Escherichia coli is a gram-negative bacillus belonging to the Enterobacteriaceae and is the
indicator organism by excellence of water quality. In fact, the need for more rapid, specific
and sensitive tests is essential in the water industry. Thus the importance of giving rapid
and accurate results on water quality is high. Several rapid methods for detection of E. coli
have been proposed. This study compares the membrane filtration method using the
culture medium Membrane Lauryl Sulphate Agar (MLSA) that was incubated at
(44+/-0.5)C for (21+/-3) hours followed by confirmation with DEV-fluorocult incubated at
(44+/-0.5)C for (21+/-3) hours with Colilert-18. incubated at (36+/-2)C for 18 hours. The two
methods are selective for E. coli but based on different characteristics, namely capacity of
hydrolyze lactose and the presence of the enzyme beta-D-glucuronidase, respectively. Water samples were analyzed from the surface water source Tejo River, Castelo do Bode
reservoir and Olhos d'¿gua, a groundwater source since September 2001, using both
methods. Samples from collaborative trials were also analyzed by both methods. The
comparison of results was made according to ISO/DIS 17994. The data collected was
sufficient to demonstrate using a standard one-sided evaluation that the alternative method
(Colilert-18.) has a higher recovery than the reference method (LO=2.90>0).
Includes 3 references, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 170 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 6 |
| Published : | 09/22/2002 |
