| Drinking water supplies are prone to contamination | | | | Researchers are still trying to establish the ideal |
| with sewage or other excreted matter may cause | | | | indicator organism to use in sanitary microbiology. The |
| outbreaks of intestinal infections such as typhoid | | | | following are among the suggested criteria for such |
| fever. Monitoring and detection of indicator and | | | | an indicator: |
| disease-causing micro-organisms are a major part of | | | | 1. The indicator bacterium should be suitable for the |
| sanitary microbiology. By chlorinating drinking water | | | | analysis of all types of water: tap river, ground, |
| supplies, control of most major disease-causing | | | | impounded, recreational, estuary, sea, and waste. |
| bacteria can be obtained. | | | | 2. The indicator bacterium should be present |
| The major concern is about the inability to | | | | whenever enteric pathogens are present. |
| consistently remove viruses and protozoa and to | | | | 3. The indicator bacterium should survive longer than |
| achieve quality standards for these micro-organisms. | | | | the hardiest enteric pathogen. |
| Bacteriological tests must be performed constantly to | | | | 4. The indicator bacterium should not reproduce in |
| ensure that drinking water supplies are safe for | | | | the contaminated water and produce an inflated |
| human consumption. | | | | value. |
| Primarily contamination of water with human fecal | | | | 5. The detailed procedure for the indicator should |
| wastes would result in viral, bacterial, and protozoan | | | | have great specificity; i.e. other bacteria should not |
| diseases. Although many of these pathogens can be | | | | give positive results. |
| detected directly, environmental microbiologists have | | | | In addition, the procedure should have considerable |
| generally used indicator organisms as an index of | | | | sensitivity and detection of the level of indicator. |
| possible water contamination by human pathogens. | | | | |