Understanding Indicator Organisms and the Multiple Tube Fermentation Technique for Determining MPN in Water Samples
Indicator Organism An indicator organism is a microorganism whose presence in water indicates the potential presence of pathogenic (disease-causing) organisms. These organisms are used as a proxy for assessing the microbiological quality of water, as direct testing for all pathogens would be complex and expensive. Common indicator organisms include: Escherichia coli (E. coli) : Indicates fecal contamination. Total Coliforms : Indicates general water quality and possible contamination. Enterococci : Also used to indicate fecal contamination, particularly in marine waters. Multiple Tube Fermentation Technique The Multiple Tube Fermentation (MTF) technique, also known as the Most Probable Number (MPN) method, is a statistical method used to estimate the concentration of viable microorganisms in a water sample. It involves a series of steps to detect and enumerate coliform bacteria. Steps in the Multiple Tube Fermentation Technique Sample Dilution : Prepare serial dilutions of the wa...