Coliform bacteria
As coliform bacteria , faecal coliform or thermotolerant coliforms is called lactose -cleaving Gram-negative , facultative anaerobic , rod-shaped bacteria, the acid and gases within 48 h at 35 ° C produce. These include the genera Citrobacter , Enterobacter , Escherichia and Klebsiella . They are indicator organisms for the sanitary quality of water and a hygiene indicator in food production. It is a historically grown, non-taxonomic classification, as it was difficult in practice to distinguish Escherichia coli from other enterobacteria using purely biochemical detection methods . As a rule, gas formation through lactose fermentation is examined using the MPN titer method . A BRILA broth ( brilliant green - bile- lactose broth) is often used here. However, there are also solid culture media: Eosin methylene blue agar (EMB) with lactose and eosin or Endo agar with lactose, fuchsin and sulfite or MacConkey agar and Violet Red Bile agar with neutral red as the pH indicator, lactose fermentation as indicates pink colonies; and membrane filtration tests that indicate aldehyde formation .
Drinking water
According to the Drinking Water Ordinance, coliform bacteria serve as a pollution indicator for drinking water. As a limit value according to the Drinking Water Ordinance, coliform bacteria must not be detectable in 100 ml water sample after an enrichment process. If elevated values are found, measures must be taken to kill these bacteria in the drinking water ( chlorination , ozonation) or to flush them out.
Individual evidence
- ↑ Peter Feng, Stephen D. Weagant, Michael A. Grant: BAM: Enumeration of Escherichia coli and the Coliform Bacteria, Bacteriological Analytical Manual, Chapter 4, Enumeration of Escherichia coli and the Coliform Bacteria ( Memento of March 8, 2013 in the Internet Archive ), September 2002, FDA.