The indicator organisms in water sanitation and hygiene

Many people take water for granted. Water in its pure form is odorless, tasteless and colorless. Any deviation from these properties implies that there are certain impurities in it. Such impurities may be suspended or dissolved. However, the absence of odor, taste, and color does not declare a water sample 100 percent safe. This is because many pathogens may still be contained in it. These pathogens, also called microbes are the cause of many diseases in humans and animals. Because the physical properties of a sample look perfect, never conclude it is free of microorganisms. Microorganisms are minute living organisms, not visible to the naked eye, many of which are pathogenic.

water sanitation and hygienehelp to remove or destroy these microorganisms. It may also be focused on reducing load count to a tolerable limit. Two key procedures in determining the load are;

• Analysis of the water source

• Microbiological investigation of the water sample

Samples for assessment are to be collected in sterile containers at different times of the day. They are then taken to the laboratory and screened by different methods. Screening methods include; culture and identification on pour plate and spread plate, ATP testing. Other methods are multiple tube method of serial dilution, membrane filtration method, etc. A rapid technique is the quantitative polymerase chain reaction.

Irrespective of the method, screening is usually done for some indicator organisms. These are non-specific coliforms, streptococci, E. coli, and Pseudomonas. The presence of any of these organisms indicates contamination of water with sewage. It is believed that the higher the concentration of the indicator organisms, so are the more pathogenic organisms. Apart from these bacteria, protozoans also screened for are Cryptosporidium and Legionella species. This analysis also includes optical, biochemical methods and molecular biology. If these organisms are observed, appropriate water sanitation and hygiene procedures proper can be set in place.