Translations:Wasseraufbereitung und Grauwassernutzung/796/en

• They should be part of the normal gut microbiota in healthy people (ideally, they should only be present in the human gastrointestinal tract).
• They should only be present when it is likely that pathogens of faecal origin are present.
• They should be present in larger numbers than the pathogens indicated by them.
• They should also grow outside the digestive tract and be more resistant than pathogenic microorganisms (pathogens).
• They should be more resistant than pathogens under natural conditions as well as after water treatment and survive in greater numbers.
• They should be easily isolated, identified and counted.
• They should themselves not cause a disease.
• Their number should be in relation to the quantity of pathogenic microorganisms.