routine monitoring (Standard Methods, 20th ed., Section 9060B); however, a 6 h holding time for all samples is highly recommended (Myers and Sylvester, 1997). |
| Less than $50 |
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