The number of coliform bacteria in water refers to the actual value of coliform bacteria contained in 100 mL water samples. Under normal circumstances, there are mainly coliform bacteria, streptococcus faecalis and anaerobic bacillus in the intestine. Escherichia coli is widely present in feces, and a large number of them need to be tested to determine whether the water is contaminated by feces, and how polluted it is. Once drinking water is contaminated, it is likely to cause intestinal infectious diseases and even epidemics. (e.g. Typhoid fever, bacillary dysentery, etc.) Therefore, the purpose of testing the number of E. coli is to determine the water quality and whether it is suitable for drinking. ‘
E.coli in Drinking Water Must be Strictly Tested to Ensure the Safety of Water Quality!
But because gut pathogens are prone to dying or mutating in water, they are relatively difficult to measure in small numbers. At present, the more widely used indicator bacteria for drinking is E. coli. If there is no E. coli in the water or if the amount is small, the water is usually not contaminated with pathogens. China’s standard is that the number of E. coli in 1000ml of drinking water should not exceed 3. Of course, the detection of E. coli in drinking water is inseparable from the water quality monitor, and the number of E. coli in the water is judged by the relevant data.
What Can be Done to Test for E. coli in Drinking Water?
The monitoring methods of Escherichia coli in water include multi-tube fermentation, filter membrane method, enzyme substrate method, etc. The multi-tube fermentation method can be applied to the inspection of all kinds of water samples, but the operation is complicated and takes a long time. The filter membrane method is only suitable for tap water and deep well water, and the operation is simple and fast, but it is not suitable for water samples with more impurities and easy to block filter holes. The enzyme substrate method is the standard method for E. coli detection included in GB5750-2006, and is currently a more advanced method for the detection of E. coli in water. At present, it has the advantages of convenience, low false positive, and rapid monitoring with a large number of samples.
Speaking of this, the WECT-900 Escherichia coli online analyzer produced by Hangzhou Modi uses the enzyme substrate method, the principle that the enzyme and the light signal after the bacterial culture reaction is proportional to the change, reflecting the total amount of bacteria or coliform bacteria in the sample. Escherichia coli test technology is a kind of Escherichia coli detection system based on biosensor technology, which provides an effective detection means to deal with water supply contamination. The number of E. coli in water samples can be expressed by comparing the degree of light intensity weakening of the solution with that of a non-toxic control blank experiment.
