Indicator organisms are specific types of microorganisms used to assess the quality of water and food. They are not necessarily harmful themselves but indicate the potential presence of pathogens. Common examples include Escherichia coli (E. coli) and Enterococci, which are found in the intestines of warm-blooded animals. Their presence suggests that fecal contamination may have occurred. These organisms are valuable in environmental monitoring because they are easier to detect than many harmful pathogens. Testing for indicator organisms helps ensure public health and safety by providing a quick assessment of contamination levels in sources like drinking water and recreational waters.