IDEXX: Enterolert:  Enterolert

  • Summary
  • Analytes
  • Revision
  • Data and Sites
Official Method Name
Enterolert Test Kit Procedure
Current Revision
1999
Media
WATER
Instrumentation
Most Probable Number
Method Subcategory
Microbiological
Method Source
  IDEXX
Citation
  Enterolert Test Kit Procedure
Brief Method Summary
Presence/Absence: Add one packet of powder to the 100 ml water sample in a sterile, non-fluorescing vessel. Cap and shake the vessel to dissolve the powder. Incubate at 41C for 24 h. Read the results at 24 h (before 28 h) by placing a 6W, 365 nm UV light within 5 inches of the sample. If no fluorescence, the test is negative. If the sample fluoresces blue, it is confirmed positive. Quantification: See Standard Methods 20th ed. for MPN analysis (5,10,15 tube serial dilution) or or pour the sample reagent mixture directly into a Quanti-Tray and seal according to instructions. Incubate and read the results as indicated above. Count the number of positive fluorescent wells. Determine the MPN/100mL using the table provided with the Quanti-Tray. For details, see the package insert. Requirements: Enterolert kit from IDEXX 98-21374-00 or 98-21375-00. Sterile pipets. Sterile, unbuffered water for dilutions. Incubator for 41oC controlled within 0.5oC. Long wavelength (365 nm) ultraviolet lamp for fluorescence readings. Cost of analysis: Presence/Absence approx. $4.00; Quantification approx. $5.00.
Scope and Application
Ambient, compliance monitoring: fresh water, drinking water and saltwater. EPA Fed Reg (Aug 2001) for enterococci, ambient only: fresh, marine, or estuarine surface waters; applicability must be demonstrated for other matrices. USEPA. 2001 (August 30). Guidelines establishing test procedures for the analysis of pollutants; Analytical methods for biological pollutants in ambient water (Final Ambient Guidelines, Aug. 20, 2004). Fed. Reg. 66(169)45811-45829. Clean Water Act section 401. 40 CFR 136.1(c). (State certification, licenses) for compliance monitoring in programs 303(c), 304(a), and 501(a). 136.3 Identification of test procedures. Pending approval for Wastewater FR, Tuesday, Aug 16th, 2005.
Applicable Concentration Range
For samples in wells (excluding dilution factors): 1 to 2419 MPN/100 mL for 97-well Quanti-Tray; 1 to 200 MPN/100 mL for 51-well Quanti-Tray
Interferences
Gram positive & gram negative bacteria at levels greater than one hundred thousand to one million per 100mL
The presence of Bacillus spp. can interfere with the testing of marine water samples. To eliminate interference, a 1:10 dilution is required with sterile water (deionized or distilled)
Quality Control Requirements
1. Control cultures: conducted on each lot of Enterolert received as a minimum. Inoculate sterile water with ATCC bacteria, E. faecium (35667) - positive control, S. marcescens (43862) - negative control. 2. Repeat counts--monthly replicate counts for the same analyst should agree within 5% and between analysts within 10%.
Sample Handling
Sample preservation: chilled, 1oC to 4oC; 0.0008% (w/w) Na2S2O3 added to chlorinated waters EPA Fed Reg (Aug 2001). Techniques for collection: Standard Methods, 20th edition, L. Clesceri, A. Greenberg, and A. Eaton (editors). APHA: Washington, DC. 1998. Section 9060A
Sample processing time: less than 5 minutes.
Maximum Holding Time
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),
Relative Cost
Less than $50
Sample Preparation Methods